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Sun Jan 20 19:52:18 2008 UTC (7 years, 3 months ago) by ph10
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Add detail to cmake update note.

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 302 Version 7.6 19-Jan-08
5 ph10 300 ---------------------
7 ph10 302 1. A character class containing a very large number of characters with
8     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
9     overflow.
11     2. Patch to cut out the "long long" test in pcrecpp_unittest when
12     HAVE_LONG_LONG is not defined.
13 ph10 303
14     3. Applied Christian Ehrlicher's patch to update the CMake build files to
15 ph10 304 bring them up to date and include new features. This patch includes:
17     - Fixed PH's badly added libz and libbz2 support.
18     - Fixed a problem with static linking.
19     - Added pcredemo.
20     - Fixed dftables problem and added an option.
21     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
23     - Added readline support for pcretest.
24     - Added an listing of the option settings after cmake has run.
25 ph10 300
27 ph10 298 Version 7.5 10-Jan-08
28 ph10 263 ---------------------
30     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
31     values in parens when parsing an RE using the C++ wrapper."
32 ph10 286
33 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
34     Characters greater than 255 were excluded from the class instead of being
35     included.
36 ph10 286
37     3. The same bug as (2) above applied to negated POSIX classes such as
38 ph10 265 [:^space:].
39 ph10 286
40 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
41     defined or documented. It seems to have been a typo for PCRE_STATIC, so
42 ph10 286 I have changed it.
44 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
45 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
46     first named subpattern whose name started with "a" (in other words, the
47 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
48     expected" is now given for (?&) (a zero-length name), and this patch also
49     makes it give the same error for \k'' (previously it complained that that
50     was a reference to a non-existent subpattern).
51 ph10 286
52 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
53 ph10 286 this is right because (?- can be followed by option settings as well as by
54 ph10 269 digits. I have, however, made the messages clearer.
55 ph10 286
56 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
57     than the number used in the conditional) now cause a compile-time error.
58     This is actually not compatible with Perl, which accepts such patterns, but
59     treats the conditional as always being FALSE (as PCRE used to), but it
60     seems to me that giving a diagnostic is better.
61 ph10 286
62 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
63 ph10 275 and messages.
64 ph10 286
65     9. Fix two occurrences of "backslash" in comments that should have been
66     "backspace".
68     10. Remove two redundant lines of code that can never be obeyed (their function
69     was moved elsewhere).
71     11. The program that makes PCRE's Unicode character property table had a bug
72     which caused it to generate incorrect table entries for sequences of
73 ph10 277 characters that have the same character type, but are in different scripts.
74 ph10 286 It amalgamated them into a single range, with the script of the first of
75 ph10 277 them. In other words, some characters were in the wrong script. There were
76     thirteen such cases, affecting characters in the following ranges:
77 ph10 286
78 ph10 277 U+002b0 - U+002c1
79     U+0060c - U+0060d
80 ph10 286 U+0061e - U+00612
81 ph10 277 U+0064b - U+0065e
82     U+0074d - U+0076d
83     U+01800 - U+01805
84     U+01d00 - U+01d77
85     U+01d9b - U+01dbf
86     U+0200b - U+0200f
87     U+030fc - U+030fe
88     U+03260 - U+0327f
89     U+0fb46 - U+0fbb1
90     U+10450 - U+1049d
91 ph10 286
92 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
93     compatible with GNU grep in that, if there was more than one match in a
94     line, it showed only the first of them. It now behaves in the same way as
95     GNU grep.
96 ph10 286
97     13. If the -o and -v options were combined for pcregrep, it printed a blank
98     line for every non-matching line. GNU grep prints nothing, and pcregrep now
99     does the same. The return code can be used to tell if there were any
100     non-matching lines.
102 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
104     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
105 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
106 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
107     and both kinds of lookbehind were skipped).
109 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
110 ph10 284 inclusion of <windows.h> to before rather than after the definition of
111     INVALID_FILE_ATTRIBUTES (patch from David Byron).
112 ph10 263
113 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
114 ph10 286 character property caused pcre_compile() to compile bad code, which led at
115     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
116     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
117     caused the error; without that there was no problem.
118 ph10 263
119 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
120 ph10 286
121 ph10 289 19. Added --enable-pcretest-libreadline.
122 ph10 286
123 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
124 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
125 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
126     later patch that removed the other one (the right fix) and added unit tests
127     that check the return values (which was not done before).
128 ph10 292
129 ph10 291 21. Several CMake things:
130 ph10 287
131 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
132 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
133 ph10 288
134 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
135     linked with the newly-built libraries, not previously installed ones.
136 ph10 291
138 ph10 298
139     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
140     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
141     UTF-8 newline character). The key issue is that the pattern starts .*;
142     this means that the match must be either at the beginning, or after a
143     newline. The bug was in the code for advancing after a failed match and
144     checking that the new position followed a newline. It was not taking
145 ph10 294 account of UTF-8 characters correctly.
146 ph10 298
147     23. PCRE was behaving differently from Perl in the way it recognized POSIX
148     character classes. PCRE was not treating the sequence [:...:] as a
149     character class unless the ... were all letters. Perl, however, seems to
150     allow any characters between [: and :], though of course it rejects as
151     unknown any "names" that contain non-letters, because all the known class
152     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
153     for example, whereas PCRE did not - it did not recognize a POSIX character
154     class. This seemed a bit dangerous, so the code has been changed to be
155     closer to Perl. The behaviour is not identical to Perl, because PCRE will
156     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
157     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
158     Perl does, and where it didn't before.
160 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
161     Windows environments %n is disabled by default.
162 ph10 292
164 ph10 260 Version 7.4 21-Sep-07
165 ph10 230 ---------------------
167     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
168 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
169     LF". That isn't really right - the whole point of the change was to try to
170     help when there was an actual mention of one of the two characters. So now
171     the change happens only if \r or \n (or a literal CR or LF) character is
172 ph10 230 encountered.
173 ph10 231
174     2. The 32-bit options word was also used for 6 internal flags, but the numbers
175     of both had grown to the point where there were only 3 bits left.
176     Fortunately, there was spare space in the data structure, and so I have
177     moved the internal flags into a new 16-bit field to free up more option
178 ph10 230 bits.
179 ph10 231
180     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
181     but did not set the internal JCHANGED flag - either of these is enough to
182     control the way the "get" function works - but the PCRE_INFO_JCHANGED
183     facility is supposed to tell if (?J) was ever used, so now (?J) at the
184 ph10 230 start sets both bits.
186 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
187     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
188 ph10 230
189 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
191     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
192 ph10 233 compatibility, even though it is no longer used.
193 ph10 243
194     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
195 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
196 ph10 259 windows.h file is present (where different names are used). [This was
197 ph10 257 reversed later after testing - see 16 below.]
198 ph10 243
199     8. Changed all #include <config.h> to #include "config.h". There were also
200 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
201 ph10 243
202 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
203 ph10 243 sequence off the lines that it output.
205     10. It was pointed out to me that arrays of string pointers cause lots of
206     relocations when a shared library is dynamically loaded. A technique of
207     using a single long string with a table of offsets can drastically reduce
208     these. I have refactored PCRE in four places to do this. The result is
209 ph10 240 dramatic:
210 ph10 243
211 ph10 240 Originally: 290
212     After changing UCP table: 187
213 ph10 243 After changing error message table: 43
214 ph10 240 After changing table of "verbs" 36
215     After changing table of Posix names 22
216 ph10 243
217 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
218 ph10 247
219 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
220 ph10 247 unicode-properties was also set.
222 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
223 ph10 231
224 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
225     checked only for CRLF.
226 ph10 233
227 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
229 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
230 ph10 253
231 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
232 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
233     entirely. This removes changes made in 7 above.
234 ph10 256
235 ph10 261 17. The CMake files have been updated, and there is now more information about
236     building with CMake in the NON-UNIX-USE document.
237 ph10 257
238 ph10 261
239 ph10 228 Version 7.3 28-Aug-07
240 ph10 157 ---------------------
242 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
243     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
244     brackets there is not right, since it causes compilers to look for an
245     installed pcre.h, not the version that is in the source that is being
246     compiled (which of course may be different). I have changed it back to:
247 ph10 197
248 ph10 189 #include "pcre.h"
249 ph10 197
250     I have a vague recollection that the change was concerned with compiling in
251     different directories, but in the new build system, that is taken care of
252     by the VPATH setting the Makefile.
254 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
255     when the subject happened to end in the byte 0x85 (e.g. if the last
256     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
257     characters but of course it shouldn't be taken as a newline when it is part
258     of another character. The bug was that, for an unlimited repeat of . in
259     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
260     characters when looking for a newline.
261 ph10 197
262     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
264     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
265     in debug output.
267 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
268     long printing in the pcrecpp unittest when running under MinGW.
269 ph10 189
270 ph10 197 6. ESC_K was left out of the EBCDIC table.
271 ph10 189
272 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
273     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
274     limit also applies to "virtual nesting" when a pattern is recursive, and in
275     this case 1000 isn't so big. I have been able to remove this limit at the
276     expense of backing off one optimization in certain circumstances. Normally,
277     when pcre_exec() would call its internal match() function recursively and
278     immediately return the result unconditionally, it uses a "tail recursion"
279     feature to save stack. However, when a subpattern that can match an empty
280     string has an unlimited repetition quantifier, it no longer makes this
281     optimization. That gives it a stack frame in which to save the data for
282     checking that an empty string has been matched. Previously this was taken
283     from the 1000-entry workspace that had been reserved. So now there is no
284     explicit limit, but more stack is used.
285 ph10 189
286 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
287     syntax that is required for Windows, and which was going wrong for the
288     pcreposix and pcrecpp parts of the library. These were overlooked when this
289     problem was solved for the main library.
290 ph10 197
291 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
292     the size of patterns that contain repeated groups with explicit upper
293     limits. As the maximum quantifier is 65535, the maximum group length was
294     set at 30,000 so that the product of these two numbers did not overflow a
295     32-bit integer. However, it turns out that people want to use groups that
296     are longer than 30,000 bytes (though not repeat them that many times).
297     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
298     made it possible to implement the integer overflow checks in a much more
299     dynamic way, which I have now done. The artificial limitation on group
300     length has been removed - we now have only the limit on the total length of
301     the compiled pattern, which depends on the LINK_SIZE setting.
302 ph10 208
303     10. Fixed a bug in the documentation for get/copy named substring when
304     duplicate names are permitted. If none of the named substrings are set, the
305     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
306     empty string.
308     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
309     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
310     because the ] is interpreted as the first data character and the
311     terminating ] is not found. PCRE has been made compatible with Perl in this
312     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
313     cause memory overwriting.
315 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
316     string has been matched (to stop an infinite loop). It was not recognizing
317 ph10 208 a conditional subpattern that could match an empty string if that
318 ph10 206 subpattern was within another subpattern. For example, it looped when
319 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
320 ph10 206 condition was not nested. This bug has been fixed.
321 ph10 208
322 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
323     past the start of the subject in the presence of bytes with the top bit
324     set, for example "\x8aBCD".
325 ph10 211
326 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
327     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
328 ph10 200
329 ph10 211 14. Optimized (?!) to (*FAIL).
330 ph10 202
331 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
332     This restricts code points to be within the range 0 to 0x10FFFF, excluding
333     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
334     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
335     does: it's just the validity check that is more restrictive.
336 ph10 220
337     16. Inserted checks for integer overflows during escape sequence (backslash)
338     processing, and also fixed erroneous offset values for syntax errors during
339     backslash processing.
341 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
342 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
344 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
345     caused an overrun.
346 ph10 220
347     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
348     something other than just ASCII characters) inside a group that had an
349     unlimited repeat caused a loop at compile time (while checking to see
350     whether the group could match an empty string).
352 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
353     [\P{Any}] did so. (Error in the code for printing property names.)
354 ph10 210
355 ph10 220 21. An orphan \E inside a character class could cause a crash.
357     22. A repeated capturing bracket such as (A)? could cause a wild memory
358 ph10 218 reference during compilation.
359 ph10 220
360     23. There are several functions in pcre_compile() that scan along a compiled
361     expression for various reasons (e.g. to see if it's fixed length for look
362 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
363 ph10 220 present in the pattern. These operators have additional parameters compared
364     with \d, etc, and these were not being taken into account when moving along
365 ph10 218 the compiled data. Specifically:
366 ph10 220
367     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
368     length.
370     (b) An item such as \pL+ within a repeated group could cause crashes or
371 ph10 218 loops.
372 ph10 220
373 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
374 ph10 220 "reference to non-existent subpattern" error.
376 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
378 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
379 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
380 ph10 211
381 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
382 ph10 218
383 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
384 ph10 223 character were causing crashes (broken optimization).
385 ph10 227
386 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
387 ph10 227 \p or \P) caused a compile-time loop.
