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Revision 248 - (hide annotations) (download)
Mon Sep 17 10:09:22 2007 UTC (7 years, 7 months ago) by ph10
File size: 141289 byte(s)
Change condition for the macros for snprintf and strtoll from _WIN32 to 
HAVE_WINDOWS_H because they are needed only when windows.h is present.

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


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