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Revision 116 - (hide annotations) (download)
Fri Mar 9 15:23:02 2007 UTC (8 years, 1 month ago) by ph10
File size: 124685 byte(s)
Tests cleanup: use -C in RunTest; add /Z to pcretest and make test 3 
independent of link size.

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 98 Version 7.1 05-Mar-07
5     ---------------------
7 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
8     that is more "standard", making use of automake and other autotools. There
9 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
10     on this.
11 ph10 111
12     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 ph10 100 alternative.
18 ph10 111
19 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
20 ph10 111 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 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
25     HTML has been updated to handle .nf/.fi and to complain if it encounters
26     .br or .in.
27 ph10 111
28 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
29 ph10 111 arranged for config.h to be included in the distribution, with the name
30     config.h.generic, for the benefit of those who have to compile without
31     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
33     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
34     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
35     makevp.bat for the current PCRE, using the additional files !compile.txt,
36 ph10 101 !linklib.txt, and pcregexp.pas.
37 ph10 111
38     6. A Windows user reported a minor discrepancy with test 2, which turned out
39     to be caused by a trailing space on an input line that had got lost in his
40 ph10 102 copy. The trailing space was an accident, so I've just removed it.
41 ph10 111
42 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
43 ph10 111 that is needed.
45 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
46     as "const" (a) because they are and (b) because it helps the PHP
47     maintainers who have recently made a script to detect big data structures
48 ph10 111 in the php code that should be moved to the .rodata section. I remembered
49     to update Builducptable as well, so it won't revert if ucptable.h is ever
50 ph10 105 re-created.
51 ph10 111
52     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
53 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
54 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
55     support is not required. This saves 1.5-2K of code, which is important in
56 ph10 107 some applications.
57 ph10 111
58 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
59 ph10 111 so as not to refer to the tables, even though these functions will never be
60     called when UTF-8 support is disabled. Otherwise there are problems with a
61     shared library.
63     10. The emulated memmove() function in pcre_internal.h (provided for those
64     environments that have neither memmove() nor bcopy()) was defining its
65 ph10 108 arguments as char * instead of void *.
67 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
68     and Detrail to create the HTML documentation, the .txt form of the man
69     pages, and it removes trailing spaces from listed files. It also creates
70     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
71     case, it wraps all the #defines with #ifndefs. This script should be run
72     before "make dist".
73 ph10 115
74     12. Fixed two fairly obscure bugs concerned with quantified caseless matching
75     with Unicode property support.
77     (a) For a maximizing quantifier, if the two different cases of the
78     character were of different lengths in their UTF-8 codings (there are
79     some cases like this - I found 11), and the matching function had to
80     back up over a mixture of the two cases, it incorrectly assumed they
81     were both the same length.
83     (b) When PCRE was configured to use the heap rather than the stack for
84     recursion during matching, it was not correctly preserving the data for
85     the other case of a UTF-8 character when checking ahead for a match
86     while processing a minimizing repeat. If the check also involved
87     matching a wide character, but failed, corruption could cause an
88     erroneous result when trying to check for a repeat of the original
89     character.
90 ph10 116
91     13. Some tidying changes to the testing mechanism:
92 ph10 98
93 ph10 116 (a) The RunTest script now detects the internal link size and whether there
94     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
95     values substituted by "configure". (The RunGrepTest script already did
96     this for UTF-8.) The configure.ac script no longer substitutes the
97     relevant variables.
99     (b) The debugging options /B and /D in pcretest show the compiled bytecode
100     with length and offset values. This means that the output is different
101     for different internal link sizes. Test 2 is skipped for link sizes
102     other than 2 because of this, bypassing the problem. Unfortunately,
103     there was also a test in test 3 (the locale tests) that used /B and
104     failed for link sizes other than 2. Rather than cut the whole test out,
105     I have added a new /Z option to pcretest that replaces the length and
106     offset values with spaces. This is now used to make test 3 independent
107     of link size.
108 ph10 111
109 ph10 116
110 nigel 93 Version 7.0 19-Dec-06
111     ---------------------
113     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
114     moving to gcc 4.1.1.
116     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
117     sys/time.h, which is documented as needed for this function. It doesn't
118     seem to matter on Linux, but it showed up on some releases of OS X.
120     3. It seems that there are systems where bytes whose values are greater than
121     127 match isprint() in the "C" locale. The "C" locale should be the
122     default when a C program starts up. In most systems, only ASCII printing
123     characters match isprint(). This difference caused the output from pcretest
124     to vary, making some of the tests fail. I have changed pcretest so that:
126     (a) When it is outputting text in the compiled version of a pattern, bytes
127     other than 32-126 are always shown as hex escapes.
129     (b) When it is outputting text that is a matched part of a subject string,
130     it does the same, unless a different locale has been set for the match
131     (using the /L modifier). In this case, it uses isprint() to decide.
133     4. Fixed a major bug that caused incorrect computation of the amount of memory
134     required for a compiled pattern when options that changed within the
135     pattern affected the logic of the preliminary scan that determines the
136     length. The relevant options are -x, and -i in UTF-8 mode. The result was
137     that the computed length was too small. The symptoms of this bug were
138     either the PCRE error "internal error: code overflow" from pcre_compile(),
139     or a glibc crash with a message such as "pcretest: free(): invalid next
140     size (fast)". Examples of patterns that provoked this bug (shown in
141     pcretest format) are:
143     /(?-x: )/x
144     /(?x)(?-x: \s*#\s*)/
145     /((?i)[\x{c0}])/8
146     /(?i:[\x{c0}])/8
148     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
149     is now done differently.
151     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
152     wrapper classes; (b) implement a new function in the C++ scanner that is
153     more efficient than the old way of doing things because it avoids levels of
154     recursion in the regex matching; (c) add a paragraph to the documentation
155     for the FullMatch() function.
157     6. The escape sequence \n was being treated as whatever was defined as
158     "newline". Not only was this contrary to the documentation, which states
159     that \n is character 10 (hex 0A), but it also went horribly wrong when
160     "newline" was defined as CRLF. This has been fixed.
162     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
163     was being set to -1 for the "end of line" case (supposedly a value that no
164     character can have). Though this value is never used (the check for end of
165     line is "zero bytes in current character"), it caused compiler complaints.
166     I've changed it to 0xffffffff.
168     8. In pcre_version.c, the version string was being built by a sequence of
169     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
170     string (as it is for production releases) called a macro with an empty
171     argument. The C standard says the result of this is undefined. The gcc
172     compiler treats it as an empty string (which was what was wanted) but it is
173     reported that Visual C gives an error. The source has been hacked around to
174     avoid this problem.
176     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
177     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
178     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
179     of them did).
181     10. Originally, pcretest opened its input and output without "b"; then I was
182     told that "b" was needed in some environments, so it was added for release
183     5.0 to both the input and output. (It makes no difference on Unix-like
184     systems.) Later I was told that it is wrong for the input on Windows. I've
185     now abstracted the modes into two macros, to make it easier to fiddle with
186     them, and removed "b" from the input mode under Windows.
188     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
190     12. Added -help and --help to pcretest as an official way of being reminded
191     of the options.
193     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
194     and pcrecpp.cc because they annoy compilers at high warning levels.
196     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
198     15. Fixed an occurrence of == in configure.ac that should have been = (shell
199     scripts are not C programs :-) and which was not noticed because it works
200     on Linux.
202     16. pcretest is supposed to handle any length of pattern and data line (as one
203     line or as a continued sequence of lines) by extending its input buffer if
204     necessary. This feature was broken for very long pattern lines, leading to
205     a string of junk being passed to pcre_compile() if the pattern was longer
206     than about 50K.
208     17. I have done a major re-factoring of the way pcre_compile() computes the
209     amount of memory needed for a compiled pattern. Previously, there was code
210     that made a preliminary scan of the pattern in order to do this. That was
211     OK when PCRE was new, but as the facilities have expanded, it has become
212     harder and harder to keep it in step with the real compile phase, and there
213     have been a number of bugs (see for example, 4 above). I have now found a
214     cunning way of running the real compile function in a "fake" mode that
215     enables it to compute how much memory it would need, while actually only
216     ever using a few hundred bytes of working memory and without too many
217     tests of the mode. This should make future maintenance and development
218     easier. A side effect of this work is that the limit of 200 on the nesting
219     depth of parentheses has been removed (though this was never a serious
220     limitation, I suspect). However, there is a downside: pcre_compile() now
221     runs more slowly than before (30% or more, depending on the pattern). I
222     hope this isn't a big issue. There is no effect on runtime performance.
224     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
225     newline (only possible for the last line of a file) and it was a
226     pattern that set a locale (followed by /Lsomething), pcretest crashed.
228     19. Added additional timing features to pcretest. (1) The -tm option now times
229     matching only, not compiling. (2) Both -t and -tm can be followed, as a
230     separate command line item, by a number that specifies the number of
231     repeats to use when timing. The default is 50000; this gives better
232     precision, but takes uncomfortably long for very large patterns.
234     20. Extended pcre_study() to be more clever in cases where a branch of a
235     subpattern has no definite first character. For example, (a*|b*)[cd] would
236     previously give no result from pcre_study(). Now it recognizes that the
237     first character must be a, b, c, or d.
239     21. There was an incorrect error "recursive call could loop indefinitely" if
240     a subpattern (or the entire pattern) that was being tested for matching an
241     empty string contained only one non-empty item after a nested subpattern.
242     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
243     incorrectly, because the \d was being skipped in the check.
245     22. The pcretest program now has a new pattern option /B and a command line
246     option -b, which is equivalent to adding /B to every pattern. This causes
247     it to show the compiled bytecode, without the additional information that
248     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
249     is the same as /B/I).
251     23. A new optimization is now able automatically to treat some sequences such
252     as a*b as a*+b. More specifically, if something simple (such as a character
253     or a simple class like \d) has an unlimited quantifier, and is followed by
254     something that cannot possibly match the quantified thing, the quantifier
255     is automatically "possessified".
257     24. A recursive reference to a subpattern whose number was greater than 39
258     went wrong under certain circumstances in UTF-8 mode. This bug could also
259     have affected the operation of pcre_study().
261     25. Realized that a little bit of performance could be had by replacing
262     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
264     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
266     27. Possessive quantifiers such as a++ were previously implemented by turning
267     them into atomic groups such as ($>a+). Now they have their own opcodes,
268     which improves performance. This includes the automatically created ones
269     from 23 above.
271     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
272     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
273     the first matched character to be a colon. This applied both to named and
274     numbered groups.
276     29. The ucpinternal.h header file was missing its idempotency #ifdef.
278     30. I was sent a "project" file called libpcre.a.dev which I understand makes
279     building PCRE on Windows easier, so I have included it in the distribution.
281     31. There is now a check in pcretest against a ridiculously large number being
282     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
283     loop, the loop is abandoned.
285     32. Forward references to subpatterns in conditions such as (?(2)...) where
286     subpattern 2 is defined later cause pcre_compile() to search forwards in
287     the pattern for the relevant set of parentheses. This search went wrong
288     when there were unescaped parentheses in a character class, parentheses
289     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
291     33. "Subroutine" calls and backreferences were previously restricted to
292     referencing subpatterns earlier in the regex. This restriction has now
293     been removed.
