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Revision 164 - (hide annotations) (download)
Fri May 4 15:11:14 2007 UTC (7 years, 11 months ago) by ph10
File size: 127767 byte(s)
Replace longjmp() with gotos when not using stack recursion.

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


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