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Revision 101 - (hide annotations) (download)
Tue Mar 6 15:19:44 2007 UTC (8 years, 1 month ago) by ph10
File size: 120725 byte(s)
Updated the support (such as it is) for Virtual Pascal, thanks to Stefan 
Weber: (1) pcre_internal.h was missing some function renames; (2) updated 
makevp.bat for the current PCRE, using the additional files !compile.txt, 
!linklib.txt, and pcregexp.pas.

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 98 Version 7.1 05-Mar-07
5     ---------------------
7     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
8 ph10 99 that is more "standard", making use of automake and other autotools. There
9     is some re-arrangement of the files and adjustment of comments consequent
10     on this.
12 ph10 100 2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
13     for recursive directory scanning broke on some systems because the files
14     are not scanned in any specific order and on different systems the order
15     was different. A call to "sort" has been inserted into RunGrepTest for the
16     approprate test as a short-term fix. In the longer term there may be an
17     alternative.
19     3. I had an email from Eric Raymond about problems translating some of PCRE's
20 ph10 99 man pages to HTML (despite the fact that I distribute HTML pages, some
21     people do their own conversions for various reasons). The problems
22     concerned the use of low-level troff macros .br and .in. I have therefore
23     removed all such uses from the man pages (some were redundant, some could
24     be replaced by .nf/.fi pairs). The maintain/132html script that I use to
25     generate HTML has been updated to handle .nf/.fi and to complain if it
26     encounters .br or .in.
28 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
29     arranged for config.h to be included in the distribution, for the benefit
30     of those who have to compile without Autotools (compare pcre.h).
32 ph10 101 5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
33     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
34     makevp.bat for the current PCRE, using the additional files !compile.txt,
35     !linklib.txt, and pcregexp.pas.
37 ph10 98
38 nigel 93 Version 7.0 19-Dec-06
39     ---------------------
41     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
42     moving to gcc 4.1.1.
44     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
45     sys/time.h, which is documented as needed for this function. It doesn't
46     seem to matter on Linux, but it showed up on some releases of OS X.
48     3. It seems that there are systems where bytes whose values are greater than
49     127 match isprint() in the "C" locale. The "C" locale should be the
50     default when a C program starts up. In most systems, only ASCII printing
51     characters match isprint(). This difference caused the output from pcretest
52     to vary, making some of the tests fail. I have changed pcretest so that:
54     (a) When it is outputting text in the compiled version of a pattern, bytes
55     other than 32-126 are always shown as hex escapes.
57     (b) When it is outputting text that is a matched part of a subject string,
58     it does the same, unless a different locale has been set for the match
59     (using the /L modifier). In this case, it uses isprint() to decide.
61     4. Fixed a major bug that caused incorrect computation of the amount of memory
62     required for a compiled pattern when options that changed within the
63     pattern affected the logic of the preliminary scan that determines the
64     length. The relevant options are -x, and -i in UTF-8 mode. The result was
65     that the computed length was too small. The symptoms of this bug were
66     either the PCRE error "internal error: code overflow" from pcre_compile(),
67     or a glibc crash with a message such as "pcretest: free(): invalid next
68     size (fast)". Examples of patterns that provoked this bug (shown in
69     pcretest format) are:
71     /(?-x: )/x
72     /(?x)(?-x: \s*#\s*)/
73     /((?i)[\x{c0}])/8
74     /(?i:[\x{c0}])/8
76     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
77     is now done differently.
79     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
80     wrapper classes; (b) implement a new function in the C++ scanner that is
81     more efficient than the old way of doing things because it avoids levels of
82     recursion in the regex matching; (c) add a paragraph to the documentation
83     for the FullMatch() function.
85     6. The escape sequence \n was being treated as whatever was defined as
86     "newline". Not only was this contrary to the documentation, which states
87     that \n is character 10 (hex 0A), but it also went horribly wrong when
88     "newline" was defined as CRLF. This has been fixed.
90     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
91     was being set to -1 for the "end of line" case (supposedly a value that no
92     character can have). Though this value is never used (the check for end of
93     line is "zero bytes in current character"), it caused compiler complaints.
94     I've changed it to 0xffffffff.
96     8. In pcre_version.c, the version string was being built by a sequence of
97     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
98     string (as it is for production releases) called a macro with an empty
99     argument. The C standard says the result of this is undefined. The gcc
100     compiler treats it as an empty string (which was what was wanted) but it is
101     reported that Visual C gives an error. The source has been hacked around to
102     avoid this problem.
104     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
105     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
106     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
107     of them did).
109     10. Originally, pcretest opened its input and output without "b"; then I was
110     told that "b" was needed in some environments, so it was added for release
111     5.0 to both the input and output. (It makes no difference on Unix-like
112     systems.) Later I was told that it is wrong for the input on Windows. I've
113     now abstracted the modes into two macros, to make it easier to fiddle with
114     them, and removed "b" from the input mode under Windows.
116     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
118     12. Added -help and --help to pcretest as an official way of being reminded
119     of the options.
121     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
122     and pcrecpp.cc because they annoy compilers at high warning levels.
124     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
126     15. Fixed an occurrence of == in configure.ac that should have been = (shell
127     scripts are not C programs :-) and which was not noticed because it works
128     on Linux.
130     16. pcretest is supposed to handle any length of pattern and data line (as one
131     line or as a continued sequence of lines) by extending its input buffer if
132     necessary. This feature was broken for very long pattern lines, leading to
133     a string of junk being passed to pcre_compile() if the pattern was longer
134     than about 50K.
136     17. I have done a major re-factoring of the way pcre_compile() computes the
137     amount of memory needed for a compiled pattern. Previously, there was code
138     that made a preliminary scan of the pattern in order to do this. That was
139     OK when PCRE was new, but as the facilities have expanded, it has become
140     harder and harder to keep it in step with the real compile phase, and there
141     have been a number of bugs (see for example, 4 above). I have now found a
142     cunning way of running the real compile function in a "fake" mode that
143     enables it to compute how much memory it would need, while actually only
144     ever using a few hundred bytes of working memory and without too many
145     tests of the mode. This should make future maintenance and development
146     easier. A side effect of this work is that the limit of 200 on the nesting
147     depth of parentheses has been removed (though this was never a serious
148     limitation, I suspect). However, there is a downside: pcre_compile() now
149     runs more slowly than before (30% or more, depending on the pattern). I
150     hope this isn't a big issue. There is no effect on runtime performance.
152     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
153     newline (only possible for the last line of a file) and it was a
154     pattern that set a locale (followed by /Lsomething), pcretest crashed.
156     19. Added additional timing features to pcretest. (1) The -tm option now times
157     matching only, not compiling. (2) Both -t and -tm can be followed, as a
158     separate command line item, by a number that specifies the number of
159     repeats to use when timing. The default is 50000; this gives better
160     precision, but takes uncomfortably long for very large patterns.
162     20. Extended pcre_study() to be more clever in cases where a branch of a
163     subpattern has no definite first character. For example, (a*|b*)[cd] would
164     previously give no result from pcre_study(). Now it recognizes that the
165     first character must be a, b, c, or d.
167     21. There was an incorrect error "recursive call could loop indefinitely" if
168     a subpattern (or the entire pattern) that was being tested for matching an
169     empty string contained only one non-empty item after a nested subpattern.
170     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
171     incorrectly, because the \d was being skipped in the check.
173     22. The pcretest program now has a new pattern option /B and a command line
174     option -b, which is equivalent to adding /B to every pattern. This causes
175     it to show the compiled bytecode, without the additional information that
176     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
177     is the same as /B/I).
179     23. A new optimization is now able automatically to treat some sequences such
180     as a*b as a*+b. More specifically, if something simple (such as a character
181     or a simple class like \d) has an unlimited quantifier, and is followed by
182     something that cannot possibly match the quantified thing, the quantifier
183     is automatically "possessified".
185     24. A recursive reference to a subpattern whose number was greater than 39
186     went wrong under certain circumstances in UTF-8 mode. This bug could also
187     have affected the operation of pcre_study().
189     25. Realized that a little bit of performance could be had by replacing
190     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
192     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
194     27. Possessive quantifiers such as a++ were previously implemented by turning
195     them into atomic groups such as ($>a+). Now they have their own opcodes,
196     which improves performance. This includes the automatically created ones
197     from 23 above.
199     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
200     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
201     the first matched character to be a colon. This applied both to named and
202     numbered groups.
204     29. The ucpinternal.h header file was missing its idempotency #ifdef.
206     30. I was sent a "project" file called libpcre.a.dev which I understand makes
207     building PCRE on Windows easier, so I have included it in the distribution.
209     31. There is now a check in pcretest against a ridiculously large number being
210     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
211     loop, the loop is abandoned.
213     32. Forward references to subpatterns in conditions such as (?(2)...) where
214     subpattern 2 is defined later cause pcre_compile() to search forwards in
215     the pattern for the relevant set of parentheses. This search went wrong
216     when there were unescaped parentheses in a character class, parentheses
217     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
219     33. "Subroutine" calls and backreferences were previously restricted to
220     referencing subpatterns earlier in the regex. This restriction has now
221     been removed.
223     34. Added a number of extra features that are going to be in Perl 5.10. On the
224     whole, these are just syntactic alternatives for features that PCRE had
225     previously implemented using the Python syntax or my own invention. The
226     other formats are all retained for compatibility.
228     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
229     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
230     also .NET compatible.
232     (b) A recursion or subroutine call to a named group can now be defined as
233     (?&name) as well as (?P>name).
235     (c) A backreference to a named group can now be defined as \k<name> or
236     \k'name' as well as (?P=name). The new forms, as well as being in Perl
237     5.10, are also .NET compatible.
239     (d) A conditional reference to a named group can now use the syntax
240     (?(<name>) or (?('name') as well as (?(name).
242     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
243     groups (named and numbered) that are never evaluated inline, but can be
244     called as "subroutines" from elsewhere. In effect, the DEFINE condition
245     is always false. There may be only one alternative in such a group.
247     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
248     as the simple (?(R). The condition is true only if the most recent
249     recursion is that of the given number or name. It does not search out
250     through the entire recursion stack.
252     (g) The escape \gN or \g{N} has been added, where N is a positive or
253     negative number, specifying an absolute or relative reference.
255     35. Tidied to get rid of some further signed/unsigned compiler warnings and
256     some "unreachable code" warnings.
258     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
259     things, this adds five new scripts.
261     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
262     There were also incompatibilities regarding the handling of \Q..\E inside
263     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
264     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
266     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
267     matches an empty string, and forcibly breaks the loop. There were bugs in
268     this code in non-simple cases. For a pattern such as ^(a()*)* matched
269     against aaaa the result was just "a" rather than "aaaa", for example. Two
270     separate and independent bugs (that affected different cases) have been
271     fixed.
