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Tue Mar 6 16:25:15 2007 UTC (8 years, 1 month ago) by ph10
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Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
that is needed.  

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 98 Version 7.1 05-Mar-07
5     ---------------------
7     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
8 ph10 99 that is more "standard", making use of automake and other autotools. There
9     is some re-arrangement of the files and adjustment of comments consequent
10     on this.
12 ph10 100 2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
13     for recursive directory scanning broke on some systems because the files
14     are not scanned in any specific order and on different systems the order
15     was different. A call to "sort" has been inserted into RunGrepTest for the
16     approprate test as a short-term fix. In the longer term there may be an
17     alternative.
19     3. I had an email from Eric Raymond about problems translating some of PCRE's
20 ph10 99 man pages to HTML (despite the fact that I distribute HTML pages, some
21     people do their own conversions for various reasons). The problems
22     concerned the use of low-level troff macros .br and .in. I have therefore
23     removed all such uses from the man pages (some were redundant, some could
24     be replaced by .nf/.fi pairs). The maintain/132html script that I use to
25     generate HTML has been updated to handle .nf/.fi and to complain if it
26     encounters .br or .in.
28 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
29     arranged for config.h to be included in the distribution, for the benefit
30     of those who have to compile without Autotools (compare pcre.h).
32 ph10 101 5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
33     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
34     makevp.bat for the current PCRE, using the additional files !compile.txt,
35     !linklib.txt, and pcregexp.pas.
37 ph10 102 6. A Windows user reported a minor discrepancy with test 2, which turned out
38     to be caused by a trailing space on an input line that had got lost in his
39     copy. The trailing space was an accident, so I've just removed it.
41 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
42     that is needed.
44 ph10 98
45 nigel 93 Version 7.0 19-Dec-06
46     ---------------------
48     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
49     moving to gcc 4.1.1.
51     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
52     sys/time.h, which is documented as needed for this function. It doesn't
53     seem to matter on Linux, but it showed up on some releases of OS X.
55     3. It seems that there are systems where bytes whose values are greater than
56     127 match isprint() in the "C" locale. The "C" locale should be the
57     default when a C program starts up. In most systems, only ASCII printing
58     characters match isprint(). This difference caused the output from pcretest
59     to vary, making some of the tests fail. I have changed pcretest so that:
61     (a) When it is outputting text in the compiled version of a pattern, bytes
62     other than 32-126 are always shown as hex escapes.
64     (b) When it is outputting text that is a matched part of a subject string,
65     it does the same, unless a different locale has been set for the match
66     (using the /L modifier). In this case, it uses isprint() to decide.
68     4. Fixed a major bug that caused incorrect computation of the amount of memory
69     required for a compiled pattern when options that changed within the
70     pattern affected the logic of the preliminary scan that determines the
71     length. The relevant options are -x, and -i in UTF-8 mode. The result was
72     that the computed length was too small. The symptoms of this bug were
73     either the PCRE error "internal error: code overflow" from pcre_compile(),
74     or a glibc crash with a message such as "pcretest: free(): invalid next
75     size (fast)". Examples of patterns that provoked this bug (shown in
76     pcretest format) are:
78     /(?-x: )/x
79     /(?x)(?-x: \s*#\s*)/
80     /((?i)[\x{c0}])/8
81     /(?i:[\x{c0}])/8
83     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
84     is now done differently.
86     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
87     wrapper classes; (b) implement a new function in the C++ scanner that is
88     more efficient than the old way of doing things because it avoids levels of
89     recursion in the regex matching; (c) add a paragraph to the documentation
90     for the FullMatch() function.
92     6. The escape sequence \n was being treated as whatever was defined as
93     "newline". Not only was this contrary to the documentation, which states
94     that \n is character 10 (hex 0A), but it also went horribly wrong when
95     "newline" was defined as CRLF. This has been fixed.
97     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
98     was being set to -1 for the "end of line" case (supposedly a value that no
99     character can have). Though this value is never used (the check for end of
100     line is "zero bytes in current character"), it caused compiler complaints.
