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Revision 166 - (hide annotations) (download)
Wed May 9 14:48:28 2007 UTC (7 years, 11 months ago) by ph10
File size: 128097 byte(s)
Add (?-n) and (?+n) relative references.

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


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