273     39. Refactored the code to abolish the use of different opcodes for small
274     capturing bracket numbers. This is a tidy that I avoided doing when I
275     removed the limit on the number of capturing brackets for 3.5 back in 2001.
276     The new approach is not only tidier, it makes it possible to reduce the
277     memory needed to fix the previous bug (38).
279     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
280     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
281     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
282     mode.
284     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
285     report.
287     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
288     copy construction and assignment in the C++ wrapper.
290     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
291     couple of bugs that could have given wrong results in the "--newline=crlf"
292     case.
294     44. Added a number of casts and did some reorganization of signed/unsigned int
295     variables following suggestions from Dair Grant. Also renamed the variable
296     "this" as "item" because it is a C++ keyword.
298     45. Arranged for dftables to add
300     #include "pcre_internal.h"
302     to pcre_chartables.c because without it, gcc 4.x may remove the array
303     definition from the final binary if PCRE is built into a static library and
304     dead code stripping is activated.
306     46. For an unanchored pattern, if a match attempt fails at the start of a
307     newline sequence, and the newline setting is CRLF or ANY, and the next two
308     characters are CRLF, advance by two characters instead of one.
311 nigel 91 Version 6.7 04-Jul-06
312     ---------------------
314     1. In order to handle tests when input lines are enormously long, pcretest has
315     been re-factored so that it automatically extends its buffers when
316     necessary. The code is crude, but this _is_ just a test program. The
317     default size has been increased from 32K to 50K.
319     2. The code in pcre_study() was using the value of the re argument before
320     testing it for NULL. (Of course, in any sensible call of the function, it
321     won't be NULL.)
323     3. The memmove() emulation function in pcre_internal.h, which is used on
324     systems that lack both memmove() and bcopy() - that is, hardly ever -
325     was missing a "static" storage class specifier.
327     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
328     containing an extended class (one that cannot be represented by a bitmap
329     because it contains high-valued characters or Unicode property items, e.g.
330     [\pZ]). Almost always one would set UTF-8 mode when processing such a
331     pattern, but PCRE should not loop if you do not (it no longer does).
332     [Detail: two cases were found: (a) a repeated subpattern containing an
333     extended class; (b) a recursive reference to a subpattern that followed a
334     previous extended class. It wasn't skipping over the extended class
335     correctly when UTF-8 mode was not set.]
337     5. A negated single-character class was not being recognized as fixed-length
338     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
339     compile error "lookbehind assertion is not fixed length".
341     6. The RunPerlTest auxiliary script was showing an unexpected difference
342     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
343     write a Perl script that can interpret lines of an input file either as
344     byte characters or as UTF-8, which is what "perltest" was being required to
345     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
346     can't do is switch easily at run time between having the "use utf8;" pragma
347     or not. In the end, I fudged it by using the RunPerlTest script to insert
348     "use utf8;" explicitly for the UTF-8 tests.
350     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
351     the end of the subject string, contrary to the documentation and to what
352     Perl does. This was true of both matching functions. Now it matches only at
353     the start of the subject and immediately after *internal* newlines.
355     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
356     a pointer to an int instead of a pointer to an unsigned long int. This
357     caused problems on 64-bit systems.
359     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
360     instance of the 'standard' template library not being so standard".
362     10. There was no check on the number of named subpatterns nor the maximum
363     length of a subpattern name. The product of these values is used to compute
364     the size of the memory block for a compiled pattern. By supplying a very
365     long subpattern name and a large number of named subpatterns, the size
366     computation could be caused to overflow. This is now prevented by limiting
367     the length of names to 32 characters, and the number of named subpatterns
368     to 10,000.
370     11. Subpatterns that are repeated with specific counts have to be replicated in
371     the compiled pattern. The size of memory for this was computed from the
372     length of the subpattern and the repeat count. The latter is limited to
373     65535, but there was no limit on the former, meaning that integer overflow
374     could in principle occur. The compiled length of a repeated subpattern is
375     now limited to 30,000 bytes in order to prevent this.
377     12. Added the optional facility to have named substrings with the same name.
379     13. Added the ability to use a named substring as a condition, using the
380     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
381     are numbers (not recommended). Forward references are permitted.
383     14. Added forward references in named backreferences (if you see what I mean).
385     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
386     pattern could run off the end of the subject. For example, the pattern
387     "(?s)(.{1,5})"8 did this with the subject "ab".
389     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
390     PCRE_CASELESS was set when matching characters that were quantified with ?
391     or *.
393     17. A character class other than a single negated character that had a minimum
394     but no maximum quantifier - for example [ab]{6,} - was not handled
395     correctly by pce_dfa_exec(). It would match only one character.
397     18. A valid (though odd) pattern that looked like a POSIX character
398     class but used an invalid character after [ (for example [[,abc,]]) caused
399     pcre_compile() to give the error "Failed: internal error: code overflow" or
400     in some cases to crash with a glibc free() error. This could even happen if
401     the pattern terminated after [[ but there just happened to be a sequence of
402     letters, a binary zero, and a closing ] in the memory that followed.
404     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
405     over the years. Originally (before any Unicode support), just the bottom 8
406     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
407     output from "man perlunicode" includes this:
409     The regular expression compiler produces polymorphic opcodes. That
410     is, the pattern adapts to the data and automatically switches to
411     the Unicode character scheme when presented with Unicode data--or
412     instead uses a traditional byte scheme when presented with byte
413     data.
415     Sadly, a wide octal escape does not cause a switch, and in a string with
416     no other multibyte characters, these octal escapes are treated as before.
417     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
418     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
419     Unicode string.
421     I have not perpetrated such confusion in PCRE. Up till now, it took just
422     the bottom 8 bits, as in old Perl. I have now made octal escapes with
423     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
424     translate to the appropriate multibyte character.
426     29. Applied some refactoring to reduce the number of warnings from Microsoft
427     and Borland compilers. This has included removing the fudge introduced
428     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
429     a warning about an unused variable.
431     21. PCRE has not included VT (character 0x0b) in the set of whitespace
432     characters since release 4.0, because Perl (from release 5.004) does not.
433     [Or at least, is documented not to: some releases seem to be in conflict
434     with the documentation.] However, when a pattern was studied with
435     pcre_study() and all its branches started with \s, PCRE still included VT
436     as a possible starting character. Of course, this did no harm; it just
437     caused an unnecessary match attempt.
439     22. Removed a now-redundant internal flag bit that recorded the fact that case
440     dependency changed within the pattern. This was once needed for "required
441     byte" processing, but is no longer used. This recovers a now-scarce options
442     bit. Also moved the least significant internal flag bit to the most-
443     significant bit of the word, which was not previously used (hangover from
444     the days when it was an int rather than a uint) to free up another bit for
445     the future.
447     23. Added support for CRLF line endings as well as CR and LF. As well as the
448     default being selectable at build time, it can now be changed at runtime
449     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
450     specify that it is scanning data with non-default line endings.
452     24. Changed the definition of CXXLINK to make it agree with the definition of
453     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
455     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
456     recursions. This makes a big different to stack usage for some patterns.
458     26. If a subpattern containing a named recursion or subroutine reference such
459     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
460     the space required for the compiled pattern went wrong and gave too small a
461     value. Depending on the environment, this could lead to "Failed: internal
462     error: code overflow at offset 49" or "glibc detected double free or
463     corruption" errors.
465     27. Applied patches from Google (a) to support the new newline modes and (b) to
466     advance over multibyte UTF-8 characters in GlobalReplace.
468     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
469     difference for some implementation of PCRE in some Windows version.
471     29. Added some extra testing facilities to pcretest:
473     \q<number> in a data line sets the "match limit" value
474     \Q<number> in a data line sets the "match recursion limt" value
475     -S <number> sets the stack size, where <number> is in megabytes
477     The -S option isn't available for Windows.
480 nigel 89 Version 6.6 06-Feb-06
481     ---------------------
483     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
484     in pcreposix.h. I have copied the definition from pcre.h.
486     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
487     because pcre.h is no longer a built file.
489     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
490     not normally included in the compiled code.
493 nigel 87 Version 6.5 01-Feb-06
494     ---------------------
496     1. When using the partial match feature with pcre_dfa_exec(), it was not
497     anchoring the second and subsequent partial matches at the new starting
498     point. This could lead to incorrect results. For example, with the pattern
499     /1234/, partially matching against "123" and then "a4" gave a match.
501     2. Changes to pcregrep:
503     (a) All non-match returns from pcre_exec() were being treated as failures
504     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
505     error message is output. Some extra information is given for the
507     probably the only errors that are likely to be caused by users (by
508     specifying a regex that has nested indefinite repeats, for instance).
509     If there are more than 20 of these errors, pcregrep is abandoned.
511     (b) A binary zero was treated as data while matching, but terminated the
512     output line if it was written out. This has been fixed: binary zeroes
513     are now no different to any other data bytes.
515     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
516     used to set a locale for matching. The --locale=xxxx long option has
517     been added (no short equivalent) to specify a locale explicitly on the
518     pcregrep command, overriding the environment variables.
520     (d) When -B was used with -n, some line numbers in the output were one less
521     than they should have been.
523     (e) Added the -o (--only-matching) option.
525     (f) If -A or -C was used with -c (count only), some lines of context were
526     accidentally printed for the final match.
528     (g) Added the -H (--with-filename) option.
530     (h) The combination of options -rh failed to suppress file names for files
531     that were found from directory arguments.
533     (i) Added the -D (--devices) and -d (--directories) options.
535     (j) Added the -F (--fixed-strings) option.
537     (k) Allow "-" to be used as a file name for -f as well as for a data file.
539     (l) Added the --colo(u)r option.
541     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
542     is not present by default.
544     3. A nasty bug was discovered in the handling of recursive patterns, that is,
545     items such as (?R) or (?1), when the recursion could match a number of
546     alternatives. If it matched one of the alternatives, but subsequently,
547     outside the recursion, there was a failure, the code tried to back up into
548     the recursion. However, because of the way PCRE is implemented, this is not
549     possible, and the result was an incorrect result from the match.
551     In order to prevent this happening, the specification of recursion has
552     been changed so that all such subpatterns are automatically treated as
553     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
555     4. I had overlooked the fact that, in some locales, there are characters for
556     which isalpha() is true but neither isupper() nor islower() are true. In
557     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
558     and ordfeminine) are like this. This affected the treatment of \w and \W
559     when they appeared in character classes, but not when they appeared outside
560     a character class. The bit map for "word" characters is now created
561     separately from the results of isalnum() instead of just taking it from the
562     upper, lower, and digit maps. (Plus the underscore character, of course.)
564     5. The above bug also affected the handling of POSIX character classes such as
565     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
566     permanent tables. Instead, the bit maps for such a class were previously
567     created as the appropriate unions of the upper, lower, and digit bitmaps.
568     Now they are created by subtraction from the [[:word:]] class, which has
569     its own bitmap.
