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Revision 213 - (hide annotations) (download)
Wed Aug 15 11:34:14 2007 UTC (7 years, 8 months ago) by ph10
File size: 135540 byte(s)
Add integer overflow tests to escape processing.

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


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