101     I've changed it to 0xffffffff.
103     8. In pcre_version.c, the version string was being built by a sequence of
104     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
105     string (as it is for production releases) called a macro with an empty
106     argument. The C standard says the result of this is undefined. The gcc
107     compiler treats it as an empty string (which was what was wanted) but it is
108     reported that Visual C gives an error. The source has been hacked around to
109     avoid this problem.
111     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
112     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
113     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
114     of them did).
116     10. Originally, pcretest opened its input and output without "b"; then I was
117     told that "b" was needed in some environments, so it was added for release
118     5.0 to both the input and output. (It makes no difference on Unix-like
119     systems.) Later I was told that it is wrong for the input on Windows. I've
120     now abstracted the modes into two macros, to make it easier to fiddle with
121     them, and removed "b" from the input mode under Windows.
123     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
125     12. Added -help and --help to pcretest as an official way of being reminded
126     of the options.
128     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
129     and pcrecpp.cc because they annoy compilers at high warning levels.
131     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
133     15. Fixed an occurrence of == in configure.ac that should have been = (shell
134     scripts are not C programs :-) and which was not noticed because it works
135     on Linux.
137     16. pcretest is supposed to handle any length of pattern and data line (as one
138     line or as a continued sequence of lines) by extending its input buffer if
139     necessary. This feature was broken for very long pattern lines, leading to
140     a string of junk being passed to pcre_compile() if the pattern was longer
141     than about 50K.
143     17. I have done a major re-factoring of the way pcre_compile() computes the
144     amount of memory needed for a compiled pattern. Previously, there was code
145     that made a preliminary scan of the pattern in order to do this. That was
146     OK when PCRE was new, but as the facilities have expanded, it has become
147     harder and harder to keep it in step with the real compile phase, and there
148     have been a number of bugs (see for example, 4 above). I have now found a
149     cunning way of running the real compile function in a "fake" mode that
150     enables it to compute how much memory it would need, while actually only
151     ever using a few hundred bytes of working memory and without too many
152     tests of the mode. This should make future maintenance and development
153     easier. A side effect of this work is that the limit of 200 on the nesting
154     depth of parentheses has been removed (though this was never a serious
155     limitation, I suspect). However, there is a downside: pcre_compile() now
156     runs more slowly than before (30% or more, depending on the pattern). I
157     hope this isn't a big issue. There is no effect on runtime performance.
159     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
160     newline (only possible for the last line of a file) and it was a
161     pattern that set a locale (followed by /Lsomething), pcretest crashed.
163     19. Added additional timing features to pcretest. (1) The -tm option now times
164     matching only, not compiling. (2) Both -t and -tm can be followed, as a
165     separate command line item, by a number that specifies the number of
166     repeats to use when timing. The default is 50000; this gives better
167     precision, but takes uncomfortably long for very large patterns.
169     20. Extended pcre_study() to be more clever in cases where a branch of a
170     subpattern has no definite first character. For example, (a*|b*)[cd] would
171     previously give no result from pcre_study(). Now it recognizes that the
172     first character must be a, b, c, or d.
174     21. There was an incorrect error "recursive call could loop indefinitely" if
175     a subpattern (or the entire pattern) that was being tested for matching an
176     empty string contained only one non-empty item after a nested subpattern.
177     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
178     incorrectly, because the \d was being skipped in the check.
180     22. The pcretest program now has a new pattern option /B and a command line
181     option -b, which is equivalent to adding /B to every pattern. This causes
182     it to show the compiled bytecode, without the additional information that
183     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
184     is the same as /B/I).
186     23. A new optimization is now able automatically to treat some sequences such
187     as a*b as a*+b. More specifically, if something simple (such as a character
188     or a simple class like \d) has an unlimited quantifier, and is followed by
189     something that cannot possibly match the quantified thing, the quantifier
190     is automatically "possessified".
192     24. A recursive reference to a subpattern whose number was greater than 39
193     went wrong under certain circumstances in UTF-8 mode. This bug could also
194     have affected the operation of pcre_study().
196     25. Realized that a little bit of performance could be had by replacing
197     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
199     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
201     27. Possessive quantifiers such as a++ were previously implemented by turning
202     them into atomic groups such as ($>a+). Now they have their own opcodes,
203     which improves performance. This includes the automatically created ones
204     from 23 above.