571     6. The [[:blank:]] character class matches horizontal, but not vertical space.
572     It is created by subtracting the vertical space characters (\x09, \x0a,
573     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
574     subtraction was done in the overall bitmap for a character class, meaning
575     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
576     be recognized. This bug has been fixed.
578     7. Patches from the folks at Google:
580     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
581     real life, but is still worth protecting against".
583     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
584     regular expressions".
586     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
587     have it.
589     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
590     "configure" and the latter not, in order to fix a problem somebody had
591     with compiling the Arg class on HP-UX.
593     (e) Improve the error-handling of the C++ wrapper a little bit.
595     (f) New tests for checking recursion limiting.
597     8. The pcre_memmove() function, which is used only if the environment does not
598     have a standard memmove() function (and is therefore rarely compiled),
599     contained two bugs: (a) use of int instead of size_t, and (b) it was not
600     returning a result (though PCRE never actually uses the result).
602     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
603     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
604     returned instead of calling malloc() with an overflowing number that would
605     most likely cause subsequent chaos.
607     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
609     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
610     with this option is matched, the nmatch and pmatch options of regexec() are
611     ignored.
613     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
614     provided in case anyone wants to the the POSIX interface with UTF-8
615     strings.
617     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
618     C++ linking (needed for some HP-UX environments).
620     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
621     (unused parameter) and in the pcre_printint() function (omitted "default"
622     switch label when the default is to do nothing).
624     15. Added some code to make it possible, when PCRE is compiled as a C++
625     library, to replace subject pointers for pcre_exec() with a smart pointer
626     class, thus making it possible to process discontinuous strings.
628     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
629     much the same function. They were added by different people who were trying
630     to make PCRE easy to compile on non-Unix systems. It has been suggested
631     that PCRE_EXPORT be abolished now that there is more automatic apparatus
632     for compiling on Windows systems. I have therefore replaced it with
633     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
634     defaults to "extern" for C or "extern C" for C++, which works fine on
635     Unix-like systems. It is now possible to override the value of PCRE_DATA_
636     SCOPE with something explicit in config.h. In addition:
638     (a) pcreposix.h still had just "extern" instead of either of these macros;
639     I have replaced it with PCRE_DATA_SCOPE.
641     (b) Functions such as _pcre_xclass(), which are internal to the library,
642     but external in the C sense, all had PCRE_EXPORT in their definitions.
643     This is apparently wrong for the Windows case, so I have removed it.
644     (It makes no difference on Unix-like systems.)
646     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
647     of recursive calls to match(). This is different to MATCH_LIMIT because
648     that limits the total number of calls to match(), not all of which increase
649     the depth of recursion. Limiting the recursion depth limits the amount of
650     stack (or heap if NO_RECURSE is set) that is used. The default can be set
651     when PCRE is compiled, and changed at run time. A patch from Google adds
652     this functionality to the C++ interface.
654     18. Changes to the handling of Unicode character properties:
656     (a) Updated the table to Unicode 4.1.0.
658     (b) Recognize characters that are not in the table as "Cn" (undefined).
660     (c) I revised the way the table is implemented to a much improved format
661     which includes recognition of ranges. It now supports the ranges that
662     are defined in UnicodeData.txt, and it also amalgamates other
663     characters into ranges. This has reduced the number of entries in the
664     table from around 16,000 to around 3,000, thus reducing its size
665     considerably. I realized I did not need to use a tree structure after
666     all - a binary chop search is just as efficient. Having reduced the
667     number of entries, I extended their size from 6 bytes to 8 bytes to
668     allow for more data.
670     (d) Added support for Unicode script names via properties such as \p{Han}.
672     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
673     matching that character.
675     20. When matching a repeated Unicode property with a minimum greater than zero,
676     (for example \pL{2,}), PCRE could look past the end of the subject if it
677     reached it while seeking the minimum number of characters. This could
678     happen only if some of the characters were more than one byte long, because
679     there is a check for at least the minimum number of bytes.
681     21. Refactored the implementation of \p and \P so as to be more general, to
682     allow for more different types of property in future. This has changed the
683     compiled form incompatibly. Anybody with saved compiled patterns that use
684     \p or \P will have to recompile them.
686     22. Added "Any" and "L&" to the supported property types.
688     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
689     but give a compile time error if the value is greater than 0xff.
691     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
692     accidentally not being installed or uninstalled.
694     25. The pcre.h file was built from pcre.h.in, but the only changes that were
695     made were to insert the current release number. This seemed silly, because
696     it made things harder for people building PCRE on systems that don't run
697     "configure". I have turned pcre.h into a distributed file, no longer built
698     by "configure", with the version identification directly included. There is
699     no longer a pcre.h.in file.
701     However, this change necessitated a change to the pcre-config script as
702     well. It is built from pcre-config.in, and one of the substitutions was the
703     release number. I have updated configure.ac so that ./configure now finds
704     the release number by grepping pcre.h.
706     26. Added the ability to run the tests under valgrind.
709 nigel 85 Version 6.4 05-Sep-05
710     ---------------------
712     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
713     "--" to be printed when multiple files were scanned, even when none of the
714     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
715     consider it to be a bug, and have restored the previous behaviour.
717     2. A couple of code tidies to get rid of compiler warnings.
719     3. The pcretest program used to cheat by referring to symbols in the library
720     whose names begin with _pcre_. These are internal symbols that are not
721     really supposed to be visible externally, and in some environments it is
722     possible to suppress them. The cheating is now confined to including
723     certain files from the library's source, which is a bit cleaner.
725     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
726     file's purpose clearer.
728     5. Reorganized pcre_ucp_findchar().
731 nigel 83 Version 6.3 15-Aug-05
732     ---------------------
734     1. The file libpcre.pc.in did not have general read permission in the tarball.
736     2. There were some problems when building without C++ support:
738     (a) If C++ support was not built, "make install" and "make test" still
739     tried to test it.
741     (b) There were problems when the value of CXX was explicitly set. Some
742     changes have been made to try to fix these, and ...
744     (c) --disable-cpp can now be used to explicitly disable C++ support.
746     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
747     backslash in a target when C++ was disabled. This confuses some
748     versions of "make", apparently. Using an intermediate variable solves
749     this. (Same for CPP_LOBJ.)
751     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
752     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
753     necessary on certain architectures.
755     4. Added a setting of -export-symbols-regex to the link command to remove
756     those symbols that are exported in the C sense, but actually are local
757     within the library, and not documented. Their names all begin with
758     "_pcre_". This is not a perfect job, because (a) we have to except some
759     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
760     available (and never for static libraries). I have made a note to try to
761     find a way round (a) in the future.
764 nigel 81 Version 6.2 01-Aug-05
765     ---------------------
767     1. There was no test for integer overflow of quantifier values. A construction
768     such as {1111111111111111} would give undefined results. What is worse, if
769     a minimum quantifier for a parenthesized subpattern overflowed and became
770     negative, the calculation of the memory size went wrong. This could have
771     led to memory overwriting.
773     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
775     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
776     operating environments where this matters.
778     4. Applied Giuseppe Maxia's patch to add additional features for controlling
779     PCRE options from within the C++ wrapper.
781     5. Named capturing subpatterns were not being correctly counted when a pattern
782     was compiled. This caused two problems: (a) If there were more than 100
783     such subpatterns, the calculation of the memory needed for the whole
784     compiled pattern went wrong, leading to an overflow error. (b) Numerical
785     back references of the form \12, where the number was greater than 9, were
786     not recognized as back references, even though there were sufficient
787     previous subpatterns.
789     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
790     versions of gcc, e.g. 2.95.4.
793 nigel 79 Version 6.1 21-Jun-05
794     ---------------------
796     1. There was one reference to the variable "posix" in pcretest.c that was not
797     surrounded by "#if !defined NOPOSIX".
799     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
800     the cross-check on the old pcre_info() function, for the benefit of the
801     cut-down version of PCRE that is currently imported into Exim.
803     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
804     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
805     patterns that start (?i) but I don't think that matters. The use of (?i) is
806     just an example; this all applies to the other options as well.
808     4. Since libtool seems to echo the compile commands it is issuing, the output
809     from "make" can be reduced a bit by putting "@" in front of each libtool
810     compile command.
812     5. Patch from the folks at Google for configure.in to be a bit more thorough
813     in checking for a suitable C++ installation before trying to compile the
814     C++ stuff. This should fix a reported problem when a compiler was present,
815     but no suitable headers.
817     6. The man pages all had just "PCRE" as their title. I have changed them to
818     be the relevant file name. I have also arranged that these names are
819     retained in the file doc/pcre.txt, which is a concatenation in text format
820     of all the man pages except the little individual ones for each function.
822     7. The NON-UNIX-USE file had not been updated for the different set of source
823     files that come with release 6. I also added a few comments about the C++
824     wrapper.
827 nigel 77 Version 6.0 07-Jun-05
828     ---------------------
830     1. Some minor internal re-organization to help with my DFA experiments.
832     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
833     didn't matter for the library itself when fully configured, but did matter
834     when compiling without UCP support, or within Exim, where the ucp files are
835     not imported.
837     3. Refactoring of the library code to split up the various functions into
838     different source modules. The addition of the new DFA matching code (see
839     below) to a single monolithic source would have made it really too
840     unwieldy, quite apart from causing all the code to be include in a
841     statically linked application, when only some functions are used. This is
842     relevant even without the DFA addition now that patterns can be compiled in
843     one application and matched in another.
845     The downside of splitting up is that there have to be some external
846     functions and data tables that are used internally in different modules of
847     the library but which are not part of the API. These have all had their
848     names changed to start with "_pcre_" so that they are unlikely to clash
849     with other external names.
851     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
852     a different (DFA) algorithm. Although it is slower than the original
853     function, it does have some advantages for certain types of matching
854     problem.
856     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
857     including restarting after a partial match.
859     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
860     defined when compiling for Windows was sent to me. I have put it into the
861     code, though I have no means of testing or verifying it.
863     7. Added the pcre_refcount() auxiliary function.
865     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
866     match before or at the first newline in the subject string. In pcretest,
867     the /f option on a pattern can be used to set this.
869     9. A repeated \w when used in UTF-8 mode with characters greater than 256
870     would behave wrongly. This has been present in PCRE since release 4.0.
872     10. A number of changes to the pcregrep command:
874     (a) Refactored how -x works; insert ^(...)$ instead of setting
875     PCRE_ANCHORED and checking the length, in preparation for adding
876     something similar for -w.
878     (b) Added the -w (match as a word) option.
880     (c) Refactored the way lines are read and buffered so as to have more
881     than one at a time available.
883     (d) Implemented a pcregrep test script.
885     (e) Added the -M (multiline match) option. This allows patterns to match
886     over several lines of the subject. The buffering ensures that at least
887     8K, or the rest of the document (whichever is the shorter) is available
888     for matching (and similarly the previous 8K for lookbehind assertions).