389 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
390     break. For example, the unstudied pattern [\r\n]A does not match the string
391     "\r\nA" because change 7.0/46 below moves the current point on by two
392     characters after failing to match at the start. However, the pattern \nA
393 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
394     the same is true. There doesn't seem any very clean way out of this, but
395     what I have chosen to do makes the common cases work: PCRE now takes note
396     of whether there can be an explicit match for \r or \n anywhere in the
397     pattern, and if so, 7.0/46 no longer applies. As part of this change,
398     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
399     pattern has explicit CR or LF references.
400 ph10 222
401 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
402 ph10 223
403 ph10 227
404 ph10 189 Version 7.2 19-Jun-07
405     ---------------------
407 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
408     which is apparently normally available under Windows.
409 ph10 159
410     2. Re-jig the pcregrep tests with different newline settings in an attempt
411     to make them independent of the local environment's newline setting.
412 ph10 157
413 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
414 ph10 165
415 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
416     was not 2, because the output contained actual offsets. The recent new
417 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
418     usable with all link sizes.
420 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
421     stack recursion. This gives a massive performance boost under BSD, but just
422 ph10 165 a small improvement under Linux. However, it saves one field in the frame
423 ph10 164 in all cases.
424 ph10 172
425 ph10 166 6. Added more features from the forthcoming Perl 5.10:
426 ph10 172
427 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
428     recursion call. It refers to the nth most recently opened parentheses.
429 ph10 172
430 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
431 ph10 172 to be opened parentheses.
433     (c) Conditions that refer to capturing parentheses can be specified
434 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
435 ph10 172
436 ph10 168 (d) \K resets the start of the current match so that everything before
437 ph10 172 is not part of it.
439 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
440 ph10 172
441 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
442 ph10 172 reference syntax.
443 ph10 182
444 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
445 ph10 182 alternative starts with the same number.
446 ph10 172
447 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
449 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
452     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
453     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
454 ph10 170 for detecting groups that can match an empty string.
455 ph10 159
456 ph10 172 9. A pattern with a very large number of alternatives (more than several
457     hundred) was running out of internal workspace during the pre-compile
458     phase, where pcre_compile() figures out how much memory will be needed. A
459     bit of new cunning has reduced the workspace needed for groups with
460     alternatives. The 1000-alternative test pattern now uses 12 bytes of
461     workspace instead of running out of the 4096 that are available.
462 ph10 182
463 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
464 ph10 172
465 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
466     The report of the bug said:
467 ph10 182
468 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
469     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
470 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
471 ph10 185
472 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
473 ph10 185 it matched the wrong number of bytes.
474 ph10 172
475 ph10 179
476 ph10 155 Version 7.1 24-Apr-07
477 ph10 98 ---------------------
479 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
480 ph10 122 that is more "standard", making use of automake and other Autotools. There
481 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
482     on this.
483 ph10 111
484     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
485     for recursive directory scanning broke on some systems because the files
486     are not scanned in any specific order and on different systems the order
487     was different. A call to "sort" has been inserted into RunGrepTest for the
488     approprate test as a short-term fix. In the longer term there may be an
489 ph10 100 alternative.
490 ph10 111
491 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
492 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
493     people do their own conversions for various reasons). The problems
494     concerned the use of low-level troff macros .br and .in. I have therefore
495     removed all such uses from the man pages (some were redundant, some could
496 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
497     HTML has been updated to handle .nf/.fi and to complain if it encounters
498     .br or .in.
499 ph10 111
500 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
501 ph10 123 arranged for config.h to be included in the distribution, with the name
502 ph10 111 config.h.generic, for the benefit of those who have to compile without
503     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
505     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
506     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
507 ph10 127 makevp.bat for the current PCRE, using the additional files
508 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
509 ph10 111
510     6. A Windows user reported a minor discrepancy with test 2, which turned out
511     to be caused by a trailing space on an input line that had got lost in his
512 ph10 102 copy. The trailing space was an accident, so I've just removed it.
513 ph10 111
514 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
515 ph10 111 that is needed.
517 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
518     as "const" (a) because they are and (b) because it helps the PHP
519     maintainers who have recently made a script to detect big data structures
520 ph10 111 in the php code that should be moved to the .rodata section. I remembered
521     to update Builducptable as well, so it won't revert if ucptable.h is ever
522 ph10 105 re-created.
523 ph10 111
524     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
525 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
526 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
527     support is not required. This saves 1.5-2K of code, which is important in
528 ph10 107 some applications.
529 ph10 111
530 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
531 ph10 111 so as not to refer to the tables, even though these functions will never be
532     called when UTF-8 support is disabled. Otherwise there are problems with a
533     shared library.
535 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
537     (a) It was defining its arguments as char * instead of void *.
539 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
540     a long time ago when I wrote it, but is no longer the case.
542 ph10 118 The emulated memove() is provided for those environments that have neither
543 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
544 ph10 118 is clearly not the case, as these two bugs were recently reported.
545 ph10 123
546 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
547 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
548     pages, and it removes trailing spaces from listed files. It also creates
549     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
550     case, it wraps all the #defines with #ifndefs. This script should be run
551 ph10 111 before "make dist".
552 ph10 123
553 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
554     with Unicode property support.
555 ph10 123
556     (a) For a maximizing quantifier, if the two different cases of the
557     character were of different lengths in their UTF-8 codings (there are
558     some cases like this - I found 11), and the matching function had to
559 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
560     were both the same length.
561 ph10 123
562     (b) When PCRE was configured to use the heap rather than the stack for
563     recursion during matching, it was not correctly preserving the data for
564     the other case of a UTF-8 character when checking ahead for a match
565     while processing a minimizing repeat. If the check also involved
566 ph10 115 matching a wide character, but failed, corruption could cause an
567     erroneous result when trying to check for a repeat of the original
568     character.
569 ph10 123
570 ph10 116 13. Some tidying changes to the testing mechanism:
571 ph10 98
572 ph10 116 (a) The RunTest script now detects the internal link size and whether there
573     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
574 ph10 123 values substituted by "configure". (The RunGrepTest script already did
575     this for UTF-8.) The configure.ac script no longer substitutes the
576     relevant variables.
578 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
579     with length and offset values. This means that the output is different
580     for different internal link sizes. Test 2 is skipped for link sizes
581     other than 2 because of this, bypassing the problem. Unfortunately,
582     there was also a test in test 3 (the locale tests) that used /B and
583 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
584     I have added a new /Z option to pcretest that replaces the length and
585     offset values with spaces. This is now used to make test 3 independent
586 ph10 122 of link size. (Test 2 will be tidied up later.)
587 ph10 123
588     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
589 ph10 122 segmentation fault instead of returning the appropriate error message.
590 ph10 134
591 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
592 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
593     This doesn't seem right; it now treats the CRLF combination as the line
594     ending, and so does not match in that case. It's only a pattern such as ^$
595     that would hit this one: something like ^ABC$ would have failed after \r
596     and then tried again after \r\n.
598 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
599 ph10 134 in an attempt to make files that differ only in their line terminators
600     compare equal. This works on Linux.
601 ph10 142
602 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
603     as it exited. This is now fixed, thanks to valgrind.
604 ph10 142
605 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
606 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
607     was because its rules for how to advance for /g after matching an empty
608 ph10 143 string at the end of a line did not allow for this case. They now check for
609     it specially.
610 ph10 150
611     20. pcretest is supposed to handle patterns and data of any length, by
612     extending its buffers when necessary. It was getting this wrong when the
613 ph10 147 buffer for a data line had to be extended.
614 ph10 150
615 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
616 ph10 150 CRLF as a newline sequence.
617 ph10 152
618 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
619 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
620     I have nevertheless tidied it up.
621 ph10 111
622 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
623 ph10 123
624 ph10 153 24. Added a man page for pcre-config.
625 ph10 152
626 ph10 153
627 nigel 93 Version 7.0 19-Dec-06
628     ---------------------
630     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
631     moving to gcc 4.1.1.
633     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
634     sys/time.h, which is documented as needed for this function. It doesn't
635     seem to matter on Linux, but it showed up on some releases of OS X.
637     3. It seems that there are systems where bytes whose values are greater than
638     127 match isprint() in the "C" locale. The "C" locale should be the
639     default when a C program starts up. In most systems, only ASCII printing
640     characters match isprint(). This difference caused the output from pcretest
641     to vary, making some of the tests fail. I have changed pcretest so that:
643     (a) When it is outputting text in the compiled version of a pattern, bytes
644     other than 32-126 are always shown as hex escapes.
646     (b) When it is outputting text that is a matched part of a subject string,
647     it does the same, unless a different locale has been set for the match
648     (using the /L modifier). In this case, it uses isprint() to decide.
650     4. Fixed a major bug that caused incorrect computation of the amount of memory
651     required for a compiled pattern when options that changed within the
652     pattern affected the logic of the preliminary scan that determines the
653     length. The relevant options are -x, and -i in UTF-8 mode. The result was
654     that the computed length was too small. The symptoms of this bug were
655     either the PCRE error "internal error: code overflow" from pcre_compile(),
656     or a glibc crash with a message such as "pcretest: free(): invalid next
657     size (fast)". Examples of patterns that provoked this bug (shown in
658     pcretest format) are:
660     /(?-x: )/x
661     /(?x)(?-x: \s*#\s*)/
662     /((?i)[\x{c0}])/8
663     /(?i:[\x{c0}])/8
665     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
666     is now done differently.
668     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
669     wrapper classes; (b) implement a new function in the C++ scanner that is
670     more efficient than the old way of doing things because it avoids levels of
671     recursion in the regex matching; (c) add a paragraph to the documentation
672     for the FullMatch() function.
674     6. The escape sequence \n was being treated as whatever was defined as
675     "newline". Not only was this contrary to the documentation, which states
676     that \n is character 10 (hex 0A), but it also went horribly wrong when
677     "newline" was defined as CRLF. This has been fixed.
679     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
680     was being set to -1 for the "end of line" case (supposedly a value that no
681     character can have). Though this value is never used (the check for end of
682     line is "zero bytes in current character"), it caused compiler complaints.
683     I've changed it to 0xffffffff.
685     8. In pcre_version.c, the version string was being built by a sequence of
686     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
687     string (as it is for production releases) called a macro with an empty
688     argument. The C standard says the result of this is undefined. The gcc
689     compiler treats it as an empty string (which was what was wanted) but it is
690     reported that Visual C gives an error. The source has been hacked around to
691     avoid this problem.
693     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
694     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
695     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
696     of them did).
698     10. Originally, pcretest opened its input and output without "b"; then I was
699     told that "b" was needed in some environments, so it was added for release
700     5.0 to both the input and output. (It makes no difference on Unix-like
701     systems.) Later I was told that it is wrong for the input on Windows. I've
702     now abstracted the modes into two macros, to make it easier to fiddle with
703     them, and removed "b" from the input mode under Windows.
705     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
707     12. Added -help and --help to pcretest as an official way of being reminded
708     of the options.
710     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
711     and pcrecpp.cc because they annoy compilers at high warning levels.
713     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
715     15. Fixed an occurrence of == in configure.ac that should have been = (shell
716     scripts are not C programs :-) and which was not noticed because it works
717     on Linux.
719     16. pcretest is supposed to handle any length of pattern and data line (as one
720     line or as a continued sequence of lines) by extending its input buffer if
721     necessary. This feature was broken for very long pattern lines, leading to
722     a string of junk being passed to pcre_compile() if the pattern was longer
723     than about 50K.
725     17. I have done a major re-factoring of the way pcre_compile() computes the
726     amount of memory needed for a compiled pattern. Previously, there was code
727     that made a preliminary scan of the pattern in order to do this. That was
728     OK when PCRE was new, but as the facilities have expanded, it has become
729     harder and harder to keep it in step with the real compile phase, and there
730     have been a number of bugs (see for example, 4 above). I have now found a
731     cunning way of running the real compile function in a "fake" mode that
732     enables it to compute how much memory it would need, while actually only
733     ever using a few hundred bytes of working memory and without too many
734     tests of the mode. This should make future maintenance and development
735     easier. A side effect of this work is that the limit of 200 on the nesting
736     depth of parentheses has been removed (though this was never a serious
737     limitation, I suspect). However, there is a downside: pcre_compile() now
738     runs more slowly than before (30% or more, depending on the pattern). I
739     hope this isn't a big issue. There is no effect on runtime performance.
741     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
742     newline (only possible for the last line of a file) and it was a
743     pattern that set a locale (followed by /Lsomething), pcretest crashed.
745     19. Added additional timing features to pcretest. (1) The -tm option now times
746     matching only, not compiling. (2) Both -t and -tm can be followed, as a
747     separate command line item, by a number that specifies the number of
748     repeats to use when timing. The default is 50000; this gives better
749     precision, but takes uncomfortably long for very large patterns.
751     20. Extended pcre_study() to be more clever in cases where a branch of a
752     subpattern has no definite first character. For example, (a*|b*)[cd] would
753     previously give no result from pcre_study(). Now it recognizes that the
754     first character must be a, b, c, or d.