295     34. Added a number of extra features that are going to be in Perl 5.10. On the
296     whole, these are just syntactic alternatives for features that PCRE had
297     previously implemented using the Python syntax or my own invention. The
298     other formats are all retained for compatibility.
300     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
301     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
302     also .NET compatible.
304     (b) A recursion or subroutine call to a named group can now be defined as
305     (?&name) as well as (?P>name).
307     (c) A backreference to a named group can now be defined as \k<name> or
308     \k'name' as well as (?P=name). The new forms, as well as being in Perl
309     5.10, are also .NET compatible.
311     (d) A conditional reference to a named group can now use the syntax
312     (?(<name>) or (?('name') as well as (?(name).
314     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
315     groups (named and numbered) that are never evaluated inline, but can be
316     called as "subroutines" from elsewhere. In effect, the DEFINE condition
317     is always false. There may be only one alternative in such a group.
319     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
320     as the simple (?(R). The condition is true only if the most recent
321     recursion is that of the given number or name. It does not search out
322     through the entire recursion stack.
324     (g) The escape \gN or \g{N} has been added, where N is a positive or
325     negative number, specifying an absolute or relative reference.
327     35. Tidied to get rid of some further signed/unsigned compiler warnings and
328     some "unreachable code" warnings.
330     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
331     things, this adds five new scripts.
333     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
334     There were also incompatibilities regarding the handling of \Q..\E inside
335     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
336     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
338     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
339     matches an empty string, and forcibly breaks the loop. There were bugs in
340     this code in non-simple cases. For a pattern such as ^(a()*)* matched
341     against aaaa the result was just "a" rather than "aaaa", for example. Two
342     separate and independent bugs (that affected different cases) have been
343     fixed.
345     39. Refactored the code to abolish the use of different opcodes for small
346     capturing bracket numbers. This is a tidy that I avoided doing when I
347     removed the limit on the number of capturing brackets for 3.5 back in 2001.
348     The new approach is not only tidier, it makes it possible to reduce the
349     memory needed to fix the previous bug (38).
351     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
352     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
353     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
354     mode.
356     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
357     report.
359     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
360     copy construction and assignment in the C++ wrapper.
362     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
363     couple of bugs that could have given wrong results in the "--newline=crlf"
364     case.
366     44. Added a number of casts and did some reorganization of signed/unsigned int
367     variables following suggestions from Dair Grant. Also renamed the variable
368     "this" as "item" because it is a C++ keyword.
370     45. Arranged for dftables to add
372     #include "pcre_internal.h"
374     to pcre_chartables.c because without it, gcc 4.x may remove the array
375     definition from the final binary if PCRE is built into a static library and
376     dead code stripping is activated.
378     46. For an unanchored pattern, if a match attempt fails at the start of a
379     newline sequence, and the newline setting is CRLF or ANY, and the next two
380     characters are CRLF, advance by two characters instead of one.
383 nigel 91 Version 6.7 04-Jul-06
384     ---------------------
386     1. In order to handle tests when input lines are enormously long, pcretest has
387     been re-factored so that it automatically extends its buffers when
388     necessary. The code is crude, but this _is_ just a test program. The
389     default size has been increased from 32K to 50K.
391     2. The code in pcre_study() was using the value of the re argument before
392     testing it for NULL. (Of course, in any sensible call of the function, it
393     won't be NULL.)
395     3. The memmove() emulation function in pcre_internal.h, which is used on
396     systems that lack both memmove() and bcopy() - that is, hardly ever -
397     was missing a "static" storage class specifier.
399     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
400     containing an extended class (one that cannot be represented by a bitmap
401     because it contains high-valued characters or Unicode property items, e.g.
402     [\pZ]). Almost always one would set UTF-8 mode when processing such a
403     pattern, but PCRE should not loop if you do not (it no longer does).
404     [Detail: two cases were found: (a) a repeated subpattern containing an
405     extended class; (b) a recursive reference to a subpattern that followed a
406     previous extended class. It wasn't skipping over the extended class
407     correctly when UTF-8 mode was not set.]
409     5. A negated single-character class was not being recognized as fixed-length
410     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
411     compile error "lookbehind assertion is not fixed length".
413     6. The RunPerlTest auxiliary script was showing an unexpected difference
414     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
415     write a Perl script that can interpret lines of an input file either as
416     byte characters or as UTF-8, which is what "perltest" was being required to
417     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
418     can't do is switch easily at run time between having the "use utf8;" pragma
419     or not. In the end, I fudged it by using the RunPerlTest script to insert
420     "use utf8;" explicitly for the UTF-8 tests.
422     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
423     the end of the subject string, contrary to the documentation and to what
424     Perl does. This was true of both matching functions. Now it matches only at
425     the start of the subject and immediately after *internal* newlines.
427     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
428     a pointer to an int instead of a pointer to an unsigned long int. This
429     caused problems on 64-bit systems.
431     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
432     instance of the 'standard' template library not being so standard".
434     10. There was no check on the number of named subpatterns nor the maximum
435     length of a subpattern name. The product of these values is used to compute
436     the size of the memory block for a compiled pattern. By supplying a very
437     long subpattern name and a large number of named subpatterns, the size
438     computation could be caused to overflow. This is now prevented by limiting
439     the length of names to 32 characters, and the number of named subpatterns
440     to 10,000.
442     11. Subpatterns that are repeated with specific counts have to be replicated in
443     the compiled pattern. The size of memory for this was computed from the
444     length of the subpattern and the repeat count. The latter is limited to
445     65535, but there was no limit on the former, meaning that integer overflow
446     could in principle occur. The compiled length of a repeated subpattern is
447     now limited to 30,000 bytes in order to prevent this.
449     12. Added the optional facility to have named substrings with the same name.
451     13. Added the ability to use a named substring as a condition, using the
452     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
453     are numbers (not recommended). Forward references are permitted.
455     14. Added forward references in named backreferences (if you see what I mean).
457     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
458     pattern could run off the end of the subject. For example, the pattern
459     "(?s)(.{1,5})"8 did this with the subject "ab".
461     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
462     PCRE_CASELESS was set when matching characters that were quantified with ?
463     or *.
465     17. A character class other than a single negated character that had a minimum
466     but no maximum quantifier - for example [ab]{6,} - was not handled
467     correctly by pce_dfa_exec(). It would match only one character.
469     18. A valid (though odd) pattern that looked like a POSIX character
470     class but used an invalid character after [ (for example [[,abc,]]) caused
471     pcre_compile() to give the error "Failed: internal error: code overflow" or
472     in some cases to crash with a glibc free() error. This could even happen if
473     the pattern terminated after [[ but there just happened to be a sequence of
474     letters, a binary zero, and a closing ] in the memory that followed.
476     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
477     over the years. Originally (before any Unicode support), just the bottom 8
478     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
479     output from "man perlunicode" includes this:
481     The regular expression compiler produces polymorphic opcodes. That
482     is, the pattern adapts to the data and automatically switches to
483     the Unicode character scheme when presented with Unicode data--or
484     instead uses a traditional byte scheme when presented with byte
485     data.
487     Sadly, a wide octal escape does not cause a switch, and in a string with
488     no other multibyte characters, these octal escapes are treated as before.
489     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
490     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
491     Unicode string.
493     I have not perpetrated such confusion in PCRE. Up till now, it took just
494     the bottom 8 bits, as in old Perl. I have now made octal escapes with
495     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
496     translate to the appropriate multibyte character.
498     29. Applied some refactoring to reduce the number of warnings from Microsoft
499     and Borland compilers. This has included removing the fudge introduced
500     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
501     a warning about an unused variable.
503     21. PCRE has not included VT (character 0x0b) in the set of whitespace
504     characters since release 4.0, because Perl (from release 5.004) does not.
505     [Or at least, is documented not to: some releases seem to be in conflict
506     with the documentation.] However, when a pattern was studied with
507     pcre_study() and all its branches started with \s, PCRE still included VT
508     as a possible starting character. Of course, this did no harm; it just
509     caused an unnecessary match attempt.
511     22. Removed a now-redundant internal flag bit that recorded the fact that case
512     dependency changed within the pattern. This was once needed for "required
513     byte" processing, but is no longer used. This recovers a now-scarce options
514     bit. Also moved the least significant internal flag bit to the most-
515     significant bit of the word, which was not previously used (hangover from
516     the days when it was an int rather than a uint) to free up another bit for
517     the future.
519     23. Added support for CRLF line endings as well as CR and LF. As well as the
520     default being selectable at build time, it can now be changed at runtime
521     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
522     specify that it is scanning data with non-default line endings.
524     24. Changed the definition of CXXLINK to make it agree with the definition of
525     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
527     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
528     recursions. This makes a big different to stack usage for some patterns.
530     26. If a subpattern containing a named recursion or subroutine reference such
531     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
532     the space required for the compiled pattern went wrong and gave too small a
533     value. Depending on the environment, this could lead to "Failed: internal
534     error: code overflow at offset 49" or "glibc detected double free or
535     corruption" errors.
537     27. Applied patches from Google (a) to support the new newline modes and (b) to
538     advance over multibyte UTF-8 characters in GlobalReplace.
540     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
541     difference for some implementation of PCRE in some Windows version.
543     29. Added some extra testing facilities to pcretest:
545     \q<number> in a data line sets the "match limit" value
546     \Q<number> in a data line sets the "match recursion limt" value
547     -S <number> sets the stack size, where <number> is in megabytes
549     The -S option isn't available for Windows.
552 nigel 89 Version 6.6 06-Feb-06
553     ---------------------
555     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
556     in pcreposix.h. I have copied the definition from pcre.h.
558     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
559     because pcre.h is no longer a built file.
561     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
562     not normally included in the compiled code.
565 nigel 87 Version 6.5 01-Feb-06
566     ---------------------
568     1. When using the partial match feature with pcre_dfa_exec(), it was not
569     anchoring the second and subsequent partial matches at the new starting
570     point. This could lead to incorrect results. For example, with the pattern
571     /1234/, partially matching against "123" and then "a4" gave a match.
573     2. Changes to pcregrep:
575     (a) All non-match returns from pcre_exec() were being treated as failures
576     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
577     error message is output. Some extra information is given for the
579     probably the only errors that are likely to be caused by users (by
580     specifying a regex that has nested indefinite repeats, for instance).
581     If there are more than 20 of these errors, pcregrep is abandoned.
583     (b) A binary zero was treated as data while matching, but terminated the
584     output line if it was written out. This has been fixed: binary zeroes
585     are now no different to any other data bytes.
587     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
588     used to set a locale for matching. The --locale=xxxx long option has
589     been added (no short equivalent) to specify a locale explicitly on the
590     pcregrep command, overriding the environment variables.
592     (d) When -B was used with -n, some line numbers in the output were one less
593     than they should have been.
595     (e) Added the -o (--only-matching) option.
597     (f) If -A or -C was used with -c (count only), some lines of context were
598     accidentally printed for the final match.