890     (f) Changed the --help output so that it now says
892     -w, --word-regex(p)
894     instead of two lines, one with "regex" and the other with "regexp"
895     because that confused at least one person since the short forms are the
896     same. (This required a bit of code, as the output is generated
897     automatically from a table. It wasn't just a text change.)
899     (g) -- can be used to terminate pcregrep options if the next thing isn't an
900     option but starts with a hyphen. Could be a pattern or a path name
901     starting with a hyphen, for instance.
903     (h) "-" can be given as a file name to represent stdin.
905     (i) When file names are being printed, "(standard input)" is used for
906     the standard input, for compatibility with GNU grep. Previously
907     "<stdin>" was used.
909     (j) The option --label=xxx can be used to supply a name to be used for
910     stdin when file names are being printed. There is no short form.
912     (k) Re-factored the options decoding logic because we are going to add
913     two more options that take data. Such options can now be given in four
914     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
916     (l) Added the -A, -B, and -C options for requesting that lines of context
917     around matches be printed.
919     (m) Added the -L option to print the names of files that do not contain
920     any matching lines, that is, the complement of -l.
922     (n) The return code is 2 if any file cannot be opened, but pcregrep does
923     continue to scan other files.
925     (o) The -s option was incorrectly implemented. For compatibility with other
926     greps, it now suppresses the error message for a non-existent or non-
927     accessible file (but not the return code). There is a new option called
928     -q that suppresses the output of matching lines, which was what -s was
929     previously doing.
931     (p) Added --include and --exclude options to specify files for inclusion
932     and exclusion when recursing.
934     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
935     Hopefully, it now does.
937     12. Missing cast in pcre_study().
939     13. Added an "uninstall" target to the makefile.
941     14. Replaced "extern" in the function prototypes in Makefile.in with
942     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
943     world, but is set differently for Windows.
945     15. Added a second compiling function called pcre_compile2(). The only
946     difference is that it has an extra argument, which is a pointer to an
947     integer error code. When there is a compile-time failure, this is set
948     non-zero, in addition to the error test pointer being set to point to an
949     error message. The new argument may be NULL if no error number is required
950     (but then you may as well call pcre_compile(), which is now just a
951     wrapper). This facility is provided because some applications need a
952     numeric error indication, but it has also enabled me to tidy up the way
953     compile-time errors are handled in the POSIX wrapper.
955     16. Added VPATH=.libs to the makefile; this should help when building with one
956     prefix path and installing with another. (Or so I'm told by someone who
957     knows more about this stuff than I do.)
959     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
960     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
961     match everything, including newlines. This is not POSIX-compatible, but
962     somebody wanted the feature. From pcretest it can be activated by using
963     both the P and the s flags.
965     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
967     19. libpcre.pc was being incorrectly installed as executable.
969     20. A couple of places in pcretest check for end-of-line by looking for '\n';
970     it now also looks for '\r' so that it will work unmodified on Windows.
972     21. Added Google's contributed C++ wrapper to the distribution.
974     22. Added some untidy missing memory free() calls in pcretest, to keep
975     Electric Fence happy when testing.
979 nigel 75 Version 5.0 13-Sep-04
980     ---------------------
982     1. Internal change: literal characters are no longer packed up into items
983     containing multiple characters in a single byte-string. Each character
984     is now matched using a separate opcode. However, there may be more than one
985     byte in the character in UTF-8 mode.
987     2. The pcre_callout_block structure has two new fields: pattern_position and
988     next_item_length. These contain the offset in the pattern to the next match
989     item, and its length, respectively.
991     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
992     insertion of callouts before each pattern item. Added the /C option to
993     pcretest to make use of this.
995     4. On the advice of a Windows user, the lines
997     #if defined(_WIN32) || defined(WIN32)
998     _setmode( _fileno( stdout ), 0x8000 );
999     #endif /* defined(_WIN32) || defined(WIN32) */
1001     have been added to the source of pcretest. This apparently does useful
1002     magic in relation to line terminators.
1004     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1005     for the benefit of those environments where the "b" makes a difference.
1007     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1008     to know about it. I have put a hack into configure.in that adds in code
1009     to set GCC=yes if CC=icc. This seems to end up at a point in the
1010     generated configure script that is early enough to affect the setting of
1011     compiler options, which is what is needed, but I have no means of testing
1012     whether it really works. (The user who reported this had patched the
1013     generated configure script, which of course I cannot do.)
1015     LATER: After change 22 below (new libtool files), the configure script
1016     seems to know about icc (and also ecc). Therefore, I have commented out
1017     this hack in configure.in.
1019     7. Added support for pkg-config (2 patches were sent in).
1021     8. Negated POSIX character classes that used a combination of internal tables
1022     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1023     [[:^ascii]]. Typically, they would match almost any characters. The other
1024     POSIX classes were not broken in this way.
1026     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1027     to find the match, as PCRE was deluded into thinking that the match had to
1028     start at the start point or following a newline. The same bug applied to
1029     patterns with negative forward assertions or any backward assertions
1030     preceding ".*" at the start, unless the pattern required a fixed first
1031     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1033     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1034     starting at the last subject character, bytes beyond the end of the subject
1035     string were read.
1037     11. Renamed the variable "class" as "classbits" to make life easier for C++
1038     users. (Previously there was a macro definition, but it apparently wasn't
1039     enough.)
1041     12. Added the new field "tables" to the extra data so that tables can be passed
1042     in at exec time, or the internal tables can be re-selected. This allows
1043     a compiled regex to be saved and re-used at a later time by a different
1044     program that might have everything at different addresses.
1046     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1047     -R library as well as a -L library.
1049     14. The debugging options of pcretest (-d on the command line or D on a
1050     pattern) showed incorrect output for anything following an extended class
1051     that contained multibyte characters and which was followed by a quantifier.
1053     15. Added optional support for general category Unicode character properties
1054     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1055     support. It adds about 90K to the size of the library. The meanings of the
1056     inbuilt class escapes such as \d and \s have NOT been changed.
1058     16. Updated pcredemo.c to include calls to free() to release the memory for the
1059     compiled pattern.
1061     17. The generated file chartables.c was being created in the source directory
1062     instead of in the building directory. This caused the build to fail if the
1063     source directory was different from the building directory, and was
1064     read-only.
1066     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1067     file. No doubt somebody will tell me if they don't make sense... Also added
1068     Dan Mooney's comments about building on OpenVMS.
1070     19. Added support for partial matching via the PCRE_PARTIAL option for
1071     pcre_exec() and the \P data escape in pcretest.
1073     20. Extended pcretest with 3 new pattern features:
1075     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1076     write the compiled pattern to the file whose name is "rest-of-line".
1077     This is a straight binary dump of the data, with the saved pointer to
1078     the character tables forced to be NULL. The study data, if any, is
1079     written too. After writing, pcretest reads a new pattern.
1081     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1082     compiled pattern from the given file. There must not be any
1083     occurrences of "<" in the file name (pretty unlikely); if there are,
1084     pcretest will instead treat the initial "<" as a pattern delimiter.
1085     After reading in the pattern, pcretest goes on to read data lines as
1086     usual.
1088     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1089     and 16-bit fields in a compiled pattern, to simulate a pattern that
1090     was compiled on a host of opposite endianness.
1092     21. The pcre-exec() function can now cope with patterns that were compiled on
1093     hosts of opposite endianness, with this restriction:
1095     As for any compiled expression that is saved and used later, the tables
1096     pointer field cannot be preserved; the extra_data field in the arguments
1097     to pcre_exec() should be used to pass in a tables address if a value
1098     other than the default internal tables were used at compile time.
1100     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1101     now diagnosed as an error. Previously, most of the time, a negative number
1102     would have been treated as zero, but if in addition "ovector" was passed as
1103     NULL, a crash could occur.
1105     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1106     new versions from the libtool 1.5 distribution (the last one is a copy of
1107     a file called libtool.m4). This seems to have fixed the need to patch
1108     "configure" to support Darwin 1.3 (which I used to do). However, I still
1109     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1110     workstation).
1112     24. Changed the PCRE licence to be the more standard "BSD" licence.
1115 nigel 73 Version 4.5 01-Dec-03
1116     ---------------------
1118     1. There has been some re-arrangement of the code for the match() function so
1119     that it can be compiled in a version that does not call itself recursively.
1120     Instead, it keeps those local variables that need separate instances for
1121     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1122     needs to "recurse". Keeping track of where control must go is done by means
1123     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1124     hide most of the details from the main code, and operates only if
1125     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1126     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1127     operating.
1129     To make it easier for callers to provide specially tailored get/free
1130     functions for this usage, two new functions, pcre_stack_malloc, and
1131     pcre_stack_free, are used. They are always called in strict stacking order,
1132     and the size of block requested is always the same.
1134     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1135     PCRE has been compiled to use the stack or the heap for recursion. The
1136     -C option of pcretest uses this to show which version is compiled.
1138     A new data escape \S, is added to pcretest; it causes the amounts of store
1139     obtained and freed by both kinds of malloc/free at match time to be added
1140     to the output.
1142     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1143     what's available on my current Linux desktop machine.
1145     3. When matching a UTF-8 string, the test for a valid string at the start has
1146     been extended. If start_offset is not zero, PCRE now checks that it points
1147     to a byte that is the start of a UTF-8 character. If not, it returns
1148     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1149     this is necessary because there may be backward assertions in the pattern.
1150     When matching the same subject several times, it may save resources to use
1151     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1153     4. The code for checking the validity of UTF-8 strings has been tightened so
1154     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1155     containing "overlong sequences".
1157     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1158     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1159     should have been "&", but it just so happened that all the cases this let
1160     through by mistake were picked up later in the function.
1162     6. I had used a variable called "isblank" - this is a C99 function, causing
1163     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1165     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1166     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1167     so the version is shown; (c) stop "make test" echoing "./RunTest".
1169     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1171     9. The prototype for memmove() for systems that don't have it was using
1172     size_t, but the inclusion of the header that defines size_t was later. I've
1173     moved the #includes for the C headers earlier to avoid this.
1175     10. Added some adjustments to the code to make it easier to compiler on certain
1176     special systems:
1178     (a) Some "const" qualifiers were missing.
1179     (b) Added the macro EXPORT before all exported functions; by default this
1180     is defined to be empty.
1181     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1182     that it reads its output file name as an argument instead of writing
1183     to the standard output and assuming this can be redirected.
1185     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1186     class containing characters with values greater than 255, PCRE compilation
1187     went into a loop.
1189     12. A recursive reference to a subpattern that was within another subpattern
1190     that had a minimum quantifier of zero caused PCRE to crash. For example,
1191     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1192     recursion. If the recursively-called subpattern itself had a zero repeat,
1193     that was OK.
