/[pcre]/code/trunk/ChangeLog
ViewVC logotype

Contents of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log


Revision 231 - (hide annotations) (download)
Tue Sep 11 11:15:33 2007 UTC (7 years, 1 month ago) by ph10
File size: 139814 byte(s)
Add facility to make \R match only CR, LF, or CRLF.

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

Properties

Name Value
svn:eol-style native
svn:keywords "Author Date Id Revision Url"

webmaster@exim.org
ViewVC Help
Powered by ViewVC 1.1.12