600     (g) Added the -H (--with-filename) option.
602     (h) The combination of options -rh failed to suppress file names for files
603     that were found from directory arguments.
605     (i) Added the -D (--devices) and -d (--directories) options.
607     (j) Added the -F (--fixed-strings) option.
609     (k) Allow "-" to be used as a file name for -f as well as for a data file.
611     (l) Added the --colo(u)r option.
613     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
614     is not present by default.
616     3. A nasty bug was discovered in the handling of recursive patterns, that is,
617     items such as (?R) or (?1), when the recursion could match a number of
618     alternatives. If it matched one of the alternatives, but subsequently,
619     outside the recursion, there was a failure, the code tried to back up into
620     the recursion. However, because of the way PCRE is implemented, this is not
621     possible, and the result was an incorrect result from the match.
623     In order to prevent this happening, the specification of recursion has
624     been changed so that all such subpatterns are automatically treated as
625     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
627     4. I had overlooked the fact that, in some locales, there are characters for
628     which isalpha() is true but neither isupper() nor islower() are true. In
629     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
630     and ordfeminine) are like this. This affected the treatment of \w and \W
631     when they appeared in character classes, but not when they appeared outside
632     a character class. The bit map for "word" characters is now created
633     separately from the results of isalnum() instead of just taking it from the
634     upper, lower, and digit maps. (Plus the underscore character, of course.)
636     5. The above bug also affected the handling of POSIX character classes such as
637     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
638     permanent tables. Instead, the bit maps for such a class were previously
639     created as the appropriate unions of the upper, lower, and digit bitmaps.
640     Now they are created by subtraction from the [[:word:]] class, which has
641     its own bitmap.
643     6. The [[:blank:]] character class matches horizontal, but not vertical space.
644     It is created by subtracting the vertical space characters (\x09, \x0a,
645     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
646     subtraction was done in the overall bitmap for a character class, meaning
647     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
648     be recognized. This bug has been fixed.
650     7. Patches from the folks at Google:
652     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
653     real life, but is still worth protecting against".
655     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
656     regular expressions".
658     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
659     have it.
661     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
662     "configure" and the latter not, in order to fix a problem somebody had
663     with compiling the Arg class on HP-UX.
665     (e) Improve the error-handling of the C++ wrapper a little bit.
667     (f) New tests for checking recursion limiting.
669     8. The pcre_memmove() function, which is used only if the environment does not
670     have a standard memmove() function (and is therefore rarely compiled),
671     contained two bugs: (a) use of int instead of size_t, and (b) it was not
672     returning a result (though PCRE never actually uses the result).
674     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
675     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
676     returned instead of calling malloc() with an overflowing number that would
677     most likely cause subsequent chaos.
679     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
681     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
682     with this option is matched, the nmatch and pmatch options of regexec() are
683     ignored.
685     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
686     provided in case anyone wants to the the POSIX interface with UTF-8
687     strings.
689     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
690     C++ linking (needed for some HP-UX environments).
692     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
693     (unused parameter) and in the pcre_printint() function (omitted "default"
694     switch label when the default is to do nothing).
696     15. Added some code to make it possible, when PCRE is compiled as a C++
697     library, to replace subject pointers for pcre_exec() with a smart pointer
698     class, thus making it possible to process discontinuous strings.
700     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
701     much the same function. They were added by different people who were trying
702     to make PCRE easy to compile on non-Unix systems. It has been suggested
703     that PCRE_EXPORT be abolished now that there is more automatic apparatus
704     for compiling on Windows systems. I have therefore replaced it with
705     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
706     defaults to "extern" for C or "extern C" for C++, which works fine on
707     Unix-like systems. It is now possible to override the value of PCRE_DATA_
708     SCOPE with something explicit in config.h. In addition:
710     (a) pcreposix.h still had just "extern" instead of either of these macros;
711     I have replaced it with PCRE_DATA_SCOPE.
713     (b) Functions such as _pcre_xclass(), which are internal to the library,
714     but external in the C sense, all had PCRE_EXPORT in their definitions.
715     This is apparently wrong for the Windows case, so I have removed it.
716     (It makes no difference on Unix-like systems.)
718     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
719     of recursive calls to match(). This is different to MATCH_LIMIT because
720     that limits the total number of calls to match(), not all of which increase
721     the depth of recursion. Limiting the recursion depth limits the amount of
722     stack (or heap if NO_RECURSE is set) that is used. The default can be set
723     when PCRE is compiled, and changed at run time. A patch from Google adds
724     this functionality to the C++ interface.
726     18. Changes to the handling of Unicode character properties:
728     (a) Updated the table to Unicode 4.1.0.
730     (b) Recognize characters that are not in the table as "Cn" (undefined).
732     (c) I revised the way the table is implemented to a much improved format
733     which includes recognition of ranges. It now supports the ranges that
734     are defined in UnicodeData.txt, and it also amalgamates other
735     characters into ranges. This has reduced the number of entries in the
736     table from around 16,000 to around 3,000, thus reducing its size
737     considerably. I realized I did not need to use a tree structure after
738     all - a binary chop search is just as efficient. Having reduced the
739     number of entries, I extended their size from 6 bytes to 8 bytes to
740     allow for more data.
742     (d) Added support for Unicode script names via properties such as \p{Han}.
744     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
745     matching that character.
747     20. When matching a repeated Unicode property with a minimum greater than zero,
748     (for example \pL{2,}), PCRE could look past the end of the subject if it
749     reached it while seeking the minimum number of characters. This could
750     happen only if some of the characters were more than one byte long, because
751     there is a check for at least the minimum number of bytes.
753     21. Refactored the implementation of \p and \P so as to be more general, to
754     allow for more different types of property in future. This has changed the
755     compiled form incompatibly. Anybody with saved compiled patterns that use
756     \p or \P will have to recompile them.
758     22. Added "Any" and "L&" to the supported property types.
760     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
761     but give a compile time error if the value is greater than 0xff.
763     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
764     accidentally not being installed or uninstalled.
766     25. The pcre.h file was built from pcre.h.in, but the only changes that were
767     made were to insert the current release number. This seemed silly, because
768     it made things harder for people building PCRE on systems that don't run
769     "configure". I have turned pcre.h into a distributed file, no longer built
770     by "configure", with the version identification directly included. There is
771     no longer a pcre.h.in file.
773     However, this change necessitated a change to the pcre-config script as
774     well. It is built from pcre-config.in, and one of the substitutions was the
775     release number. I have updated configure.ac so that ./configure now finds
776     the release number by grepping pcre.h.
778     26. Added the ability to run the tests under valgrind.
781 nigel 85 Version 6.4 05-Sep-05
782     ---------------------
784     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
785     "--" to be printed when multiple files were scanned, even when none of the
786     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
787     consider it to be a bug, and have restored the previous behaviour.
789     2. A couple of code tidies to get rid of compiler warnings.
791     3. The pcretest program used to cheat by referring to symbols in the library
792     whose names begin with _pcre_. These are internal symbols that are not
793     really supposed to be visible externally, and in some environments it is
794     possible to suppress them. The cheating is now confined to including
795     certain files from the library's source, which is a bit cleaner.
797     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
798     file's purpose clearer.
800     5. Reorganized pcre_ucp_findchar().
803 nigel 83 Version 6.3 15-Aug-05
804     ---------------------
806     1. The file libpcre.pc.in did not have general read permission in the tarball.
808     2. There were some problems when building without C++ support:
810     (a) If C++ support was not built, "make install" and "make test" still
811     tried to test it.
813     (b) There were problems when the value of CXX was explicitly set. Some
814     changes have been made to try to fix these, and ...
816     (c) --disable-cpp can now be used to explicitly disable C++ support.
818     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
819     backslash in a target when C++ was disabled. This confuses some
820     versions of "make", apparently. Using an intermediate variable solves
821     this. (Same for CPP_LOBJ.)
823     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
824     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
825     necessary on certain architectures.
827     4. Added a setting of -export-symbols-regex to the link command to remove
828     those symbols that are exported in the C sense, but actually are local
829     within the library, and not documented. Their names all begin with
830     "_pcre_". This is not a perfect job, because (a) we have to except some
831     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
832     available (and never for static libraries). I have made a note to try to
833     find a way round (a) in the future.
836 nigel 81 Version 6.2 01-Aug-05
837     ---------------------
839     1. There was no test for integer overflow of quantifier values. A construction
840     such as {1111111111111111} would give undefined results. What is worse, if
841     a minimum quantifier for a parenthesized subpattern overflowed and became
842     negative, the calculation of the memory size went wrong. This could have
843     led to memory overwriting.
845     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
847     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
848     operating environments where this matters.
850     4. Applied Giuseppe Maxia's patch to add additional features for controlling
851     PCRE options from within the C++ wrapper.
853     5. Named capturing subpatterns were not being correctly counted when a pattern
854     was compiled. This caused two problems: (a) If there were more than 100
855     such subpatterns, the calculation of the memory needed for the whole
856     compiled pattern went wrong, leading to an overflow error. (b) Numerical
857     back references of the form \12, where the number was greater than 9, were
858     not recognized as back references, even though there were sufficient
859     previous subpatterns.
861     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
862     versions of gcc, e.g. 2.95.4.
865 nigel 79 Version 6.1 21-Jun-05
866     ---------------------
868     1. There was one reference to the variable "posix" in pcretest.c that was not
869     surrounded by "#if !defined NOPOSIX".
871     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
872     the cross-check on the old pcre_info() function, for the benefit of the
873     cut-down version of PCRE that is currently imported into Exim.
875     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
876     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
877     patterns that start (?i) but I don't think that matters. The use of (?i) is
878     just an example; this all applies to the other options as well.
880     4. Since libtool seems to echo the compile commands it is issuing, the output
881     from "make" can be reduced a bit by putting "@" in front of each libtool
882     compile command.
884     5. Patch from the folks at Google for configure.in to be a bit more thorough
885     in checking for a suitable C++ installation before trying to compile the
886     C++ stuff. This should fix a reported problem when a compiler was present,
887     but no suitable headers.
889     6. The man pages all had just "PCRE" as their title. I have changed them to
890     be the relevant file name. I have also arranged that these names are
891     retained in the file doc/pcre.txt, which is a concatenation in text format
892     of all the man pages except the little individual ones for each function.
894     7. The NON-UNIX-USE file had not been updated for the different set of source
895     files that come with release 6. I also added a few comments about the C++
896     wrapper.
899 nigel 77 Version 6.0 07-Jun-05
900     ---------------------
902     1. Some minor internal re-organization to help with my DFA experiments.
904     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
905     didn't matter for the library itself when fully configured, but did matter
906     when compiling without UCP support, or within Exim, where the ucp files are
907     not imported.
909     3. Refactoring of the library code to split up the various functions into
910     different source modules. The addition of the new DFA matching code (see
911     below) to a single monolithic source would have made it really too
912     unwieldy, quite apart from causing all the code to be include in a
913     statically linked application, when only some functions are used. This is
914     relevant even without the DFA addition now that patterns can be compiled in
915     one application and matched in another.
