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Revision 233 - (hide annotations) (download)
Tue Sep 11 11:26:11 2007 UTC (7 years, 3 months ago) by ph10
File size: 140002 byte(s)
Put back the definition of PCRE_ERROR_NULLWSLIMIT for compatibility, even 
though it is no longer used.

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

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