756     21. There was an incorrect error "recursive call could loop indefinitely" if
757     a subpattern (or the entire pattern) that was being tested for matching an
758     empty string contained only one non-empty item after a nested subpattern.
759     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
760     incorrectly, because the \d was being skipped in the check.
762     22. The pcretest program now has a new pattern option /B and a command line
763     option -b, which is equivalent to adding /B to every pattern. This causes
764     it to show the compiled bytecode, without the additional information that
765     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
766     is the same as /B/I).
768     23. A new optimization is now able automatically to treat some sequences such
769     as a*b as a*+b. More specifically, if something simple (such as a character
770     or a simple class like \d) has an unlimited quantifier, and is followed by
771     something that cannot possibly match the quantified thing, the quantifier
772     is automatically "possessified".
774     24. A recursive reference to a subpattern whose number was greater than 39
775     went wrong under certain circumstances in UTF-8 mode. This bug could also
776     have affected the operation of pcre_study().
778     25. Realized that a little bit of performance could be had by replacing
779     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
781     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
783     27. Possessive quantifiers such as a++ were previously implemented by turning
784     them into atomic groups such as ($>a+). Now they have their own opcodes,
785     which improves performance. This includes the automatically created ones
786     from 23 above.
788     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
789     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
790     the first matched character to be a colon. This applied both to named and
791     numbered groups.
793     29. The ucpinternal.h header file was missing its idempotency #ifdef.
795     30. I was sent a "project" file called libpcre.a.dev which I understand makes
796     building PCRE on Windows easier, so I have included it in the distribution.
798     31. There is now a check in pcretest against a ridiculously large number being
799     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
800     loop, the loop is abandoned.
802     32. Forward references to subpatterns in conditions such as (?(2)...) where
803     subpattern 2 is defined later cause pcre_compile() to search forwards in
804     the pattern for the relevant set of parentheses. This search went wrong
805     when there were unescaped parentheses in a character class, parentheses
806     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
808     33. "Subroutine" calls and backreferences were previously restricted to
809     referencing subpatterns earlier in the regex. This restriction has now
810     been removed.
812     34. Added a number of extra features that are going to be in Perl 5.10. On the
813     whole, these are just syntactic alternatives for features that PCRE had
814     previously implemented using the Python syntax or my own invention. The
815     other formats are all retained for compatibility.
817     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
818     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
819     also .NET compatible.
821     (b) A recursion or subroutine call to a named group can now be defined as
822     (?&name) as well as (?P>name).
824     (c) A backreference to a named group can now be defined as \k<name> or
825     \k'name' as well as (?P=name). The new forms, as well as being in Perl
826     5.10, are also .NET compatible.
828     (d) A conditional reference to a named group can now use the syntax
829     (?(<name>) or (?('name') as well as (?(name).
831     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
832     groups (named and numbered) that are never evaluated inline, but can be
833     called as "subroutines" from elsewhere. In effect, the DEFINE condition
834     is always false. There may be only one alternative in such a group.
836     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
837     as the simple (?(R). The condition is true only if the most recent
838     recursion is that of the given number or name. It does not search out
839     through the entire recursion stack.
841     (g) The escape \gN or \g{N} has been added, where N is a positive or
842     negative number, specifying an absolute or relative reference.
844     35. Tidied to get rid of some further signed/unsigned compiler warnings and
845     some "unreachable code" warnings.
847     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
848     things, this adds five new scripts.
850     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
851     There were also incompatibilities regarding the handling of \Q..\E inside
852     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
853     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
855     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
856     matches an empty string, and forcibly breaks the loop. There were bugs in
857     this code in non-simple cases. For a pattern such as ^(a()*)* matched
858     against aaaa the result was just "a" rather than "aaaa", for example. Two
859     separate and independent bugs (that affected different cases) have been
860     fixed.
862     39. Refactored the code to abolish the use of different opcodes for small
863     capturing bracket numbers. This is a tidy that I avoided doing when I
864     removed the limit on the number of capturing brackets for 3.5 back in 2001.
865     The new approach is not only tidier, it makes it possible to reduce the
866     memory needed to fix the previous bug (38).
868     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
869     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
870     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
871     mode.
873     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
874     report.
876     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
877     copy construction and assignment in the C++ wrapper.
879     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
880     couple of bugs that could have given wrong results in the "--newline=crlf"
881     case.
883     44. Added a number of casts and did some reorganization of signed/unsigned int
884     variables following suggestions from Dair Grant. Also renamed the variable
885     "this" as "item" because it is a C++ keyword.
887     45. Arranged for dftables to add
889     #include "pcre_internal.h"
891     to pcre_chartables.c because without it, gcc 4.x may remove the array
892     definition from the final binary if PCRE is built into a static library and
893     dead code stripping is activated.
895     46. For an unanchored pattern, if a match attempt fails at the start of a
896     newline sequence, and the newline setting is CRLF or ANY, and the next two
897     characters are CRLF, advance by two characters instead of one.
900 nigel 91 Version 6.7 04-Jul-06
901     ---------------------
903     1. In order to handle tests when input lines are enormously long, pcretest has
904     been re-factored so that it automatically extends its buffers when
905     necessary. The code is crude, but this _is_ just a test program. The
906     default size has been increased from 32K to 50K.
908     2. The code in pcre_study() was using the value of the re argument before
909     testing it for NULL. (Of course, in any sensible call of the function, it
910     won't be NULL.)
912     3. The memmove() emulation function in pcre_internal.h, which is used on
913     systems that lack both memmove() and bcopy() - that is, hardly ever -
914     was missing a "static" storage class specifier.
916     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
917     containing an extended class (one that cannot be represented by a bitmap
918     because it contains high-valued characters or Unicode property items, e.g.
919     [\pZ]). Almost always one would set UTF-8 mode when processing such a
920     pattern, but PCRE should not loop if you do not (it no longer does).
921     [Detail: two cases were found: (a) a repeated subpattern containing an
922     extended class; (b) a recursive reference to a subpattern that followed a
923     previous extended class. It wasn't skipping over the extended class
924     correctly when UTF-8 mode was not set.]
926     5. A negated single-character class was not being recognized as fixed-length
927     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
928     compile error "lookbehind assertion is not fixed length".
930     6. The RunPerlTest auxiliary script was showing an unexpected difference
931     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
932     write a Perl script that can interpret lines of an input file either as
933     byte characters or as UTF-8, which is what "perltest" was being required to
934     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
935     can't do is switch easily at run time between having the "use utf8;" pragma
936     or not. In the end, I fudged it by using the RunPerlTest script to insert
937     "use utf8;" explicitly for the UTF-8 tests.
939     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
940     the end of the subject string, contrary to the documentation and to what
941     Perl does. This was true of both matching functions. Now it matches only at
942     the start of the subject and immediately after *internal* newlines.
944     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
945     a pointer to an int instead of a pointer to an unsigned long int. This
946     caused problems on 64-bit systems.
948     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
949     instance of the 'standard' template library not being so standard".
951     10. There was no check on the number of named subpatterns nor the maximum
952     length of a subpattern name. The product of these values is used to compute
953     the size of the memory block for a compiled pattern. By supplying a very
954     long subpattern name and a large number of named subpatterns, the size
955     computation could be caused to overflow. This is now prevented by limiting
956     the length of names to 32 characters, and the number of named subpatterns
957     to 10,000.
959     11. Subpatterns that are repeated with specific counts have to be replicated in
960     the compiled pattern. The size of memory for this was computed from the
961     length of the subpattern and the repeat count. The latter is limited to
962     65535, but there was no limit on the former, meaning that integer overflow
963     could in principle occur. The compiled length of a repeated subpattern is
964     now limited to 30,000 bytes in order to prevent this.
966     12. Added the optional facility to have named substrings with the same name.
968     13. Added the ability to use a named substring as a condition, using the
969     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
970     are numbers (not recommended). Forward references are permitted.
972     14. Added forward references in named backreferences (if you see what I mean).
974     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
975     pattern could run off the end of the subject. For example, the pattern
976     "(?s)(.{1,5})"8 did this with the subject "ab".
978     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
979     PCRE_CASELESS was set when matching characters that were quantified with ?
980     or *.
982     17. A character class other than a single negated character that had a minimum
983     but no maximum quantifier - for example [ab]{6,} - was not handled
984     correctly by pce_dfa_exec(). It would match only one character.
986     18. A valid (though odd) pattern that looked like a POSIX character
987     class but used an invalid character after [ (for example [[,abc,]]) caused
988     pcre_compile() to give the error "Failed: internal error: code overflow" or
989     in some cases to crash with a glibc free() error. This could even happen if
990     the pattern terminated after [[ but there just happened to be a sequence of
991     letters, a binary zero, and a closing ] in the memory that followed.
993     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
994     over the years. Originally (before any Unicode support), just the bottom 8
995     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
996     output from "man perlunicode" includes this:
998     The regular expression compiler produces polymorphic opcodes. That
999     is, the pattern adapts to the data and automatically switches to
1000     the Unicode character scheme when presented with Unicode data--or
1001     instead uses a traditional byte scheme when presented with byte
1002     data.
1004     Sadly, a wide octal escape does not cause a switch, and in a string with
1005     no other multibyte characters, these octal escapes are treated as before.
1006     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1007     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1008     Unicode string.
1010     I have not perpetrated such confusion in PCRE. Up till now, it took just
1011     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1012     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1013     translate to the appropriate multibyte character.
1015     29. Applied some refactoring to reduce the number of warnings from Microsoft
1016     and Borland compilers. This has included removing the fudge introduced
1017     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1018     a warning about an unused variable.
1020     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1021     characters since release 4.0, because Perl (from release 5.004) does not.
1022     [Or at least, is documented not to: some releases seem to be in conflict
1023     with the documentation.] However, when a pattern was studied with
1024     pcre_study() and all its branches started with \s, PCRE still included VT
1025     as a possible starting character. Of course, this did no harm; it just
1026     caused an unnecessary match attempt.
1028     22. Removed a now-redundant internal flag bit that recorded the fact that case
1029     dependency changed within the pattern. This was once needed for "required
1030     byte" processing, but is no longer used. This recovers a now-scarce options
1031     bit. Also moved the least significant internal flag bit to the most-
1032     significant bit of the word, which was not previously used (hangover from
1033     the days when it was an int rather than a uint) to free up another bit for
1034     the future.
1036     23. Added support for CRLF line endings as well as CR and LF. As well as the
1037     default being selectable at build time, it can now be changed at runtime
1038     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1039     specify that it is scanning data with non-default line endings.
1041     24. Changed the definition of CXXLINK to make it agree with the definition of
1042     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1044     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1045     recursions. This makes a big different to stack usage for some patterns.
1047     26. If a subpattern containing a named recursion or subroutine reference such
1048     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1049     the space required for the compiled pattern went wrong and gave too small a
1050     value. Depending on the environment, this could lead to "Failed: internal
1051     error: code overflow at offset 49" or "glibc detected double free or
1052     corruption" errors.
1054     27. Applied patches from Google (a) to support the new newline modes and (b) to
1055     advance over multibyte UTF-8 characters in GlobalReplace.
1057     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1058     difference for some implementation of PCRE in some Windows version.
1060     29. Added some extra testing facilities to pcretest:
1062     \q<number> in a data line sets the "match limit" value
1063     \Q<number> in a data line sets the "match recursion limt" value
1064     -S <number> sets the stack size, where <number> is in megabytes
1066     The -S option isn't available for Windows.
1069 nigel 89 Version 6.6 06-Feb-06
1070     ---------------------
1072     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1073     in pcreposix.h. I have copied the definition from pcre.h.
1075     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1076     because pcre.h is no longer a built file.
1078     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1079     not normally included in the compiled code.
1082 nigel 87 Version 6.5 01-Feb-06
1083     ---------------------
1085     1. When using the partial match feature with pcre_dfa_exec(), it was not
1086     anchoring the second and subsequent partial matches at the new starting
1087     point. This could lead to incorrect results. For example, with the pattern
1088     /1234/, partially matching against "123" and then "a4" gave a match.
1090     2. Changes to pcregrep:
1092     (a) All non-match returns from pcre_exec() were being treated as failures
1093     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1094     error message is output. Some extra information is given for the
1096     probably the only errors that are likely to be caused by users (by
1097     specifying a regex that has nested indefinite repeats, for instance).
1098     If there are more than 20 of these errors, pcregrep is abandoned.
1100     (b) A binary zero was treated as data while matching, but terminated the
1101     output line if it was written out. This has been fixed: binary zeroes
1102     are now no different to any other data bytes.
1104     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1105     used to set a locale for matching. The --locale=xxxx long option has
1106     been added (no short equivalent) to specify a locale explicitly on the
1107     pcregrep command, overriding the environment variables.
1109     (d) When -B was used with -n, some line numbers in the output were one less
1110     than they should have been.
1112     (e) Added the -o (--only-matching) option.
1114     (f) If -A or -C was used with -c (count only), some lines of context were
1115     accidentally printed for the final match.
1117     (g) Added the -H (--with-filename) option.
