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Sat Apr 12 15:59:03 2008 UTC (7 years ago) by ph10
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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 324
66 ph10 332
67 ph10 319 Version 7.6 28-Jan-08
68 ph10 300 ---------------------
70 ph10 302 1. A character class containing a very large number of characters with
71     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
72     overflow.
73 ph10 309
74     2. Patch to cut out the "long long" test in pcrecpp_unittest when
75     HAVE_LONG_LONG is not defined.
77 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
78 ph10 304 bring them up to date and include new features. This patch includes:
79 ph10 309
80 ph10 304 - Fixed PH's badly added libz and libbz2 support.
81     - Fixed a problem with static linking.
82 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
83 ph10 304 - Fixed dftables problem and added an option.
84     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
86     - Added readline support for pcretest.
87 ph10 309 - Added an listing of the option settings after cmake has run.
89 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
90     "pcre.dll" under mingw when using Configure/Make. I added stuff to
91     Makefile.am that cause it to include this special target, without
92     affecting anything else. Note that the same mingw target plus all
93     the other distribution libraries and programs are now supported
94     when configuring with CMake (see 6 below) instead of with
95     Configure/Make.
96 ph10 309
97 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
98     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
99 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
100     solves the problem, but it does no harm.
101 ph10 313
102 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
103 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
104 ph10 314 with CMake, and also correct the comment about stack recursion.
105 ph10 313
106 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
107 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
108     of a program that users should build themselves after PCRE is installed, so
109     building it automatically is not really right. What is more, it gave
110 ph10 312 trouble in some build environments.
111 ph10 300
112 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
113 ph10 308
114 ph10 319
115 ph10 298 Version 7.5 10-Jan-08
116 ph10 263 ---------------------
118     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
119     values in parens when parsing an RE using the C++ wrapper."
120 ph10 286
121 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
122     Characters greater than 255 were excluded from the class instead of being
123     included.
124 ph10 286
125     3. The same bug as (2) above applied to negated POSIX classes such as
126 ph10 265 [:^space:].
127 ph10 286
128 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
129     defined or documented. It seems to have been a typo for PCRE_STATIC, so
130 ph10 286 I have changed it.
132 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
133 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
134     first named subpattern whose name started with "a" (in other words, the
135 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
136     expected" is now given for (?&) (a zero-length name), and this patch also
137     makes it give the same error for \k'' (previously it complained that that
138     was a reference to a non-existent subpattern).
139 ph10 286
140 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
141 ph10 286 this is right because (?- can be followed by option settings as well as by
142 ph10 269 digits. I have, however, made the messages clearer.
143 ph10 286
144 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
145     than the number used in the conditional) now cause a compile-time error.
146     This is actually not compatible with Perl, which accepts such patterns, but
147     treats the conditional as always being FALSE (as PCRE used to), but it
148     seems to me that giving a diagnostic is better.
149 ph10 286
150 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
151 ph10 275 and messages.
152 ph10 286
153     9. Fix two occurrences of "backslash" in comments that should have been
154     "backspace".
156     10. Remove two redundant lines of code that can never be obeyed (their function
157     was moved elsewhere).
159     11. The program that makes PCRE's Unicode character property table had a bug
160     which caused it to generate incorrect table entries for sequences of
161 ph10 277 characters that have the same character type, but are in different scripts.
162 ph10 286 It amalgamated them into a single range, with the script of the first of
163 ph10 277 them. In other words, some characters were in the wrong script. There were
164     thirteen such cases, affecting characters in the following ranges:
165 ph10 286
166 ph10 277 U+002b0 - U+002c1
167     U+0060c - U+0060d
168 ph10 286 U+0061e - U+00612
169 ph10 277 U+0064b - U+0065e
170     U+0074d - U+0076d
171     U+01800 - U+01805
172     U+01d00 - U+01d77
173     U+01d9b - U+01dbf
174     U+0200b - U+0200f
175     U+030fc - U+030fe
176     U+03260 - U+0327f
177     U+0fb46 - U+0fbb1
178     U+10450 - U+1049d
179 ph10 286
180 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
181     compatible with GNU grep in that, if there was more than one match in a
182     line, it showed only the first of them. It now behaves in the same way as
183     GNU grep.
184 ph10 286
185     13. If the -o and -v options were combined for pcregrep, it printed a blank
186     line for every non-matching line. GNU grep prints nothing, and pcregrep now
187     does the same. The return code can be used to tell if there were any
188     non-matching lines.
190 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
192     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
193 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
194 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
195     and both kinds of lookbehind were skipped).
197 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
198 ph10 284 inclusion of <windows.h> to before rather than after the definition of
199     INVALID_FILE_ATTRIBUTES (patch from David Byron).
200 ph10 263
201 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
202 ph10 286 character property caused pcre_compile() to compile bad code, which led at
203     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
204     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
205     caused the error; without that there was no problem.
206 ph10 263
207 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
208 ph10 286
209 ph10 289 19. Added --enable-pcretest-libreadline.
210 ph10 286
211 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
212 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
213 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
214     later patch that removed the other one (the right fix) and added unit tests
215     that check the return values (which was not done before).
216 ph10 292
217 ph10 291 21. Several CMake things:
218 ph10 287
219 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
220 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
221 ph10 288
222 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
223     linked with the newly-built libraries, not previously installed ones.
224 ph10 291
226 ph10 298
227     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
228     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
229     UTF-8 newline character). The key issue is that the pattern starts .*;
230     this means that the match must be either at the beginning, or after a
231     newline. The bug was in the code for advancing after a failed match and
232     checking that the new position followed a newline. It was not taking
233 ph10 294 account of UTF-8 characters correctly.
234 ph10 298
235     23. PCRE was behaving differently from Perl in the way it recognized POSIX
236     character classes. PCRE was not treating the sequence [:...:] as a
237     character class unless the ... were all letters. Perl, however, seems to
238     allow any characters between [: and :], though of course it rejects as
239     unknown any "names" that contain non-letters, because all the known class
240     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
241     for example, whereas PCRE did not - it did not recognize a POSIX character
242     class. This seemed a bit dangerous, so the code has been changed to be
243     closer to Perl. The behaviour is not identical to Perl, because PCRE will
244     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
245     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
246     Perl does, and where it didn't before.
248 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
249     Windows environments %n is disabled by default.
250 ph10 292
252 ph10 260 Version 7.4 21-Sep-07
253 ph10 230 ---------------------
255     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
256 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
257     LF". That isn't really right - the whole point of the change was to try to
258     help when there was an actual mention of one of the two characters. So now
259     the change happens only if \r or \n (or a literal CR or LF) character is
260 ph10 230 encountered.
261 ph10 231
262     2. The 32-bit options word was also used for 6 internal flags, but the numbers
263     of both had grown to the point where there were only 3 bits left.
264     Fortunately, there was spare space in the data structure, and so I have
265     moved the internal flags into a new 16-bit field to free up more option
266 ph10 230 bits.
267 ph10 231
268     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
269     but did not set the internal JCHANGED flag - either of these is enough to
270     control the way the "get" function works - but the PCRE_INFO_JCHANGED
271     facility is supposed to tell if (?J) was ever used, so now (?J) at the
272 ph10 230 start sets both bits.
274 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
275     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
276 ph10 230
277 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
279     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
280 ph10 233 compatibility, even though it is no longer used.
281 ph10 243
282     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
283 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
284 ph10 259 windows.h file is present (where different names are used). [This was
285 ph10 257 reversed later after testing - see 16 below.]
286 ph10 243
287     8. Changed all #include <config.h> to #include "config.h". There were also
288 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
289 ph10 243
290 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
291 ph10 243 sequence off the lines that it output.
293     10. It was pointed out to me that arrays of string pointers cause lots of
294     relocations when a shared library is dynamically loaded. A technique of
295     using a single long string with a table of offsets can drastically reduce
296     these. I have refactored PCRE in four places to do this. The result is
297 ph10 240 dramatic:
298 ph10 243
299 ph10 240 Originally: 290
300     After changing UCP table: 187
301 ph10 243 After changing error message table: 43
302 ph10 240 After changing table of "verbs" 36
303     After changing table of Posix names 22
304 ph10 243
305 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
306 ph10 247
307 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
308 ph10 247 unicode-properties was also set.
310 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
311 ph10 231
312 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
313     checked only for CRLF.
314 ph10 233
315 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
317 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
318 ph10 253
319 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
320 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
321     entirely. This removes changes made in 7 above.
322 ph10 256
323 ph10 261 17. The CMake files have been updated, and there is now more information about
324     building with CMake in the NON-UNIX-USE document.
325 ph10 257
326 ph10 261
327 ph10 228 Version 7.3 28-Aug-07
328 ph10 157 ---------------------
330 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
331     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
332     brackets there is not right, since it causes compilers to look for an
333     installed pcre.h, not the version that is in the source that is being
334     compiled (which of course may be different). I have changed it back to:
335 ph10 197
336 ph10 189 #include "pcre.h"
337 ph10 197
338     I have a vague recollection that the change was concerned with compiling in
339     different directories, but in the new build system, that is taken care of
340     by the VPATH setting the Makefile.
342 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
343     when the subject happened to end in the byte 0x85 (e.g. if the last
344     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
345     characters but of course it shouldn't be taken as a newline when it is part
346     of another character. The bug was that, for an unlimited repeat of . in
347     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
348     characters when looking for a newline.
349 ph10 197
350     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
352     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
353     in debug output.
355 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
356     long printing in the pcrecpp unittest when running under MinGW.
357 ph10 189
358 ph10 197 6. ESC_K was left out of the EBCDIC table.
359 ph10 189
360 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
361     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
362     limit also applies to "virtual nesting" when a pattern is recursive, and in
363     this case 1000 isn't so big. I have been able to remove this limit at the
364     expense of backing off one optimization in certain circumstances. Normally,
365     when pcre_exec() would call its internal match() function recursively and
366     immediately return the result unconditionally, it uses a "tail recursion"
367     feature to save stack. However, when a subpattern that can match an empty
368     string has an unlimited repetition quantifier, it no longer makes this
369     optimization. That gives it a stack frame in which to save the data for
370     checking that an empty string has been matched. Previously this was taken
371     from the 1000-entry workspace that had been reserved. So now there is no
372     explicit limit, but more stack is used.
373 ph10 189
374 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
375     syntax that is required for Windows, and which was going wrong for the
376     pcreposix and pcrecpp parts of the library. These were overlooked when this
377     problem was solved for the main library.
378 ph10 197
379 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
380     the size of patterns that contain repeated groups with explicit upper
381     limits. As the maximum quantifier is 65535, the maximum group length was
382     set at 30,000 so that the product of these two numbers did not overflow a
383     32-bit integer. However, it turns out that people want to use groups that
384     are longer than 30,000 bytes (though not repeat them that many times).
385     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
386     made it possible to implement the integer overflow checks in a much more
387     dynamic way, which I have now done. The artificial limitation on group
388     length has been removed - we now have only the limit on the total length of
389     the compiled pattern, which depends on the LINK_SIZE setting.
390 ph10 208
391     10. Fixed a bug in the documentation for get/copy named substring when
392     duplicate names are permitted. If none of the named substrings are set, the
393     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
394     empty string.
396     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
397     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
398     because the ] is interpreted as the first data character and the
399     terminating ] is not found. PCRE has been made compatible with Perl in this
400     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
401     cause memory overwriting.
403 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
404     string has been matched (to stop an infinite loop). It was not recognizing
405 ph10 208 a conditional subpattern that could match an empty string if that
406 ph10 206 subpattern was within another subpattern. For example, it looped when
407 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
408 ph10 206 condition was not nested. This bug has been fixed.
409 ph10 208
410 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
411     past the start of the subject in the presence of bytes with the top bit
412     set, for example "\x8aBCD".
413 ph10 211
414 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
415     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
416 ph10 200
417 ph10 211 14. Optimized (?!) to (*FAIL).
418 ph10 202
419 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
420     This restricts code points to be within the range 0 to 0x10FFFF, excluding
421     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
422     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
423     does: it's just the validity check that is more restrictive.
424 ph10 220
425     16. Inserted checks for integer overflows during escape sequence (backslash)
426     processing, and also fixed erroneous offset values for syntax errors during
427     backslash processing.
429 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
430 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
432 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
433     caused an overrun.
434 ph10 220
435     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
436     something other than just ASCII characters) inside a group that had an
437     unlimited repeat caused a loop at compile time (while checking to see
438     whether the group could match an empty string).
440 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
441     [\P{Any}] did so. (Error in the code for printing property names.)
442 ph10 210
443 ph10 220 21. An orphan \E inside a character class could cause a crash.
445     22. A repeated capturing bracket such as (A)? could cause a wild memory
446 ph10 218 reference during compilation.
447 ph10 220
448     23. There are several functions in pcre_compile() that scan along a compiled
449     expression for various reasons (e.g. to see if it's fixed length for look
450 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
451 ph10 220 present in the pattern. These operators have additional parameters compared
452     with \d, etc, and these were not being taken into account when moving along
453 ph10 218 the compiled data. Specifically:
454 ph10 220
455     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
456     length.