1195     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1196     buffer into which it was copied (for escape processing) was still set at
1197     1024, so long lines caused crashes.
1199     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1200     "internal error: code overflow...". This applied to any character class
1201     that was followed by a possessive quantifier.
1203     15. Modified the Makefile to add libpcre.la as a prerequisite for
1204     libpcreposix.la because I was told this is needed for a parallel build to
1205     work.
1207     16. If a pattern that contained .* following optional items at the start was
1208     studied, the wrong optimizing data was generated, leading to matching
1209     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1210     matching string must start with a or b or c. The correct conclusion for
1211     this pattern is that a match can start with any character.
1214 nigel 71 Version 4.4 13-Aug-03
1215     ---------------------
1217     1. In UTF-8 mode, a character class containing characters with values between
1218     127 and 255 was not handled correctly if the compiled pattern was studied.
1219     In fixing this, I have also improved the studying algorithm for such
1220     classes (slightly).
1222     2. Three internal functions had redundant arguments passed to them. Removal
1223     might give a very teeny performance improvement.
1225     3. Documentation bug: the value of the capture_top field in a callout is *one
1226     more than* the number of the hightest numbered captured substring.
1228     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1229     in incorrectly linking with a previously installed version. They now link
1230     explicitly with libpcre.la.
1232     5. configure.in no longer needs to recognize Cygwin specially.
1234     6. A problem in pcre.in for Windows platforms is fixed.
1236     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1237     pcretest, it used to include the size of the study block as part of its
1238     output. Unfortunately, the structure contains a field that has a different
1239     size on different hardware architectures. This meant that the tests that
1240     showed this size failed. As the block is currently always of a fixed size,
1241     this information isn't actually particularly useful in pcretest output, so
1242     I have just removed it.
1244     8. Three pre-processor statements accidentally did not start in column 1.
1245     Sadly, there are *still* compilers around that complain, even though
1246     standard C has not required this for well over a decade. Sigh.
1248     9. In pcretest, the code for checking callouts passed small integers in the
1249     callout_data field, which is a void * field. However, some picky compilers
1250     complained about the casts involved for this on 64-bit systems. Now
1251     pcretest passes the address of the small integer instead, which should get
1252     rid of the warnings.
1254     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1255     both compile and run time, and gives an error if an invalid UTF-8 sequence
1256     is found. There is a option for disabling this check in cases where the
1257     string is known to be correct and/or the maximum performance is wanted.
1259     11. In response to a bug report, I changed one line in Makefile.in from
1261     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1262     to
1263     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1265     to look similar to other lines, but I have no way of telling whether this
1266     is the right thing to do, as I do not use Windows. No doubt I'll get told
1267     if it's wrong...
1270 nigel 69 Version 4.3 21-May-03
1271     ---------------------
1273     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1274     Makefile.
1276     2. Some refactoring to improve the quality of the code:
1278     (i) The utf8_table... variables are now declared "const".
1280     (ii) The code for \cx, which used the "case flipping" table to upper case
1281     lower case letters, now just substracts 32. This is ASCII-specific,
1282     but the whole concept of \cx is ASCII-specific, so it seems
1283     reasonable.
1285     (iii) PCRE was using its character types table to recognize decimal and
1286     hexadecimal digits in the pattern. This is silly, because it handles
1287     only 0-9, a-f, and A-F, but the character types table is locale-
1288     specific, which means strange things might happen. A private
1289     table is now used for this - though it costs 256 bytes, a table is
1290     much faster than multiple explicit tests. Of course, the standard
1291     character types table is still used for matching digits in subject
1292     strings against \d.
1294     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1295     ending in _t are). So I've renamed it as ESC_tee.
1297     3. The first argument for regexec() in the POSIX wrapper should have been
1298     defined as "const".
1300     4. Changed pcretest to use malloc() for its buffers so that they can be
1301     Electric Fenced for debugging.
1303     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1304     to read one or more bytes before the start of the subject string. Often this
1305     had no effect on PCRE's behaviour, but in some circumstances it could
1306     provoke a segmentation fault.
1308     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1309     to try to read one or more bytes before the start of the subject string.
1311     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1312     UTF-8 support could misbehave in various ways if the subject string
1313     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1314     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1315     back over UTF-8 characters.)
1318 nigel 67 Version 4.2 14-Apr-03
1319     ---------------------
1321     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1323     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1324     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1325     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1326     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1327     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1328     and BUILD_EXEEXT
1329     Note: automatic setting of the BUILD variables is not yet working
1330     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1331     compile-time but not at link-time
1332     [LINK]: use for linking executables only
1333     make different versions for Windows and non-Windows
1334     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1335     libraries
1336     [LINK_FOR_BUILD]: new variable
1337     [OBJEXT]: use throughout
1338     [EXEEXT]: use throughout
1339     <winshared>: new target
1340     <wininstall>: new target
1341     <dftables.o>: use native compiler
1342     <dftables>: use native linker
1343     <install>: handle Windows platform correctly
1344     <clean>: ditto
1345     <check>: ditto
1346     copy DLL to top builddir before testing
1348     As part of these changes, -no-undefined was removed again. This was reported
1349     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1350     in any case.
1352     3. Some tidies to get rid of compiler warnings:
1354     . In the match_data structure, match_limit was an unsigned long int, whereas
1355     match_call_count was an int. I've made them both unsigned long ints.
1357     . In pcretest the fact that a const uschar * doesn't automatically cast to
1358     a void * provoked a warning.
1360     . Turning on some more compiler warnings threw up some "shadow" variables
1361     and a few more missing casts.
1363     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1364     option, a class that contained a single character with a value between 128
1365     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1367     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1368     option, a class that contained several characters, but with at least one
1369     whose value was between 128 and 255 caused PCRE to crash.
1372 nigel 65 Version 4.1 12-Mar-03
1373     ---------------------
1374 nigel 63
1375 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1376     needed, and a string in dftables.c that was longer than standard compilers are
1377     required to support.
1379     2. Compiling with Sun's compiler found a few more places where the code could
1380     be tidied up in order to avoid warnings.
1382     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1383     first of these names is deprecated in the latest Autoconf in favour of the name
1384     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1385     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1386     analogy I have changed it to CFLAGS_FOR_BUILD.
1388     4. Added -no-undefined to the linking command in the Makefile, because this is
1389     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1390     linking step for the pcreposix library.
1392     5. PCRE was failing to diagnose the case of two named groups with the same
1393     name.
1395     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1396     literal character that is needed in the subject for a match, and scans along to
1397     ensure that it is present before embarking on the full matching process. This
1398     saves time in cases of nested unlimited repeats that are never going to match.
1399     Problem: the scan can take a lot of time if the subject is very long (e.g.
1400     megabytes), thus penalizing straightforward matches. It is now done only if the
1401     amount of subject to be scanned is less than 1000 bytes.
1403     7. A lesser problem with the same optimization is that it was recording the
1404     first character of an anchored pattern as "needed", thus provoking a search
1405     right along the subject, even when the first match of the pattern was going to
1406     fail. The "needed" character is now not set for anchored patterns, unless it
1407     follows something in the pattern that is of non-fixed length. Thus, it still
1408     fulfils its original purpose of finding quick non-matches in cases of nested
1409     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1412     Version 4.0 17-Feb-03
1413     ---------------------
1415 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1416     extended to the end of string, PCRE compiled incorrect data. This could lead to
1417     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1419     2. Moved to autoconf 2.53 and libtool 1.4.2.
1421     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1422     the special perltest8 script is no longer needed - all the tests can be run
1423     from a single perltest script.
1425     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1426     by \s. It has now been removed in PCRE. This means it isn't recognized as
1427     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1428     class [:space:] *does* include VT, thereby creating a mess.
1430     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1431     space and tab.
1433     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1434     its new features into the main test script, reducing the number of scripts.
1436     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1437     were backward compatible, and made the (?i) apply to the whole pattern, as if
1438     /i were given. Now it behaves more logically, and applies the option setting
1439     only to what follows. PCRE has been changed to follow suit. However, if it
1440     finds options settings right at the start of the pattern, it extracts them into
1441     the global options, as before. Thus, they show up in the info data.
1443     8. Added support for the \Q...\E escape sequence. Characters in between are
1444     treated as literals. This is slightly different from Perl in that $ and @ are
1445     also handled as literals inside the quotes. In Perl, they will cause variable
1446     interpolation. Note the following examples:
1448     Pattern PCRE matches Perl matches
1450     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1451     \Qabc\$xyz\E abc\$xyz abc\$xyz
1452     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1454     For compatibility with Perl, \Q...\E sequences are recognized inside character
1455     classes as well as outside them.
1457     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1458     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1459     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1460     signed/unsigned warnings.
1462     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1463     option for pcretest, so I've replaced it by a simple function that does just
1464     that job.
1466     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1467     "pcregrep -".
1469     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1470     Java package. This provides some syntactic sugar for simple cases of what my
1471     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1472     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1473     item, you can use this simplified notation. Note that only makes sense with
1474     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1475     greediness, whatever the setting of the PCRE_UNGREEDY option.
1477     13. A change of greediness default within a pattern was not taking effect at
1478     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1479     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1480     was abstracted outside.
1482     14. PCRE now supports the \G assertion. It is true when the current matching
1483     position is at the start point of the match. This differs from \A when the
1484     starting offset is non-zero. Used with the /g option of pcretest (or similar
1485     code), it works in the same way as it does for Perl's /g option. If all
1486     alternatives of a regex begin with \G, the expression is anchored to the start
1487     match position, and the "anchored" flag is set in the compiled expression.
1489     15. Some bugs concerning the handling of certain option changes within patterns
1490     have been fixed. These applied to options other than (?ims). For example,
1491     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1492     been the other way round. Some of this was related to change 7 above.
1494     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1495     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1496     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1497     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1499     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1500     mode. Unlike ".", it always matches newline, whatever the setting of
1501     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1502     assertions. Perl allows it, but it doesn't (in general) work because it can't
1503     calculate the length of the lookbehind. At least, that's the case for Perl
1504     5.8.0 - I've been told they are going to document that it doesn't work in
1505     future.
1507     18. Added an error diagnosis for escapes that PCRE does not support: these are
1508     \L, \l, \N, \P, \p, \U, \u, and \X.
1510     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1511     reading past the end of the pattern in cases such as /[abcd/.
1513     20. PCRE was getting more memory than necessary for patterns with classes that
1514     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1516     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1517     compiling PCRE for use with Virtual Pascal.
1519     22. Small fix to the Makefile to make it work properly if the build is done
1520     outside the source tree.
1522     23. Added a new extension: a condition to go with recursion. If a conditional
1523     subpattern starts with (?(R) the "true" branch is used if recursion has
1524     happened, whereas the "false" branch is used only at the top level.
