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Revision 212 - (hide annotations) (download)
Thu Aug 9 11:16:34 2007 UTC (6 years, 8 months ago) by ph10
File size: 135349 byte(s)
Updating docs for release; fix heap-related bugs in pcre_exec shown up by 
release testing.

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

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