458     (b) An item such as \pL+ within a repeated group could cause crashes or
459 ph10 218 loops.
460 ph10 220
461 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
462 ph10 220 "reference to non-existent subpattern" error.
464 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
466 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
467 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
468 ph10 211
469 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
470 ph10 218
471 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
472 ph10 223 character were causing crashes (broken optimization).
473 ph10 227
474 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
475 ph10 227 \p or \P) caused a compile-time loop.
477 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
478     break. For example, the unstudied pattern [\r\n]A does not match the string
479     "\r\nA" because change 7.0/46 below moves the current point on by two
480     characters after failing to match at the start. However, the pattern \nA
481 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
482     the same is true. There doesn't seem any very clean way out of this, but
483     what I have chosen to do makes the common cases work: PCRE now takes note
484     of whether there can be an explicit match for \r or \n anywhere in the
485     pattern, and if so, 7.0/46 no longer applies. As part of this change,
486     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
487     pattern has explicit CR or LF references.
488 ph10 222
489 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
490 ph10 223
491 ph10 227
492 ph10 189 Version 7.2 19-Jun-07
493     ---------------------
495 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
496     which is apparently normally available under Windows.
497 ph10 159
498     2. Re-jig the pcregrep tests with different newline settings in an attempt
499     to make them independent of the local environment's newline setting.
500 ph10 157
501 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
502 ph10 165
503 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
504     was not 2, because the output contained actual offsets. The recent new
505 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
506     usable with all link sizes.
508 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
509     stack recursion. This gives a massive performance boost under BSD, but just
510 ph10 165 a small improvement under Linux. However, it saves one field in the frame
511 ph10 164 in all cases.
512 ph10 172
513 ph10 166 6. Added more features from the forthcoming Perl 5.10:
514 ph10 172
515 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
516     recursion call. It refers to the nth most recently opened parentheses.
517 ph10 172
518 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
519 ph10 172 to be opened parentheses.
521     (c) Conditions that refer to capturing parentheses can be specified
522 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
523 ph10 172
524 ph10 168 (d) \K resets the start of the current match so that everything before
525 ph10 172 is not part of it.
527 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
528 ph10 172
529 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
530 ph10 172 reference syntax.
531 ph10 182
532 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
533 ph10 182 alternative starts with the same number.
534 ph10 172
535 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
537 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
540     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
541     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
542 ph10 170 for detecting groups that can match an empty string.
543 ph10 159
544 ph10 172 9. A pattern with a very large number of alternatives (more than several
545     hundred) was running out of internal workspace during the pre-compile
546     phase, where pcre_compile() figures out how much memory will be needed. A
547     bit of new cunning has reduced the workspace needed for groups with
548     alternatives. The 1000-alternative test pattern now uses 12 bytes of
549     workspace instead of running out of the 4096 that are available.
550 ph10 182
551 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
552 ph10 172
553 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
554     The report of the bug said:
555 ph10 182
556 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
557     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
558 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
559 ph10 185
560 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
561 ph10 185 it matched the wrong number of bytes.
562 ph10 172
563 ph10 179
564 ph10 155 Version 7.1 24-Apr-07
565 ph10 98 ---------------------
567 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
568 ph10 122 that is more "standard", making use of automake and other Autotools. There
569 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
570     on this.
571 ph10 111
572     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
573     for recursive directory scanning broke on some systems because the files
574     are not scanned in any specific order and on different systems the order
575     was different. A call to "sort" has been inserted into RunGrepTest for the
576     approprate test as a short-term fix. In the longer term there may be an
577 ph10 100 alternative.
578 ph10 111
579 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
580 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
581     people do their own conversions for various reasons). The problems
582     concerned the use of low-level troff macros .br and .in. I have therefore
583     removed all such uses from the man pages (some were redundant, some could
584 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
585     HTML has been updated to handle .nf/.fi and to complain if it encounters
586     .br or .in.
587 ph10 111
588 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
589 ph10 123 arranged for config.h to be included in the distribution, with the name
590 ph10 111 config.h.generic, for the benefit of those who have to compile without
591     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
593     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
594     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
595 ph10 127 makevp.bat for the current PCRE, using the additional files
596 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
597 ph10 111
598     6. A Windows user reported a minor discrepancy with test 2, which turned out
599     to be caused by a trailing space on an input line that had got lost in his
600 ph10 102 copy. The trailing space was an accident, so I've just removed it.
601 ph10 111
602 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
603 ph10 111 that is needed.
605 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
606     as "const" (a) because they are and (b) because it helps the PHP
607     maintainers who have recently made a script to detect big data structures
608 ph10 111 in the php code that should be moved to the .rodata section. I remembered
609     to update Builducptable as well, so it won't revert if ucptable.h is ever
610 ph10 105 re-created.
611 ph10 111
612     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
613 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
614 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
615     support is not required. This saves 1.5-2K of code, which is important in
616 ph10 107 some applications.
617 ph10 111
618 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
619 ph10 111 so as not to refer to the tables, even though these functions will never be
620     called when UTF-8 support is disabled. Otherwise there are problems with a
621     shared library.
623 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
625     (a) It was defining its arguments as char * instead of void *.
627 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
628     a long time ago when I wrote it, but is no longer the case.
630 ph10 118 The emulated memove() is provided for those environments that have neither
631 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
632 ph10 118 is clearly not the case, as these two bugs were recently reported.
633 ph10 123
634 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
635 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
636     pages, and it removes trailing spaces from listed files. It also creates
637     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
638     case, it wraps all the #defines with #ifndefs. This script should be run
639 ph10 111 before "make dist".
640 ph10 123
641 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
642     with Unicode property support.
643 ph10 123
644     (a) For a maximizing quantifier, if the two different cases of the
645     character were of different lengths in their UTF-8 codings (there are
646     some cases like this - I found 11), and the matching function had to
647 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
648     were both the same length.
649 ph10 123
650     (b) When PCRE was configured to use the heap rather than the stack for
651     recursion during matching, it was not correctly preserving the data for
652     the other case of a UTF-8 character when checking ahead for a match
653     while processing a minimizing repeat. If the check also involved
654 ph10 115 matching a wide character, but failed, corruption could cause an
655     erroneous result when trying to check for a repeat of the original
656     character.
657 ph10 123
658 ph10 116 13. Some tidying changes to the testing mechanism:
659 ph10 98
660 ph10 116 (a) The RunTest script now detects the internal link size and whether there
661     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
662 ph10 123 values substituted by "configure". (The RunGrepTest script already did
663     this for UTF-8.) The configure.ac script no longer substitutes the
664     relevant variables.
666 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
667     with length and offset values. This means that the output is different
668     for different internal link sizes. Test 2 is skipped for link sizes
669     other than 2 because of this, bypassing the problem. Unfortunately,
670     there was also a test in test 3 (the locale tests) that used /B and
671 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
672     I have added a new /Z option to pcretest that replaces the length and
673     offset values with spaces. This is now used to make test 3 independent
674 ph10 122 of link size. (Test 2 will be tidied up later.)
675 ph10 123
676     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
677 ph10 122 segmentation fault instead of returning the appropriate error message.
678 ph10 134
679 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
680 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
681     This doesn't seem right; it now treats the CRLF combination as the line
682     ending, and so does not match in that case. It's only a pattern such as ^$
683     that would hit this one: something like ^ABC$ would have failed after \r
684     and then tried again after \r\n.
686 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
687 ph10 134 in an attempt to make files that differ only in their line terminators
688     compare equal. This works on Linux.
689 ph10 142
690 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
691     as it exited. This is now fixed, thanks to valgrind.
692 ph10 142
693 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
694 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
695     was because its rules for how to advance for /g after matching an empty
696 ph10 143 string at the end of a line did not allow for this case. They now check for
697     it specially.
698 ph10 150
699     20. pcretest is supposed to handle patterns and data of any length, by
700     extending its buffers when necessary. It was getting this wrong when the
701 ph10 147 buffer for a data line had to be extended.
702 ph10 150
703 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
704 ph10 150 CRLF as a newline sequence.
705 ph10 152
706 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
707 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
708     I have nevertheless tidied it up.
709 ph10 111
710 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
711 ph10 123
712 ph10 153 24. Added a man page for pcre-config.
713 ph10 152
714 ph10 153
715 nigel 93 Version 7.0 19-Dec-06
716     ---------------------
718     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
719     moving to gcc 4.1.1.
721     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
722     sys/time.h, which is documented as needed for this function. It doesn't
723     seem to matter on Linux, but it showed up on some releases of OS X.
725     3. It seems that there are systems where bytes whose values are greater than
726     127 match isprint() in the "C" locale. The "C" locale should be the
727     default when a C program starts up. In most systems, only ASCII printing
728     characters match isprint(). This difference caused the output from pcretest
729     to vary, making some of the tests fail. I have changed pcretest so that:
731     (a) When it is outputting text in the compiled version of a pattern, bytes
732     other than 32-126 are always shown as hex escapes.
734     (b) When it is outputting text that is a matched part of a subject string,
735     it does the same, unless a different locale has been set for the match
736     (using the /L modifier). In this case, it uses isprint() to decide.
738     4. Fixed a major bug that caused incorrect computation of the amount of memory
739     required for a compiled pattern when options that changed within the
740     pattern affected the logic of the preliminary scan that determines the
741     length. The relevant options are -x, and -i in UTF-8 mode. The result was
742     that the computed length was too small. The symptoms of this bug were
743     either the PCRE error "internal error: code overflow" from pcre_compile(),
744     or a glibc crash with a message such as "pcretest: free(): invalid next
745     size (fast)". Examples of patterns that provoked this bug (shown in
746     pcretest format) are:
748     /(?-x: )/x
749     /(?x)(?-x: \s*#\s*)/
750     /((?i)[\x{c0}])/8
751     /(?i:[\x{c0}])/8
753     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
754     is now done differently.
756     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
757     wrapper classes; (b) implement a new function in the C++ scanner that is
758     more efficient than the old way of doing things because it avoids levels of
759     recursion in the regex matching; (c) add a paragraph to the documentation
760     for the FullMatch() function.
762     6. The escape sequence \n was being treated as whatever was defined as
763     "newline". Not only was this contrary to the documentation, which states
764     that \n is character 10 (hex 0A), but it also went horribly wrong when
765     "newline" was defined as CRLF. This has been fixed.
767     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
768     was being set to -1 for the "end of line" case (supposedly a value that no
769     character can have). Though this value is never used (the check for end of
770     line is "zero bytes in current character"), it caused compiler complaints.
771     I've changed it to 0xffffffff.
773     8. In pcre_version.c, the version string was being built by a sequence of
774     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
775     string (as it is for production releases) called a macro with an empty
776     argument. The C standard says the result of this is undefined. The gcc
777     compiler treats it as an empty string (which was what was wanted) but it is
778     reported that Visual C gives an error. The source has been hacked around to
779     avoid this problem.
781     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
782     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
783     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
784     of them did).
786     10. Originally, pcretest opened its input and output without "b"; then I was
787     told that "b" was needed in some environments, so it was added for release
788     5.0 to both the input and output. (It makes no difference on Unix-like
789     systems.) Later I was told that it is wrong for the input on Windows. I've
790     now abstracted the modes into two macros, to make it easier to fiddle with
791     them, and removed "b" from the input mode under Windows.
793     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
795     12. Added -help and --help to pcretest as an official way of being reminded
796     of the options.
798     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
799     and pcrecpp.cc because they annoy compilers at high warning levels.
801     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
803     15. Fixed an occurrence of == in configure.ac that should have been = (shell
804     scripts are not C programs :-) and which was not noticed because it works
805     on Linux.
807     16. pcretest is supposed to handle any length of pattern and data line (as one
808     line or as a continued sequence of lines) by extending its input buffer if
809     necessary. This feature was broken for very long pattern lines, leading to
810     a string of junk being passed to pcre_compile() if the pattern was longer
811     than about 50K.
813     17. I have done a major re-factoring of the way pcre_compile() computes the
814     amount of memory needed for a compiled pattern. Previously, there was code
815     that made a preliminary scan of the pattern in order to do this. That was
816     OK when PCRE was new, but as the facilities have expanded, it has become
817     harder and harder to keep it in step with the real compile phase, and there
818     have been a number of bugs (see for example, 4 above). I have now found a
819     cunning way of running the real compile function in a "fake" mode that
820     enables it to compute how much memory it would need, while actually only
821     ever using a few hundred bytes of working memory and without too many
822     tests of the mode. This should make future maintenance and development
823     easier. A side effect of this work is that the limit of 200 on the nesting
824     depth of parentheses has been removed (though this was never a serious
825     limitation, I suspect). However, there is a downside: pcre_compile() now
826     runs more slowly than before (30% or more, depending on the pattern). I
827     hope this isn't a big issue. There is no effect on runtime performance.
829     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
830     newline (only possible for the last line of a file) and it was a
831     pattern that set a locale (followed by /Lsomething), pcretest crashed.
