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Revision 107 - (hide annotations) (download)
Wed Mar 7 11:02:28 2007 UTC (8 years, 1 month ago) by ph10
File size: 121794 byte(s)
Added some additional #ifdef SUPPORT_UTF8 to minimize the code when UTF-8 
support is not compiled.

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


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