917     The downside of splitting up is that there have to be some external
918     functions and data tables that are used internally in different modules of
919     the library but which are not part of the API. These have all had their
920     names changed to start with "_pcre_" so that they are unlikely to clash
921     with other external names.
923     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
924     a different (DFA) algorithm. Although it is slower than the original
925     function, it does have some advantages for certain types of matching
926     problem.
928     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
929     including restarting after a partial match.
931     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
932     defined when compiling for Windows was sent to me. I have put it into the
933     code, though I have no means of testing or verifying it.
935     7. Added the pcre_refcount() auxiliary function.
937     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
938     match before or at the first newline in the subject string. In pcretest,
939     the /f option on a pattern can be used to set this.
941     9. A repeated \w when used in UTF-8 mode with characters greater than 256
942     would behave wrongly. This has been present in PCRE since release 4.0.
944     10. A number of changes to the pcregrep command:
946     (a) Refactored how -x works; insert ^(...)$ instead of setting
947     PCRE_ANCHORED and checking the length, in preparation for adding
948     something similar for -w.
950     (b) Added the -w (match as a word) option.
952     (c) Refactored the way lines are read and buffered so as to have more
953     than one at a time available.
955     (d) Implemented a pcregrep test script.
957     (e) Added the -M (multiline match) option. This allows patterns to match
958     over several lines of the subject. The buffering ensures that at least
959     8K, or the rest of the document (whichever is the shorter) is available
960     for matching (and similarly the previous 8K for lookbehind assertions).
962     (f) Changed the --help output so that it now says
964     -w, --word-regex(p)
966     instead of two lines, one with "regex" and the other with "regexp"
967     because that confused at least one person since the short forms are the
968     same. (This required a bit of code, as the output is generated
969     automatically from a table. It wasn't just a text change.)
971     (g) -- can be used to terminate pcregrep options if the next thing isn't an
972     option but starts with a hyphen. Could be a pattern or a path name
973     starting with a hyphen, for instance.
975     (h) "-" can be given as a file name to represent stdin.
977     (i) When file names are being printed, "(standard input)" is used for
978     the standard input, for compatibility with GNU grep. Previously
979     "<stdin>" was used.
981     (j) The option --label=xxx can be used to supply a name to be used for
982     stdin when file names are being printed. There is no short form.
984     (k) Re-factored the options decoding logic because we are going to add
985     two more options that take data. Such options can now be given in four
986     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
988     (l) Added the -A, -B, and -C options for requesting that lines of context
989     around matches be printed.
991     (m) Added the -L option to print the names of files that do not contain
992     any matching lines, that is, the complement of -l.
994     (n) The return code is 2 if any file cannot be opened, but pcregrep does
995     continue to scan other files.
997     (o) The -s option was incorrectly implemented. For compatibility with other
998     greps, it now suppresses the error message for a non-existent or non-
999     accessible file (but not the return code). There is a new option called
1000     -q that suppresses the output of matching lines, which was what -s was
1001     previously doing.
1003     (p) Added --include and --exclude options to specify files for inclusion
1004     and exclusion when recursing.
1006     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1007     Hopefully, it now does.
1009     12. Missing cast in pcre_study().
1011     13. Added an "uninstall" target to the makefile.
1013     14. Replaced "extern" in the function prototypes in Makefile.in with
1014     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1015     world, but is set differently for Windows.
1017     15. Added a second compiling function called pcre_compile2(). The only
1018     difference is that it has an extra argument, which is a pointer to an
1019     integer error code. When there is a compile-time failure, this is set
1020     non-zero, in addition to the error test pointer being set to point to an
1021     error message. The new argument may be NULL if no error number is required
1022     (but then you may as well call pcre_compile(), which is now just a
1023     wrapper). This facility is provided because some applications need a
1024     numeric error indication, but it has also enabled me to tidy up the way
1025     compile-time errors are handled in the POSIX wrapper.
1027     16. Added VPATH=.libs to the makefile; this should help when building with one
1028     prefix path and installing with another. (Or so I'm told by someone who
1029     knows more about this stuff than I do.)
1031     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1032     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1033     match everything, including newlines. This is not POSIX-compatible, but
1034     somebody wanted the feature. From pcretest it can be activated by using
1035     both the P and the s flags.
1037     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1039     19. libpcre.pc was being incorrectly installed as executable.
1041     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1042     it now also looks for '\r' so that it will work unmodified on Windows.
1044     21. Added Google's contributed C++ wrapper to the distribution.
1046     22. Added some untidy missing memory free() calls in pcretest, to keep
1047     Electric Fence happy when testing.
1051 nigel 75 Version 5.0 13-Sep-04
1052     ---------------------
1054     1. Internal change: literal characters are no longer packed up into items
1055     containing multiple characters in a single byte-string. Each character
1056     is now matched using a separate opcode. However, there may be more than one
1057     byte in the character in UTF-8 mode.
1059     2. The pcre_callout_block structure has two new fields: pattern_position and
1060     next_item_length. These contain the offset in the pattern to the next match
1061     item, and its length, respectively.
1063     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1064     insertion of callouts before each pattern item. Added the /C option to
1065     pcretest to make use of this.
1067     4. On the advice of a Windows user, the lines
1069     #if defined(_WIN32) || defined(WIN32)
1070     _setmode( _fileno( stdout ), 0x8000 );
1071     #endif /* defined(_WIN32) || defined(WIN32) */
1073     have been added to the source of pcretest. This apparently does useful
1074     magic in relation to line terminators.
1076     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1077     for the benefit of those environments where the "b" makes a difference.
1079     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1080     to know about it. I have put a hack into configure.in that adds in code
1081     to set GCC=yes if CC=icc. This seems to end up at a point in the
1082     generated configure script that is early enough to affect the setting of
1083     compiler options, which is what is needed, but I have no means of testing
1084     whether it really works. (The user who reported this had patched the
1085     generated configure script, which of course I cannot do.)
1087     LATER: After change 22 below (new libtool files), the configure script
1088     seems to know about icc (and also ecc). Therefore, I have commented out
1089     this hack in configure.in.
1091     7. Added support for pkg-config (2 patches were sent in).
1093     8. Negated POSIX character classes that used a combination of internal tables
1094     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1095     [[:^ascii]]. Typically, they would match almost any characters. The other
1096     POSIX classes were not broken in this way.
1098     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1099     to find the match, as PCRE was deluded into thinking that the match had to
1100     start at the start point or following a newline. The same bug applied to
1101     patterns with negative forward assertions or any backward assertions
1102     preceding ".*" at the start, unless the pattern required a fixed first
1103     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1105     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1106     starting at the last subject character, bytes beyond the end of the subject
1107     string were read.
1109     11. Renamed the variable "class" as "classbits" to make life easier for C++
1110     users. (Previously there was a macro definition, but it apparently wasn't
1111     enough.)
1113     12. Added the new field "tables" to the extra data so that tables can be passed
1114     in at exec time, or the internal tables can be re-selected. This allows
1115     a compiled regex to be saved and re-used at a later time by a different
1116     program that might have everything at different addresses.
1118     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1119     -R library as well as a -L library.
1121     14. The debugging options of pcretest (-d on the command line or D on a
1122     pattern) showed incorrect output for anything following an extended class
1123     that contained multibyte characters and which was followed by a quantifier.
1125     15. Added optional support for general category Unicode character properties
1126     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1127     support. It adds about 90K to the size of the library. The meanings of the
1128     inbuilt class escapes such as \d and \s have NOT been changed.
1130     16. Updated pcredemo.c to include calls to free() to release the memory for the
1131     compiled pattern.
1133     17. The generated file chartables.c was being created in the source directory
1134     instead of in the building directory. This caused the build to fail if the
1135     source directory was different from the building directory, and was
1136     read-only.
1138     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1139     file. No doubt somebody will tell me if they don't make sense... Also added
1140     Dan Mooney's comments about building on OpenVMS.
1142     19. Added support for partial matching via the PCRE_PARTIAL option for
1143     pcre_exec() and the \P data escape in pcretest.
1145     20. Extended pcretest with 3 new pattern features:
1147     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1148     write the compiled pattern to the file whose name is "rest-of-line".
1149     This is a straight binary dump of the data, with the saved pointer to
1150     the character tables forced to be NULL. The study data, if any, is
1151     written too. After writing, pcretest reads a new pattern.
1153     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1154     compiled pattern from the given file. There must not be any
1155     occurrences of "<" in the file name (pretty unlikely); if there are,
1156     pcretest will instead treat the initial "<" as a pattern delimiter.
1157     After reading in the pattern, pcretest goes on to read data lines as
1158     usual.
1160     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1161     and 16-bit fields in a compiled pattern, to simulate a pattern that
1162     was compiled on a host of opposite endianness.
1164     21. The pcre-exec() function can now cope with patterns that were compiled on
1165     hosts of opposite endianness, with this restriction:
1167     As for any compiled expression that is saved and used later, the tables
1168     pointer field cannot be preserved; the extra_data field in the arguments
1169     to pcre_exec() should be used to pass in a tables address if a value
1170     other than the default internal tables were used at compile time.
1172     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1173     now diagnosed as an error. Previously, most of the time, a negative number
1174     would have been treated as zero, but if in addition "ovector" was passed as
1175     NULL, a crash could occur.
1177     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1178     new versions from the libtool 1.5 distribution (the last one is a copy of
1179     a file called libtool.m4). This seems to have fixed the need to patch
1180     "configure" to support Darwin 1.3 (which I used to do). However, I still
1181     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1182     workstation).
1184     24. Changed the PCRE licence to be the more standard "BSD" licence.
1187 nigel 73 Version 4.5 01-Dec-03
1188     ---------------------
1190     1. There has been some re-arrangement of the code for the match() function so
1191     that it can be compiled in a version that does not call itself recursively.
1192     Instead, it keeps those local variables that need separate instances for
1193     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1194     needs to "recurse". Keeping track of where control must go is done by means
1195     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1196     hide most of the details from the main code, and operates only if
1197     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1198     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1199     operating.
1201     To make it easier for callers to provide specially tailored get/free
1202     functions for this usage, two new functions, pcre_stack_malloc, and
1203     pcre_stack_free, are used. They are always called in strict stacking order,
1204     and the size of block requested is always the same.
1206     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1207     PCRE has been compiled to use the stack or the heap for recursion. The
1208     -C option of pcretest uses this to show which version is compiled.
1210     A new data escape \S, is added to pcretest; it causes the amounts of store
1211     obtained and freed by both kinds of malloc/free at match time to be added
1212     to the output.
1214     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1215     what's available on my current Linux desktop machine.
1217     3. When matching a UTF-8 string, the test for a valid string at the start has
1218     been extended. If start_offset is not zero, PCRE now checks that it points
1219     to a byte that is the start of a UTF-8 character. If not, it returns
1220     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1221     this is necessary because there may be backward assertions in the pattern.
1222     When matching the same subject several times, it may save resources to use
1223     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1225     4. The code for checking the validity of UTF-8 strings has been tightened so
1226     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1227     containing "overlong sequences".