833     19. Added additional timing features to pcretest. (1) The -tm option now times
834     matching only, not compiling. (2) Both -t and -tm can be followed, as a
835     separate command line item, by a number that specifies the number of
836     repeats to use when timing. The default is 50000; this gives better
837     precision, but takes uncomfortably long for very large patterns.
839     20. Extended pcre_study() to be more clever in cases where a branch of a
840     subpattern has no definite first character. For example, (a*|b*)[cd] would
841     previously give no result from pcre_study(). Now it recognizes that the
842     first character must be a, b, c, or d.
844     21. There was an incorrect error "recursive call could loop indefinitely" if
845     a subpattern (or the entire pattern) that was being tested for matching an
846     empty string contained only one non-empty item after a nested subpattern.
847     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
848     incorrectly, because the \d was being skipped in the check.
850     22. The pcretest program now has a new pattern option /B and a command line
851     option -b, which is equivalent to adding /B to every pattern. This causes
852     it to show the compiled bytecode, without the additional information that
853     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
854     is the same as /B/I).
856     23. A new optimization is now able automatically to treat some sequences such
857     as a*b as a*+b. More specifically, if something simple (such as a character
858     or a simple class like \d) has an unlimited quantifier, and is followed by
859     something that cannot possibly match the quantified thing, the quantifier
860     is automatically "possessified".
862     24. A recursive reference to a subpattern whose number was greater than 39
863     went wrong under certain circumstances in UTF-8 mode. This bug could also
864     have affected the operation of pcre_study().
866     25. Realized that a little bit of performance could be had by replacing
867     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
869     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
871     27. Possessive quantifiers such as a++ were previously implemented by turning
872     them into atomic groups such as ($>a+). Now they have their own opcodes,
873     which improves performance. This includes the automatically created ones
874     from 23 above.
876     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
877     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
878     the first matched character to be a colon. This applied both to named and
879     numbered groups.
881     29. The ucpinternal.h header file was missing its idempotency #ifdef.
883     30. I was sent a "project" file called libpcre.a.dev which I understand makes
884     building PCRE on Windows easier, so I have included it in the distribution.
886     31. There is now a check in pcretest against a ridiculously large number being
887     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
888     loop, the loop is abandoned.
890     32. Forward references to subpatterns in conditions such as (?(2)...) where
891     subpattern 2 is defined later cause pcre_compile() to search forwards in
892     the pattern for the relevant set of parentheses. This search went wrong
893     when there were unescaped parentheses in a character class, parentheses
894     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
896     33. "Subroutine" calls and backreferences were previously restricted to
897     referencing subpatterns earlier in the regex. This restriction has now
898     been removed.
900     34. Added a number of extra features that are going to be in Perl 5.10. On the
901     whole, these are just syntactic alternatives for features that PCRE had
902     previously implemented using the Python syntax or my own invention. The
903     other formats are all retained for compatibility.
905     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
906     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
907     also .NET compatible.
909     (b) A recursion or subroutine call to a named group can now be defined as
910     (?&name) as well as (?P>name).
912     (c) A backreference to a named group can now be defined as \k<name> or
913     \k'name' as well as (?P=name). The new forms, as well as being in Perl
914     5.10, are also .NET compatible.
916     (d) A conditional reference to a named group can now use the syntax
917     (?(<name>) or (?('name') as well as (?(name).
919     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
920     groups (named and numbered) that are never evaluated inline, but can be
921     called as "subroutines" from elsewhere. In effect, the DEFINE condition
922     is always false. There may be only one alternative in such a group.
924     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
925     as the simple (?(R). The condition is true only if the most recent
926     recursion is that of the given number or name. It does not search out
927     through the entire recursion stack.
929     (g) The escape \gN or \g{N} has been added, where N is a positive or
930     negative number, specifying an absolute or relative reference.
932     35. Tidied to get rid of some further signed/unsigned compiler warnings and
933     some "unreachable code" warnings.
935     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
936     things, this adds five new scripts.
938     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
939     There were also incompatibilities regarding the handling of \Q..\E inside
940     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
941     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
943     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
944     matches an empty string, and forcibly breaks the loop. There were bugs in
945     this code in non-simple cases. For a pattern such as ^(a()*)* matched
946     against aaaa the result was just "a" rather than "aaaa", for example. Two
947     separate and independent bugs (that affected different cases) have been
948     fixed.
950     39. Refactored the code to abolish the use of different opcodes for small
951     capturing bracket numbers. This is a tidy that I avoided doing when I
952     removed the limit on the number of capturing brackets for 3.5 back in 2001.
953     The new approach is not only tidier, it makes it possible to reduce the
954     memory needed to fix the previous bug (38).
956     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
957     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
958     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
959     mode.
961     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
962     report.
964     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
965     copy construction and assignment in the C++ wrapper.
967     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
968     couple of bugs that could have given wrong results in the "--newline=crlf"
969     case.
971     44. Added a number of casts and did some reorganization of signed/unsigned int
972     variables following suggestions from Dair Grant. Also renamed the variable
973     "this" as "item" because it is a C++ keyword.
975     45. Arranged for dftables to add
977     #include "pcre_internal.h"
979     to pcre_chartables.c because without it, gcc 4.x may remove the array
980     definition from the final binary if PCRE is built into a static library and
981     dead code stripping is activated.
983     46. For an unanchored pattern, if a match attempt fails at the start of a
984     newline sequence, and the newline setting is CRLF or ANY, and the next two
985     characters are CRLF, advance by two characters instead of one.
988 nigel 91 Version 6.7 04-Jul-06
989     ---------------------
991     1. In order to handle tests when input lines are enormously long, pcretest has
992     been re-factored so that it automatically extends its buffers when
993     necessary. The code is crude, but this _is_ just a test program. The
994     default size has been increased from 32K to 50K.
996     2. The code in pcre_study() was using the value of the re argument before
997     testing it for NULL. (Of course, in any sensible call of the function, it
998     won't be NULL.)
1000     3. The memmove() emulation function in pcre_internal.h, which is used on
1001     systems that lack both memmove() and bcopy() - that is, hardly ever -
1002     was missing a "static" storage class specifier.
1004     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1005     containing an extended class (one that cannot be represented by a bitmap
1006     because it contains high-valued characters or Unicode property items, e.g.
1007     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1008     pattern, but PCRE should not loop if you do not (it no longer does).
1009     [Detail: two cases were found: (a) a repeated subpattern containing an
1010     extended class; (b) a recursive reference to a subpattern that followed a
1011     previous extended class. It wasn't skipping over the extended class
1012     correctly when UTF-8 mode was not set.]
1014     5. A negated single-character class was not being recognized as fixed-length
1015     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1016     compile error "lookbehind assertion is not fixed length".
1018     6. The RunPerlTest auxiliary script was showing an unexpected difference
1019     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1020     write a Perl script that can interpret lines of an input file either as
1021     byte characters or as UTF-8, which is what "perltest" was being required to
1022     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1023     can't do is switch easily at run time between having the "use utf8;" pragma
1024     or not. In the end, I fudged it by using the RunPerlTest script to insert
1025     "use utf8;" explicitly for the UTF-8 tests.
1027     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1028     the end of the subject string, contrary to the documentation and to what
1029     Perl does. This was true of both matching functions. Now it matches only at
1030     the start of the subject and immediately after *internal* newlines.
1032     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1033     a pointer to an int instead of a pointer to an unsigned long int. This
1034     caused problems on 64-bit systems.
1036     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1037     instance of the 'standard' template library not being so standard".
1039     10. There was no check on the number of named subpatterns nor the maximum
1040     length of a subpattern name. The product of these values is used to compute
1041     the size of the memory block for a compiled pattern. By supplying a very
1042     long subpattern name and a large number of named subpatterns, the size
1043     computation could be caused to overflow. This is now prevented by limiting
1044     the length of names to 32 characters, and the number of named subpatterns
1045     to 10,000.
1047     11. Subpatterns that are repeated with specific counts have to be replicated in
1048     the compiled pattern. The size of memory for this was computed from the
1049     length of the subpattern and the repeat count. The latter is limited to
1050     65535, but there was no limit on the former, meaning that integer overflow
1051     could in principle occur. The compiled length of a repeated subpattern is
1052     now limited to 30,000 bytes in order to prevent this.
1054     12. Added the optional facility to have named substrings with the same name.
1056     13. Added the ability to use a named substring as a condition, using the
1057     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1058     are numbers (not recommended). Forward references are permitted.
1060     14. Added forward references in named backreferences (if you see what I mean).
1062     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1063     pattern could run off the end of the subject. For example, the pattern
1064     "(?s)(.{1,5})"8 did this with the subject "ab".
1066     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1067     PCRE_CASELESS was set when matching characters that were quantified with ?
1068     or *.
1070     17. A character class other than a single negated character that had a minimum
1071     but no maximum quantifier - for example [ab]{6,} - was not handled
1072     correctly by pce_dfa_exec(). It would match only one character.
1074     18. A valid (though odd) pattern that looked like a POSIX character
1075     class but used an invalid character after [ (for example [[,abc,]]) caused
1076     pcre_compile() to give the error "Failed: internal error: code overflow" or
1077     in some cases to crash with a glibc free() error. This could even happen if
1078     the pattern terminated after [[ but there just happened to be a sequence of
1079     letters, a binary zero, and a closing ] in the memory that followed.
1081     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1082     over the years. Originally (before any Unicode support), just the bottom 8
1083     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1084     output from "man perlunicode" includes this:
1086     The regular expression compiler produces polymorphic opcodes. That
1087     is, the pattern adapts to the data and automatically switches to
1088     the Unicode character scheme when presented with Unicode data--or
1089     instead uses a traditional byte scheme when presented with byte
1090     data.
1092     Sadly, a wide octal escape does not cause a switch, and in a string with
1093     no other multibyte characters, these octal escapes are treated as before.
1094     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1095     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1096     Unicode string.
1098     I have not perpetrated such confusion in PCRE. Up till now, it took just
1099     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1100     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1101     translate to the appropriate multibyte character.
1103     29. Applied some refactoring to reduce the number of warnings from Microsoft
1104     and Borland compilers. This has included removing the fudge introduced
1105     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1106     a warning about an unused variable.
1108     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1109     characters since release 4.0, because Perl (from release 5.004) does not.
1110     [Or at least, is documented not to: some releases seem to be in conflict
1111     with the documentation.] However, when a pattern was studied with
1112     pcre_study() and all its branches started with \s, PCRE still included VT
1113     as a possible starting character. Of course, this did no harm; it just
1114     caused an unnecessary match attempt.
1116     22. Removed a now-redundant internal flag bit that recorded the fact that case
1117     dependency changed within the pattern. This was once needed for "required
1118     byte" processing, but is no longer used. This recovers a now-scarce options
1119     bit. Also moved the least significant internal flag bit to the most-
1120     significant bit of the word, which was not previously used (hangover from
1121     the days when it was an int rather than a uint) to free up another bit for
1122     the future.
1124     23. Added support for CRLF line endings as well as CR and LF. As well as the
1125     default being selectable at build time, it can now be changed at runtime
1126     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1127     specify that it is scanning data with non-default line endings.
1129     24. Changed the definition of CXXLINK to make it agree with the definition of
1130     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1132     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1133     recursions. This makes a big different to stack usage for some patterns.
1135     26. If a subpattern containing a named recursion or subroutine reference such
1136     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1137     the space required for the compiled pattern went wrong and gave too small a
1138     value. Depending on the environment, this could lead to "Failed: internal
1139     error: code overflow at offset 49" or "glibc detected double free or
1140     corruption" errors.
1142     27. Applied patches from Google (a) to support the new newline modes and (b) to
1143     advance over multibyte UTF-8 characters in GlobalReplace.
1145     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1146     difference for some implementation of PCRE in some Windows version.
1148     29. Added some extra testing facilities to pcretest:
1150     \q<number> in a data line sets the "match limit" value
1151     \Q<number> in a data line sets the "match recursion limt" value
1152     -S <number> sets the stack size, where <number> is in megabytes
1154     The -S option isn't available for Windows.
1157 nigel 89 Version 6.6 06-Feb-06
1158     ---------------------
1160     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1161     in pcreposix.h. I have copied the definition from pcre.h.
1163     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1164     because pcre.h is no longer a built file.
1166     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1167     not normally included in the compiled code.
1170 nigel 87 Version 6.5 01-Feb-06
1171     ---------------------
1173     1. When using the partial match feature with pcre_dfa_exec(), it was not
1174     anchoring the second and subsequent partial matches at the new starting
1175     point. This could lead to incorrect results. For example, with the pattern
1176     /1234/, partially matching against "123" and then "a4" gave a match.
1178     2. Changes to pcregrep:
1180     (a) All non-match returns from pcre_exec() were being treated as failures
1181     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1182     error message is output. Some extra information is given for the
1184     probably the only errors that are likely to be caused by users (by
1185     specifying a regex that has nested indefinite repeats, for instance).
1186     If there are more than 20 of these errors, pcregrep is abandoned.
1188     (b) A binary zero was treated as data while matching, but terminated the
1189     output line if it was written out. This has been fixed: binary zeroes
1190     are now no different to any other data bytes.
