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Revision 247 - (hide annotations) (download)
Mon Sep 17 09:38:32 2007 UTC (6 years, 10 months ago) by ph10
File size: 141280 byte(s)
(1) Update tests 2,5,7,8 to run when --enable-bsr-anycrlf is used.
(2) Updates files changed by building test release.

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

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