1119     (h) The combination of options -rh failed to suppress file names for files
1120     that were found from directory arguments.
1122     (i) Added the -D (--devices) and -d (--directories) options.
1124     (j) Added the -F (--fixed-strings) option.
1126     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1128     (l) Added the --colo(u)r option.
1130     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1131     is not present by default.
1133     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1134     items such as (?R) or (?1), when the recursion could match a number of
1135     alternatives. If it matched one of the alternatives, but subsequently,
1136     outside the recursion, there was a failure, the code tried to back up into
1137     the recursion. However, because of the way PCRE is implemented, this is not
1138     possible, and the result was an incorrect result from the match.
1140     In order to prevent this happening, the specification of recursion has
1141     been changed so that all such subpatterns are automatically treated as
1142     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1144     4. I had overlooked the fact that, in some locales, there are characters for
1145     which isalpha() is true but neither isupper() nor islower() are true. In
1146     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1147     and ordfeminine) are like this. This affected the treatment of \w and \W
1148     when they appeared in character classes, but not when they appeared outside
1149     a character class. The bit map for "word" characters is now created
1150     separately from the results of isalnum() instead of just taking it from the
1151     upper, lower, and digit maps. (Plus the underscore character, of course.)
1153     5. The above bug also affected the handling of POSIX character classes such as
1154     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1155     permanent tables. Instead, the bit maps for such a class were previously
1156     created as the appropriate unions of the upper, lower, and digit bitmaps.
1157     Now they are created by subtraction from the [[:word:]] class, which has
1158     its own bitmap.
1160     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1161     It is created by subtracting the vertical space characters (\x09, \x0a,
1162     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1163     subtraction was done in the overall bitmap for a character class, meaning
1164     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1165     be recognized. This bug has been fixed.
1167     7. Patches from the folks at Google:
1169     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1170     real life, but is still worth protecting against".
1172     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1173     regular expressions".
1175     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1176     have it.
1178     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1179     "configure" and the latter not, in order to fix a problem somebody had
1180     with compiling the Arg class on HP-UX.
1182     (e) Improve the error-handling of the C++ wrapper a little bit.
1184     (f) New tests for checking recursion limiting.
1186     8. The pcre_memmove() function, which is used only if the environment does not
1187     have a standard memmove() function (and is therefore rarely compiled),
1188     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1189     returning a result (though PCRE never actually uses the result).
1191     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1192     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1193     returned instead of calling malloc() with an overflowing number that would
1194     most likely cause subsequent chaos.
1196     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1198     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1199     with this option is matched, the nmatch and pmatch options of regexec() are
1200     ignored.
1202     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1203     provided in case anyone wants to the the POSIX interface with UTF-8
1204     strings.
1206     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1207     C++ linking (needed for some HP-UX environments).
1209     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1210     (unused parameter) and in the pcre_printint() function (omitted "default"
1211     switch label when the default is to do nothing).
1213     15. Added some code to make it possible, when PCRE is compiled as a C++
1214     library, to replace subject pointers for pcre_exec() with a smart pointer
1215     class, thus making it possible to process discontinuous strings.
1217     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1218     much the same function. They were added by different people who were trying
1219     to make PCRE easy to compile on non-Unix systems. It has been suggested
1220     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1221     for compiling on Windows systems. I have therefore replaced it with
1222     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1223     defaults to "extern" for C or "extern C" for C++, which works fine on
1224     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1225     SCOPE with something explicit in config.h. In addition:
1227     (a) pcreposix.h still had just "extern" instead of either of these macros;
1228     I have replaced it with PCRE_DATA_SCOPE.
1230     (b) Functions such as _pcre_xclass(), which are internal to the library,
1231     but external in the C sense, all had PCRE_EXPORT in their definitions.
1232     This is apparently wrong for the Windows case, so I have removed it.
1233     (It makes no difference on Unix-like systems.)
1235     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1236     of recursive calls to match(). This is different to MATCH_LIMIT because
1237     that limits the total number of calls to match(), not all of which increase
1238     the depth of recursion. Limiting the recursion depth limits the amount of
1239     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1240     when PCRE is compiled, and changed at run time. A patch from Google adds
1241     this functionality to the C++ interface.
1243     18. Changes to the handling of Unicode character properties:
1245     (a) Updated the table to Unicode 4.1.0.
1247     (b) Recognize characters that are not in the table as "Cn" (undefined).
1249     (c) I revised the way the table is implemented to a much improved format
1250     which includes recognition of ranges. It now supports the ranges that
1251     are defined in UnicodeData.txt, and it also amalgamates other
1252     characters into ranges. This has reduced the number of entries in the
1253     table from around 16,000 to around 3,000, thus reducing its size
1254     considerably. I realized I did not need to use a tree structure after
1255     all - a binary chop search is just as efficient. Having reduced the
1256     number of entries, I extended their size from 6 bytes to 8 bytes to
1257     allow for more data.
1259     (d) Added support for Unicode script names via properties such as \p{Han}.
1261     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1262     matching that character.
1264     20. When matching a repeated Unicode property with a minimum greater than zero,
1265     (for example \pL{2,}), PCRE could look past the end of the subject if it
1266     reached it while seeking the minimum number of characters. This could
1267     happen only if some of the characters were more than one byte long, because
1268     there is a check for at least the minimum number of bytes.
1270     21. Refactored the implementation of \p and \P so as to be more general, to
1271     allow for more different types of property in future. This has changed the
1272     compiled form incompatibly. Anybody with saved compiled patterns that use
1273     \p or \P will have to recompile them.
1275     22. Added "Any" and "L&" to the supported property types.
1277     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1278     but give a compile time error if the value is greater than 0xff.
1280     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1281     accidentally not being installed or uninstalled.
1283     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1284     made were to insert the current release number. This seemed silly, because
1285     it made things harder for people building PCRE on systems that don't run
1286     "configure". I have turned pcre.h into a distributed file, no longer built
1287     by "configure", with the version identification directly included. There is
1288     no longer a pcre.h.in file.
1290     However, this change necessitated a change to the pcre-config script as
1291     well. It is built from pcre-config.in, and one of the substitutions was the
1292     release number. I have updated configure.ac so that ./configure now finds
1293     the release number by grepping pcre.h.
1295     26. Added the ability to run the tests under valgrind.
1298 nigel 85 Version 6.4 05-Sep-05
1299     ---------------------
1301     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1302     "--" to be printed when multiple files were scanned, even when none of the
1303     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1304     consider it to be a bug, and have restored the previous behaviour.
1306     2. A couple of code tidies to get rid of compiler warnings.
1308     3. The pcretest program used to cheat by referring to symbols in the library
1309     whose names begin with _pcre_. These are internal symbols that are not
1310     really supposed to be visible externally, and in some environments it is
1311     possible to suppress them. The cheating is now confined to including
1312     certain files from the library's source, which is a bit cleaner.
1314     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1315     file's purpose clearer.
1317     5. Reorganized pcre_ucp_findchar().
1320 nigel 83 Version 6.3 15-Aug-05
1321     ---------------------
1323     1. The file libpcre.pc.in did not have general read permission in the tarball.
1325     2. There were some problems when building without C++ support:
1327     (a) If C++ support was not built, "make install" and "make test" still
1328     tried to test it.
1330     (b) There were problems when the value of CXX was explicitly set. Some
1331     changes have been made to try to fix these, and ...
1333     (c) --disable-cpp can now be used to explicitly disable C++ support.
1335     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1336     backslash in a target when C++ was disabled. This confuses some
1337     versions of "make", apparently. Using an intermediate variable solves
1338     this. (Same for CPP_LOBJ.)
1340     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1341     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1342     necessary on certain architectures.
1344     4. Added a setting of -export-symbols-regex to the link command to remove
1345     those symbols that are exported in the C sense, but actually are local
1346     within the library, and not documented. Their names all begin with
1347     "_pcre_". This is not a perfect job, because (a) we have to except some
1348     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1349     available (and never for static libraries). I have made a note to try to
1350     find a way round (a) in the future.
1353 nigel 81 Version 6.2 01-Aug-05
1354     ---------------------
1356     1. There was no test for integer overflow of quantifier values. A construction
1357     such as {1111111111111111} would give undefined results. What is worse, if
1358     a minimum quantifier for a parenthesized subpattern overflowed and became
1359     negative, the calculation of the memory size went wrong. This could have
1360     led to memory overwriting.
1362     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1364     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1365     operating environments where this matters.
1367     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1368     PCRE options from within the C++ wrapper.
1370     5. Named capturing subpatterns were not being correctly counted when a pattern
1371     was compiled. This caused two problems: (a) If there were more than 100
1372     such subpatterns, the calculation of the memory needed for the whole
1373     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1374     back references of the form \12, where the number was greater than 9, were
1375     not recognized as back references, even though there were sufficient
1376     previous subpatterns.
1378     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1379     versions of gcc, e.g. 2.95.4.
1382 nigel 79 Version 6.1 21-Jun-05
1383     ---------------------
1385     1. There was one reference to the variable "posix" in pcretest.c that was not
1386     surrounded by "#if !defined NOPOSIX".
1388     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1389     the cross-check on the old pcre_info() function, for the benefit of the
1390     cut-down version of PCRE that is currently imported into Exim.
1392     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1393     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1394     patterns that start (?i) but I don't think that matters. The use of (?i) is
1395     just an example; this all applies to the other options as well.
1397     4. Since libtool seems to echo the compile commands it is issuing, the output
1398     from "make" can be reduced a bit by putting "@" in front of each libtool
1399     compile command.
1401     5. Patch from the folks at Google for configure.in to be a bit more thorough
1402     in checking for a suitable C++ installation before trying to compile the
1403     C++ stuff. This should fix a reported problem when a compiler was present,
1404     but no suitable headers.
1406     6. The man pages all had just "PCRE" as their title. I have changed them to
1407     be the relevant file name. I have also arranged that these names are
1408     retained in the file doc/pcre.txt, which is a concatenation in text format
1409     of all the man pages except the little individual ones for each function.
1411     7. The NON-UNIX-USE file had not been updated for the different set of source
1412     files that come with release 6. I also added a few comments about the C++
1413     wrapper.
1416 nigel 77 Version 6.0 07-Jun-05
1417     ---------------------
1419     1. Some minor internal re-organization to help with my DFA experiments.
1421     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1422     didn't matter for the library itself when fully configured, but did matter
1423     when compiling without UCP support, or within Exim, where the ucp files are
1424     not imported.
1426     3. Refactoring of the library code to split up the various functions into
1427     different source modules. The addition of the new DFA matching code (see
1428     below) to a single monolithic source would have made it really too
1429     unwieldy, quite apart from causing all the code to be include in a
1430     statically linked application, when only some functions are used. This is
1431     relevant even without the DFA addition now that patterns can be compiled in
1432     one application and matched in another.
1434     The downside of splitting up is that there have to be some external
1435     functions and data tables that are used internally in different modules of
1436     the library but which are not part of the API. These have all had their
1437     names changed to start with "_pcre_" so that they are unlikely to clash
1438     with other external names.
1440     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1441     a different (DFA) algorithm. Although it is slower than the original
1442     function, it does have some advantages for certain types of matching
1443     problem.
1445     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1446     including restarting after a partial match.
1448     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1449     defined when compiling for Windows was sent to me. I have put it into the
1450     code, though I have no means of testing or verifying it.
1452     7. Added the pcre_refcount() auxiliary function.
1454     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1455     match before or at the first newline in the subject string. In pcretest,
1456     the /f option on a pattern can be used to set this.
1458     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1459     would behave wrongly. This has been present in PCRE since release 4.0.
1461     10. A number of changes to the pcregrep command:
1463     (a) Refactored how -x works; insert ^(...)$ instead of setting
1464     PCRE_ANCHORED and checking the length, in preparation for adding
1465     something similar for -w.
1467     (b) Added the -w (match as a word) option.
1469     (c) Refactored the way lines are read and buffered so as to have more
1470     than one at a time available.
1472     (d) Implemented a pcregrep test script.
1474     (e) Added the -M (multiline match) option. This allows patterns to match
1475     over several lines of the subject. The buffering ensures that at least
1476     8K, or the rest of the document (whichever is the shorter) is available
1477     for matching (and similarly the previous 8K for lookbehind assertions).
1479     (f) Changed the --help output so that it now says
1481     -w, --word-regex(p)
1483     instead of two lines, one with "regex" and the other with "regexp"
1484     because that confused at least one person since the short forms are the
1485     same. (This required a bit of code, as the output is generated
1486     automatically from a table. It wasn't just a text change.)
1488     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1489     option but starts with a hyphen. Could be a pattern or a path name
1490     starting with a hyphen, for instance.
1492     (h) "-" can be given as a file name to represent stdin.
1494     (i) When file names are being printed, "(standard input)" is used for
1495     the standard input, for compatibility with GNU grep. Previously
1496     "<stdin>" was used.
1498     (j) The option --label=xxx can be used to supply a name to be used for
1499     stdin when file names are being printed. There is no short form.