1229     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1230     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1231     should have been "&", but it just so happened that all the cases this let
1232     through by mistake were picked up later in the function.
1234     6. I had used a variable called "isblank" - this is a C99 function, causing
1235     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1237     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1238     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1239     so the version is shown; (c) stop "make test" echoing "./RunTest".
1241     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1243     9. The prototype for memmove() for systems that don't have it was using
1244     size_t, but the inclusion of the header that defines size_t was later. I've
1245     moved the #includes for the C headers earlier to avoid this.
1247     10. Added some adjustments to the code to make it easier to compiler on certain
1248     special systems:
1250     (a) Some "const" qualifiers were missing.
1251     (b) Added the macro EXPORT before all exported functions; by default this
1252     is defined to be empty.
1253     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1254     that it reads its output file name as an argument instead of writing
1255     to the standard output and assuming this can be redirected.
1257     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1258     class containing characters with values greater than 255, PCRE compilation
1259     went into a loop.
1261     12. A recursive reference to a subpattern that was within another subpattern
1262     that had a minimum quantifier of zero caused PCRE to crash. For example,
1263     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1264     recursion. If the recursively-called subpattern itself had a zero repeat,
1265     that was OK.
1267     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1268     buffer into which it was copied (for escape processing) was still set at
1269     1024, so long lines caused crashes.
1271     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1272     "internal error: code overflow...". This applied to any character class
1273     that was followed by a possessive quantifier.
1275     15. Modified the Makefile to add libpcre.la as a prerequisite for
1276     libpcreposix.la because I was told this is needed for a parallel build to
1277     work.
1279     16. If a pattern that contained .* following optional items at the start was
1280     studied, the wrong optimizing data was generated, leading to matching
1281     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1282     matching string must start with a or b or c. The correct conclusion for
1283     this pattern is that a match can start with any character.
1286 nigel 71 Version 4.4 13-Aug-03
1287     ---------------------
1289     1. In UTF-8 mode, a character class containing characters with values between
1290     127 and 255 was not handled correctly if the compiled pattern was studied.
1291     In fixing this, I have also improved the studying algorithm for such
1292     classes (slightly).
1294     2. Three internal functions had redundant arguments passed to them. Removal
1295     might give a very teeny performance improvement.
1297     3. Documentation bug: the value of the capture_top field in a callout is *one
1298     more than* the number of the hightest numbered captured substring.
1300     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1301     in incorrectly linking with a previously installed version. They now link
1302     explicitly with libpcre.la.
1304     5. configure.in no longer needs to recognize Cygwin specially.
1306     6. A problem in pcre.in for Windows platforms is fixed.
1308     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1309     pcretest, it used to include the size of the study block as part of its
1310     output. Unfortunately, the structure contains a field that has a different
1311     size on different hardware architectures. This meant that the tests that
1312     showed this size failed. As the block is currently always of a fixed size,
1313     this information isn't actually particularly useful in pcretest output, so
1314     I have just removed it.
1316     8. Three pre-processor statements accidentally did not start in column 1.
1317     Sadly, there are *still* compilers around that complain, even though
1318     standard C has not required this for well over a decade. Sigh.
1320     9. In pcretest, the code for checking callouts passed small integers in the
1321     callout_data field, which is a void * field. However, some picky compilers
1322     complained about the casts involved for this on 64-bit systems. Now
1323     pcretest passes the address of the small integer instead, which should get
1324     rid of the warnings.
1326     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1327     both compile and run time, and gives an error if an invalid UTF-8 sequence
1328     is found. There is a option for disabling this check in cases where the
1329     string is known to be correct and/or the maximum performance is wanted.
1331     11. In response to a bug report, I changed one line in Makefile.in from
1333     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1334     to
1335     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1337     to look similar to other lines, but I have no way of telling whether this
1338     is the right thing to do, as I do not use Windows. No doubt I'll get told
1339     if it's wrong...
1342 nigel 69 Version 4.3 21-May-03
1343     ---------------------
1345     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1346     Makefile.
1348     2. Some refactoring to improve the quality of the code:
1350     (i) The utf8_table... variables are now declared "const".
1352     (ii) The code for \cx, which used the "case flipping" table to upper case
1353     lower case letters, now just substracts 32. This is ASCII-specific,
1354     but the whole concept of \cx is ASCII-specific, so it seems
1355     reasonable.
1357     (iii) PCRE was using its character types table to recognize decimal and
1358     hexadecimal digits in the pattern. This is silly, because it handles
1359     only 0-9, a-f, and A-F, but the character types table is locale-
1360     specific, which means strange things might happen. A private
1361     table is now used for this - though it costs 256 bytes, a table is
1362     much faster than multiple explicit tests. Of course, the standard
1363     character types table is still used for matching digits in subject
1364     strings against \d.
1366     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1367     ending in _t are). So I've renamed it as ESC_tee.
1369     3. The first argument for regexec() in the POSIX wrapper should have been
1370     defined as "const".
1372     4. Changed pcretest to use malloc() for its buffers so that they can be
1373     Electric Fenced for debugging.
1375     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1376     to read one or more bytes before the start of the subject string. Often this
1377     had no effect on PCRE's behaviour, but in some circumstances it could
1378     provoke a segmentation fault.
1380     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1381     to try to read one or more bytes before the start of the subject string.
1383     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1384     UTF-8 support could misbehave in various ways if the subject string
1385     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1386     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1387     back over UTF-8 characters.)
1390 nigel 67 Version 4.2 14-Apr-03
1391     ---------------------
1393     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1395     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1396     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1397     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1398     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1399     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1400     and BUILD_EXEEXT
1401     Note: automatic setting of the BUILD variables is not yet working
1402     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1403     compile-time but not at link-time
1404     [LINK]: use for linking executables only
1405     make different versions for Windows and non-Windows
1406     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1407     libraries
1408     [LINK_FOR_BUILD]: new variable
1409     [OBJEXT]: use throughout
1410     [EXEEXT]: use throughout
1411     <winshared>: new target
1412     <wininstall>: new target
1413     <dftables.o>: use native compiler
1414     <dftables>: use native linker
1415     <install>: handle Windows platform correctly
1416     <clean>: ditto
1417     <check>: ditto
1418     copy DLL to top builddir before testing
1420     As part of these changes, -no-undefined was removed again. This was reported
1421     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1422     in any case.
1424     3. Some tidies to get rid of compiler warnings:
1426     . In the match_data structure, match_limit was an unsigned long int, whereas
1427     match_call_count was an int. I've made them both unsigned long ints.
1429     . In pcretest the fact that a const uschar * doesn't automatically cast to
1430     a void * provoked a warning.
1432     . Turning on some more compiler warnings threw up some "shadow" variables
1433     and a few more missing casts.
1435     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1436     option, a class that contained a single character with a value between 128
1437     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1439     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1440     option, a class that contained several characters, but with at least one
1441     whose value was between 128 and 255 caused PCRE to crash.
1444 nigel 65 Version 4.1 12-Mar-03
1445     ---------------------
1446 nigel 63
1447 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1448     needed, and a string in dftables.c that was longer than standard compilers are
1449     required to support.
1451     2. Compiling with Sun's compiler found a few more places where the code could
1452     be tidied up in order to avoid warnings.
1454     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1455     first of these names is deprecated in the latest Autoconf in favour of the name
1456     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1457     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1458     analogy I have changed it to CFLAGS_FOR_BUILD.
1460     4. Added -no-undefined to the linking command in the Makefile, because this is
1461     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1462     linking step for the pcreposix library.
1464     5. PCRE was failing to diagnose the case of two named groups with the same
1465     name.
1467     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1468     literal character that is needed in the subject for a match, and scans along to
1469     ensure that it is present before embarking on the full matching process. This
1470     saves time in cases of nested unlimited repeats that are never going to match.
1471     Problem: the scan can take a lot of time if the subject is very long (e.g.
1472     megabytes), thus penalizing straightforward matches. It is now done only if the
1473     amount of subject to be scanned is less than 1000 bytes.
1475     7. A lesser problem with the same optimization is that it was recording the
1476     first character of an anchored pattern as "needed", thus provoking a search
1477     right along the subject, even when the first match of the pattern was going to
1478     fail. The "needed" character is now not set for anchored patterns, unless it
1479     follows something in the pattern that is of non-fixed length. Thus, it still
1480     fulfils its original purpose of finding quick non-matches in cases of nested
1481     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1484     Version 4.0 17-Feb-03
1485     ---------------------
1487 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1488     extended to the end of string, PCRE compiled incorrect data. This could lead to
1489     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1491     2. Moved to autoconf 2.53 and libtool 1.4.2.
1493     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1494     the special perltest8 script is no longer needed - all the tests can be run
1495     from a single perltest script.
1497     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1498     by \s. It has now been removed in PCRE. This means it isn't recognized as
1499     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1500     class [:space:] *does* include VT, thereby creating a mess.
1502     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1503     space and tab.
1505     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1506     its new features into the main test script, reducing the number of scripts.
1508     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1509     were backward compatible, and made the (?i) apply to the whole pattern, as if
1510     /i were given. Now it behaves more logically, and applies the option setting
1511     only to what follows. PCRE has been changed to follow suit. However, if it
1512     finds options settings right at the start of the pattern, it extracts them into
1513     the global options, as before. Thus, they show up in the info data.
1515     8. Added support for the \Q...\E escape sequence. Characters in between are
1516     treated as literals. This is slightly different from Perl in that $ and @ are
1517     also handled as literals inside the quotes. In Perl, they will cause variable
1518     interpolation. Note the following examples:
1520     Pattern PCRE matches Perl matches
1522     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1523     \Qabc\$xyz\E abc\$xyz abc\$xyz
1524     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1526     For compatibility with Perl, \Q...\E sequences are recognized inside character
1527     classes as well as outside them.
1529     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1530     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1531     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1532     signed/unsigned warnings.
1534     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1535     option for pcretest, so I've replaced it by a simple function that does just
1536     that job.
1538     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1539     "pcregrep -".
1541     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1542     Java package. This provides some syntactic sugar for simple cases of what my
1543     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1544     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1545     item, you can use this simplified notation. Note that only makes sense with
1546     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1547     greediness, whatever the setting of the PCRE_UNGREEDY option.
1549     13. A change of greediness default within a pattern was not taking effect at
1550     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1551     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1552     was abstracted outside.
1554     14. PCRE now supports the \G assertion. It is true when the current matching
1555     position is at the start point of the match. This differs from \A when the
1556     starting offset is non-zero. Used with the /g option of pcretest (or similar
1557     code), it works in the same way as it does for Perl's /g option. If all
1558     alternatives of a regex begin with \G, the expression is anchored to the start
1559     match position, and the "anchored" flag is set in the compiled expression.
1561     15. Some bugs concerning the handling of certain option changes within patterns
1562     have been fixed. These applied to options other than (?ims). For example,
1563     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1564     been the other way round. Some of this was related to change 7 above.