1192     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1193     used to set a locale for matching. The --locale=xxxx long option has
1194     been added (no short equivalent) to specify a locale explicitly on the
1195     pcregrep command, overriding the environment variables.
1197     (d) When -B was used with -n, some line numbers in the output were one less
1198     than they should have been.
1200     (e) Added the -o (--only-matching) option.
1202     (f) If -A or -C was used with -c (count only), some lines of context were
1203     accidentally printed for the final match.
1205     (g) Added the -H (--with-filename) option.
1207     (h) The combination of options -rh failed to suppress file names for files
1208     that were found from directory arguments.
1210     (i) Added the -D (--devices) and -d (--directories) options.
1212     (j) Added the -F (--fixed-strings) option.
1214     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1216     (l) Added the --colo(u)r option.
1218     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1219     is not present by default.
1221     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1222     items such as (?R) or (?1), when the recursion could match a number of
1223     alternatives. If it matched one of the alternatives, but subsequently,
1224     outside the recursion, there was a failure, the code tried to back up into
1225     the recursion. However, because of the way PCRE is implemented, this is not
1226     possible, and the result was an incorrect result from the match.
1228     In order to prevent this happening, the specification of recursion has
1229     been changed so that all such subpatterns are automatically treated as
1230     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1232     4. I had overlooked the fact that, in some locales, there are characters for
1233     which isalpha() is true but neither isupper() nor islower() are true. In
1234     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1235     and ordfeminine) are like this. This affected the treatment of \w and \W
1236     when they appeared in character classes, but not when they appeared outside
1237     a character class. The bit map for "word" characters is now created
1238     separately from the results of isalnum() instead of just taking it from the
1239     upper, lower, and digit maps. (Plus the underscore character, of course.)
1241     5. The above bug also affected the handling of POSIX character classes such as
1242     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1243     permanent tables. Instead, the bit maps for such a class were previously
1244     created as the appropriate unions of the upper, lower, and digit bitmaps.
1245     Now they are created by subtraction from the [[:word:]] class, which has
1246     its own bitmap.
1248     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1249     It is created by subtracting the vertical space characters (\x09, \x0a,
1250     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1251     subtraction was done in the overall bitmap for a character class, meaning
1252     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1253     be recognized. This bug has been fixed.
1255     7. Patches from the folks at Google:
1257     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1258     real life, but is still worth protecting against".
1260     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1261     regular expressions".
1263     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1264     have it.
1266     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1267     "configure" and the latter not, in order to fix a problem somebody had
1268     with compiling the Arg class on HP-UX.
1270     (e) Improve the error-handling of the C++ wrapper a little bit.
1272     (f) New tests for checking recursion limiting.
1274     8. The pcre_memmove() function, which is used only if the environment does not
1275     have a standard memmove() function (and is therefore rarely compiled),
1276     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1277     returning a result (though PCRE never actually uses the result).
1279     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1280     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1281     returned instead of calling malloc() with an overflowing number that would
1282     most likely cause subsequent chaos.
1284     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1286     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1287     with this option is matched, the nmatch and pmatch options of regexec() are
1288     ignored.
1290     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1291     provided in case anyone wants to the the POSIX interface with UTF-8
1292     strings.
1294     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1295     C++ linking (needed for some HP-UX environments).
1297     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1298     (unused parameter) and in the pcre_printint() function (omitted "default"
1299     switch label when the default is to do nothing).
1301     15. Added some code to make it possible, when PCRE is compiled as a C++
1302     library, to replace subject pointers for pcre_exec() with a smart pointer
1303     class, thus making it possible to process discontinuous strings.
1305     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1306     much the same function. They were added by different people who were trying
1307     to make PCRE easy to compile on non-Unix systems. It has been suggested
1308     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1309     for compiling on Windows systems. I have therefore replaced it with
1310     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1311     defaults to "extern" for C or "extern C" for C++, which works fine on
1312     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1313     SCOPE with something explicit in config.h. In addition:
1315     (a) pcreposix.h still had just "extern" instead of either of these macros;
1316     I have replaced it with PCRE_DATA_SCOPE.
1318     (b) Functions such as _pcre_xclass(), which are internal to the library,
1319     but external in the C sense, all had PCRE_EXPORT in their definitions.
1320     This is apparently wrong for the Windows case, so I have removed it.
1321     (It makes no difference on Unix-like systems.)
1323     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1324     of recursive calls to match(). This is different to MATCH_LIMIT because
1325     that limits the total number of calls to match(), not all of which increase
1326     the depth of recursion. Limiting the recursion depth limits the amount of
1327     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1328     when PCRE is compiled, and changed at run time. A patch from Google adds
1329     this functionality to the C++ interface.
1331     18. Changes to the handling of Unicode character properties:
1333     (a) Updated the table to Unicode 4.1.0.
1335     (b) Recognize characters that are not in the table as "Cn" (undefined).
1337     (c) I revised the way the table is implemented to a much improved format
1338     which includes recognition of ranges. It now supports the ranges that
1339     are defined in UnicodeData.txt, and it also amalgamates other
1340     characters into ranges. This has reduced the number of entries in the
1341     table from around 16,000 to around 3,000, thus reducing its size
1342     considerably. I realized I did not need to use a tree structure after
1343     all - a binary chop search is just as efficient. Having reduced the
1344     number of entries, I extended their size from 6 bytes to 8 bytes to
1345     allow for more data.
1347     (d) Added support for Unicode script names via properties such as \p{Han}.
1349     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1350     matching that character.
1352     20. When matching a repeated Unicode property with a minimum greater than zero,
1353     (for example \pL{2,}), PCRE could look past the end of the subject if it
1354     reached it while seeking the minimum number of characters. This could
1355     happen only if some of the characters were more than one byte long, because
1356     there is a check for at least the minimum number of bytes.
1358     21. Refactored the implementation of \p and \P so as to be more general, to
1359     allow for more different types of property in future. This has changed the
1360     compiled form incompatibly. Anybody with saved compiled patterns that use
1361     \p or \P will have to recompile them.
1363     22. Added "Any" and "L&" to the supported property types.
1365     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1366     but give a compile time error if the value is greater than 0xff.
1368     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1369     accidentally not being installed or uninstalled.
1371     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1372     made were to insert the current release number. This seemed silly, because
1373     it made things harder for people building PCRE on systems that don't run
1374     "configure". I have turned pcre.h into a distributed file, no longer built
1375     by "configure", with the version identification directly included. There is
1376     no longer a pcre.h.in file.
1378     However, this change necessitated a change to the pcre-config script as
1379     well. It is built from pcre-config.in, and one of the substitutions was the
1380     release number. I have updated configure.ac so that ./configure now finds
1381     the release number by grepping pcre.h.
1383     26. Added the ability to run the tests under valgrind.
1386 nigel 85 Version 6.4 05-Sep-05
1387     ---------------------
1389     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1390     "--" to be printed when multiple files were scanned, even when none of the
1391     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1392     consider it to be a bug, and have restored the previous behaviour.
1394     2. A couple of code tidies to get rid of compiler warnings.
1396     3. The pcretest program used to cheat by referring to symbols in the library
1397     whose names begin with _pcre_. These are internal symbols that are not
1398     really supposed to be visible externally, and in some environments it is
1399     possible to suppress them. The cheating is now confined to including
1400     certain files from the library's source, which is a bit cleaner.
1402     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1403     file's purpose clearer.
1405     5. Reorganized pcre_ucp_findchar().
1408 nigel 83 Version 6.3 15-Aug-05
1409     ---------------------
1411     1. The file libpcre.pc.in did not have general read permission in the tarball.
1413     2. There were some problems when building without C++ support:
1415     (a) If C++ support was not built, "make install" and "make test" still
1416     tried to test it.
1418     (b) There were problems when the value of CXX was explicitly set. Some
1419     changes have been made to try to fix these, and ...
1421     (c) --disable-cpp can now be used to explicitly disable C++ support.
1423     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1424     backslash in a target when C++ was disabled. This confuses some
1425     versions of "make", apparently. Using an intermediate variable solves
1426     this. (Same for CPP_LOBJ.)
1428     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1429     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1430     necessary on certain architectures.
1432     4. Added a setting of -export-symbols-regex to the link command to remove
1433     those symbols that are exported in the C sense, but actually are local
1434     within the library, and not documented. Their names all begin with
1435     "_pcre_". This is not a perfect job, because (a) we have to except some
1436     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1437     available (and never for static libraries). I have made a note to try to
1438     find a way round (a) in the future.
1441 nigel 81 Version 6.2 01-Aug-05
1442     ---------------------
1444     1. There was no test for integer overflow of quantifier values. A construction
1445     such as {1111111111111111} would give undefined results. What is worse, if
1446     a minimum quantifier for a parenthesized subpattern overflowed and became
1447     negative, the calculation of the memory size went wrong. This could have
1448     led to memory overwriting.
1450     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1452     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1453     operating environments where this matters.
1455     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1456     PCRE options from within the C++ wrapper.
1458     5. Named capturing subpatterns were not being correctly counted when a pattern
1459     was compiled. This caused two problems: (a) If there were more than 100
1460     such subpatterns, the calculation of the memory needed for the whole
1461     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1462     back references of the form \12, where the number was greater than 9, were
1463     not recognized as back references, even though there were sufficient
1464     previous subpatterns.
1466     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1467     versions of gcc, e.g. 2.95.4.
1470 nigel 79 Version 6.1 21-Jun-05
1471     ---------------------
1473     1. There was one reference to the variable "posix" in pcretest.c that was not
1474     surrounded by "#if !defined NOPOSIX".
1476     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1477     the cross-check on the old pcre_info() function, for the benefit of the
1478     cut-down version of PCRE that is currently imported into Exim.
1480     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1481     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1482     patterns that start (?i) but I don't think that matters. The use of (?i) is
1483     just an example; this all applies to the other options as well.
1485     4. Since libtool seems to echo the compile commands it is issuing, the output
1486     from "make" can be reduced a bit by putting "@" in front of each libtool
1487     compile command.
1489     5. Patch from the folks at Google for configure.in to be a bit more thorough
1490     in checking for a suitable C++ installation before trying to compile the
1491     C++ stuff. This should fix a reported problem when a compiler was present,
1492     but no suitable headers.
1494     6. The man pages all had just "PCRE" as their title. I have changed them to
1495     be the relevant file name. I have also arranged that these names are
1496     retained in the file doc/pcre.txt, which is a concatenation in text format
1497     of all the man pages except the little individual ones for each function.
1499     7. The NON-UNIX-USE file had not been updated for the different set of source
1500     files that come with release 6. I also added a few comments about the C++
1501     wrapper.
1504 nigel 77 Version 6.0 07-Jun-05
1505     ---------------------
1507     1. Some minor internal re-organization to help with my DFA experiments.
1509     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1510     didn't matter for the library itself when fully configured, but did matter
1511     when compiling without UCP support, or within Exim, where the ucp files are
1512     not imported.
1514     3. Refactoring of the library code to split up the various functions into
1515     different source modules. The addition of the new DFA matching code (see
1516     below) to a single monolithic source would have made it really too
1517     unwieldy, quite apart from causing all the code to be include in a
1518     statically linked application, when only some functions are used. This is
1519     relevant even without the DFA addition now that patterns can be compiled in
1520     one application and matched in another.
1522     The downside of splitting up is that there have to be some external
1523     functions and data tables that are used internally in different modules of
1524     the library but which are not part of the API. These have all had their
1525     names changed to start with "_pcre_" so that they are unlikely to clash
1526     with other external names.
1528     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1529     a different (DFA) algorithm. Although it is slower than the original
1530     function, it does have some advantages for certain types of matching
1531     problem.
1533     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1534     including restarting after a partial match.
1536     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1537     defined when compiling for Windows was sent to me. I have put it into the
1538     code, though I have no means of testing or verifying it.
1540     7. Added the pcre_refcount() auxiliary function.
1542     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1543     match before or at the first newline in the subject string. In pcretest,
1544     the /f option on a pattern can be used to set this.
1546     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1547     would behave wrongly. This has been present in PCRE since release 4.0.
1549     10. A number of changes to the pcregrep command:
1551     (a) Refactored how -x works; insert ^(...)$ instead of setting
1552     PCRE_ANCHORED and checking the length, in preparation for adding
1553     something similar for -w.
1555     (b) Added the -w (match as a word) option.
1557     (c) Refactored the way lines are read and buffered so as to have more
1558     than one at a time available.
1560     (d) Implemented a pcregrep test script.
1562     (e) Added the -M (multiline match) option. This allows patterns to match
1563     over several lines of the subject. The buffering ensures that at least
1564     8K, or the rest of the document (whichever is the shorter) is available
1565     for matching (and similarly the previous 8K for lookbehind assertions).
1567     (f) Changed the --help output so that it now says
1569     -w, --word-regex(p)
1571     instead of two lines, one with "regex" and the other with "regexp"
1572     because that confused at least one person since the short forms are the
1573     same. (This required a bit of code, as the output is generated
1574     automatically from a table. It wasn't just a text change.)