1501     (k) Re-factored the options decoding logic because we are going to add
1502     two more options that take data. Such options can now be given in four
1503     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1505     (l) Added the -A, -B, and -C options for requesting that lines of context
1506     around matches be printed.
1508     (m) Added the -L option to print the names of files that do not contain
1509     any matching lines, that is, the complement of -l.
1511     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1512     continue to scan other files.
1514     (o) The -s option was incorrectly implemented. For compatibility with other
1515     greps, it now suppresses the error message for a non-existent or non-
1516     accessible file (but not the return code). There is a new option called
1517     -q that suppresses the output of matching lines, which was what -s was
1518     previously doing.
1520     (p) Added --include and --exclude options to specify files for inclusion
1521     and exclusion when recursing.
1523     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1524     Hopefully, it now does.
1526     12. Missing cast in pcre_study().
1528     13. Added an "uninstall" target to the makefile.
1530     14. Replaced "extern" in the function prototypes in Makefile.in with
1531     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1532     world, but is set differently for Windows.
1534     15. Added a second compiling function called pcre_compile2(). The only
1535     difference is that it has an extra argument, which is a pointer to an
1536     integer error code. When there is a compile-time failure, this is set
1537     non-zero, in addition to the error test pointer being set to point to an
1538     error message. The new argument may be NULL if no error number is required
1539     (but then you may as well call pcre_compile(), which is now just a
1540     wrapper). This facility is provided because some applications need a
1541     numeric error indication, but it has also enabled me to tidy up the way
1542     compile-time errors are handled in the POSIX wrapper.
1544     16. Added VPATH=.libs to the makefile; this should help when building with one
1545     prefix path and installing with another. (Or so I'm told by someone who
1546     knows more about this stuff than I do.)
1548     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1549     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1550     match everything, including newlines. This is not POSIX-compatible, but
1551     somebody wanted the feature. From pcretest it can be activated by using
1552     both the P and the s flags.
1554     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1556     19. libpcre.pc was being incorrectly installed as executable.
1558     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1559     it now also looks for '\r' so that it will work unmodified on Windows.
1561     21. Added Google's contributed C++ wrapper to the distribution.
1563     22. Added some untidy missing memory free() calls in pcretest, to keep
1564     Electric Fence happy when testing.
1568 nigel 75 Version 5.0 13-Sep-04
1569     ---------------------
1571     1. Internal change: literal characters are no longer packed up into items
1572     containing multiple characters in a single byte-string. Each character
1573     is now matched using a separate opcode. However, there may be more than one
1574     byte in the character in UTF-8 mode.
1576     2. The pcre_callout_block structure has two new fields: pattern_position and
1577     next_item_length. These contain the offset in the pattern to the next match
1578     item, and its length, respectively.
1580     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1581     insertion of callouts before each pattern item. Added the /C option to
1582     pcretest to make use of this.
1584     4. On the advice of a Windows user, the lines
1586     #if defined(_WIN32) || defined(WIN32)
1587     _setmode( _fileno( stdout ), 0x8000 );
1588     #endif /* defined(_WIN32) || defined(WIN32) */
1590     have been added to the source of pcretest. This apparently does useful
1591     magic in relation to line terminators.
1593     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1594     for the benefit of those environments where the "b" makes a difference.
1596     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1597     to know about it. I have put a hack into configure.in that adds in code
1598     to set GCC=yes if CC=icc. This seems to end up at a point in the
1599     generated configure script that is early enough to affect the setting of
1600     compiler options, which is what is needed, but I have no means of testing
1601     whether it really works. (The user who reported this had patched the
1602     generated configure script, which of course I cannot do.)
1604     LATER: After change 22 below (new libtool files), the configure script
1605     seems to know about icc (and also ecc). Therefore, I have commented out
1606     this hack in configure.in.
1608     7. Added support for pkg-config (2 patches were sent in).
1610     8. Negated POSIX character classes that used a combination of internal tables
1611     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1612     [[:^ascii]]. Typically, they would match almost any characters. The other
1613     POSIX classes were not broken in this way.
1615     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1616     to find the match, as PCRE was deluded into thinking that the match had to
1617     start at the start point or following a newline. The same bug applied to
1618     patterns with negative forward assertions or any backward assertions
1619     preceding ".*" at the start, unless the pattern required a fixed first
1620     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1622     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1623     starting at the last subject character, bytes beyond the end of the subject
1624     string were read.
1626     11. Renamed the variable "class" as "classbits" to make life easier for C++
1627     users. (Previously there was a macro definition, but it apparently wasn't
1628     enough.)
1630     12. Added the new field "tables" to the extra data so that tables can be passed
1631     in at exec time, or the internal tables can be re-selected. This allows
1632     a compiled regex to be saved and re-used at a later time by a different
1633     program that might have everything at different addresses.
1635     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1636     -R library as well as a -L library.
1638     14. The debugging options of pcretest (-d on the command line or D on a
1639     pattern) showed incorrect output for anything following an extended class
1640     that contained multibyte characters and which was followed by a quantifier.
1642     15. Added optional support for general category Unicode character properties
1643     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1644     support. It adds about 90K to the size of the library. The meanings of the
1645     inbuilt class escapes such as \d and \s have NOT been changed.
1647     16. Updated pcredemo.c to include calls to free() to release the memory for the
1648     compiled pattern.
1650     17. The generated file chartables.c was being created in the source directory
1651     instead of in the building directory. This caused the build to fail if the
1652     source directory was different from the building directory, and was
1653     read-only.
1655     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1656     file. No doubt somebody will tell me if they don't make sense... Also added
1657     Dan Mooney's comments about building on OpenVMS.
1659     19. Added support for partial matching via the PCRE_PARTIAL option for
1660     pcre_exec() and the \P data escape in pcretest.
1662     20. Extended pcretest with 3 new pattern features:
1664     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1665     write the compiled pattern to the file whose name is "rest-of-line".
1666     This is a straight binary dump of the data, with the saved pointer to
1667     the character tables forced to be NULL. The study data, if any, is
1668     written too. After writing, pcretest reads a new pattern.
1670     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1671     compiled pattern from the given file. There must not be any
1672     occurrences of "<" in the file name (pretty unlikely); if there are,
1673     pcretest will instead treat the initial "<" as a pattern delimiter.
1674     After reading in the pattern, pcretest goes on to read data lines as
1675     usual.
1677     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1678     and 16-bit fields in a compiled pattern, to simulate a pattern that
1679     was compiled on a host of opposite endianness.
1681     21. The pcre-exec() function can now cope with patterns that were compiled on
1682     hosts of opposite endianness, with this restriction:
1684     As for any compiled expression that is saved and used later, the tables
1685     pointer field cannot be preserved; the extra_data field in the arguments
1686     to pcre_exec() should be used to pass in a tables address if a value
1687     other than the default internal tables were used at compile time.
1689     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1690     now diagnosed as an error. Previously, most of the time, a negative number
1691     would have been treated as zero, but if in addition "ovector" was passed as
1692     NULL, a crash could occur.
1694     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1695     new versions from the libtool 1.5 distribution (the last one is a copy of
1696     a file called libtool.m4). This seems to have fixed the need to patch
1697     "configure" to support Darwin 1.3 (which I used to do). However, I still
1698     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1699     workstation).
1701     24. Changed the PCRE licence to be the more standard "BSD" licence.
1704 nigel 73 Version 4.5 01-Dec-03
1705     ---------------------
1707     1. There has been some re-arrangement of the code for the match() function so
1708     that it can be compiled in a version that does not call itself recursively.
1709     Instead, it keeps those local variables that need separate instances for
1710     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1711     needs to "recurse". Keeping track of where control must go is done by means
1712     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1713     hide most of the details from the main code, and operates only if
1714     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1715     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1716     operating.
1718     To make it easier for callers to provide specially tailored get/free
1719     functions for this usage, two new functions, pcre_stack_malloc, and
1720     pcre_stack_free, are used. They are always called in strict stacking order,
1721     and the size of block requested is always the same.
1723     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1724     PCRE has been compiled to use the stack or the heap for recursion. The
1725     -C option of pcretest uses this to show which version is compiled.
1727     A new data escape \S, is added to pcretest; it causes the amounts of store
1728     obtained and freed by both kinds of malloc/free at match time to be added
1729     to the output.
1731     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1732     what's available on my current Linux desktop machine.
1734     3. When matching a UTF-8 string, the test for a valid string at the start has
1735     been extended. If start_offset is not zero, PCRE now checks that it points
1736     to a byte that is the start of a UTF-8 character. If not, it returns
1737     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1738     this is necessary because there may be backward assertions in the pattern.
1739     When matching the same subject several times, it may save resources to use
1740     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1742     4. The code for checking the validity of UTF-8 strings has been tightened so
1743     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1744     containing "overlong sequences".
1746     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1747     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1748     should have been "&", but it just so happened that all the cases this let
1749     through by mistake were picked up later in the function.
1751     6. I had used a variable called "isblank" - this is a C99 function, causing
1752     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1754     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1755     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1756     so the version is shown; (c) stop "make test" echoing "./RunTest".
1758     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1760     9. The prototype for memmove() for systems that don't have it was using
1761     size_t, but the inclusion of the header that defines size_t was later. I've
1762     moved the #includes for the C headers earlier to avoid this.
1764     10. Added some adjustments to the code to make it easier to compiler on certain
1765     special systems:
1767     (a) Some "const" qualifiers were missing.
1768     (b) Added the macro EXPORT before all exported functions; by default this
1769     is defined to be empty.
1770     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1771     that it reads its output file name as an argument instead of writing
1772     to the standard output and assuming this can be redirected.
1774     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1775     class containing characters with values greater than 255, PCRE compilation
1776     went into a loop.
1778     12. A recursive reference to a subpattern that was within another subpattern
1779     that had a minimum quantifier of zero caused PCRE to crash. For example,
1780     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1781     recursion. If the recursively-called subpattern itself had a zero repeat,
1782     that was OK.
1784     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1785     buffer into which it was copied (for escape processing) was still set at
1786     1024, so long lines caused crashes.
1788     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1789     "internal error: code overflow...". This applied to any character class
1790     that was followed by a possessive quantifier.
1792     15. Modified the Makefile to add libpcre.la as a prerequisite for
1793     libpcreposix.la because I was told this is needed for a parallel build to
1794     work.
1796     16. If a pattern that contained .* following optional items at the start was
1797     studied, the wrong optimizing data was generated, leading to matching
1798     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1799     matching string must start with a or b or c. The correct conclusion for
1800     this pattern is that a match can start with any character.
1803 nigel 71 Version 4.4 13-Aug-03
1804     ---------------------
1806     1. In UTF-8 mode, a character class containing characters with values between
1807     127 and 255 was not handled correctly if the compiled pattern was studied.
1808     In fixing this, I have also improved the studying algorithm for such
1809     classes (slightly).
1811     2. Three internal functions had redundant arguments passed to them. Removal
1812     might give a very teeny performance improvement.
1814     3. Documentation bug: the value of the capture_top field in a callout is *one
1815     more than* the number of the hightest numbered captured substring.
1817     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1818     in incorrectly linking with a previously installed version. They now link
1819     explicitly with libpcre.la.
1821     5. configure.in no longer needs to recognize Cygwin specially.
1823     6. A problem in pcre.in for Windows platforms is fixed.
1825     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1826     pcretest, it used to include the size of the study block as part of its
1827     output. Unfortunately, the structure contains a field that has a different
1828     size on different hardware architectures. This meant that the tests that
1829     showed this size failed. As the block is currently always of a fixed size,
1830     this information isn't actually particularly useful in pcretest output, so
1831     I have just removed it.
1833     8. Three pre-processor statements accidentally did not start in column 1.
1834     Sadly, there are *still* compilers around that complain, even though
1835     standard C has not required this for well over a decade. Sigh.
1837     9. In pcretest, the code for checking callouts passed small integers in the
1838     callout_data field, which is a void * field. However, some picky compilers
1839     complained about the casts involved for this on 64-bit systems. Now
1840     pcretest passes the address of the small integer instead, which should get
1841     rid of the warnings.
1843     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1844     both compile and run time, and gives an error if an invalid UTF-8 sequence
1845     is found. There is a option for disabling this check in cases where the
1846     string is known to be correct and/or the maximum performance is wanted.
1848     11. In response to a bug report, I changed one line in Makefile.in from
1850     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1851     to
1852     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1854     to look similar to other lines, but I have no way of telling whether this
1855     is the right thing to do, as I do not use Windows. No doubt I'll get told
1856     if it's wrong...
1859 nigel 69 Version 4.3 21-May-03
1860     ---------------------
1862     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1863     Makefile.
1865     2. Some refactoring to improve the quality of the code:
1867     (i) The utf8_table... variables are now declared "const".
1869     (ii) The code for \cx, which used the "case flipping" table to upper case
1870     lower case letters, now just substracts 32. This is ASCII-specific,
1871     but the whole concept of \cx is ASCII-specific, so it seems
1872     reasonable.