1566     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1567     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1568     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1569     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1571     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1572     mode. Unlike ".", it always matches newline, whatever the setting of
1573     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1574     assertions. Perl allows it, but it doesn't (in general) work because it can't
1575     calculate the length of the lookbehind. At least, that's the case for Perl
1576     5.8.0 - I've been told they are going to document that it doesn't work in
1577     future.
1579     18. Added an error diagnosis for escapes that PCRE does not support: these are
1580     \L, \l, \N, \P, \p, \U, \u, and \X.
1582     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1583     reading past the end of the pattern in cases such as /[abcd/.
1585     20. PCRE was getting more memory than necessary for patterns with classes that
1586     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1588     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1589     compiling PCRE for use with Virtual Pascal.
1591     22. Small fix to the Makefile to make it work properly if the build is done
1592     outside the source tree.
1594     23. Added a new extension: a condition to go with recursion. If a conditional
1595     subpattern starts with (?(R) the "true" branch is used if recursion has
1596     happened, whereas the "false" branch is used only at the top level.
1598     24. When there was a very long string of literal characters (over 255 bytes
1599     without UTF support, over 250 bytes with UTF support), the computation of how
1600     much memory was required could be incorrect, leading to segfaults or other
1601     strange effects.
1603     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1604     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1605     there was a subsequent back reference to those brackets. This meant that, for
1606     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1607     possible to check for precisely this case. All we can do is abandon the
1608     optimization if .* occurs inside capturing brackets when there are any back
1609     references whatsoever. (See below for a better fix that came later.)
1611     26. The handling of the optimization for finding the first character of a
1612     non-anchored pattern, and for finding a character that is required later in the
1613     match were failing in some cases. This didn't break the matching; it just
1614     failed to optimize when it could. The way this is done has been re-implemented.
1616     27. Fixed typo in error message for invalid (?R item (it said "(?p").
1618     28. Added a new feature that provides some of the functionality that Perl
1619     provides with (?{...}). The facility is termed a "callout". The way it is done
1620     in PCRE is for the caller to provide an optional function, by setting
1621     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1622     global variable. By default it is unset, which disables all calling out. To get
1623     the function called, the regex must include (?C) at appropriate points. This
1624     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1625     This provides a means of identifying different callout points. When PCRE
1626     reaches such a point in the regex, if pcre_callout has been set, the external
1627     function is called. It is provided with data in a structure called
1628     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1629     matching continues; if it returns a non-zero value, the match at the current
1630     point fails. However, backtracking will occur if possible. [This was changed
1631     later and other features added - see item 49 below.]
1633     29. pcretest is upgraded to test the callout functionality. It provides a
1634     callout function that displays information. By default, it shows the start of
1635     the match and the current position in the text. There are some new data escapes
1636     to vary what happens:
1638     \C+ in addition, show current contents of captured substrings
1639     \C- do not supply a callout function
1640     \C!n return 1 when callout number n is reached
1641     \C!n!m return 1 when callout number n is reached for the mth time
1643     30. If pcregrep was called with the -l option and just a single file name, it
1644     output "<stdin>" if a match was found, instead of the file name.
1646     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1647     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1648     pcre_exec(). This saves a malloc/free per call. The default value of
1649     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1650     when configuring.
1652     32. The default maximum size of a compiled pattern is 64K. There have been a
1653     few cases of people hitting this limit. The code now uses macros to handle the
1654     storing of links as offsets within the compiled pattern. It defaults to 2-byte
1655     links, but this can be changed to 3 or 4 bytes by --with-link-size when
1656     configuring. Tests 2 and 5 work only with 2-byte links because they output
1657     debugging information about compiled patterns.
1659     33. Internal code re-arrangements:
1661     (a) Moved the debugging function for printing out a compiled regex into
1662     its own source file (printint.c) and used #include to pull it into
1663     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1664     separate copies.
1666     (b) Defined the list of op-code names for debugging as a macro in
1667     internal.h so that it is next to the definition of the opcodes.
1669     (c) Defined a table of op-code lengths for simpler skipping along compiled
1670     code. This is again a macro in internal.h so that it is next to the
1671     definition of the opcodes.
1673     34. Added support for recursive calls to individual subpatterns, along the
1674     lines of Robin Houston's patch (but implemented somewhat differently).
1676     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1677     allow it to read and process whole directories in Win32. This code was
1678     contributed by Lionel Fourquaux; it has not been tested by me.
1680     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1681     used to name a group. Names consist of alphanumerics and underscores, and must
1682     be unique. Back references use the syntax (?P=name) and recursive calls use
1683     (?P>name) which is a PCRE extension to the Python extension. Groups still have
1684     numbers. The function pcre_fullinfo() can be used after compilation to extract
1685     a name/number map. There are three relevant calls:
1687     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1688     PCRE_INFO_NAMECOUNT yields the number of entries
1689     PCRE_INFO_NAMETABLE yields a pointer to the map.
1691     The map is a vector of fixed-size entries. The size of each entry depends on
1692     the length of the longest name used. The first two bytes of each entry are the
1693     group number, most significant byte first. There follows the corresponding
1694     name, zero terminated. The names are in alphabetical order.
1696     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1697     case instead of 255. Making it the same both with and without UTF-8 support
1698     means that the same test output works with both.
1700     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1701     calling malloc() with a zero argument.
1703     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1704     optimization. I've improved things by keeping a bitmap of backreferences with
1705     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1706     fact referenced, the optimization can be applied. It is unlikely that a
1707     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1708     the match to follow \n) will appear inside brackets with a number greater than
1709     31, but if it does, any back reference > 31 suppresses the optimization.
1711     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1712     of disabling numbered capturing parentheses. Any opening parenthesis that is
1713     not followed by ? behaves as if it were followed by ?: but named parentheses
1714     can still be used for capturing (and they will acquire numbers in the usual
1715     way).
1717     41. Redesigned the return codes from the match() function into yes/no/error so
1718     that errors can be passed back from deep inside the nested calls. A malloc
1719     failure while inside a recursive subpattern call now causes the
1720     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1722     42. It is now possible to set a limit on the number of times the match()
1723     function is called in a call to pcre_exec(). This facility makes it possible to
1724     limit the amount of recursion and backtracking, though not in a directly
1725     obvious way, because the match() function is used in a number of different
1726     circumstances. The count starts from zero for each position in the subject
1727     string (for non-anchored patterns). The default limit is, for compatibility, a
1728     large number, namely 10 000 000. You can change this in two ways:
1730     (a) When configuring PCRE before making, you can use --with-match-limit=n
1731     to set a default value for the compiled library.
1733     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1734     a different value is set. See 45 below.
1736     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1738     43. Added a new function pcre_config(int, void *) to enable run-time extraction
1739     of things that can be changed at compile time. The first argument specifies
1740     what is wanted and the second points to where the information is to be placed.
1741     The current list of available information is:
1745     The output is an integer that is set to one if UTF-8 support is available;
1746     otherwise it is set to zero.
1750     The output is an integer that it set to the value of the code that is used for
1751     newline. It is either LF (10) or CR (13).
1755     The output is an integer that contains the number of bytes used for internal
1756     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1760     The output is an integer that contains the threshold above which the POSIX
1761     interface uses malloc() for output vectors. See item 31 above.
1765     The output is an unsigned integer that contains the default limit of the number
1766     of match() calls in a pcre_exec() execution. See 42 above.
1768     44. pcretest has been upgraded by the addition of the -C option. This causes it
1769     to extract all the available output from the new pcre_config() function, and to
1770     output it. The program then exits immediately.
1772     45. A need has arisen to pass over additional data with calls to pcre_exec() in
1773     order to support additional features. One way would have been to define
1774     pcre_exec2() (for example) with extra arguments, but this would not have been
1775     extensible, and would also have required all calls to the original function to
1776     be mapped to the new one. Instead, I have chosen to extend the mechanism that
1777     is used for passing in "extra" data from pcre_study().
1779     The pcre_extra structure is now exposed and defined in pcre.h. It currently
1780     contains the following fields:
1782     flags a bitmap indicating which of the following fields are set
1783     study_data opaque data from pcre_study()
1784     match_limit a way of specifying a limit on match() calls for a specific
1785     call to pcre_exec()
1786     callout_data data for callouts (see 49 below)
1788     The flag bits are also defined in pcre.h, and are
1794     The pcre_study() function now returns one of these new pcre_extra blocks, with
1795     the actual study data pointed to by the study_data field, and the
1796     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1797     before. That is, this change is entirely upwards-compatible and requires no
1798     change to existing code.
1800     If you want to pass in additional data to pcre_exec(), you can either place it
1801     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1802     block.
1804     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1805     data string contains the escape sequence \M, pcretest calls pcre_exec() several
1806     times with different match limits, until it finds the minimum value needed for
1807     pcre_exec() to complete. The value is then output. This can be instructive; for
1808     most simple matches the number is quite small, but for pathological cases it
1809     gets very large very quickly.
1811     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1812     returns the size of the data block pointed to by the study_data field in a
1813     pcre_extra block, that is, the value that was passed as the argument to
1814     pcre_malloc() when PCRE was getting memory in which to place the information
1815     created by pcre_study(). The fourth argument should point to a size_t variable.
1816     pcretest has been extended so that this information is shown after a successful
1817     pcre_study() call when information about the compiled regex is being displayed.
1819     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1820     because what follows is always an absolute path. (Later: it turns out that this
1821     is more than cosmetic for MinGW, because it doesn't like empty path
1822     components.)
1824     49. Some changes have been made to the callout feature (see 28 above):
1826     (i) A callout function now has three choices for what it returns:
1828     0 => success, carry on matching
1829     > 0 => failure at this point, but backtrack if possible
1830     < 0 => serious error, return this value from pcre_exec()
1832     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1833     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1834     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1835     use by callout functions. It will never be used by PCRE itself.
1837     (ii) The pcre_extra structure (see 45 above) has a void * field called
1838     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1839     pcre_callout_block structure has a field of the same name. The contents of
1840     the field passed in the pcre_extra structure are passed to the callout
1841     function in the corresponding field in the callout block. This makes it
1842     easier to use the same callout-containing regex from multiple threads. For
1843     testing, the pcretest program has a new data escape
1845     \C*n pass the number n (may be negative) as callout_data
1847     If the callout function in pcretest receives a non-zero value as
1848     callout_data, it returns that value.
1850     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1851     there were some redundant $(CFLAGS) in commands that are now specified as
1852     $(LINK), which already includes $(CFLAGS).
1854     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1855     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1856     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1857     one-byte characters throughout. Note that case-insensitive matching applies
1858     only to characters whose values are less than 256. PCRE doesn't support the
1859     notion of cases for higher-valued characters.
1861     (i) A character class whose characters are all within 0-255 is handled as
1862     a bit map, and the map is inverted for negative classes. Previously, a
1863     character > 255 always failed to match such a class; however it should
1864     match if the class was a negative one (e.g. [^ab]). This has been fixed.
1866     (ii) A negated character class with a single character < 255 is coded as
1867     "not this character" (OP_NOT). This wasn't working properly when the test
1868     character was multibyte, either singly or repeated.
1870     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1871     mode, for example: \x{100}{2,3}.