1576     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1577     option but starts with a hyphen. Could be a pattern or a path name
1578     starting with a hyphen, for instance.
1580     (h) "-" can be given as a file name to represent stdin.
1582     (i) When file names are being printed, "(standard input)" is used for
1583     the standard input, for compatibility with GNU grep. Previously
1584     "<stdin>" was used.
1586     (j) The option --label=xxx can be used to supply a name to be used for
1587     stdin when file names are being printed. There is no short form.
1589     (k) Re-factored the options decoding logic because we are going to add
1590     two more options that take data. Such options can now be given in four
1591     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1593     (l) Added the -A, -B, and -C options for requesting that lines of context
1594     around matches be printed.
1596     (m) Added the -L option to print the names of files that do not contain
1597     any matching lines, that is, the complement of -l.
1599     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1600     continue to scan other files.
1602     (o) The -s option was incorrectly implemented. For compatibility with other
1603     greps, it now suppresses the error message for a non-existent or non-
1604     accessible file (but not the return code). There is a new option called
1605     -q that suppresses the output of matching lines, which was what -s was
1606     previously doing.
1608     (p) Added --include and --exclude options to specify files for inclusion
1609     and exclusion when recursing.
1611     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1612     Hopefully, it now does.
1614     12. Missing cast in pcre_study().
1616     13. Added an "uninstall" target to the makefile.
1618     14. Replaced "extern" in the function prototypes in Makefile.in with
1619     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1620     world, but is set differently for Windows.
1622     15. Added a second compiling function called pcre_compile2(). The only
1623     difference is that it has an extra argument, which is a pointer to an
1624     integer error code. When there is a compile-time failure, this is set
1625     non-zero, in addition to the error test pointer being set to point to an
1626     error message. The new argument may be NULL if no error number is required
1627     (but then you may as well call pcre_compile(), which is now just a
1628     wrapper). This facility is provided because some applications need a
1629     numeric error indication, but it has also enabled me to tidy up the way
1630     compile-time errors are handled in the POSIX wrapper.
1632     16. Added VPATH=.libs to the makefile; this should help when building with one
1633     prefix path and installing with another. (Or so I'm told by someone who
1634     knows more about this stuff than I do.)
1636     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1637     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1638     match everything, including newlines. This is not POSIX-compatible, but
1639     somebody wanted the feature. From pcretest it can be activated by using
1640     both the P and the s flags.
1642     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1644     19. libpcre.pc was being incorrectly installed as executable.
1646     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1647     it now also looks for '\r' so that it will work unmodified on Windows.
1649     21. Added Google's contributed C++ wrapper to the distribution.
1651     22. Added some untidy missing memory free() calls in pcretest, to keep
1652     Electric Fence happy when testing.
1656 nigel 75 Version 5.0 13-Sep-04
1657     ---------------------
1659     1. Internal change: literal characters are no longer packed up into items
1660     containing multiple characters in a single byte-string. Each character
1661     is now matched using a separate opcode. However, there may be more than one
1662     byte in the character in UTF-8 mode.
1664     2. The pcre_callout_block structure has two new fields: pattern_position and
1665     next_item_length. These contain the offset in the pattern to the next match
1666     item, and its length, respectively.
1668     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1669     insertion of callouts before each pattern item. Added the /C option to
1670     pcretest to make use of this.
1672     4. On the advice of a Windows user, the lines
1674     #if defined(_WIN32) || defined(WIN32)
1675     _setmode( _fileno( stdout ), 0x8000 );
1676     #endif /* defined(_WIN32) || defined(WIN32) */
1678     have been added to the source of pcretest. This apparently does useful
1679     magic in relation to line terminators.
1681     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1682     for the benefit of those environments where the "b" makes a difference.
1684     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1685     to know about it. I have put a hack into configure.in that adds in code
1686     to set GCC=yes if CC=icc. This seems to end up at a point in the
1687     generated configure script that is early enough to affect the setting of
1688     compiler options, which is what is needed, but I have no means of testing
1689     whether it really works. (The user who reported this had patched the
1690     generated configure script, which of course I cannot do.)
1692     LATER: After change 22 below (new libtool files), the configure script
1693     seems to know about icc (and also ecc). Therefore, I have commented out
1694     this hack in configure.in.
1696     7. Added support for pkg-config (2 patches were sent in).
1698     8. Negated POSIX character classes that used a combination of internal tables
1699     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1700     [[:^ascii]]. Typically, they would match almost any characters. The other
1701     POSIX classes were not broken in this way.
1703     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1704     to find the match, as PCRE was deluded into thinking that the match had to
1705     start at the start point or following a newline. The same bug applied to
1706     patterns with negative forward assertions or any backward assertions
1707     preceding ".*" at the start, unless the pattern required a fixed first
1708     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1710     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1711     starting at the last subject character, bytes beyond the end of the subject
1712     string were read.
1714     11. Renamed the variable "class" as "classbits" to make life easier for C++
1715     users. (Previously there was a macro definition, but it apparently wasn't
1716     enough.)
1718     12. Added the new field "tables" to the extra data so that tables can be passed
1719     in at exec time, or the internal tables can be re-selected. This allows
1720     a compiled regex to be saved and re-used at a later time by a different
1721     program that might have everything at different addresses.
1723     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1724     -R library as well as a -L library.
1726     14. The debugging options of pcretest (-d on the command line or D on a
1727     pattern) showed incorrect output for anything following an extended class
1728     that contained multibyte characters and which was followed by a quantifier.
1730     15. Added optional support for general category Unicode character properties
1731     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1732     support. It adds about 90K to the size of the library. The meanings of the
1733     inbuilt class escapes such as \d and \s have NOT been changed.
1735     16. Updated pcredemo.c to include calls to free() to release the memory for the
1736     compiled pattern.
1738     17. The generated file chartables.c was being created in the source directory
1739     instead of in the building directory. This caused the build to fail if the
1740     source directory was different from the building directory, and was
1741     read-only.
1743     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1744     file. No doubt somebody will tell me if they don't make sense... Also added
1745     Dan Mooney's comments about building on OpenVMS.
1747     19. Added support for partial matching via the PCRE_PARTIAL option for
1748     pcre_exec() and the \P data escape in pcretest.
1750     20. Extended pcretest with 3 new pattern features:
1752     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1753     write the compiled pattern to the file whose name is "rest-of-line".
1754     This is a straight binary dump of the data, with the saved pointer to
1755     the character tables forced to be NULL. The study data, if any, is
1756     written too. After writing, pcretest reads a new pattern.
1758     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1759     compiled pattern from the given file. There must not be any
1760     occurrences of "<" in the file name (pretty unlikely); if there are,
1761     pcretest will instead treat the initial "<" as a pattern delimiter.
1762     After reading in the pattern, pcretest goes on to read data lines as
1763     usual.
1765     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1766     and 16-bit fields in a compiled pattern, to simulate a pattern that
1767     was compiled on a host of opposite endianness.
1769     21. The pcre-exec() function can now cope with patterns that were compiled on
1770     hosts of opposite endianness, with this restriction:
1772     As for any compiled expression that is saved and used later, the tables
1773     pointer field cannot be preserved; the extra_data field in the arguments
1774     to pcre_exec() should be used to pass in a tables address if a value
1775     other than the default internal tables were used at compile time.
1777     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1778     now diagnosed as an error. Previously, most of the time, a negative number
1779     would have been treated as zero, but if in addition "ovector" was passed as
1780     NULL, a crash could occur.
1782     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1783     new versions from the libtool 1.5 distribution (the last one is a copy of
1784     a file called libtool.m4). This seems to have fixed the need to patch
1785     "configure" to support Darwin 1.3 (which I used to do). However, I still
1786     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1787     workstation).
1789     24. Changed the PCRE licence to be the more standard "BSD" licence.
1792 nigel 73 Version 4.5 01-Dec-03
1793     ---------------------
1795     1. There has been some re-arrangement of the code for the match() function so
1796     that it can be compiled in a version that does not call itself recursively.
1797     Instead, it keeps those local variables that need separate instances for
1798     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1799     needs to "recurse". Keeping track of where control must go is done by means
1800     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1801     hide most of the details from the main code, and operates only if
1802     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1803     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1804     operating.
1806     To make it easier for callers to provide specially tailored get/free
1807     functions for this usage, two new functions, pcre_stack_malloc, and
1808     pcre_stack_free, are used. They are always called in strict stacking order,
1809     and the size of block requested is always the same.
1811     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1812     PCRE has been compiled to use the stack or the heap for recursion. The
1813     -C option of pcretest uses this to show which version is compiled.
1815     A new data escape \S, is added to pcretest; it causes the amounts of store
1816     obtained and freed by both kinds of malloc/free at match time to be added
1817     to the output.
1819     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1820     what's available on my current Linux desktop machine.
1822     3. When matching a UTF-8 string, the test for a valid string at the start has
1823     been extended. If start_offset is not zero, PCRE now checks that it points
1824     to a byte that is the start of a UTF-8 character. If not, it returns
1825     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1826     this is necessary because there may be backward assertions in the pattern.
1827     When matching the same subject several times, it may save resources to use
1828     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1830     4. The code for checking the validity of UTF-8 strings has been tightened so
1831     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1832     containing "overlong sequences".
1834     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1835     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1836     should have been "&", but it just so happened that all the cases this let
1837     through by mistake were picked up later in the function.
1839     6. I had used a variable called "isblank" - this is a C99 function, causing
1840     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1842     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1843     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1844     so the version is shown; (c) stop "make test" echoing "./RunTest".
1846     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1848     9. The prototype for memmove() for systems that don't have it was using
1849     size_t, but the inclusion of the header that defines size_t was later. I've
1850     moved the #includes for the C headers earlier to avoid this.
1852     10. Added some adjustments to the code to make it easier to compiler on certain
1853     special systems:
1855     (a) Some "const" qualifiers were missing.
1856     (b) Added the macro EXPORT before all exported functions; by default this
1857     is defined to be empty.
1858     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1859     that it reads its output file name as an argument instead of writing
1860     to the standard output and assuming this can be redirected.
1862     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1863     class containing characters with values greater than 255, PCRE compilation
1864     went into a loop.
1866     12. A recursive reference to a subpattern that was within another subpattern
1867     that had a minimum quantifier of zero caused PCRE to crash. For example,
1868     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1869     recursion. If the recursively-called subpattern itself had a zero repeat,
1870     that was OK.
1872     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1873     buffer into which it was copied (for escape processing) was still set at
1874     1024, so long lines caused crashes.
1876     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1877     "internal error: code overflow...". This applied to any character class
1878     that was followed by a possessive quantifier.
1880     15. Modified the Makefile to add libpcre.la as a prerequisite for
1881     libpcreposix.la because I was told this is needed for a parallel build to
1882     work.
1884     16. If a pattern that contained .* following optional items at the start was
1885     studied, the wrong optimizing data was generated, leading to matching
1886     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1887     matching string must start with a or b or c. The correct conclusion for
1888     this pattern is that a match can start with any character.
1891 nigel 71 Version 4.4 13-Aug-03
1892     ---------------------
1894     1. In UTF-8 mode, a character class containing characters with values between
1895     127 and 255 was not handled correctly if the compiled pattern was studied.
1896     In fixing this, I have also improved the studying algorithm for such
1897     classes (slightly).
1899     2. Three internal functions had redundant arguments passed to them. Removal
1900     might give a very teeny performance improvement.
1902     3. Documentation bug: the value of the capture_top field in a callout is *one
1903     more than* the number of the hightest numbered captured substring.
1905     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1906     in incorrectly linking with a previously installed version. They now link
1907     explicitly with libpcre.la.
1909     5. configure.in no longer needs to recognize Cygwin specially.
1911     6. A problem in pcre.in for Windows platforms is fixed.
1913     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1914     pcretest, it used to include the size of the study block as part of its
1915     output. Unfortunately, the structure contains a field that has a different
1916     size on different hardware architectures. This meant that the tests that
1917     showed this size failed. As the block is currently always of a fixed size,
1918     this information isn't actually particularly useful in pcretest output, so
1919     I have just removed it.
1921     8. Three pre-processor statements accidentally did not start in column 1.
1922     Sadly, there are *still* compilers around that complain, even though
1923     standard C has not required this for well over a decade. Sigh.
1925     9. In pcretest, the code for checking callouts passed small integers in the
1926     callout_data field, which is a void * field. However, some picky compilers
1927     complained about the casts involved for this on 64-bit systems. Now
1928     pcretest passes the address of the small integer instead, which should get
1929     rid of the warnings.
1931     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1932     both compile and run time, and gives an error if an invalid UTF-8 sequence
1933     is found. There is a option for disabling this check in cases where the
1934     string is known to be correct and/or the maximum performance is wanted.
1936     11. In response to a bug report, I changed one line in Makefile.in from
1938     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1939     to
1940     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1942     to look similar to other lines, but I have no way of telling whether this
1943     is the right thing to do, as I do not use Windows. No doubt I'll get told
1944     if it's wrong...
1947 nigel 69 Version 4.3 21-May-03
1948     ---------------------
1950     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1951     Makefile.
