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Revision 255 - (hide annotations) (download)
Wed Sep 19 08:50:04 2007 UTC (6 years, 7 months ago) by ph10
File size: 141451 byte(s)
Add casts to pcretest.c to avoid compiler warnings.

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

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