1874     (iii) PCRE was using its character types table to recognize decimal and
1875     hexadecimal digits in the pattern. This is silly, because it handles
1876     only 0-9, a-f, and A-F, but the character types table is locale-
1877     specific, which means strange things might happen. A private
1878     table is now used for this - though it costs 256 bytes, a table is
1879     much faster than multiple explicit tests. Of course, the standard
1880     character types table is still used for matching digits in subject
1881     strings against \d.
1883     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1884     ending in _t are). So I've renamed it as ESC_tee.
1886     3. The first argument for regexec() in the POSIX wrapper should have been
1887     defined as "const".
1889     4. Changed pcretest to use malloc() for its buffers so that they can be
1890     Electric Fenced for debugging.
1892     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1893     to read one or more bytes before the start of the subject string. Often this
1894     had no effect on PCRE's behaviour, but in some circumstances it could
1895     provoke a segmentation fault.
1897     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1898     to try to read one or more bytes before the start of the subject string.
1900     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1901     UTF-8 support could misbehave in various ways if the subject string
1902     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1903     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1904     back over UTF-8 characters.)
1907 nigel 67 Version 4.2 14-Apr-03
1908     ---------------------
1910     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1912     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1913     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1914     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1915     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1916     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1917     and BUILD_EXEEXT
1918     Note: automatic setting of the BUILD variables is not yet working
1919     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1920     compile-time but not at link-time
1921     [LINK]: use for linking executables only
1922     make different versions for Windows and non-Windows
1923     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1924     libraries
1925     [LINK_FOR_BUILD]: new variable
1926     [OBJEXT]: use throughout
1927     [EXEEXT]: use throughout
1928     <winshared>: new target
1929     <wininstall>: new target
1930     <dftables.o>: use native compiler
1931     <dftables>: use native linker
1932     <install>: handle Windows platform correctly
1933     <clean>: ditto
1934     <check>: ditto
1935     copy DLL to top builddir before testing
1937     As part of these changes, -no-undefined was removed again. This was reported
1938     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1939     in any case.
1941     3. Some tidies to get rid of compiler warnings:
1943     . In the match_data structure, match_limit was an unsigned long int, whereas
1944     match_call_count was an int. I've made them both unsigned long ints.
1946     . In pcretest the fact that a const uschar * doesn't automatically cast to
1947     a void * provoked a warning.
1949     . Turning on some more compiler warnings threw up some "shadow" variables
1950     and a few more missing casts.
1952     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1953     option, a class that contained a single character with a value between 128
1954     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1956     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1957     option, a class that contained several characters, but with at least one
1958     whose value was between 128 and 255 caused PCRE to crash.
1961 nigel 65 Version 4.1 12-Mar-03
1962     ---------------------
1963 nigel 63
1964 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1965     needed, and a string in dftables.c that was longer than standard compilers are
1966     required to support.
1968     2. Compiling with Sun's compiler found a few more places where the code could
1969     be tidied up in order to avoid warnings.
1971     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1972     first of these names is deprecated in the latest Autoconf in favour of the name
1973     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1974     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1975     analogy I have changed it to CFLAGS_FOR_BUILD.
1977     4. Added -no-undefined to the linking command in the Makefile, because this is
1978     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1979     linking step for the pcreposix library.
1981     5. PCRE was failing to diagnose the case of two named groups with the same
1982     name.
1984     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1985     literal character that is needed in the subject for a match, and scans along to
1986     ensure that it is present before embarking on the full matching process. This
1987     saves time in cases of nested unlimited repeats that are never going to match.
1988     Problem: the scan can take a lot of time if the subject is very long (e.g.
1989     megabytes), thus penalizing straightforward matches. It is now done only if the
1990     amount of subject to be scanned is less than 1000 bytes.
1992     7. A lesser problem with the same optimization is that it was recording the
1993     first character of an anchored pattern as "needed", thus provoking a search
1994     right along the subject, even when the first match of the pattern was going to
1995     fail. The "needed" character is now not set for anchored patterns, unless it
1996     follows something in the pattern that is of non-fixed length. Thus, it still
1997     fulfils its original purpose of finding quick non-matches in cases of nested
1998     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2001     Version 4.0 17-Feb-03
2002     ---------------------
2004 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2005     extended to the end of string, PCRE compiled incorrect data. This could lead to
2006     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2008     2. Moved to autoconf 2.53 and libtool 1.4.2.
2010     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2011     the special perltest8 script is no longer needed - all the tests can be run
2012     from a single perltest script.
2014     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2015     by \s. It has now been removed in PCRE. This means it isn't recognized as
2016     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2017     class [:space:] *does* include VT, thereby creating a mess.
2019     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2020     space and tab.
2022     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2023     its new features into the main test script, reducing the number of scripts.
2025     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2026     were backward compatible, and made the (?i) apply to the whole pattern, as if
2027     /i were given. Now it behaves more logically, and applies the option setting
2028     only to what follows. PCRE has been changed to follow suit. However, if it
2029     finds options settings right at the start of the pattern, it extracts them into
2030     the global options, as before. Thus, they show up in the info data.
2032     8. Added support for the \Q...\E escape sequence. Characters in between are
2033     treated as literals. This is slightly different from Perl in that $ and @ are
2034     also handled as literals inside the quotes. In Perl, they will cause variable
2035     interpolation. Note the following examples:
2037     Pattern PCRE matches Perl matches
2039     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2040     \Qabc\$xyz\E abc\$xyz abc\$xyz
2041     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2043     For compatibility with Perl, \Q...\E sequences are recognized inside character
2044     classes as well as outside them.
2046     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2047     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2048     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2049     signed/unsigned warnings.
2051     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2052     option for pcretest, so I've replaced it by a simple function that does just
2053     that job.
2055     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2056     "pcregrep -".
2058     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2059     Java package. This provides some syntactic sugar for simple cases of what my
2060     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2061     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2062     item, you can use this simplified notation. Note that only makes sense with
2063     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2064     greediness, whatever the setting of the PCRE_UNGREEDY option.
2066     13. A change of greediness default within a pattern was not taking effect at
2067     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2068     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2069     was abstracted outside.
2071     14. PCRE now supports the \G assertion. It is true when the current matching
2072     position is at the start point of the match. This differs from \A when the
2073     starting offset is non-zero. Used with the /g option of pcretest (or similar
2074     code), it works in the same way as it does for Perl's /g option. If all
2075     alternatives of a regex begin with \G, the expression is anchored to the start
2076     match position, and the "anchored" flag is set in the compiled expression.
2078     15. Some bugs concerning the handling of certain option changes within patterns
2079     have been fixed. These applied to options other than (?ims). For example,
2080     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2081     been the other way round. Some of this was related to change 7 above.
2083     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2084     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2085     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2086     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2088     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2089     mode. Unlike ".", it always matches newline, whatever the setting of
2090     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2091     assertions. Perl allows it, but it doesn't (in general) work because it can't
2092     calculate the length of the lookbehind. At least, that's the case for Perl
2093     5.8.0 - I've been told they are going to document that it doesn't work in
2094     future.
2096     18. Added an error diagnosis for escapes that PCRE does not support: these are
2097     \L, \l, \N, \P, \p, \U, \u, and \X.
2099     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2100     reading past the end of the pattern in cases such as /[abcd/.
2102     20. PCRE was getting more memory than necessary for patterns with classes that
2103     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2105     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2106     compiling PCRE for use with Virtual Pascal.
2108     22. Small fix to the Makefile to make it work properly if the build is done
2109     outside the source tree.
2111     23. Added a new extension: a condition to go with recursion. If a conditional
2112     subpattern starts with (?(R) the "true" branch is used if recursion has
2113     happened, whereas the "false" branch is used only at the top level.
2115     24. When there was a very long string of literal characters (over 255 bytes
2116     without UTF support, over 250 bytes with UTF support), the computation of how
2117     much memory was required could be incorrect, leading to segfaults or other
2118     strange effects.
2120     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2121     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2122     there was a subsequent back reference to those brackets. This meant that, for
2123     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2124     possible to check for precisely this case. All we can do is abandon the
2125     optimization if .* occurs inside capturing brackets when there are any back
2126     references whatsoever. (See below for a better fix that came later.)
2128     26. The handling of the optimization for finding the first character of a
2129     non-anchored pattern, and for finding a character that is required later in the
2130     match were failing in some cases. This didn't break the matching; it just
2131     failed to optimize when it could. The way this is done has been re-implemented.
2133     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2135     28. Added a new feature that provides some of the functionality that Perl
2136     provides with (?{...}). The facility is termed a "callout". The way it is done
2137     in PCRE is for the caller to provide an optional function, by setting
2138     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2139     global variable. By default it is unset, which disables all calling out. To get
2140     the function called, the regex must include (?C) at appropriate points. This
2141     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2142     This provides a means of identifying different callout points. When PCRE
2143     reaches such a point in the regex, if pcre_callout has been set, the external
2144     function is called. It is provided with data in a structure called
2145     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2146     matching continues; if it returns a non-zero value, the match at the current
2147     point fails. However, backtracking will occur if possible. [This was changed
2148     later and other features added - see item 49 below.]
2150     29. pcretest is upgraded to test the callout functionality. It provides a
2151     callout function that displays information. By default, it shows the start of
2152     the match and the current position in the text. There are some new data escapes
2153     to vary what happens:
2155     \C+ in addition, show current contents of captured substrings
2156     \C- do not supply a callout function
2157     \C!n return 1 when callout number n is reached
2158     \C!n!m return 1 when callout number n is reached for the mth time
2160     30. If pcregrep was called with the -l option and just a single file name, it
2161     output "<stdin>" if a match was found, instead of the file name.
2163     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2164     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2165     pcre_exec(). This saves a malloc/free per call. The default value of
2166     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2167     when configuring.
2169     32. The default maximum size of a compiled pattern is 64K. There have been a
2170     few cases of people hitting this limit. The code now uses macros to handle the
2171     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2172     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2173     configuring. Tests 2 and 5 work only with 2-byte links because they output
2174     debugging information about compiled patterns.
2176     33. Internal code re-arrangements:
2178     (a) Moved the debugging function for printing out a compiled regex into
2179     its own source file (printint.c) and used #include to pull it into
2180     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2181     separate copies.
2183     (b) Defined the list of op-code names for debugging as a macro in
2184     internal.h so that it is next to the definition of the opcodes.
2186     (c) Defined a table of op-code lengths for simpler skipping along compiled
2187     code. This is again a macro in internal.h so that it is next to the
2188     definition of the opcodes.
2190     34. Added support for recursive calls to individual subpatterns, along the
2191     lines of Robin Houston's patch (but implemented somewhat differently).
2193     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2194     allow it to read and process whole directories in Win32. This code was
2195     contributed by Lionel Fourquaux; it has not been tested by me.
2197     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2198     used to name a group. Names consist of alphanumerics and underscores, and must
2199     be unique. Back references use the syntax (?P=name) and recursive calls use
2200     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2201     numbers. The function pcre_fullinfo() can be used after compilation to extract
2202     a name/number map. There are three relevant calls:
2204     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2205     PCRE_INFO_NAMECOUNT yields the number of entries
2206     PCRE_INFO_NAMETABLE yields a pointer to the map.
2208     The map is a vector of fixed-size entries. The size of each entry depends on
2209     the length of the longest name used. The first two bytes of each entry are the
2210     group number, most significant byte first. There follows the corresponding
2211     name, zero terminated. The names are in alphabetical order.
2213     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2214     case instead of 255. Making it the same both with and without UTF-8 support
2215     means that the same test output works with both.
2217     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2218     calling malloc() with a zero argument.
2220     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2221     optimization. I've improved things by keeping a bitmap of backreferences with
2222     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2223     fact referenced, the optimization can be applied. It is unlikely that a
2224     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2225     the match to follow \n) will appear inside brackets with a number greater than
2226     31, but if it does, any back reference > 31 suppresses the optimization.
2228     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2229     of disabling numbered capturing parentheses. Any opening parenthesis that is
2230     not followed by ? behaves as if it were followed by ?: but named parentheses
2231     can still be used for capturing (and they will acquire numbers in the usual
2232     way).
2234     41. Redesigned the return codes from the match() function into yes/no/error so
2235     that errors can be passed back from deep inside the nested calls. A malloc
2236     failure while inside a recursive subpattern call now causes the
2237     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2239     42. It is now possible to set a limit on the number of times the match()
2240     function is called in a call to pcre_exec(). This facility makes it possible to
2241     limit the amount of recursion and backtracking, though not in a directly
2242     obvious way, because the match() function is used in a number of different
2243     circumstances. The count starts from zero for each position in the subject
2244     string (for non-anchored patterns). The default limit is, for compatibility, a
2245     large number, namely 10 000 000. You can change this in two ways:
2247     (a) When configuring PCRE before making, you can use --with-match-limit=n
2248     to set a default value for the compiled library.
2250     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2251     a different value is set. See 45 below.