1953     2. Some refactoring to improve the quality of the code:
1955     (i) The utf8_table... variables are now declared "const".
1957     (ii) The code for \cx, which used the "case flipping" table to upper case
1958     lower case letters, now just substracts 32. This is ASCII-specific,
1959     but the whole concept of \cx is ASCII-specific, so it seems
1960     reasonable.
1962     (iii) PCRE was using its character types table to recognize decimal and
1963     hexadecimal digits in the pattern. This is silly, because it handles
1964     only 0-9, a-f, and A-F, but the character types table is locale-
1965     specific, which means strange things might happen. A private
1966     table is now used for this - though it costs 256 bytes, a table is
1967     much faster than multiple explicit tests. Of course, the standard
1968     character types table is still used for matching digits in subject
1969     strings against \d.
1971     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1972     ending in _t are). So I've renamed it as ESC_tee.
1974     3. The first argument for regexec() in the POSIX wrapper should have been
1975     defined as "const".
1977     4. Changed pcretest to use malloc() for its buffers so that they can be
1978     Electric Fenced for debugging.
1980     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1981     to read one or more bytes before the start of the subject string. Often this
1982     had no effect on PCRE's behaviour, but in some circumstances it could
1983     provoke a segmentation fault.
1985     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1986     to try to read one or more bytes before the start of the subject string.
1988     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1989     UTF-8 support could misbehave in various ways if the subject string
1990     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1991     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1992     back over UTF-8 characters.)
1995 nigel 67 Version 4.2 14-Apr-03
1996     ---------------------
1998     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2000     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2001     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2002     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2003     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2004     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2005     and BUILD_EXEEXT
2006     Note: automatic setting of the BUILD variables is not yet working
2007     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2008     compile-time but not at link-time
2009     [LINK]: use for linking executables only
2010     make different versions for Windows and non-Windows
2011     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2012     libraries
2013     [LINK_FOR_BUILD]: new variable
2014     [OBJEXT]: use throughout
2015     [EXEEXT]: use throughout
2016     <winshared>: new target
2017     <wininstall>: new target
2018     <dftables.o>: use native compiler
2019     <dftables>: use native linker
2020     <install>: handle Windows platform correctly
2021     <clean>: ditto
2022     <check>: ditto
2023     copy DLL to top builddir before testing
2025     As part of these changes, -no-undefined was removed again. This was reported
2026     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2027     in any case.
2029     3. Some tidies to get rid of compiler warnings:
2031     . In the match_data structure, match_limit was an unsigned long int, whereas
2032     match_call_count was an int. I've made them both unsigned long ints.
2034     . In pcretest the fact that a const uschar * doesn't automatically cast to
2035     a void * provoked a warning.
2037     . Turning on some more compiler warnings threw up some "shadow" variables
2038     and a few more missing casts.
2040     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2041     option, a class that contained a single character with a value between 128
2042     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2044     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2045     option, a class that contained several characters, but with at least one
2046     whose value was between 128 and 255 caused PCRE to crash.
2049 nigel 65 Version 4.1 12-Mar-03
2050     ---------------------
2051 nigel 63
2052 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2053     needed, and a string in dftables.c that was longer than standard compilers are
2054     required to support.
2056     2. Compiling with Sun's compiler found a few more places where the code could
2057     be tidied up in order to avoid warnings.
2059     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2060     first of these names is deprecated in the latest Autoconf in favour of the name
2061     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2062     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2063     analogy I have changed it to CFLAGS_FOR_BUILD.
2065     4. Added -no-undefined to the linking command in the Makefile, because this is
2066     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2067     linking step for the pcreposix library.
2069     5. PCRE was failing to diagnose the case of two named groups with the same
2070     name.
2072     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2073     literal character that is needed in the subject for a match, and scans along to
2074     ensure that it is present before embarking on the full matching process. This
2075     saves time in cases of nested unlimited repeats that are never going to match.
2076     Problem: the scan can take a lot of time if the subject is very long (e.g.
2077     megabytes), thus penalizing straightforward matches. It is now done only if the
2078     amount of subject to be scanned is less than 1000 bytes.
2080     7. A lesser problem with the same optimization is that it was recording the
2081     first character of an anchored pattern as "needed", thus provoking a search
2082     right along the subject, even when the first match of the pattern was going to
2083     fail. The "needed" character is now not set for anchored patterns, unless it
2084     follows something in the pattern that is of non-fixed length. Thus, it still
2085     fulfils its original purpose of finding quick non-matches in cases of nested
2086     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2089     Version 4.0 17-Feb-03
2090     ---------------------
2092 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2093     extended to the end of string, PCRE compiled incorrect data. This could lead to
2094     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2096     2. Moved to autoconf 2.53 and libtool 1.4.2.
2098     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2099     the special perltest8 script is no longer needed - all the tests can be run
2100     from a single perltest script.
2102     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2103     by \s. It has now been removed in PCRE. This means it isn't recognized as
2104     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2105     class [:space:] *does* include VT, thereby creating a mess.
2107     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2108     space and tab.
2110     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2111     its new features into the main test script, reducing the number of scripts.
2113     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2114     were backward compatible, and made the (?i) apply to the whole pattern, as if
2115     /i were given. Now it behaves more logically, and applies the option setting
2116     only to what follows. PCRE has been changed to follow suit. However, if it
2117     finds options settings right at the start of the pattern, it extracts them into
2118     the global options, as before. Thus, they show up in the info data.
2120     8. Added support for the \Q...\E escape sequence. Characters in between are
2121     treated as literals. This is slightly different from Perl in that $ and @ are
2122     also handled as literals inside the quotes. In Perl, they will cause variable
2123     interpolation. Note the following examples:
2125     Pattern PCRE matches Perl matches
2127     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2128     \Qabc\$xyz\E abc\$xyz abc\$xyz
2129     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2131     For compatibility with Perl, \Q...\E sequences are recognized inside character
2132     classes as well as outside them.
2134     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2135     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2136     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2137     signed/unsigned warnings.
2139     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2140     option for pcretest, so I've replaced it by a simple function that does just
2141     that job.
2143     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2144     "pcregrep -".
2146     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2147     Java package. This provides some syntactic sugar for simple cases of what my
2148     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2149     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2150     item, you can use this simplified notation. Note that only makes sense with
2151     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2152     greediness, whatever the setting of the PCRE_UNGREEDY option.
2154     13. A change of greediness default within a pattern was not taking effect at
2155     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2156     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2157     was abstracted outside.
2159     14. PCRE now supports the \G assertion. It is true when the current matching
2160     position is at the start point of the match. This differs from \A when the
2161     starting offset is non-zero. Used with the /g option of pcretest (or similar
2162     code), it works in the same way as it does for Perl's /g option. If all
2163     alternatives of a regex begin with \G, the expression is anchored to the start
2164     match position, and the "anchored" flag is set in the compiled expression.
2166     15. Some bugs concerning the handling of certain option changes within patterns
2167     have been fixed. These applied to options other than (?ims). For example,
2168     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2169     been the other way round. Some of this was related to change 7 above.
2171     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2172     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2173     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2174     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2176     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2177     mode. Unlike ".", it always matches newline, whatever the setting of
2178     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2179     assertions. Perl allows it, but it doesn't (in general) work because it can't
2180     calculate the length of the lookbehind. At least, that's the case for Perl
2181     5.8.0 - I've been told they are going to document that it doesn't work in
2182     future.
2184     18. Added an error diagnosis for escapes that PCRE does not support: these are
2185     \L, \l, \N, \P, \p, \U, \u, and \X.
2187     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2188     reading past the end of the pattern in cases such as /[abcd/.
2190     20. PCRE was getting more memory than necessary for patterns with classes that
2191     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2193     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2194     compiling PCRE for use with Virtual Pascal.
2196     22. Small fix to the Makefile to make it work properly if the build is done
2197     outside the source tree.
2199     23. Added a new extension: a condition to go with recursion. If a conditional
2200     subpattern starts with (?(R) the "true" branch is used if recursion has
2201     happened, whereas the "false" branch is used only at the top level.
2203     24. When there was a very long string of literal characters (over 255 bytes
2204     without UTF support, over 250 bytes with UTF support), the computation of how
2205     much memory was required could be incorrect, leading to segfaults or other
2206     strange effects.
2208     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2209     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2210     there was a subsequent back reference to those brackets. This meant that, for
2211     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2212     possible to check for precisely this case. All we can do is abandon the
2213     optimization if .* occurs inside capturing brackets when there are any back
2214     references whatsoever. (See below for a better fix that came later.)
2216     26. The handling of the optimization for finding the first character of a
2217     non-anchored pattern, and for finding a character that is required later in the
2218     match were failing in some cases. This didn't break the matching; it just
2219     failed to optimize when it could. The way this is done has been re-implemented.
2221     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2223     28. Added a new feature that provides some of the functionality that Perl
2224     provides with (?{...}). The facility is termed a "callout". The way it is done
2225     in PCRE is for the caller to provide an optional function, by setting
2226     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2227     global variable. By default it is unset, which disables all calling out. To get
2228     the function called, the regex must include (?C) at appropriate points. This
2229     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2230     This provides a means of identifying different callout points. When PCRE
2231     reaches such a point in the regex, if pcre_callout has been set, the external
2232     function is called. It is provided with data in a structure called
2233     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2234     matching continues; if it returns a non-zero value, the match at the current
2235     point fails. However, backtracking will occur if possible. [This was changed
2236     later and other features added - see item 49 below.]
2238     29. pcretest is upgraded to test the callout functionality. It provides a
2239     callout function that displays information. By default, it shows the start of
2240     the match and the current position in the text. There are some new data escapes
2241     to vary what happens:
2243     \C+ in addition, show current contents of captured substrings
2244     \C- do not supply a callout function
2245     \C!n return 1 when callout number n is reached
2246     \C!n!m return 1 when callout number n is reached for the mth time
2248     30. If pcregrep was called with the -l option and just a single file name, it
2249     output "<stdin>" if a match was found, instead of the file name.
2251     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2252     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2253     pcre_exec(). This saves a malloc/free per call. The default value of
2254     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2255     when configuring.
2257     32. The default maximum size of a compiled pattern is 64K. There have been a
2258     few cases of people hitting this limit. The code now uses macros to handle the
2259     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2260     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2261     configuring. Tests 2 and 5 work only with 2-byte links because they output
2262     debugging information about compiled patterns.
2264     33. Internal code re-arrangements:
2266     (a) Moved the debugging function for printing out a compiled regex into
2267     its own source file (printint.c) and used #include to pull it into
2268     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2269     separate copies.
2271     (b) Defined the list of op-code names for debugging as a macro in
2272     internal.h so that it is next to the definition of the opcodes.
2274     (c) Defined a table of op-code lengths for simpler skipping along compiled
2275     code. This is again a macro in internal.h so that it is next to the
2276     definition of the opcodes.
2278     34. Added support for recursive calls to individual subpatterns, along the
2279     lines of Robin Houston's patch (but implemented somewhat differently).
2281     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2282     allow it to read and process whole directories in Win32. This code was
2283     contributed by Lionel Fourquaux; it has not been tested by me.
2285     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2286     used to name a group. Names consist of alphanumerics and underscores, and must
2287     be unique. Back references use the syntax (?P=name) and recursive calls use
2288     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2289     numbers. The function pcre_fullinfo() can be used after compilation to extract
2290     a name/number map. There are three relevant calls:
2292     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2293     PCRE_INFO_NAMECOUNT yields the number of entries
2294     PCRE_INFO_NAMETABLE yields a pointer to the map.
2296     The map is a vector of fixed-size entries. The size of each entry depends on
2297     the length of the longest name used. The first two bytes of each entry are the
2298     group number, most significant byte first. There follows the corresponding
2299     name, zero terminated. The names are in alphabetical order.
2301     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2302     case instead of 255. Making it the same both with and without UTF-8 support
2303     means that the same test output works with both.
2305     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2306     calling malloc() with a zero argument.
2308     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2309     optimization. I've improved things by keeping a bitmap of backreferences with
2310     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2311     fact referenced, the optimization can be applied. It is unlikely that a
2312     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2313     the match to follow \n) will appear inside brackets with a number greater than
2314     31, but if it does, any back reference > 31 suppresses the optimization.
2316     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2317     of disabling numbered capturing parentheses. Any opening parenthesis that is
2318     not followed by ? behaves as if it were followed by ?: but named parentheses
2319     can still be used for capturing (and they will acquire numbers in the usual
2320     way).
2322     41. Redesigned the return codes from the match() function into yes/no/error so
2323     that errors can be passed back from deep inside the nested calls. A malloc
2324     failure while inside a recursive subpattern call now causes the
2325     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2327     42. It is now possible to set a limit on the number of times the match()
2328     function is called in a call to pcre_exec(). This facility makes it possible to
2329     limit the amount of recursion and backtracking, though not in a directly
2330     obvious way, because the match() function is used in a number of different
2331     circumstances. The count starts from zero for each position in the subject
2332     string (for non-anchored patterns). The default limit is, for compatibility, a
2333     large number, namely 10 000 000. You can change this in two ways:
2335     (a) When configuring PCRE before making, you can use --with-match-limit=n
2336     to set a default value for the compiled library.