1526     24. When there was a very long string of literal characters (over 255 bytes
1527     without UTF support, over 250 bytes with UTF support), the computation of how
1528     much memory was required could be incorrect, leading to segfaults or other
1529     strange effects.
1531     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1532     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1533     there was a subsequent back reference to those brackets. This meant that, for
1534     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1535     possible to check for precisely this case. All we can do is abandon the
1536     optimization if .* occurs inside capturing brackets when there are any back
1537     references whatsoever. (See below for a better fix that came later.)
1539     26. The handling of the optimization for finding the first character of a
1540     non-anchored pattern, and for finding a character that is required later in the
1541     match were failing in some cases. This didn't break the matching; it just
1542     failed to optimize when it could. The way this is done has been re-implemented.
1544     27. Fixed typo in error message for invalid (?R item (it said "(?p").
1546     28. Added a new feature that provides some of the functionality that Perl
1547     provides with (?{...}). The facility is termed a "callout". The way it is done
1548     in PCRE is for the caller to provide an optional function, by setting
1549     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1550     global variable. By default it is unset, which disables all calling out. To get
1551     the function called, the regex must include (?C) at appropriate points. This
1552     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1553     This provides a means of identifying different callout points. When PCRE
1554     reaches such a point in the regex, if pcre_callout has been set, the external
1555     function is called. It is provided with data in a structure called
1556     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1557     matching continues; if it returns a non-zero value, the match at the current
1558     point fails. However, backtracking will occur if possible. [This was changed
1559     later and other features added - see item 49 below.]
1561     29. pcretest is upgraded to test the callout functionality. It provides a
1562     callout function that displays information. By default, it shows the start of
1563     the match and the current position in the text. There are some new data escapes
1564     to vary what happens:
1566     \C+ in addition, show current contents of captured substrings
1567     \C- do not supply a callout function
1568     \C!n return 1 when callout number n is reached
1569     \C!n!m return 1 when callout number n is reached for the mth time
1571     30. If pcregrep was called with the -l option and just a single file name, it
1572     output "<stdin>" if a match was found, instead of the file name.
1574     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1575     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1576     pcre_exec(). This saves a malloc/free per call. The default value of
1577     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1578     when configuring.
1580     32. The default maximum size of a compiled pattern is 64K. There have been a
1581     few cases of people hitting this limit. The code now uses macros to handle the
1582     storing of links as offsets within the compiled pattern. It defaults to 2-byte
1583     links, but this can be changed to 3 or 4 bytes by --with-link-size when
1584     configuring. Tests 2 and 5 work only with 2-byte links because they output
1585     debugging information about compiled patterns.
1587     33. Internal code re-arrangements:
1589     (a) Moved the debugging function for printing out a compiled regex into
1590     its own source file (printint.c) and used #include to pull it into
1591     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1592     separate copies.
1594     (b) Defined the list of op-code names for debugging as a macro in
1595     internal.h so that it is next to the definition of the opcodes.
1597     (c) Defined a table of op-code lengths for simpler skipping along compiled
1598     code. This is again a macro in internal.h so that it is next to the
1599     definition of the opcodes.
1601     34. Added support for recursive calls to individual subpatterns, along the
1602     lines of Robin Houston's patch (but implemented somewhat differently).
1604     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1605     allow it to read and process whole directories in Win32. This code was
1606     contributed by Lionel Fourquaux; it has not been tested by me.
1608     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1609     used to name a group. Names consist of alphanumerics and underscores, and must
1610     be unique. Back references use the syntax (?P=name) and recursive calls use
1611     (?P>name) which is a PCRE extension to the Python extension. Groups still have
1612     numbers. The function pcre_fullinfo() can be used after compilation to extract
1613     a name/number map. There are three relevant calls:
1615     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1616     PCRE_INFO_NAMECOUNT yields the number of entries
1617     PCRE_INFO_NAMETABLE yields a pointer to the map.
1619     The map is a vector of fixed-size entries. The size of each entry depends on
1620     the length of the longest name used. The first two bytes of each entry are the
1621     group number, most significant byte first. There follows the corresponding
1622     name, zero terminated. The names are in alphabetical order.
1624     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1625     case instead of 255. Making it the same both with and without UTF-8 support
1626     means that the same test output works with both.
1628     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1629     calling malloc() with a zero argument.
1631     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1632     optimization. I've improved things by keeping a bitmap of backreferences with
1633     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1634     fact referenced, the optimization can be applied. It is unlikely that a
1635     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1636     the match to follow \n) will appear inside brackets with a number greater than
1637     31, but if it does, any back reference > 31 suppresses the optimization.
1639     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1640     of disabling numbered capturing parentheses. Any opening parenthesis that is
1641     not followed by ? behaves as if it were followed by ?: but named parentheses
1642     can still be used for capturing (and they will acquire numbers in the usual
1643     way).
1645     41. Redesigned the return codes from the match() function into yes/no/error so
1646     that errors can be passed back from deep inside the nested calls. A malloc
1647     failure while inside a recursive subpattern call now causes the
1648     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1650     42. It is now possible to set a limit on the number of times the match()
1651     function is called in a call to pcre_exec(). This facility makes it possible to
1652     limit the amount of recursion and backtracking, though not in a directly
1653     obvious way, because the match() function is used in a number of different
1654     circumstances. The count starts from zero for each position in the subject
1655     string (for non-anchored patterns). The default limit is, for compatibility, a
1656     large number, namely 10 000 000. You can change this in two ways:
1658     (a) When configuring PCRE before making, you can use --with-match-limit=n
1659     to set a default value for the compiled library.
1661     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1662     a different value is set. See 45 below.
1664     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1666     43. Added a new function pcre_config(int, void *) to enable run-time extraction
1667     of things that can be changed at compile time. The first argument specifies
1668     what is wanted and the second points to where the information is to be placed.
1669     The current list of available information is:
1673     The output is an integer that is set to one if UTF-8 support is available;
1674     otherwise it is set to zero.
1678     The output is an integer that it set to the value of the code that is used for
1679     newline. It is either LF (10) or CR (13).
1683     The output is an integer that contains the number of bytes used for internal
1684     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1688     The output is an integer that contains the threshold above which the POSIX
1689     interface uses malloc() for output vectors. See item 31 above.
1693     The output is an unsigned integer that contains the default limit of the number
1694     of match() calls in a pcre_exec() execution. See 42 above.
1696     44. pcretest has been upgraded by the addition of the -C option. This causes it
1697     to extract all the available output from the new pcre_config() function, and to
1698     output it. The program then exits immediately.
1700     45. A need has arisen to pass over additional data with calls to pcre_exec() in
1701     order to support additional features. One way would have been to define
1702     pcre_exec2() (for example) with extra arguments, but this would not have been
1703     extensible, and would also have required all calls to the original function to
1704     be mapped to the new one. Instead, I have chosen to extend the mechanism that
1705     is used for passing in "extra" data from pcre_study().
1707     The pcre_extra structure is now exposed and defined in pcre.h. It currently
1708     contains the following fields:
1710     flags a bitmap indicating which of the following fields are set
1711     study_data opaque data from pcre_study()
1712     match_limit a way of specifying a limit on match() calls for a specific
1713     call to pcre_exec()
1714     callout_data data for callouts (see 49 below)
1716     The flag bits are also defined in pcre.h, and are
1722     The pcre_study() function now returns one of these new pcre_extra blocks, with
1723     the actual study data pointed to by the study_data field, and the
1724     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1725     before. That is, this change is entirely upwards-compatible and requires no
1726     change to existing code.
1728     If you want to pass in additional data to pcre_exec(), you can either place it
1729     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1730     block.
1732     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1733     data string contains the escape sequence \M, pcretest calls pcre_exec() several
1734     times with different match limits, until it finds the minimum value needed for
1735     pcre_exec() to complete. The value is then output. This can be instructive; for
1736     most simple matches the number is quite small, but for pathological cases it
1737     gets very large very quickly.
1739     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1740     returns the size of the data block pointed to by the study_data field in a
1741     pcre_extra block, that is, the value that was passed as the argument to
1742     pcre_malloc() when PCRE was getting memory in which to place the information
1743     created by pcre_study(). The fourth argument should point to a size_t variable.
1744     pcretest has been extended so that this information is shown after a successful
1745     pcre_study() call when information about the compiled regex is being displayed.
1747     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1748     because what follows is always an absolute path. (Later: it turns out that this
1749     is more than cosmetic for MinGW, because it doesn't like empty path
1750     components.)
1752     49. Some changes have been made to the callout feature (see 28 above):
1754     (i) A callout function now has three choices for what it returns:
1756     0 => success, carry on matching
1757     > 0 => failure at this point, but backtrack if possible
1758     < 0 => serious error, return this value from pcre_exec()
1760     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1761     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1762     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1763     use by callout functions. It will never be used by PCRE itself.
1765     (ii) The pcre_extra structure (see 45 above) has a void * field called
1766     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1767     pcre_callout_block structure has a field of the same name. The contents of
1768     the field passed in the pcre_extra structure are passed to the callout
1769     function in the corresponding field in the callout block. This makes it
1770     easier to use the same callout-containing regex from multiple threads. For
1771     testing, the pcretest program has a new data escape
1773     \C*n pass the number n (may be negative) as callout_data
1775     If the callout function in pcretest receives a non-zero value as
1776     callout_data, it returns that value.
1778     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1779     there were some redundant $(CFLAGS) in commands that are now specified as
1780     $(LINK), which already includes $(CFLAGS).
1782     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1783     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1784     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1785     one-byte characters throughout. Note that case-insensitive matching applies
1786     only to characters whose values are less than 256. PCRE doesn't support the
1787     notion of cases for higher-valued characters.
1789     (i) A character class whose characters are all within 0-255 is handled as
1790     a bit map, and the map is inverted for negative classes. Previously, a
1791     character > 255 always failed to match such a class; however it should
1792     match if the class was a negative one (e.g. [^ab]). This has been fixed.
1794     (ii) A negated character class with a single character < 255 is coded as
1795     "not this character" (OP_NOT). This wasn't working properly when the test
1796     character was multibyte, either singly or repeated.
1798     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1799     mode, for example: \x{100}{2,3}.
1801     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1802     singly or repeated) now correctly test multibyte characters. However,
1803     PCRE doesn't recognize any characters with values greater than 255 as
1804     digits, spaces, or word characters. Such characters always match \D, \S,
1805     and \W, and never match \d, \s, or \w.
1807     (v) Classes may now contain characters and character ranges with values
1808     greater than 255. For example: [ab\x{100}-\x{400}].
1810     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1811     PCRE in UTF-8 mode.
1813     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1814     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1815     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1816     value.)
1818     53. The single man page has become too large. I have therefore split it up into
1819     a number of separate man pages. These also give rise to individual HTML pages;
1820     these are now put in a separate directory, and there is an index.html page that
1821     lists them all. Some hyperlinking between the pages has been installed.
