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Wed Nov 21 15:35:09 2007 UTC (6 years, 10 months ago) by ph10
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s/backslash/backspace in two comments where it was wrong.

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

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