2338     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2339     a different value is set. See 45 below.
2341     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2343     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2344     of things that can be changed at compile time. The first argument specifies
2345     what is wanted and the second points to where the information is to be placed.
2346     The current list of available information is:
2350     The output is an integer that is set to one if UTF-8 support is available;
2351     otherwise it is set to zero.
2355     The output is an integer that it set to the value of the code that is used for
2356     newline. It is either LF (10) or CR (13).
2360     The output is an integer that contains the number of bytes used for internal
2361     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2365     The output is an integer that contains the threshold above which the POSIX
2366     interface uses malloc() for output vectors. See item 31 above.
2370     The output is an unsigned integer that contains the default limit of the number
2371     of match() calls in a pcre_exec() execution. See 42 above.
2373     44. pcretest has been upgraded by the addition of the -C option. This causes it
2374     to extract all the available output from the new pcre_config() function, and to
2375     output it. The program then exits immediately.
2377     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2378     order to support additional features. One way would have been to define
2379     pcre_exec2() (for example) with extra arguments, but this would not have been
2380     extensible, and would also have required all calls to the original function to
2381     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2382     is used for passing in "extra" data from pcre_study().
2384     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2385     contains the following fields:
2387     flags a bitmap indicating which of the following fields are set
2388     study_data opaque data from pcre_study()
2389     match_limit a way of specifying a limit on match() calls for a specific
2390     call to pcre_exec()
2391     callout_data data for callouts (see 49 below)
2393     The flag bits are also defined in pcre.h, and are
2399     The pcre_study() function now returns one of these new pcre_extra blocks, with
2400     the actual study data pointed to by the study_data field, and the
2401     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2402     before. That is, this change is entirely upwards-compatible and requires no
2403     change to existing code.
2405     If you want to pass in additional data to pcre_exec(), you can either place it
2406     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2407     block.
2409     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2410     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2411     times with different match limits, until it finds the minimum value needed for
2412     pcre_exec() to complete. The value is then output. This can be instructive; for
2413     most simple matches the number is quite small, but for pathological cases it
2414     gets very large very quickly.
2416     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2417     returns the size of the data block pointed to by the study_data field in a
2418     pcre_extra block, that is, the value that was passed as the argument to
2419     pcre_malloc() when PCRE was getting memory in which to place the information
2420     created by pcre_study(). The fourth argument should point to a size_t variable.
2421     pcretest has been extended so that this information is shown after a successful
2422     pcre_study() call when information about the compiled regex is being displayed.
2424     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2425     because what follows is always an absolute path. (Later: it turns out that this
2426     is more than cosmetic for MinGW, because it doesn't like empty path
2427     components.)
2429     49. Some changes have been made to the callout feature (see 28 above):
2431     (i) A callout function now has three choices for what it returns:
2433     0 => success, carry on matching
2434     > 0 => failure at this point, but backtrack if possible
2435     < 0 => serious error, return this value from pcre_exec()
2437     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2438     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2439     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2440     use by callout functions. It will never be used by PCRE itself.
2442     (ii) The pcre_extra structure (see 45 above) has a void * field called
2443     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2444     pcre_callout_block structure has a field of the same name. The contents of
2445     the field passed in the pcre_extra structure are passed to the callout
2446     function in the corresponding field in the callout block. This makes it
2447     easier to use the same callout-containing regex from multiple threads. For
2448     testing, the pcretest program has a new data escape
2450     \C*n pass the number n (may be negative) as callout_data
2452     If the callout function in pcretest receives a non-zero value as
2453     callout_data, it returns that value.
2455     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2456     there were some redundant $(CFLAGS) in commands that are now specified as
2457     $(LINK), which already includes $(CFLAGS).
2459     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2460     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2461     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2462     one-byte characters throughout. Note that case-insensitive matching applies
2463     only to characters whose values are less than 256. PCRE doesn't support the
2464     notion of cases for higher-valued characters.
2466     (i) A character class whose characters are all within 0-255 is handled as
2467     a bit map, and the map is inverted for negative classes. Previously, a
2468     character > 255 always failed to match such a class; however it should
2469     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2471     (ii) A negated character class with a single character < 255 is coded as
2472     "not this character" (OP_NOT). This wasn't working properly when the test
2473     character was multibyte, either singly or repeated.
2475     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2476     mode, for example: \x{100}{2,3}.
2478     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2479     singly or repeated) now correctly test multibyte characters. However,
2480     PCRE doesn't recognize any characters with values greater than 255 as
2481     digits, spaces, or word characters. Such characters always match \D, \S,
2482     and \W, and never match \d, \s, or \w.
2484     (v) Classes may now contain characters and character ranges with values
2485     greater than 255. For example: [ab\x{100}-\x{400}].
2487     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2488     PCRE in UTF-8 mode.
2490     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2491     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2492     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2493     value.)
2495     53. The single man page has become too large. I have therefore split it up into
2496     a number of separate man pages. These also give rise to individual HTML pages;
2497     these are now put in a separate directory, and there is an index.html page that
2498     lists them all. Some hyperlinking between the pages has been installed.
2500     54. Added convenience functions for handling named capturing parentheses.
2502     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2503     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2504     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2505     are faulted.
2507     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2508     calling configure. These values are used when compiling the dftables.c program
2509     which is run to generate the source of the default character tables. They
2510     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2511     you will need to set these values.
2513     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2516     Version 3.9 02-Jan-02
2517 nigel 61 ---------------------
2519     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2521     2. If --disable-static was given, the building process failed when trying to
2522     build pcretest and pcregrep. (For some reason it was using libtool to compile
2523     them, which is not right, as they aren't part of the library.)
2526 nigel 59 Version 3.8 18-Dec-01
2527     ---------------------
2529     1. The experimental UTF-8 code was completely screwed up. It was packing the
2530     bytes in the wrong order. How dumb can you get?
2533 nigel 57 Version 3.7 29-Oct-01
2534     ---------------------
2536     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2537     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2538     this didn't happen under Solaris 8, where I normally test things.
2540 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2541     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2542     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2543     this fix an hour or so after the initial 3.7 release.)
2544 nigel 57
2545 nigel 59
2546 nigel 55 Version 3.6 23-Oct-01
2547     ---------------------
2549     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2550     offsets passed as NULL with zero offset count.
2552     2. The config.guess and config.sub files had not been updated when I moved to
2553     the latest autoconf.
2556 nigel 53 Version 3.5 15-Aug-01
2557     ---------------------
2558 nigel 5
2559 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2560     had been forgotten.
2562     2. By using declared but undefined structures, we can avoid using "void"
2563     definitions in pcre.h while keeping the internal definitions of the structures
2564     private.
2566     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2567     user point of view, this means that both static and shared libraries are built
2568     by default, but this can be individually controlled. More of the work of
2569     handling this static/shared cases is now inside libtool instead of PCRE's make
2570     file.
2572     4. The pcretest utility is now installed along with pcregrep because it is
2573     useful for users (to test regexs) and by doing this, it automatically gets
2574     relinked by libtool. The documentation has been turned into a man page, so
2575     there are now .1, .txt, and .html versions in /doc.
2577     5. Upgrades to pcregrep:
2578     (i) Added long-form option names like gnu grep.
2579     (ii) Added --help to list all options with an explanatory phrase.
2580     (iii) Added -r, --recursive to recurse into sub-directories.
2581     (iv) Added -f, --file to read patterns from a file.
2583     6. pcre_exec() was referring to its "code" argument before testing that
2584     argument for NULL (and giving an error if it was NULL).
2586     7. Upgraded Makefile.in to allow for compiling in a different directory from
2587     the source directory.
2589     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2590     options bits, the pointer it was passed was to an int instead of to an unsigned
2591     long int. This mattered only on 64-bit systems.
2593     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2594     generated) instead of pcre.in, which it its source. Also made the same change
2595     in several of the .c files.
2597     10. A new release of gcc defines printf() as a macro, which broke pcretest
2598     because it had an ifdef in the middle of a string argument for printf(). Fixed
2599     by using separate calls to printf().
2601     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2602     script, to force use of CR or LF instead of \n in the source. On non-Unix
2603     systems, the value can be set in config.h.
2605     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2606     absolute limit. Changed the text of the error message to make this clear, and
2607     likewise updated the man page.
2609     13. The limit of 99 on the number of capturing subpatterns has been removed.
2610     The new limit is 65535, which I hope will not be a "real" limit.
2613 nigel 51 Version 3.4 22-Aug-00
2614     ---------------------
2616     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2618     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2621 nigel 49 Version 3.3 01-Aug-00
2622     ---------------------
2624     1. If an octal character was given, but the value was greater than \377, it
2625     was not getting masked to the least significant bits, as documented. This could
2626     lead to crashes in some systems.
2628     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2629     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2631     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2632     These just pass their arguments on to (pcre_free)(), but they are provided
2633     because some uses of PCRE bind it to non-C systems that can call its functions,
2634     but cannot call free() or pcre_free() directly.
2636     4. Add "make test" as a synonym for "make check". Corrected some comments in
2637     the Makefile.
2639     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2640     Makefile.
2642     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2643     command called pgrep for grepping around the active processes.
2645     7. Added the beginnings of support for UTF-8 character strings.
2647     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2648     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2649     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2650     out for the ar command.)
2653 nigel 47 Version 3.2 12-May-00
2654     ---------------------
2656     This is purely a bug fixing release.
2658     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2659     of ZA. This was just one example of several cases that could provoke this bug,
2660     which was introduced by change 9 of version 2.00. The code for breaking
2661     infinite loops after an iteration that matches an empty string was't working
2662     correctly.
2664     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2665     when matched against abbab (for example). After matching an empty string, it
2666     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2667     caused it to match further down the string than it should.
2669     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2670     was there because it doesn't seem to be needed, and it causes trouble on some
2671     systems, as it is not a Standard C header. It has been removed.
2673     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2674     were reported on the Macintosh. The changes were from
2676     while ((c = *(++ptr)) != 0 && c != '\n');
2677     to
2678     while ((c = *(++ptr)) != 0 && c != '\n') ;
2680     Totally extraordinary, but if that's what it takes...
2682     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2683     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2684     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2685     assumes the way PCRE uses memmove() (always moving upwards).
2687     6. PCRE is being used in one environment where strchr() is not available. There
2688     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2689     faster code anyway.
2692 nigel 45 Version 3.1 09-Feb-00
2693     ---------------------
2695     The only change in this release is the fixing of some bugs in Makefile.in for
2696     the "install" target:
2698     (1) It was failing to install pcreposix.h.
2700     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2703 nigel 43 Version 3.0 01-Feb-00
2704     ---------------------
2705 nigel 41
2706     1. Add support for the /+ modifier to perltest (to output $` like it does in
2707     pcretest).
2709     2. Add support for the /g modifier to perltest.
2711     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2712     matches null strings.
2714     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2715     pattern. Perl treats empty patterns specially - it reuses the most recent
2716     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2717     effect.
2719     5. The POSIX interface was broken in that it was just handing over the POSIX
2720     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2721     required a bigger vector, with some working space on the end. This means that
2722     the POSIX wrapper now has to get and free some memory, and copy the results.
2724 nigel 43 6. Added some simple autoconf support, placing the test data and the
2725     documentation in separate directories, re-organizing some of the
2726     information files, and making it build pcre-config (a GNU standard). Also added
2727     libtool support for building PCRE as a shared library, which is now the
2728     default.
2729 nigel 41
2730 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2731     09 are not valid octal constants. Single digits will be used for minor values
2732     less than 10.
2734     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2735     existing programs that set these in the POSIX interface can use PCRE without
2736     modification.
2738     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2739     return all that pcre_info() returns, plus additional data. The pcre_info()
2740     function is retained for compatibility, but is considered to be obsolete.
2742     10. Added experimental recursion feature (?R) to handle one common case that
2743     Perl 5.6 will be able to do with (?p{...}).
2745     11. Added support for POSIX character classes like [:alpha:], which Perl is
2746     adopting.
2749 nigel 39 Version 2.08 31-Aug-99
2750     ----------------------
2752     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2753     trying to match at the startoffset position, but instead was moving forward to
2754     the next newline as if a previous match had failed.
2756     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2757     and could get into a loop if a null string was matched other than at the start
2758     of the subject.
2760     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2761     be distinguished at compile time, and for completeness also added PCRE_DATE.
2763     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2764     in GnuWin32 environments.
2767 nigel 37 Version 2.07 29-Jul-99
2768     ----------------------
2770     1. The documentation is now supplied in plain text form and HTML as well as in
2771     the form of man page sources.
2773     2. C++ compilers don't like assigning (void *) values to other pointer types.
2774     In particular this affects malloc(). Although there is no problem in Standard
2775     C, I've put in casts to keep C++ compilers happy.
2777     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2778     should be (const char *).
2780     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2781     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2782     However, I haven't made this a standard facility. The documentation doesn't
2783     mention it, and the Makefile doesn't support it.
2785     5. The Makefile now contains an "install" target, with editable destinations at
2786     the top of the file. The pcretest program is not installed.