1823     54. Added convenience functions for handling named capturing parentheses.
1825     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1826     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1827     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1828     are faulted.
1830     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1831     calling configure. These values are used when compiling the dftables.c program
1832     which is run to generate the source of the default character tables. They
1833     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1834     you will need to set these values.
1836     57. Updated the building process for Windows DLL, as provided by Fred Cox.
1839     Version 3.9 02-Jan-02
1840 nigel 61 ---------------------
1842     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1844     2. If --disable-static was given, the building process failed when trying to
1845     build pcretest and pcregrep. (For some reason it was using libtool to compile
1846     them, which is not right, as they aren't part of the library.)
1849 nigel 59 Version 3.8 18-Dec-01
1850     ---------------------
1852     1. The experimental UTF-8 code was completely screwed up. It was packing the
1853     bytes in the wrong order. How dumb can you get?
1856 nigel 57 Version 3.7 29-Oct-01
1857     ---------------------
1859     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1860     This caused pcretest, when used on the test data, to segfault. Unfortunately,
1861     this didn't happen under Solaris 8, where I normally test things.
1863 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1864     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1865     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
1866     this fix an hour or so after the initial 3.7 release.)
1867 nigel 57
1868 nigel 59
1869 nigel 55 Version 3.6 23-Oct-01
1870     ---------------------
1872     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1873     offsets passed as NULL with zero offset count.
1875     2. The config.guess and config.sub files had not been updated when I moved to
1876     the latest autoconf.
1879 nigel 53 Version 3.5 15-Aug-01
1880     ---------------------
1881 nigel 5
1882 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
1883     had been forgotten.
1885     2. By using declared but undefined structures, we can avoid using "void"
1886     definitions in pcre.h while keeping the internal definitions of the structures
1887     private.
1889     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
1890     user point of view, this means that both static and shared libraries are built
1891     by default, but this can be individually controlled. More of the work of
1892     handling this static/shared cases is now inside libtool instead of PCRE's make
1893     file.
1895     4. The pcretest utility is now installed along with pcregrep because it is
1896     useful for users (to test regexs) and by doing this, it automatically gets
1897     relinked by libtool. The documentation has been turned into a man page, so
1898     there are now .1, .txt, and .html versions in /doc.
1900     5. Upgrades to pcregrep:
1901     (i) Added long-form option names like gnu grep.
1902     (ii) Added --help to list all options with an explanatory phrase.
1903     (iii) Added -r, --recursive to recurse into sub-directories.
1904     (iv) Added -f, --file to read patterns from a file.
1906     6. pcre_exec() was referring to its "code" argument before testing that
1907     argument for NULL (and giving an error if it was NULL).
1909     7. Upgraded Makefile.in to allow for compiling in a different directory from
1910     the source directory.
1912     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
1913     options bits, the pointer it was passed was to an int instead of to an unsigned
1914     long int. This mattered only on 64-bit systems.
1916     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
1917     generated) instead of pcre.in, which it its source. Also made the same change
1918     in several of the .c files.
1920     10. A new release of gcc defines printf() as a macro, which broke pcretest
1921     because it had an ifdef in the middle of a string argument for printf(). Fixed
1922     by using separate calls to printf().
1924     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
1925     script, to force use of CR or LF instead of \n in the source. On non-Unix
1926     systems, the value can be set in config.h.
1928     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
1929     absolute limit. Changed the text of the error message to make this clear, and
1930     likewise updated the man page.
1932     13. The limit of 99 on the number of capturing subpatterns has been removed.
1933     The new limit is 65535, which I hope will not be a "real" limit.
1936 nigel 51 Version 3.4 22-Aug-00
1937     ---------------------
1939     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
1941     2. Diagnose condition (?(0) as an error instead of crashing on matching.
1944 nigel 49 Version 3.3 01-Aug-00
1945     ---------------------
1947     1. If an octal character was given, but the value was greater than \377, it
1948     was not getting masked to the least significant bits, as documented. This could
1949     lead to crashes in some systems.
1951     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
1952     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
1954     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
1955     These just pass their arguments on to (pcre_free)(), but they are provided
1956     because some uses of PCRE bind it to non-C systems that can call its functions,
1957     but cannot call free() or pcre_free() directly.
1959     4. Add "make test" as a synonym for "make check". Corrected some comments in
1960     the Makefile.
1962     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
1963     Makefile.
1965     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
1966     command called pgrep for grepping around the active processes.
1968     7. Added the beginnings of support for UTF-8 character strings.
1970     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
1971     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
1972     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
1973     out for the ar command.)
1976 nigel 47 Version 3.2 12-May-00
1977     ---------------------
1979     This is purely a bug fixing release.
1981     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
1982     of ZA. This was just one example of several cases that could provoke this bug,
1983     which was introduced by change 9 of version 2.00. The code for breaking
1984     infinite loops after an iteration that matches an empty string was't working
1985     correctly.
1987     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
1988     when matched against abbab (for example). After matching an empty string, it
1989     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
1990     caused it to match further down the string than it should.
1992     3. The code contained an inclusion of sys/types.h. It isn't clear why this
1993     was there because it doesn't seem to be needed, and it causes trouble on some
1994     systems, as it is not a Standard C header. It has been removed.
1996     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
1997     were reported on the Macintosh. The changes were from
1999     while ((c = *(++ptr)) != 0 && c != '\n');
2000     to
2001     while ((c = *(++ptr)) != 0 && c != '\n') ;
2003     Totally extraordinary, but if that's what it takes...
2005     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2006     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2007     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2008     assumes the way PCRE uses memmove() (always moving upwards).
2010     6. PCRE is being used in one environment where strchr() is not available. There
2011     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2012     faster code anyway.
2015 nigel 45 Version 3.1 09-Feb-00
2016     ---------------------
2018     The only change in this release is the fixing of some bugs in Makefile.in for
2019     the "install" target:
2021     (1) It was failing to install pcreposix.h.
2023     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2026 nigel 43 Version 3.0 01-Feb-00
2027     ---------------------
2028 nigel 41
2029     1. Add support for the /+ modifier to perltest (to output $` like it does in
2030     pcretest).
2032     2. Add support for the /g modifier to perltest.
2034     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2035     matches null strings.
2037     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2038     pattern. Perl treats empty patterns specially - it reuses the most recent
2039     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2040     effect.
2042     5. The POSIX interface was broken in that it was just handing over the POSIX
2043     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2044     required a bigger vector, with some working space on the end. This means that
2045     the POSIX wrapper now has to get and free some memory, and copy the results.
2047 nigel 43 6. Added some simple autoconf support, placing the test data and the
2048     documentation in separate directories, re-organizing some of the
2049     information files, and making it build pcre-config (a GNU standard). Also added
2050     libtool support for building PCRE as a shared library, which is now the
2051     default.
2052 nigel 41
2053 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2054     09 are not valid octal constants. Single digits will be used for minor values
2055     less than 10.
2057     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2058     existing programs that set these in the POSIX interface can use PCRE without
2059     modification.
2061     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2062     return all that pcre_info() returns, plus additional data. The pcre_info()
2063     function is retained for compatibility, but is considered to be obsolete.
2065     10. Added experimental recursion feature (?R) to handle one common case that
2066     Perl 5.6 will be able to do with (?p{...}).
2068     11. Added support for POSIX character classes like [:alpha:], which Perl is
2069     adopting.
2072 nigel 39 Version 2.08 31-Aug-99
2073     ----------------------
2075     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2076     trying to match at the startoffset position, but instead was moving forward to
2077     the next newline as if a previous match had failed.
2079     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2080     and could get into a loop if a null string was matched other than at the start
2081     of the subject.
2083     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2084     be distinguished at compile time, and for completeness also added PCRE_DATE.
2086     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2087     in GnuWin32 environments.
2090 nigel 37 Version 2.07 29-Jul-99
2091     ----------------------
2093     1. The documentation is now supplied in plain text form and HTML as well as in
2094     the form of man page sources.
2096     2. C++ compilers don't like assigning (void *) values to other pointer types.
2097     In particular this affects malloc(). Although there is no problem in Standard
2098     C, I've put in casts to keep C++ compilers happy.
2100     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2101     should be (const char *).
2103     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2104     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2105     However, I haven't made this a standard facility. The documentation doesn't
2106     mention it, and the Makefile doesn't support it.
2108     5. The Makefile now contains an "install" target, with editable destinations at
2109     the top of the file. The pcretest program is not installed.
2111     6. pgrep -V now gives the PCRE version number and date.
2113     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2114     causing the entire string to be ignored, instead of just the last character.
2116     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2117     non-matching string, it can take a very, very long time, even for strings of
2118     quite modest length, because of the nested recursion. PCRE now does better in
2119     some of these cases. It does this by remembering the last required literal
2120     character in the pattern, and pre-searching the subject to ensure it is present
2121     before running the real match. In other words, it applies a heuristic to detect
2122     some types of certain failure quickly, and in the above example, if presented
2123     with a string that has no trailing " it gives "no match" very quickly.
2125     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2126     other alternatives are tried instead.
2129 nigel 35 Version 2.06 09-Jun-99
2130     ----------------------
2132     1. Change pcretest's output for amount of store used to show just the code
2133     space, because the remainder (the data block) varies in size between 32-bit and
2134     64-bit systems.
2136     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2137     start matching at. This allows lookbehinds to work when searching for multiple
2138     occurrences in a string.
2140     3. Added additional options to pcretest for testing multiple occurrences:
2142     /+ outputs the rest of the string that follows a match
2143     /g loops for multiple occurrences, using the new startoffset argument
2144     /G loops for multiple occurrences by passing an incremented pointer
2146     4. PCRE wasn't doing the "first character" optimization for patterns starting
2147     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2148     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2149     the letter 'x'. On long subject strings, this gives a significant speed-up.
2152 nigel 33 Version 2.05 21-Apr-99
2153     ----------------------
2155     1. Changed the type of magic_number from int to long int so that it works
2156     properly on 16-bit systems.
2158     2. Fixed a bug which caused patterns starting with .* not to work correctly
2159     when the subject string contained newline characters. PCRE was assuming
2160     anchoring for such patterns in all cases, which is not correct because .* will
2161     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2162     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2163     must be retried after every newline in the subject.
2166 nigel 31 Version 2.04 18-Feb-99
2167     ----------------------
2169     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2170     computation of the store needed to hold the pattern was incorrect (too large).
2171     If such patterns were nested a few deep, this could multiply and become a real
2172     problem.
2174     2. Added /M option to pcretest to show the memory requirement of a specific
2175     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2177     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2178     compiled in such a way that the backtracking after subsequent failure was
2179     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2180     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2183 nigel 29 Version 2.03 02-Feb-99
2184     ----------------------
2186     1. Fixed typo and small mistake in man page.
2188 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2189     LICENCE file containing the conditions.