1873     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1874     singly or repeated) now correctly test multibyte characters. However,
1875     PCRE doesn't recognize any characters with values greater than 255 as
1876     digits, spaces, or word characters. Such characters always match \D, \S,
1877     and \W, and never match \d, \s, or \w.
1879     (v) Classes may now contain characters and character ranges with values
1880     greater than 255. For example: [ab\x{100}-\x{400}].
1882     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1883     PCRE in UTF-8 mode.
1885     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1886     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1887     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1888     value.)
1890     53. The single man page has become too large. I have therefore split it up into
1891     a number of separate man pages. These also give rise to individual HTML pages;
1892     these are now put in a separate directory, and there is an index.html page that
1893     lists them all. Some hyperlinking between the pages has been installed.
1895     54. Added convenience functions for handling named capturing parentheses.
1897     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1898     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1899     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1900     are faulted.
1902     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1903     calling configure. These values are used when compiling the dftables.c program
1904     which is run to generate the source of the default character tables. They
1905     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1906     you will need to set these values.
1908     57. Updated the building process for Windows DLL, as provided by Fred Cox.
1911     Version 3.9 02-Jan-02
1912 nigel 61 ---------------------
1914     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1916     2. If --disable-static was given, the building process failed when trying to
1917     build pcretest and pcregrep. (For some reason it was using libtool to compile
1918     them, which is not right, as they aren't part of the library.)
1921 nigel 59 Version 3.8 18-Dec-01
1922     ---------------------
1924     1. The experimental UTF-8 code was completely screwed up. It was packing the
1925     bytes in the wrong order. How dumb can you get?
1928 nigel 57 Version 3.7 29-Oct-01
1929     ---------------------
1931     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1932     This caused pcretest, when used on the test data, to segfault. Unfortunately,
1933     this didn't happen under Solaris 8, where I normally test things.
1935 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1936     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1937     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
1938     this fix an hour or so after the initial 3.7 release.)
1939 nigel 57
1940 nigel 59
1941 nigel 55 Version 3.6 23-Oct-01
1942     ---------------------
1944     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1945     offsets passed as NULL with zero offset count.
1947     2. The config.guess and config.sub files had not been updated when I moved to
1948     the latest autoconf.
1951 nigel 53 Version 3.5 15-Aug-01
1952     ---------------------
1953 nigel 5
1954 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
1955     had been forgotten.
1957     2. By using declared but undefined structures, we can avoid using "void"
1958     definitions in pcre.h while keeping the internal definitions of the structures
1959     private.
1961     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
1962     user point of view, this means that both static and shared libraries are built
1963     by default, but this can be individually controlled. More of the work of
1964     handling this static/shared cases is now inside libtool instead of PCRE's make
1965     file.
1967     4. The pcretest utility is now installed along with pcregrep because it is
1968     useful for users (to test regexs) and by doing this, it automatically gets
1969     relinked by libtool. The documentation has been turned into a man page, so
1970     there are now .1, .txt, and .html versions in /doc.
1972     5. Upgrades to pcregrep:
1973     (i) Added long-form option names like gnu grep.
1974     (ii) Added --help to list all options with an explanatory phrase.
1975     (iii) Added -r, --recursive to recurse into sub-directories.
1976     (iv) Added -f, --file to read patterns from a file.
1978     6. pcre_exec() was referring to its "code" argument before testing that
1979     argument for NULL (and giving an error if it was NULL).
1981     7. Upgraded Makefile.in to allow for compiling in a different directory from
1982     the source directory.
1984     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
1985     options bits, the pointer it was passed was to an int instead of to an unsigned
1986     long int. This mattered only on 64-bit systems.
1988     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
1989     generated) instead of pcre.in, which it its source. Also made the same change
1990     in several of the .c files.
1992     10. A new release of gcc defines printf() as a macro, which broke pcretest
1993     because it had an ifdef in the middle of a string argument for printf(). Fixed
1994     by using separate calls to printf().
1996     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
1997     script, to force use of CR or LF instead of \n in the source. On non-Unix
1998     systems, the value can be set in config.h.
2000     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2001     absolute limit. Changed the text of the error message to make this clear, and
2002     likewise updated the man page.
2004     13. The limit of 99 on the number of capturing subpatterns has been removed.
2005     The new limit is 65535, which I hope will not be a "real" limit.
2008 nigel 51 Version 3.4 22-Aug-00
2009     ---------------------
2011     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2013     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2016 nigel 49 Version 3.3 01-Aug-00
2017     ---------------------
2019     1. If an octal character was given, but the value was greater than \377, it
2020     was not getting masked to the least significant bits, as documented. This could
2021     lead to crashes in some systems.
2023     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2024     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2026     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2027     These just pass their arguments on to (pcre_free)(), but they are provided
2028     because some uses of PCRE bind it to non-C systems that can call its functions,
2029     but cannot call free() or pcre_free() directly.
2031     4. Add "make test" as a synonym for "make check". Corrected some comments in
2032     the Makefile.
2034     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2035     Makefile.
2037     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2038     command called pgrep for grepping around the active processes.
2040     7. Added the beginnings of support for UTF-8 character strings.
2042     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2043     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2044     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2045     out for the ar command.)
2048 nigel 47 Version 3.2 12-May-00
2049     ---------------------
2051     This is purely a bug fixing release.
2053     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2054     of ZA. This was just one example of several cases that could provoke this bug,
2055     which was introduced by change 9 of version 2.00. The code for breaking
2056     infinite loops after an iteration that matches an empty string was't working
2057     correctly.
2059     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2060     when matched against abbab (for example). After matching an empty string, it
2061     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2062     caused it to match further down the string than it should.
2064     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2065     was there because it doesn't seem to be needed, and it causes trouble on some
2066     systems, as it is not a Standard C header. It has been removed.
2068     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2069     were reported on the Macintosh. The changes were from
2071     while ((c = *(++ptr)) != 0 && c != '\n');
2072     to
2073     while ((c = *(++ptr)) != 0 && c != '\n') ;
2075     Totally extraordinary, but if that's what it takes...
2077     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2078     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2079     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2080     assumes the way PCRE uses memmove() (always moving upwards).
2082     6. PCRE is being used in one environment where strchr() is not available. There
2083     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2084     faster code anyway.
2087 nigel 45 Version 3.1 09-Feb-00
2088     ---------------------
2090     The only change in this release is the fixing of some bugs in Makefile.in for
2091     the "install" target:
2093     (1) It was failing to install pcreposix.h.
2095     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2098 nigel 43 Version 3.0 01-Feb-00
2099     ---------------------
2100 nigel 41
2101     1. Add support for the /+ modifier to perltest (to output $` like it does in
2102     pcretest).
2104     2. Add support for the /g modifier to perltest.
2106     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2107     matches null strings.
2109     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2110     pattern. Perl treats empty patterns specially - it reuses the most recent
2111     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2112     effect.
2114     5. The POSIX interface was broken in that it was just handing over the POSIX
2115     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2116     required a bigger vector, with some working space on the end. This means that
2117     the POSIX wrapper now has to get and free some memory, and copy the results.
2119 nigel 43 6. Added some simple autoconf support, placing the test data and the
2120     documentation in separate directories, re-organizing some of the
2121     information files, and making it build pcre-config (a GNU standard). Also added
2122     libtool support for building PCRE as a shared library, which is now the
2123     default.
2124 nigel 41
2125 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2126     09 are not valid octal constants. Single digits will be used for minor values
2127     less than 10.
2129     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2130     existing programs that set these in the POSIX interface can use PCRE without
2131     modification.
2133     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2134     return all that pcre_info() returns, plus additional data. The pcre_info()
2135     function is retained for compatibility, but is considered to be obsolete.
2137     10. Added experimental recursion feature (?R) to handle one common case that
2138     Perl 5.6 will be able to do with (?p{...}).
2140     11. Added support for POSIX character classes like [:alpha:], which Perl is
2141     adopting.
2144 nigel 39 Version 2.08 31-Aug-99
2145     ----------------------
2147     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2148     trying to match at the startoffset position, but instead was moving forward to
2149     the next newline as if a previous match had failed.
2151     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2152     and could get into a loop if a null string was matched other than at the start
2153     of the subject.
2155     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2156     be distinguished at compile time, and for completeness also added PCRE_DATE.
2158     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2159     in GnuWin32 environments.
2162 nigel 37 Version 2.07 29-Jul-99
2163     ----------------------
2165     1. The documentation is now supplied in plain text form and HTML as well as in
2166     the form of man page sources.
2168     2. C++ compilers don't like assigning (void *) values to other pointer types.
2169     In particular this affects malloc(). Although there is no problem in Standard
2170     C, I've put in casts to keep C++ compilers happy.
2172     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2173     should be (const char *).
2175     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2176     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2177     However, I haven't made this a standard facility. The documentation doesn't
2178     mention it, and the Makefile doesn't support it.
2180     5. The Makefile now contains an "install" target, with editable destinations at
2181     the top of the file. The pcretest program is not installed.
2183     6. pgrep -V now gives the PCRE version number and date.
2185     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2186     causing the entire string to be ignored, instead of just the last character.
2188     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2189     non-matching string, it can take a very, very long time, even for strings of
2190     quite modest length, because of the nested recursion. PCRE now does better in
2191     some of these cases. It does this by remembering the last required literal
2192     character in the pattern, and pre-searching the subject to ensure it is present
2193     before running the real match. In other words, it applies a heuristic to detect
2194     some types of certain failure quickly, and in the above example, if presented
2195     with a string that has no trailing " it gives "no match" very quickly.
2197     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2198     other alternatives are tried instead.
2201 nigel 35 Version 2.06 09-Jun-99
2202     ----------------------
2204     1. Change pcretest's output for amount of store used to show just the code
2205     space, because the remainder (the data block) varies in size between 32-bit and
2206     64-bit systems.
2208     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2209     start matching at. This allows lookbehinds to work when searching for multiple
2210     occurrences in a string.
2212     3. Added additional options to pcretest for testing multiple occurrences:
2214     /+ outputs the rest of the string that follows a match
2215     /g loops for multiple occurrences, using the new startoffset argument
2216     /G loops for multiple occurrences by passing an incremented pointer
2218     4. PCRE wasn't doing the "first character" optimization for patterns starting
2219     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2220     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2221     the letter 'x'. On long subject strings, this gives a significant speed-up.
2224 nigel 33 Version 2.05 21-Apr-99
2225     ----------------------
2227     1. Changed the type of magic_number from int to long int so that it works
2228     properly on 16-bit systems.
2230     2. Fixed a bug which caused patterns starting with .* not to work correctly
2231     when the subject string contained newline characters. PCRE was assuming
2232     anchoring for such patterns in all cases, which is not correct because .* will
2233     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2234     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2235     must be retried after every newline in the subject.
2238 nigel 31 Version 2.04 18-Feb-99
2239     ----------------------
2241     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2242     computation of the store needed to hold the pattern was incorrect (too large).
2243     If such patterns were nested a few deep, this could multiply and become a real
2244     problem.
