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Revision 244 - (hide annotations) (download)
Fri Sep 14 09:14:24 2007 UTC (7 years, 3 months ago) by ph10
File size: 141184 byte(s)
Fix broken --disable-stack-for-recursion without --enable-unicode-properties.

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

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