2788     6. pgrep -V now gives the PCRE version number and date.
2790     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2791     causing the entire string to be ignored, instead of just the last character.
2793     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2794     non-matching string, it can take a very, very long time, even for strings of
2795     quite modest length, because of the nested recursion. PCRE now does better in
2796     some of these cases. It does this by remembering the last required literal
2797     character in the pattern, and pre-searching the subject to ensure it is present
2798     before running the real match. In other words, it applies a heuristic to detect
2799     some types of certain failure quickly, and in the above example, if presented
2800     with a string that has no trailing " it gives "no match" very quickly.
2802     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2803     other alternatives are tried instead.
2806 nigel 35 Version 2.06 09-Jun-99
2807     ----------------------
2809     1. Change pcretest's output for amount of store used to show just the code
2810     space, because the remainder (the data block) varies in size between 32-bit and
2811     64-bit systems.
2813     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2814     start matching at. This allows lookbehinds to work when searching for multiple
2815     occurrences in a string.
2817     3. Added additional options to pcretest for testing multiple occurrences:
2819     /+ outputs the rest of the string that follows a match
2820     /g loops for multiple occurrences, using the new startoffset argument
2821     /G loops for multiple occurrences by passing an incremented pointer
2823     4. PCRE wasn't doing the "first character" optimization for patterns starting
2824     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2825     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2826     the letter 'x'. On long subject strings, this gives a significant speed-up.
2829 nigel 33 Version 2.05 21-Apr-99
2830     ----------------------
2832     1. Changed the type of magic_number from int to long int so that it works
2833     properly on 16-bit systems.
2835     2. Fixed a bug which caused patterns starting with .* not to work correctly
2836     when the subject string contained newline characters. PCRE was assuming
2837     anchoring for such patterns in all cases, which is not correct because .* will
2838     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2839     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2840     must be retried after every newline in the subject.
2843 nigel 31 Version 2.04 18-Feb-99
2844     ----------------------
2846     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2847     computation of the store needed to hold the pattern was incorrect (too large).
2848     If such patterns were nested a few deep, this could multiply and become a real
2849     problem.
2851     2. Added /M option to pcretest to show the memory requirement of a specific
2852     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2854     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2855     compiled in such a way that the backtracking after subsequent failure was
2856     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2857     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2860 nigel 29 Version 2.03 02-Feb-99
2861     ----------------------
2863     1. Fixed typo and small mistake in man page.
2865 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2866     LICENCE file containing the conditions.
2867 nigel 29
2868     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2869     Perl, that is the internal \ allows the delimiter to be included in the
2870     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2871     the final delimiter, add \ to the end of the pattern (to test the error).
2873     4. Added the convenience functions for extracting substrings after a successful
2874     match. Updated pcretest to make it able to test these functions.
2877 nigel 27 Version 2.02 14-Jan-99
2878     ----------------------
2880     1. Initialized the working variables associated with each extraction so that
2881     their saving and restoring doesn't refer to uninitialized store.
2883     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2884     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2885     fix the problem.
2887     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2888     calls, and wasn't printing the correct value for compiling calls. Increased the
2889     default value of LOOPREPEAT, and the number of significant figures in the
2890     times.
2892     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2894     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2895     a building problem on Windows NT with a FAT file system.
2898 nigel 25 Version 2.01 21-Oct-98
2899     ----------------------
2901     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2902     to character tables built by pcre_maketables() in the current locale. If NULL
2903     is passed, the default tables are used.
2906 nigel 23 Version 2.00 24-Sep-98
2907 nigel 21 ----------------------
2909 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2910     it any more.
2912     2. Allow quantification of (?>) groups, and make it work correctly.
2914     3. The first character computation wasn't working for (?>) groups.
2916     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2917     end of the subject) and add 5.005's \z, which really does match only at the
2918     very end of the subject.
2920     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2922     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2923     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2924     localized options. All options to pcre_study() were also removed.
2926     7. Add other new features from 5.005:
2928     $(?<= positive lookbehind
2929     $(?<! negative lookbehind
2930     (?imsx-imsx) added the unsetting capability
2931     such a setting is global if at outer level; local otherwise
2932     (?imsx-imsx:) non-capturing groups with option setting
2933     (?(cond)re|re) conditional pattern matching
2935     A backreference to itself in a repeated group matches the previous
2936     captured string.
2938     8. General tidying up of studying (both automatic and via "study")
2939     consequential on the addition of new assertions.
2941     9. As in 5.005, unlimited repeated groups that could match an empty substring
2942     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2943     runtime if any iteration does actually match an empty substring.
2945     10. Include the RunTest script in the distribution.
2947     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2948     discrepancies, some of which were old and were also with respect to 5.004. They
2949     have now been fixed.
2952     Version 1.09 28-Apr-98
2953     ----------------------
2955 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2956     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2957     program crashes, or just wrong answers. This did not apply to negated classes
2958     containing more than one character, or to minima other than one.
2961 nigel 19 Version 1.08 27-Mar-98
2962     ----------------------
2964     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2966     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2967     latter must appear before anything that relies on it in the pattern.
2970 nigel 17 Version 1.07 16-Feb-98
2971     ----------------------
2973     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2974     repeat of a potentially empty string).
2977 nigel 15 Version 1.06 23-Jan-98
2978     ----------------------
2980     1. Added Markus Oberhumer's little patches for C++.
2982     2. Literal strings longer than 255 characters were broken.
2985 nigel 13 Version 1.05 23-Dec-97
2986     ----------------------
2988     1. Negated character classes containing more than one character were failing if
2989     PCRE_CASELESS was set at run time.
2992 nigel 11 Version 1.04 19-Dec-97
2993     ----------------------
2995     1. Corrected the man page, where some "const" qualifiers had been omitted.
2997     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2998     input syntax.
3000     3. Fixed memory leak which occurred when a regex with back references was
3001     matched with an offsets vector that wasn't big enough. The temporary memory
3002     that is used in this case wasn't being freed if the match failed.
3004     4. Tidied pcretest to ensure it frees memory that it gets.
3006     5. Temporary memory was being obtained in the case where the passed offsets
3007     vector was exactly big enough.
3009     6. Corrected definition of offsetof() from change 5 below.
3011     7. I had screwed up change 6 below and broken the rules for the use of
3012     setjmp(). Now fixed.
3015 nigel 9 Version 1.03 18-Dec-97
3016     ----------------------
3018     1. A erroneous regex with a missing opening parenthesis was correctly
3019     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3020     on some systems.
3022     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3023     it was reported that one broken compiler failed on the former because "code" is
3024     also an independent variable.
3026     3. The erroneous regex a[]b caused an array overrun reference.
3028     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3029     fail on data ending with that character. (It was going on too far, and checking
3030     the next character, typically a binary zero.) This was specific to the
3031     optimized code for single-character negative classes.
3033     5. Added a contributed patch from the TIN world which does the following:
3035     + Add an undef for memmove, in case the the system defines a macro for it.
3037     + Add a definition of offsetof(), in case there isn't one. (I don't know
3038     the reason behind this - offsetof() is part of the ANSI standard - but
3039     it does no harm).
3041     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3042     most of the places where whitespace preceded '#'. I have given up and
3043     allowed the remaining 2 cases to be at the margin.
3045     + Rename some variables in pcre to eliminate shadowing. This seems very
3046     pedantic, but does no harm, of course.
3048     6. Moved the call to setjmp() into its own function, to get rid of warnings
3049     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3051     7. Constructs such as \d{8,} were compiling into the equivalent of
3052 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3053 nigel 9 outcome, but in this particular case used more store than had been allocated,
3054     which caused the bug to be discovered because it threw up an internal error.
3056     8. The debugging code in both pcre and pcretest for outputting the compiled
3057     form of a regex was going wrong in the case of back references followed by
3058     curly-bracketed repeats.
3061 nigel 7 Version 1.02 12-Dec-97
3062     ----------------------
3064     1. Typos in pcre.3 and comments in the source fixed.
3066     2. Applied a contributed patch to get rid of places where it used to remove
3067     'const' from variables, and fixed some signed/unsigned and uninitialized
3068     variable warnings.
3070     3. Added the "runtest" target to Makefile.
3072     4. Set default compiler flag to -O2 rather than just -O.
3075 nigel 5 Version 1.01 19-Nov-97
3076     ----------------------
3078     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3079     like /([ab]*)*/, that is, for classes with more than one character in them.
3081     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3082     as /((?>a*))*/ (a PCRE_EXTRA facility).
3085     Version 1.00 18-Nov-97
3086     ----------------------
3088     1. Added compile-time macros to support systems such as SunOS4 which don't have
3089     memmove() or strerror() but have other things that can be used instead.
3091     2. Arranged that "make clean" removes the executables.
3094 nigel 3 Version 0.99 27-Oct-97
3095     ----------------------
3097     1. Fixed bug in code for optimizing classes with only one character. It was
3098     initializing a 32-byte map regardless, which could cause it to run off the end
3099     of the memory it had got.
3101     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3104     Version 0.98 22-Oct-97
3105     ----------------------
3107     1. Fixed bug in code for handling temporary memory usage when there are more
3108     back references than supplied space in the ovector. This could cause segfaults.
3111     Version 0.97 21-Oct-97
3112     ----------------------
3114     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3116     2. Optimized negated single characters not to use a bit map.
3118     3. Brought error texts together as macro definitions; clarified some of them;
3119     fixed one that was wrong - it said "range out of order" when it meant "invalid
3120     escape sequence".
3122     4. Changed some char * arguments to const char *.
3124     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3126     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3127     pcretest.
3130     Version 0.96 16-Oct-97
3131     ----------------------
3133     1. Added a simple "pgrep" utility to the distribution.
3135     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3136     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3137     where "ddd" means "one or more decimal digits".
3139     3. Fixed serious bug. If a pattern had a back reference, but the call to
3140     pcre_exec() didn't supply a large enough ovector to record the related
3141     identifying subpattern, the match always failed. PCRE now remembers the number
3142     of the largest back reference, and gets some temporary memory in which to save
3143     the offsets during matching if necessary, in order to ensure that
3144     backreferences always work.
3146     4. Increased the compatibility with Perl in a number of ways:
3148     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3149     to request this handling. The option can be set at compile or exec time.
3151     (b) $ matches before a terminating newline by default; an option
3152     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3153     mode). The option can be set at compile or exec time.
3155     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3156     the same as Perl's. If the decimal number it represents is less than 10
3157     or there aren't that many previous left capturing parentheses, an octal
3158     escape is read. Inside a character class, it's always an octal escape,
3159     even if it is a single digit.
3161     (d) An escaped but undefined alphabetic character is taken as a literal,
3162     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3163     escapes.
3165     (e) {0} is now permitted. (The previous item is removed from the compiled
3166     pattern).
3168     5. Changed all the names of code files so that the basic parts are no longer
3169     than 10 characters, and abolished the teeny "globals.c" file.
3171     6. Changed the handling of character classes; they are now done with a 32-byte
3172     bit map always.
3174     7. Added the -d and /D options to pcretest to make it possible to look at the
3175     internals of compilation without having to recompile pcre.
3178     Version 0.95 23-Sep-97
3179     ----------------------
3181     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3182     \x20 at the start of a run of normal characters. These were being treated as
3183     real characters, instead of the source characters being re-checked.
3186     Version 0.94 18-Sep-97
3187     ----------------------
3189     1. The functions are now thread-safe, with the caveat that the global variables
3190     containing pointers to malloc() and free() or alternative functions are the
3191     same for all threads.
3193     2. Get pcre_study() to generate a bitmap of initial characters for non-
3194     anchored patterns when this is possible, and use it if passed to pcre_exec().
3197     Version 0.93 15-Sep-97
3198     ----------------------
3200     1. /(b)|(:+)/ was computing an incorrect first character.
3202     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3203     but not actually doing anything yet.
3205     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3206     as Perl does (e.g. [-az] or [az-]).
3208     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3209     all possible positions.
3211     5. Split up into different modules to avoid including unneeded functions in a
3212     compiled binary. However, compile and exec are still in one module. The "study"
3213     function is split off.
3215     6. The character tables are now in a separate module whose source is generated
3216     by an auxiliary program - but can then be edited by hand if required. There are
3217     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3218     toupper() in the code.
3220     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3221     make them global. Abolish the function for setting them, as the caller can now
3222     set them directly.
3225     Version 0.92 11-Sep-97
3226     ----------------------
3228     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3229     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3231     2. Caseless matching was not working in character classes if the characters in
3232     the pattern were in upper case.
3234     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3236     4. Make PCRE_ANCHORED public and accept as a compile option.
3238     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3239     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3240     pass them.
3242     6. Give an error if bad option bits passed at compile or run time.
3244     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3245     pcretest to cause it to pass that flag.
3247     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3248     options, and the first character, if set.
3250     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3253     Version 0.91 10-Sep-97
3254     ----------------------
3256     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3257     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3259     2. PCRE was looping on encountering an indefinitely repeated back reference to
3260     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3261     Perl does - treats the match as successful.
3263     ****


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