2253     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2255     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2256     of things that can be changed at compile time. The first argument specifies
2257     what is wanted and the second points to where the information is to be placed.
2258     The current list of available information is:
2262     The output is an integer that is set to one if UTF-8 support is available;
2263     otherwise it is set to zero.
2267     The output is an integer that it set to the value of the code that is used for
2268     newline. It is either LF (10) or CR (13).
2272     The output is an integer that contains the number of bytes used for internal
2273     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2277     The output is an integer that contains the threshold above which the POSIX
2278     interface uses malloc() for output vectors. See item 31 above.
2282     The output is an unsigned integer that contains the default limit of the number
2283     of match() calls in a pcre_exec() execution. See 42 above.
2285     44. pcretest has been upgraded by the addition of the -C option. This causes it
2286     to extract all the available output from the new pcre_config() function, and to
2287     output it. The program then exits immediately.
2289     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2290     order to support additional features. One way would have been to define
2291     pcre_exec2() (for example) with extra arguments, but this would not have been
2292     extensible, and would also have required all calls to the original function to
2293     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2294     is used for passing in "extra" data from pcre_study().
2296     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2297     contains the following fields:
2299     flags a bitmap indicating which of the following fields are set
2300     study_data opaque data from pcre_study()
2301     match_limit a way of specifying a limit on match() calls for a specific
2302     call to pcre_exec()
2303     callout_data data for callouts (see 49 below)
2305     The flag bits are also defined in pcre.h, and are
2311     The pcre_study() function now returns one of these new pcre_extra blocks, with
2312     the actual study data pointed to by the study_data field, and the
2313     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2314     before. That is, this change is entirely upwards-compatible and requires no
2315     change to existing code.
2317     If you want to pass in additional data to pcre_exec(), you can either place it
2318     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2319     block.
2321     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2322     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2323     times with different match limits, until it finds the minimum value needed for
2324     pcre_exec() to complete. The value is then output. This can be instructive; for
2325     most simple matches the number is quite small, but for pathological cases it
2326     gets very large very quickly.
2328     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2329     returns the size of the data block pointed to by the study_data field in a
2330     pcre_extra block, that is, the value that was passed as the argument to
2331     pcre_malloc() when PCRE was getting memory in which to place the information
2332     created by pcre_study(). The fourth argument should point to a size_t variable.
2333     pcretest has been extended so that this information is shown after a successful
2334     pcre_study() call when information about the compiled regex is being displayed.
2336     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2337     because what follows is always an absolute path. (Later: it turns out that this
2338     is more than cosmetic for MinGW, because it doesn't like empty path
2339     components.)
2341     49. Some changes have been made to the callout feature (see 28 above):
2343     (i) A callout function now has three choices for what it returns:
2345     0 => success, carry on matching
2346     > 0 => failure at this point, but backtrack if possible
2347     < 0 => serious error, return this value from pcre_exec()
2349     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2350     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2351     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2352     use by callout functions. It will never be used by PCRE itself.
2354     (ii) The pcre_extra structure (see 45 above) has a void * field called
2355     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2356     pcre_callout_block structure has a field of the same name. The contents of
2357     the field passed in the pcre_extra structure are passed to the callout
2358     function in the corresponding field in the callout block. This makes it
2359     easier to use the same callout-containing regex from multiple threads. For
2360     testing, the pcretest program has a new data escape
2362     \C*n pass the number n (may be negative) as callout_data
2364     If the callout function in pcretest receives a non-zero value as
2365     callout_data, it returns that value.
2367     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2368     there were some redundant $(CFLAGS) in commands that are now specified as
2369     $(LINK), which already includes $(CFLAGS).
2371     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2372     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2373     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2374     one-byte characters throughout. Note that case-insensitive matching applies
2375     only to characters whose values are less than 256. PCRE doesn't support the
2376     notion of cases for higher-valued characters.
2378     (i) A character class whose characters are all within 0-255 is handled as
2379     a bit map, and the map is inverted for negative classes. Previously, a
2380     character > 255 always failed to match such a class; however it should
2381     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2383     (ii) A negated character class with a single character < 255 is coded as
2384     "not this character" (OP_NOT). This wasn't working properly when the test
2385     character was multibyte, either singly or repeated.
2387     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2388     mode, for example: \x{100}{2,3}.
2390     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2391     singly or repeated) now correctly test multibyte characters. However,
2392     PCRE doesn't recognize any characters with values greater than 255 as
2393     digits, spaces, or word characters. Such characters always match \D, \S,
2394     and \W, and never match \d, \s, or \w.
2396     (v) Classes may now contain characters and character ranges with values
2397     greater than 255. For example: [ab\x{100}-\x{400}].
2399     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2400     PCRE in UTF-8 mode.
2402     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2403     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2404     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2405     value.)
2407     53. The single man page has become too large. I have therefore split it up into
2408     a number of separate man pages. These also give rise to individual HTML pages;
2409     these are now put in a separate directory, and there is an index.html page that
2410     lists them all. Some hyperlinking between the pages has been installed.
2412     54. Added convenience functions for handling named capturing parentheses.
2414     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2415     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2416     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2417     are faulted.
2419     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2420     calling configure. These values are used when compiling the dftables.c program
2421     which is run to generate the source of the default character tables. They
2422     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2423     you will need to set these values.
2425     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2428     Version 3.9 02-Jan-02
2429 nigel 61 ---------------------
2431     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2433     2. If --disable-static was given, the building process failed when trying to
2434     build pcretest and pcregrep. (For some reason it was using libtool to compile
2435     them, which is not right, as they aren't part of the library.)
2438 nigel 59 Version 3.8 18-Dec-01
2439     ---------------------
2441     1. The experimental UTF-8 code was completely screwed up. It was packing the
2442     bytes in the wrong order. How dumb can you get?
2445 nigel 57 Version 3.7 29-Oct-01
2446     ---------------------
2448     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2449     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2450     this didn't happen under Solaris 8, where I normally test things.
2452 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2453     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2454     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2455     this fix an hour or so after the initial 3.7 release.)
2456 nigel 57
2457 nigel 59
2458 nigel 55 Version 3.6 23-Oct-01
2459     ---------------------
2461     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2462     offsets passed as NULL with zero offset count.
2464     2. The config.guess and config.sub files had not been updated when I moved to
2465     the latest autoconf.
2468 nigel 53 Version 3.5 15-Aug-01
2469     ---------------------
2470 nigel 5
2471 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2472     had been forgotten.
2474     2. By using declared but undefined structures, we can avoid using "void"
2475     definitions in pcre.h while keeping the internal definitions of the structures
2476     private.
2478     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2479     user point of view, this means that both static and shared libraries are built
2480     by default, but this can be individually controlled. More of the work of
2481     handling this static/shared cases is now inside libtool instead of PCRE's make
2482     file.
2484     4. The pcretest utility is now installed along with pcregrep because it is
2485     useful for users (to test regexs) and by doing this, it automatically gets
2486     relinked by libtool. The documentation has been turned into a man page, so
2487     there are now .1, .txt, and .html versions in /doc.
2489     5. Upgrades to pcregrep:
2490     (i) Added long-form option names like gnu grep.
2491     (ii) Added --help to list all options with an explanatory phrase.
2492     (iii) Added -r, --recursive to recurse into sub-directories.
2493     (iv) Added -f, --file to read patterns from a file.
2495     6. pcre_exec() was referring to its "code" argument before testing that
2496     argument for NULL (and giving an error if it was NULL).
2498     7. Upgraded Makefile.in to allow for compiling in a different directory from
2499     the source directory.
2501     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2502     options bits, the pointer it was passed was to an int instead of to an unsigned
2503     long int. This mattered only on 64-bit systems.
2505     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2506     generated) instead of pcre.in, which it its source. Also made the same change
2507     in several of the .c files.
2509     10. A new release of gcc defines printf() as a macro, which broke pcretest
2510     because it had an ifdef in the middle of a string argument for printf(). Fixed
2511     by using separate calls to printf().
2513     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2514     script, to force use of CR or LF instead of \n in the source. On non-Unix
2515     systems, the value can be set in config.h.
2517     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2518     absolute limit. Changed the text of the error message to make this clear, and
2519     likewise updated the man page.
2521     13. The limit of 99 on the number of capturing subpatterns has been removed.
2522     The new limit is 65535, which I hope will not be a "real" limit.
2525 nigel 51 Version 3.4 22-Aug-00
2526     ---------------------
2528     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2530     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2533 nigel 49 Version 3.3 01-Aug-00
2534     ---------------------
2536     1. If an octal character was given, but the value was greater than \377, it
2537     was not getting masked to the least significant bits, as documented. This could
2538     lead to crashes in some systems.
2540     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2541     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2543     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2544     These just pass their arguments on to (pcre_free)(), but they are provided
2545     because some uses of PCRE bind it to non-C systems that can call its functions,
2546     but cannot call free() or pcre_free() directly.
2548     4. Add "make test" as a synonym for "make check". Corrected some comments in
2549     the Makefile.
2551     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2552     Makefile.
2554     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2555     command called pgrep for grepping around the active processes.
2557     7. Added the beginnings of support for UTF-8 character strings.
2559     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2560     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2561     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2562     out for the ar command.)
2565 nigel 47 Version 3.2 12-May-00
2566     ---------------------
2568     This is purely a bug fixing release.
2570     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2571     of ZA. This was just one example of several cases that could provoke this bug,
2572     which was introduced by change 9 of version 2.00. The code for breaking
2573     infinite loops after an iteration that matches an empty string was't working
2574     correctly.
2576     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2577     when matched against abbab (for example). After matching an empty string, it
2578     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2579     caused it to match further down the string than it should.
2581     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2582     was there because it doesn't seem to be needed, and it causes trouble on some
2583     systems, as it is not a Standard C header. It has been removed.
2585     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2586     were reported on the Macintosh. The changes were from
2588     while ((c = *(++ptr)) != 0 && c != '\n');
2589     to
2590     while ((c = *(++ptr)) != 0 && c != '\n') ;
2592     Totally extraordinary, but if that's what it takes...
2594     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2595     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2596     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2597     assumes the way PCRE uses memmove() (always moving upwards).
2599     6. PCRE is being used in one environment where strchr() is not available. There
2600     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2601     faster code anyway.
2604 nigel 45 Version 3.1 09-Feb-00
2605     ---------------------
2607     The only change in this release is the fixing of some bugs in Makefile.in for
2608     the "install" target:
2610     (1) It was failing to install pcreposix.h.
2612     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2615 nigel 43 Version 3.0 01-Feb-00
2616     ---------------------
2617 nigel 41
2618     1. Add support for the /+ modifier to perltest (to output $` like it does in
2619     pcretest).
2621     2. Add support for the /g modifier to perltest.
2623     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2624     matches null strings.
2626     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2627     pattern. Perl treats empty patterns specially - it reuses the most recent
2628     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2629     effect.
2631     5. The POSIX interface was broken in that it was just handing over the POSIX
2632     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2633     required a bigger vector, with some working space on the end. This means that
2634     the POSIX wrapper now has to get and free some memory, and copy the results.
2636 nigel 43 6. Added some simple autoconf support, placing the test data and the
2637     documentation in separate directories, re-organizing some of the
2638     information files, and making it build pcre-config (a GNU standard). Also added
2639     libtool support for building PCRE as a shared library, which is now the
2640     default.
2641 nigel 41
2642 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2643     09 are not valid octal constants. Single digits will be used for minor values
2644     less than 10.
2646     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2647     existing programs that set these in the POSIX interface can use PCRE without
2648     modification.
2650     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2651     return all that pcre_info() returns, plus additional data. The pcre_info()
2652     function is retained for compatibility, but is considered to be obsolete.
2654     10. Added experimental recursion feature (?R) to handle one common case that
2655     Perl 5.6 will be able to do with (?p{...}).
2657     11. Added support for POSIX character classes like [:alpha:], which Perl is
2658     adopting.
2661 nigel 39 Version 2.08 31-Aug-99
2662     ----------------------
2664     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2665     trying to match at the startoffset position, but instead was moving forward to
2666     the next newline as if a previous match had failed.
2668     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2669     and could get into a loop if a null string was matched other than at the start
2670     of the subject.
2672     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2673     be distinguished at compile time, and for completeness also added PCRE_DATE.
2675     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2676     in GnuWin32 environments.
2679 nigel 37 Version 2.07 29-Jul-99
2680     ----------------------
2682     1. The documentation is now supplied in plain text form and HTML as well as in
2683     the form of man page sources.
2685     2. C++ compilers don't like assigning (void *) values to other pointer types.
2686     In particular this affects malloc(). Although there is no problem in Standard
2687     C, I've put in casts to keep C++ compilers happy.
2689     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2690     should be (const char *).
2692     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2693     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2694     However, I haven't made this a standard facility. The documentation doesn't
2695     mention it, and the Makefile doesn't support it.
2697     5. The Makefile now contains an "install" target, with editable destinations at
2698     the top of the file. The pcretest program is not installed.
2700     6. pgrep -V now gives the PCRE version number and date.
