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Revision 282 - (hide annotations) (download)
Fri Dec 7 19:32:32 2007 UTC (6 years, 7 months ago) by ph10
File size: 145570 byte(s)
Fix non-diagnosis of (?=a)(?R) (positive lookaheads not skipped when checking 
for an empty match).

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

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