2246     2. Added /M option to pcretest to show the memory requirement of a specific
2247     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2249     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2250     compiled in such a way that the backtracking after subsequent failure was
2251     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2252     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2255 nigel 29 Version 2.03 02-Feb-99
2256     ----------------------
2258     1. Fixed typo and small mistake in man page.
2260 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2261     LICENCE file containing the conditions.
2262 nigel 29
2263     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2264     Perl, that is the internal \ allows the delimiter to be included in the
2265     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2266     the final delimiter, add \ to the end of the pattern (to test the error).
2268     4. Added the convenience functions for extracting substrings after a successful
2269     match. Updated pcretest to make it able to test these functions.
2272 nigel 27 Version 2.02 14-Jan-99
2273     ----------------------
2275     1. Initialized the working variables associated with each extraction so that
2276     their saving and restoring doesn't refer to uninitialized store.
2278     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2279     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2280     fix the problem.
2282     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2283     calls, and wasn't printing the correct value for compiling calls. Increased the
2284     default value of LOOPREPEAT, and the number of significant figures in the
2285     times.
2287     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2289     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2290     a building problem on Windows NT with a FAT file system.
2293 nigel 25 Version 2.01 21-Oct-98
2294     ----------------------
2296     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2297     to character tables built by pcre_maketables() in the current locale. If NULL
2298     is passed, the default tables are used.
2301 nigel 23 Version 2.00 24-Sep-98
2302 nigel 21 ----------------------
2304 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2305     it any more.
2307     2. Allow quantification of (?>) groups, and make it work correctly.
2309     3. The first character computation wasn't working for (?>) groups.
2311     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2312     end of the subject) and add 5.005's \z, which really does match only at the
2313     very end of the subject.
2315     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2317     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2318     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2319     localized options. All options to pcre_study() were also removed.
2321     7. Add other new features from 5.005:
2323     $(?<= positive lookbehind
2324     $(?<! negative lookbehind
2325     (?imsx-imsx) added the unsetting capability
2326     such a setting is global if at outer level; local otherwise
2327     (?imsx-imsx:) non-capturing groups with option setting
2328     (?(cond)re|re) conditional pattern matching
2330     A backreference to itself in a repeated group matches the previous
2331     captured string.
2333     8. General tidying up of studying (both automatic and via "study")
2334     consequential on the addition of new assertions.
2336     9. As in 5.005, unlimited repeated groups that could match an empty substring
2337     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2338     runtime if any iteration does actually match an empty substring.
2340     10. Include the RunTest script in the distribution.
2342     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2343     discrepancies, some of which were old and were also with respect to 5.004. They
2344     have now been fixed.
2347     Version 1.09 28-Apr-98
2348     ----------------------
2350 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2351     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2352     program crashes, or just wrong answers. This did not apply to negated classes
2353     containing more than one character, or to minima other than one.
2356 nigel 19 Version 1.08 27-Mar-98
2357     ----------------------
2359     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2361     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2362     latter must appear before anything that relies on it in the pattern.
2365 nigel 17 Version 1.07 16-Feb-98
2366     ----------------------
2368     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2369     repeat of a potentially empty string).
2372 nigel 15 Version 1.06 23-Jan-98
2373     ----------------------
2375     1. Added Markus Oberhumer's little patches for C++.
2377     2. Literal strings longer than 255 characters were broken.
2380 nigel 13 Version 1.05 23-Dec-97
2381     ----------------------
2383     1. Negated character classes containing more than one character were failing if
2384     PCRE_CASELESS was set at run time.
2387 nigel 11 Version 1.04 19-Dec-97
2388     ----------------------
2390     1. Corrected the man page, where some "const" qualifiers had been omitted.
2392     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2393     input syntax.
2395     3. Fixed memory leak which occurred when a regex with back references was
2396     matched with an offsets vector that wasn't big enough. The temporary memory
2397     that is used in this case wasn't being freed if the match failed.
2399     4. Tidied pcretest to ensure it frees memory that it gets.
2401     5. Temporary memory was being obtained in the case where the passed offsets
2402     vector was exactly big enough.
2404     6. Corrected definition of offsetof() from change 5 below.
2406     7. I had screwed up change 6 below and broken the rules for the use of
2407     setjmp(). Now fixed.
2410 nigel 9 Version 1.03 18-Dec-97
2411     ----------------------
2413     1. A erroneous regex with a missing opening parenthesis was correctly
2414     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2415     on some systems.
2417     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2418     it was reported that one broken compiler failed on the former because "code" is
2419     also an independent variable.
2421     3. The erroneous regex a[]b caused an array overrun reference.
2423     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2424     fail on data ending with that character. (It was going on too far, and checking
2425     the next character, typically a binary zero.) This was specific to the
2426     optimized code for single-character negative classes.
2428     5. Added a contributed patch from the TIN world which does the following:
2430     + Add an undef for memmove, in case the the system defines a macro for it.
2432     + Add a definition of offsetof(), in case there isn't one. (I don't know
2433     the reason behind this - offsetof() is part of the ANSI standard - but
2434     it does no harm).
2436     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2437     most of the places where whitespace preceded '#'. I have given up and
2438     allowed the remaining 2 cases to be at the margin.
2440     + Rename some variables in pcre to eliminate shadowing. This seems very
2441     pedantic, but does no harm, of course.
2443     6. Moved the call to setjmp() into its own function, to get rid of warnings
2444     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2446     7. Constructs such as \d{8,} were compiling into the equivalent of
2447 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2448 nigel 9 outcome, but in this particular case used more store than had been allocated,
2449     which caused the bug to be discovered because it threw up an internal error.
2451     8. The debugging code in both pcre and pcretest for outputting the compiled
2452     form of a regex was going wrong in the case of back references followed by
2453     curly-bracketed repeats.
2456 nigel 7 Version 1.02 12-Dec-97
2457     ----------------------
2459     1. Typos in pcre.3 and comments in the source fixed.
2461     2. Applied a contributed patch to get rid of places where it used to remove
2462     'const' from variables, and fixed some signed/unsigned and uninitialized
2463     variable warnings.
2465     3. Added the "runtest" target to Makefile.
2467     4. Set default compiler flag to -O2 rather than just -O.
2470 nigel 5 Version 1.01 19-Nov-97
2471     ----------------------
2473     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2474     like /([ab]*)*/, that is, for classes with more than one character in them.
2476     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2477     as /((?>a*))*/ (a PCRE_EXTRA facility).
2480     Version 1.00 18-Nov-97
2481     ----------------------
2483     1. Added compile-time macros to support systems such as SunOS4 which don't have
2484     memmove() or strerror() but have other things that can be used instead.
2486     2. Arranged that "make clean" removes the executables.
2489 nigel 3 Version 0.99 27-Oct-97
2490     ----------------------
2492     1. Fixed bug in code for optimizing classes with only one character. It was
2493     initializing a 32-byte map regardless, which could cause it to run off the end
2494     of the memory it had got.
2496     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2499     Version 0.98 22-Oct-97
2500     ----------------------
2502     1. Fixed bug in code for handling temporary memory usage when there are more
2503     back references than supplied space in the ovector. This could cause segfaults.
2506     Version 0.97 21-Oct-97
2507     ----------------------
2509     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2511     2. Optimized negated single characters not to use a bit map.
2513     3. Brought error texts together as macro definitions; clarified some of them;
2514     fixed one that was wrong - it said "range out of order" when it meant "invalid
2515     escape sequence".
2517     4. Changed some char * arguments to const char *.
2519     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2521     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2522     pcretest.
2525     Version 0.96 16-Oct-97
2526     ----------------------
2528     1. Added a simple "pgrep" utility to the distribution.
2530     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2531     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2532     where "ddd" means "one or more decimal digits".
2534     3. Fixed serious bug. If a pattern had a back reference, but the call to
2535     pcre_exec() didn't supply a large enough ovector to record the related
2536     identifying subpattern, the match always failed. PCRE now remembers the number
2537     of the largest back reference, and gets some temporary memory in which to save
2538     the offsets during matching if necessary, in order to ensure that
2539     backreferences always work.
2541     4. Increased the compatibility with Perl in a number of ways:
2543     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2544     to request this handling. The option can be set at compile or exec time.
2546     (b) $ matches before a terminating newline by default; an option
2547     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2548     mode). The option can be set at compile or exec time.
2550     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2551     the same as Perl's. If the decimal number it represents is less than 10
2552     or there aren't that many previous left capturing parentheses, an octal
2553     escape is read. Inside a character class, it's always an octal escape,
2554     even if it is a single digit.
2556     (d) An escaped but undefined alphabetic character is taken as a literal,
2557     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2558     escapes.
2560     (e) {0} is now permitted. (The previous item is removed from the compiled
2561     pattern).
2563     5. Changed all the names of code files so that the basic parts are no longer
2564     than 10 characters, and abolished the teeny "globals.c" file.
2566     6. Changed the handling of character classes; they are now done with a 32-byte
2567     bit map always.
2569     7. Added the -d and /D options to pcretest to make it possible to look at the
2570     internals of compilation without having to recompile pcre.
2573     Version 0.95 23-Sep-97
2574     ----------------------
2576     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2577     \x20 at the start of a run of normal characters. These were being treated as
2578     real characters, instead of the source characters being re-checked.
2581     Version 0.94 18-Sep-97
2582     ----------------------
2584     1. The functions are now thread-safe, with the caveat that the global variables
2585     containing pointers to malloc() and free() or alternative functions are the
2586     same for all threads.
2588     2. Get pcre_study() to generate a bitmap of initial characters for non-
2589     anchored patterns when this is possible, and use it if passed to pcre_exec().
2592     Version 0.93 15-Sep-97
2593     ----------------------
2595     1. /(b)|(:+)/ was computing an incorrect first character.
2597     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2598     but not actually doing anything yet.
2600     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2601     as Perl does (e.g. [-az] or [az-]).
2603     4. Set the anchored flag if a branch starts with .* or .*? because that tests
2604     all possible positions.
2606     5. Split up into different modules to avoid including unneeded functions in a
2607     compiled binary. However, compile and exec are still in one module. The "study"
2608     function is split off.
2610     6. The character tables are now in a separate module whose source is generated
2611     by an auxiliary program - but can then be edited by hand if required. There are
2612     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2613     toupper() in the code.
2615     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2616     make them global. Abolish the function for setting them, as the caller can now
2617     set them directly.
2620     Version 0.92 11-Sep-97
2621     ----------------------
2623     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2624     (e.g. /a{1,3}/) was broken (I mis-optimized it).
2626     2. Caseless matching was not working in character classes if the characters in
2627     the pattern were in upper case.
2629     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2631     4. Make PCRE_ANCHORED public and accept as a compile option.
2633     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2634     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2635     pass them.
2637     6. Give an error if bad option bits passed at compile or run time.
2639     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2640     pcretest to cause it to pass that flag.
2642     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2643     options, and the first character, if set.
2645     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2648     Version 0.91 10-Sep-97
2649     ----------------------
2651     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2652     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2654     2. PCRE was looping on encountering an indefinitely repeated back reference to
2655     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2656     Perl does - treats the match as successful.
2658     ****


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