2702     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2703     causing the entire string to be ignored, instead of just the last character.
2705     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2706     non-matching string, it can take a very, very long time, even for strings of
2707     quite modest length, because of the nested recursion. PCRE now does better in
2708     some of these cases. It does this by remembering the last required literal
2709     character in the pattern, and pre-searching the subject to ensure it is present
2710     before running the real match. In other words, it applies a heuristic to detect
2711     some types of certain failure quickly, and in the above example, if presented
2712     with a string that has no trailing " it gives "no match" very quickly.
2714     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2715     other alternatives are tried instead.
2718 nigel 35 Version 2.06 09-Jun-99
2719     ----------------------
2721     1. Change pcretest's output for amount of store used to show just the code
2722     space, because the remainder (the data block) varies in size between 32-bit and
2723     64-bit systems.
2725     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2726     start matching at. This allows lookbehinds to work when searching for multiple
2727     occurrences in a string.
2729     3. Added additional options to pcretest for testing multiple occurrences:
2731     /+ outputs the rest of the string that follows a match
2732     /g loops for multiple occurrences, using the new startoffset argument
2733     /G loops for multiple occurrences by passing an incremented pointer
2735     4. PCRE wasn't doing the "first character" optimization for patterns starting
2736     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2737     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2738     the letter 'x'. On long subject strings, this gives a significant speed-up.
2741 nigel 33 Version 2.05 21-Apr-99
2742     ----------------------
2744     1. Changed the type of magic_number from int to long int so that it works
2745     properly on 16-bit systems.
2747     2. Fixed a bug which caused patterns starting with .* not to work correctly
2748     when the subject string contained newline characters. PCRE was assuming
2749     anchoring for such patterns in all cases, which is not correct because .* will
2750     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2751     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2752     must be retried after every newline in the subject.
2755 nigel 31 Version 2.04 18-Feb-99
2756     ----------------------
2758     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2759     computation of the store needed to hold the pattern was incorrect (too large).
2760     If such patterns were nested a few deep, this could multiply and become a real
2761     problem.
2763     2. Added /M option to pcretest to show the memory requirement of a specific
2764     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2766     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2767     compiled in such a way that the backtracking after subsequent failure was
2768     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2769     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2772 nigel 29 Version 2.03 02-Feb-99
2773     ----------------------
2775     1. Fixed typo and small mistake in man page.
2777 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2778     LICENCE file containing the conditions.
2779 nigel 29
2780     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2781     Perl, that is the internal \ allows the delimiter to be included in the
2782     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2783     the final delimiter, add \ to the end of the pattern (to test the error).
2785     4. Added the convenience functions for extracting substrings after a successful
2786     match. Updated pcretest to make it able to test these functions.
2789 nigel 27 Version 2.02 14-Jan-99
2790     ----------------------
2792     1. Initialized the working variables associated with each extraction so that
2793     their saving and restoring doesn't refer to uninitialized store.
2795     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2796     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2797     fix the problem.
2799     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2800     calls, and wasn't printing the correct value for compiling calls. Increased the
2801     default value of LOOPREPEAT, and the number of significant figures in the
2802     times.
2804     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2806     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2807     a building problem on Windows NT with a FAT file system.
2810 nigel 25 Version 2.01 21-Oct-98
2811     ----------------------
2813     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2814     to character tables built by pcre_maketables() in the current locale. If NULL
2815     is passed, the default tables are used.
2818 nigel 23 Version 2.00 24-Sep-98
2819 nigel 21 ----------------------
2821 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2822     it any more.
2824     2. Allow quantification of (?>) groups, and make it work correctly.
2826     3. The first character computation wasn't working for (?>) groups.
2828     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2829     end of the subject) and add 5.005's \z, which really does match only at the
2830     very end of the subject.
2832     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2834     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2835     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2836     localized options. All options to pcre_study() were also removed.
2838     7. Add other new features from 5.005:
2840     $(?<= positive lookbehind
2841     $(?<! negative lookbehind
2842     (?imsx-imsx) added the unsetting capability
2843     such a setting is global if at outer level; local otherwise
2844     (?imsx-imsx:) non-capturing groups with option setting
2845     (?(cond)re|re) conditional pattern matching
2847     A backreference to itself in a repeated group matches the previous
2848     captured string.
2850     8. General tidying up of studying (both automatic and via "study")
2851     consequential on the addition of new assertions.
2853     9. As in 5.005, unlimited repeated groups that could match an empty substring
2854     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2855     runtime if any iteration does actually match an empty substring.
2857     10. Include the RunTest script in the distribution.
2859     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2860     discrepancies, some of which were old and were also with respect to 5.004. They
2861     have now been fixed.
2864     Version 1.09 28-Apr-98
2865     ----------------------
2867 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2868     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2869     program crashes, or just wrong answers. This did not apply to negated classes
2870     containing more than one character, or to minima other than one.
2873 nigel 19 Version 1.08 27-Mar-98
2874     ----------------------
2876     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2878     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2879     latter must appear before anything that relies on it in the pattern.
2882 nigel 17 Version 1.07 16-Feb-98
2883     ----------------------
2885     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2886     repeat of a potentially empty string).
2889 nigel 15 Version 1.06 23-Jan-98
2890     ----------------------
2892     1. Added Markus Oberhumer's little patches for C++.
2894     2. Literal strings longer than 255 characters were broken.
2897 nigel 13 Version 1.05 23-Dec-97
2898     ----------------------
2900     1. Negated character classes containing more than one character were failing if
2901     PCRE_CASELESS was set at run time.
2904 nigel 11 Version 1.04 19-Dec-97
2905     ----------------------
2907     1. Corrected the man page, where some "const" qualifiers had been omitted.
2909     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2910     input syntax.
2912     3. Fixed memory leak which occurred when a regex with back references was
2913     matched with an offsets vector that wasn't big enough. The temporary memory
2914     that is used in this case wasn't being freed if the match failed.
2916     4. Tidied pcretest to ensure it frees memory that it gets.
2918     5. Temporary memory was being obtained in the case where the passed offsets
2919     vector was exactly big enough.
2921     6. Corrected definition of offsetof() from change 5 below.
2923     7. I had screwed up change 6 below and broken the rules for the use of
2924     setjmp(). Now fixed.
2927 nigel 9 Version 1.03 18-Dec-97
2928     ----------------------
2930     1. A erroneous regex with a missing opening parenthesis was correctly
2931     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2932     on some systems.
2934     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2935     it was reported that one broken compiler failed on the former because "code" is
2936     also an independent variable.
2938     3. The erroneous regex a[]b caused an array overrun reference.
2940     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2941     fail on data ending with that character. (It was going on too far, and checking
2942     the next character, typically a binary zero.) This was specific to the
2943     optimized code for single-character negative classes.
2945     5. Added a contributed patch from the TIN world which does the following:
2947     + Add an undef for memmove, in case the the system defines a macro for it.
2949     + Add a definition of offsetof(), in case there isn't one. (I don't know
2950     the reason behind this - offsetof() is part of the ANSI standard - but
2951     it does no harm).
2953     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2954     most of the places where whitespace preceded '#'. I have given up and
2955     allowed the remaining 2 cases to be at the margin.
2957     + Rename some variables in pcre to eliminate shadowing. This seems very
2958     pedantic, but does no harm, of course.
2960     6. Moved the call to setjmp() into its own function, to get rid of warnings
2961     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2963     7. Constructs such as \d{8,} were compiling into the equivalent of
2964 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2965 nigel 9 outcome, but in this particular case used more store than had been allocated,
2966     which caused the bug to be discovered because it threw up an internal error.
2968     8. The debugging code in both pcre and pcretest for outputting the compiled
2969     form of a regex was going wrong in the case of back references followed by
2970     curly-bracketed repeats.
2973 nigel 7 Version 1.02 12-Dec-97
2974     ----------------------
2976     1. Typos in pcre.3 and comments in the source fixed.
2978     2. Applied a contributed patch to get rid of places where it used to remove
2979     'const' from variables, and fixed some signed/unsigned and uninitialized
2980     variable warnings.
2982     3. Added the "runtest" target to Makefile.
2984     4. Set default compiler flag to -O2 rather than just -O.
2987 nigel 5 Version 1.01 19-Nov-97
2988     ----------------------
2990     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2991     like /([ab]*)*/, that is, for classes with more than one character in them.
2993     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2994     as /((?>a*))*/ (a PCRE_EXTRA facility).
2997     Version 1.00 18-Nov-97
2998     ----------------------
3000     1. Added compile-time macros to support systems such as SunOS4 which don't have
3001     memmove() or strerror() but have other things that can be used instead.
3003     2. Arranged that "make clean" removes the executables.
3006 nigel 3 Version 0.99 27-Oct-97
3007     ----------------------
3009     1. Fixed bug in code for optimizing classes with only one character. It was
3010     initializing a 32-byte map regardless, which could cause it to run off the end
3011     of the memory it had got.
3013     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3016     Version 0.98 22-Oct-97
3017     ----------------------
3019     1. Fixed bug in code for handling temporary memory usage when there are more
3020     back references than supplied space in the ovector. This could cause segfaults.
3023     Version 0.97 21-Oct-97
3024     ----------------------
3026     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3028     2. Optimized negated single characters not to use a bit map.
3030     3. Brought error texts together as macro definitions; clarified some of them;
3031     fixed one that was wrong - it said "range out of order" when it meant "invalid
3032     escape sequence".
3034     4. Changed some char * arguments to const char *.
3036     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3038     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3039     pcretest.
3042     Version 0.96 16-Oct-97
3043     ----------------------
3045     1. Added a simple "pgrep" utility to the distribution.
3047     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3048     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3049     where "ddd" means "one or more decimal digits".
3051     3. Fixed serious bug. If a pattern had a back reference, but the call to
3052     pcre_exec() didn't supply a large enough ovector to record the related
3053     identifying subpattern, the match always failed. PCRE now remembers the number
3054     of the largest back reference, and gets some temporary memory in which to save
3055     the offsets during matching if necessary, in order to ensure that
3056     backreferences always work.
3058     4. Increased the compatibility with Perl in a number of ways:
3060     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3061     to request this handling. The option can be set at compile or exec time.
3063     (b) $ matches before a terminating newline by default; an option
3064     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3065     mode). The option can be set at compile or exec time.
3067     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3068     the same as Perl's. If the decimal number it represents is less than 10
3069     or there aren't that many previous left capturing parentheses, an octal
3070     escape is read. Inside a character class, it's always an octal escape,
3071     even if it is a single digit.
3073     (d) An escaped but undefined alphabetic character is taken as a literal,
3074     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3075     escapes.
3077     (e) {0} is now permitted. (The previous item is removed from the compiled
3078     pattern).
3080     5. Changed all the names of code files so that the basic parts are no longer
3081     than 10 characters, and abolished the teeny "globals.c" file.
3083     6. Changed the handling of character classes; they are now done with a 32-byte
3084     bit map always.
3086     7. Added the -d and /D options to pcretest to make it possible to look at the
3087     internals of compilation without having to recompile pcre.
3090     Version 0.95 23-Sep-97
3091     ----------------------
3093     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3094     \x20 at the start of a run of normal characters. These were being treated as
3095     real characters, instead of the source characters being re-checked.
3098     Version 0.94 18-Sep-97
3099     ----------------------
3101     1. The functions are now thread-safe, with the caveat that the global variables
3102     containing pointers to malloc() and free() or alternative functions are the
3103     same for all threads.
3105     2. Get pcre_study() to generate a bitmap of initial characters for non-
3106     anchored patterns when this is possible, and use it if passed to pcre_exec().
3109     Version 0.93 15-Sep-97
3110     ----------------------
3112     1. /(b)|(:+)/ was computing an incorrect first character.
3114     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3115     but not actually doing anything yet.
3117     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3118     as Perl does (e.g. [-az] or [az-]).
3120     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3121     all possible positions.
3123     5. Split up into different modules to avoid including unneeded functions in a
3124     compiled binary. However, compile and exec are still in one module. The "study"
3125     function is split off.
3127     6. The character tables are now in a separate module whose source is generated
3128     by an auxiliary program - but can then be edited by hand if required. There are
3129     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3130     toupper() in the code.
3132     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3133     make them global. Abolish the function for setting them, as the caller can now
3134     set them directly.
3137     Version 0.92 11-Sep-97
3138     ----------------------
3140     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3141     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3143     2. Caseless matching was not working in character classes if the characters in
3144     the pattern were in upper case.
3146     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3148     4. Make PCRE_ANCHORED public and accept as a compile option.
3150     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3151     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3152     pass them.
3154     6. Give an error if bad option bits passed at compile or run time.
3156     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3157     pcretest to cause it to pass that flag.
3159     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3160     options, and the first character, if set.
3162     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3165     Version 0.91 10-Sep-97
3166     ----------------------
3168     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3169     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3171     2. PCRE was looping on encountering an indefinitely repeated back reference to
3172     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3173     Perl does - treats the match as successful.
3175     ****


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