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Revision 263 - (hide annotations) (download)
Mon Nov 12 16:53:25 2007 UTC (6 years, 10 months ago) by ph10
File size: 142116 byte(s)
Apply Craig's patch, which makes it possible to "ignore" values in parens 
when parsing an RE using the c++ wrapper.

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

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