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Revision 216 - (hide annotations) (download)
Wed Aug 15 14:35:57 2007 UTC (6 years, 8 months ago) by ph10
File size: 136085 byte(s)
Fixed compile-time loop for patterns like (?:[\PPa*]*){8,} (extended class 
inside group with unlimited repeat).

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

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