2190 nigel 29
2191     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2192     Perl, that is the internal \ allows the delimiter to be included in the
2193     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2194     the final delimiter, add \ to the end of the pattern (to test the error).
2196     4. Added the convenience functions for extracting substrings after a successful
2197     match. Updated pcretest to make it able to test these functions.
2200 nigel 27 Version 2.02 14-Jan-99
2201     ----------------------
2203     1. Initialized the working variables associated with each extraction so that
2204     their saving and restoring doesn't refer to uninitialized store.
2206     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2207     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2208     fix the problem.
2210     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2211     calls, and wasn't printing the correct value for compiling calls. Increased the
2212     default value of LOOPREPEAT, and the number of significant figures in the
2213     times.
2215     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2217     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2218     a building problem on Windows NT with a FAT file system.
2221 nigel 25 Version 2.01 21-Oct-98
2222     ----------------------
2224     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2225     to character tables built by pcre_maketables() in the current locale. If NULL
2226     is passed, the default tables are used.
2229 nigel 23 Version 2.00 24-Sep-98
2230 nigel 21 ----------------------
2232 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2233     it any more.
2235     2. Allow quantification of (?>) groups, and make it work correctly.
2237     3. The first character computation wasn't working for (?>) groups.
2239     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2240     end of the subject) and add 5.005's \z, which really does match only at the
2241     very end of the subject.
2243     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2245     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2246     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2247     localized options. All options to pcre_study() were also removed.
2249     7. Add other new features from 5.005:
2251     $(?<= positive lookbehind
2252     $(?<! negative lookbehind
2253     (?imsx-imsx) added the unsetting capability
2254     such a setting is global if at outer level; local otherwise
2255     (?imsx-imsx:) non-capturing groups with option setting
2256     (?(cond)re|re) conditional pattern matching
2258     A backreference to itself in a repeated group matches the previous
2259     captured string.
2261     8. General tidying up of studying (both automatic and via "study")
2262     consequential on the addition of new assertions.
2264     9. As in 5.005, unlimited repeated groups that could match an empty substring
2265     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2266     runtime if any iteration does actually match an empty substring.
2268     10. Include the RunTest script in the distribution.
2270     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2271     discrepancies, some of which were old and were also with respect to 5.004. They
2272     have now been fixed.
2275     Version 1.09 28-Apr-98
2276     ----------------------
2278 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2279     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2280     program crashes, or just wrong answers. This did not apply to negated classes
2281     containing more than one character, or to minima other than one.
2284 nigel 19 Version 1.08 27-Mar-98
2285     ----------------------
2287     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2289     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2290     latter must appear before anything that relies on it in the pattern.
2293 nigel 17 Version 1.07 16-Feb-98
2294     ----------------------
2296     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2297     repeat of a potentially empty string).
2300 nigel 15 Version 1.06 23-Jan-98
2301     ----------------------
2303     1. Added Markus Oberhumer's little patches for C++.
2305     2. Literal strings longer than 255 characters were broken.
2308 nigel 13 Version 1.05 23-Dec-97
2309     ----------------------
2311     1. Negated character classes containing more than one character were failing if
2312     PCRE_CASELESS was set at run time.
2315 nigel 11 Version 1.04 19-Dec-97
2316     ----------------------
2318     1. Corrected the man page, where some "const" qualifiers had been omitted.
2320     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2321     input syntax.
2323     3. Fixed memory leak which occurred when a regex with back references was
2324     matched with an offsets vector that wasn't big enough. The temporary memory
2325     that is used in this case wasn't being freed if the match failed.
2327     4. Tidied pcretest to ensure it frees memory that it gets.
2329     5. Temporary memory was being obtained in the case where the passed offsets
2330     vector was exactly big enough.
2332     6. Corrected definition of offsetof() from change 5 below.
2334     7. I had screwed up change 6 below and broken the rules for the use of
2335     setjmp(). Now fixed.
2338 nigel 9 Version 1.03 18-Dec-97
2339     ----------------------
2341     1. A erroneous regex with a missing opening parenthesis was correctly
2342     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2343     on some systems.
2345     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2346     it was reported that one broken compiler failed on the former because "code" is
2347     also an independent variable.
2349     3. The erroneous regex a[]b caused an array overrun reference.
2351     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2352     fail on data ending with that character. (It was going on too far, and checking
2353     the next character, typically a binary zero.) This was specific to the
2354     optimized code for single-character negative classes.
2356     5. Added a contributed patch from the TIN world which does the following:
2358     + Add an undef for memmove, in case the the system defines a macro for it.
2360     + Add a definition of offsetof(), in case there isn't one. (I don't know
2361     the reason behind this - offsetof() is part of the ANSI standard - but
2362     it does no harm).
2364     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2365     most of the places where whitespace preceded '#'. I have given up and
2366     allowed the remaining 2 cases to be at the margin.
2368     + Rename some variables in pcre to eliminate shadowing. This seems very
2369     pedantic, but does no harm, of course.
2371     6. Moved the call to setjmp() into its own function, to get rid of warnings
2372     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2374     7. Constructs such as \d{8,} were compiling into the equivalent of
2375 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2376 nigel 9 outcome, but in this particular case used more store than had been allocated,
2377     which caused the bug to be discovered because it threw up an internal error.
2379     8. The debugging code in both pcre and pcretest for outputting the compiled
2380     form of a regex was going wrong in the case of back references followed by
2381     curly-bracketed repeats.
2384 nigel 7 Version 1.02 12-Dec-97
2385     ----------------------
2387     1. Typos in pcre.3 and comments in the source fixed.
2389     2. Applied a contributed patch to get rid of places where it used to remove
2390     'const' from variables, and fixed some signed/unsigned and uninitialized
2391     variable warnings.
2393     3. Added the "runtest" target to Makefile.
2395     4. Set default compiler flag to -O2 rather than just -O.
2398 nigel 5 Version 1.01 19-Nov-97
2399     ----------------------
2401     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2402     like /([ab]*)*/, that is, for classes with more than one character in them.
2404     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2405     as /((?>a*))*/ (a PCRE_EXTRA facility).
2408     Version 1.00 18-Nov-97
2409     ----------------------
2411     1. Added compile-time macros to support systems such as SunOS4 which don't have
2412     memmove() or strerror() but have other things that can be used instead.
2414     2. Arranged that "make clean" removes the executables.
2417 nigel 3 Version 0.99 27-Oct-97
2418     ----------------------
2420     1. Fixed bug in code for optimizing classes with only one character. It was
2421     initializing a 32-byte map regardless, which could cause it to run off the end
2422     of the memory it had got.
2424     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2427     Version 0.98 22-Oct-97
2428     ----------------------
2430     1. Fixed bug in code for handling temporary memory usage when there are more
2431     back references than supplied space in the ovector. This could cause segfaults.
2434     Version 0.97 21-Oct-97
2435     ----------------------
2437     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2439     2. Optimized negated single characters not to use a bit map.
2441     3. Brought error texts together as macro definitions; clarified some of them;
2442     fixed one that was wrong - it said "range out of order" when it meant "invalid
2443     escape sequence".
2445     4. Changed some char * arguments to const char *.
2447     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2449     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2450     pcretest.
2453     Version 0.96 16-Oct-97
2454     ----------------------
2456     1. Added a simple "pgrep" utility to the distribution.
2458     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2459     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2460     where "ddd" means "one or more decimal digits".
2462     3. Fixed serious bug. If a pattern had a back reference, but the call to
2463     pcre_exec() didn't supply a large enough ovector to record the related
2464     identifying subpattern, the match always failed. PCRE now remembers the number
2465     of the largest back reference, and gets some temporary memory in which to save
2466     the offsets during matching if necessary, in order to ensure that
2467     backreferences always work.
2469     4. Increased the compatibility with Perl in a number of ways:
2471     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2472     to request this handling. The option can be set at compile or exec time.
2474     (b) $ matches before a terminating newline by default; an option
2475     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2476     mode). The option can be set at compile or exec time.
2478     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2479     the same as Perl's. If the decimal number it represents is less than 10
2480     or there aren't that many previous left capturing parentheses, an octal
2481     escape is read. Inside a character class, it's always an octal escape,
2482     even if it is a single digit.
2484     (d) An escaped but undefined alphabetic character is taken as a literal,
2485     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2486     escapes.
2488     (e) {0} is now permitted. (The previous item is removed from the compiled
2489     pattern).
2491     5. Changed all the names of code files so that the basic parts are no longer
2492     than 10 characters, and abolished the teeny "globals.c" file.
2494     6. Changed the handling of character classes; they are now done with a 32-byte
2495     bit map always.
2497     7. Added the -d and /D options to pcretest to make it possible to look at the
2498     internals of compilation without having to recompile pcre.
2501     Version 0.95 23-Sep-97
2502     ----------------------
2504     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2505     \x20 at the start of a run of normal characters. These were being treated as
2506     real characters, instead of the source characters being re-checked.
2509     Version 0.94 18-Sep-97
2510     ----------------------
2512     1. The functions are now thread-safe, with the caveat that the global variables
2513     containing pointers to malloc() and free() or alternative functions are the
2514     same for all threads.
2516     2. Get pcre_study() to generate a bitmap of initial characters for non-
2517     anchored patterns when this is possible, and use it if passed to pcre_exec().
2520     Version 0.93 15-Sep-97
2521     ----------------------
2523     1. /(b)|(:+)/ was computing an incorrect first character.
2525     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2526     but not actually doing anything yet.
2528     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2529     as Perl does (e.g. [-az] or [az-]).
2531     4. Set the anchored flag if a branch starts with .* or .*? because that tests
2532     all possible positions.
2534     5. Split up into different modules to avoid including unneeded functions in a
2535     compiled binary. However, compile and exec are still in one module. The "study"
2536     function is split off.
2538     6. The character tables are now in a separate module whose source is generated
2539     by an auxiliary program - but can then be edited by hand if required. There are
2540     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2541     toupper() in the code.
2543     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2544     make them global. Abolish the function for setting them, as the caller can now
2545     set them directly.
2548     Version 0.92 11-Sep-97
2549     ----------------------
2551     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2552     (e.g. /a{1,3}/) was broken (I mis-optimized it).
2554     2. Caseless matching was not working in character classes if the characters in
2555     the pattern were in upper case.
2557     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2559     4. Make PCRE_ANCHORED public and accept as a compile option.
2561     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2562     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2563     pass them.
2565     6. Give an error if bad option bits passed at compile or run time.
2567     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2568     pcretest to cause it to pass that flag.
2570     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2571     options, and the first character, if set.
2573     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2576     Version 0.91 10-Sep-97
2577     ----------------------
2579     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2580     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2582     2. PCRE was looping on encountering an indefinitely repeated back reference to
2583     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2584     Perl does - treats the match as successful.
2586     ****


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