206     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
207     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
208     the first matched character to be a colon. This applied both to named and
209     numbered groups.
211     29. The ucpinternal.h header file was missing its idempotency #ifdef.
213     30. I was sent a "project" file called libpcre.a.dev which I understand makes
214     building PCRE on Windows easier, so I have included it in the distribution.
216     31. There is now a check in pcretest against a ridiculously large number being
217     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
218     loop, the loop is abandoned.
220     32. Forward references to subpatterns in conditions such as (?(2)...) where
221     subpattern 2 is defined later cause pcre_compile() to search forwards in
222     the pattern for the relevant set of parentheses. This search went wrong
223     when there were unescaped parentheses in a character class, parentheses
224     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
226     33. "Subroutine" calls and backreferences were previously restricted to
227     referencing subpatterns earlier in the regex. This restriction has now
228     been removed.
230     34. Added a number of extra features that are going to be in Perl 5.10. On the
231     whole, these are just syntactic alternatives for features that PCRE had
232     previously implemented using the Python syntax or my own invention. The
233     other formats are all retained for compatibility.
235     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
236     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
237     also .NET compatible.
239     (b) A recursion or subroutine call to a named group can now be defined as
240     (?&name) as well as (?P>name).
242     (c) A backreference to a named group can now be defined as \k<name> or
243     \k'name' as well as (?P=name). The new forms, as well as being in Perl
244     5.10, are also .NET compatible.
246     (d) A conditional reference to a named group can now use the syntax
247     (?(<name>) or (?('name') as well as (?(name).
249     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
250     groups (named and numbered) that are never evaluated inline, but can be
251     called as "subroutines" from elsewhere. In effect, the DEFINE condition
252     is always false. There may be only one alternative in such a group.
254     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
255     as the simple (?(R). The condition is true only if the most recent
256     recursion is that of the given number or name. It does not search out
257     through the entire recursion stack.
259     (g) The escape \gN or \g{N} has been added, where N is a positive or
260     negative number, specifying an absolute or relative reference.
262     35. Tidied to get rid of some further signed/unsigned compiler warnings and
263     some "unreachable code" warnings.
265     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
266     things, this adds five new scripts.
268     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
269     There were also incompatibilities regarding the handling of \Q..\E inside
270     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
271     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
273     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
274     matches an empty string, and forcibly breaks the loop. There were bugs in
275     this code in non-simple cases. For a pattern such as ^(a()*)* matched
276     against aaaa the result was just "a" rather than "aaaa", for example. Two
277     separate and independent bugs (that affected different cases) have been
278     fixed.
280     39. Refactored the code to abolish the use of different opcodes for small
281     capturing bracket numbers. This is a tidy that I avoided doing when I
282     removed the limit on the number of capturing brackets for 3.5 back in 2001.
283     The new approach is not only tidier, it makes it possible to reduce the
284     memory needed to fix the previous bug (38).
286     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
287     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
288     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
289     mode.
291     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
292     report.
294     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
295     copy construction and assignment in the C++ wrapper.
297     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
298     couple of bugs that could have given wrong results in the "--newline=crlf"
299     case.
301     44. Added a number of casts and did some reorganization of signed/unsigned int
302     variables following suggestions from Dair Grant. Also renamed the variable
303     "this" as "item" because it is a C++ keyword.
305     45. Arranged for dftables to add
307     #include "pcre_internal.h"
309     to pcre_chartables.c because without it, gcc 4.x may remove the array
310     definition from the final binary if PCRE is built into a static library and
311     dead code stripping is activated.
313     46. For an unanchored pattern, if a match attempt fails at the start of a
314     newline sequence, and the newline setting is CRLF or ANY, and the next two
315     characters are CRLF, advance by two characters instead of one.
318 nigel 91 Version 6.7 04-Jul-06
319     ---------------------
321     1. In order to handle tests when input lines are enormously long, pcretest has
322     been re-factored so that it automatically extends its buffers when
323     necessary. The code is crude, but this _is_ just a test program. The
324     default size has been increased from 32K to 50K.
326     2. The code in pcre_study() was using the value of the re argument before
327     testing it for NULL. (Of course, in any sensible call of the function, it
328     won't be NULL.)
330     3. The memmove() emulation function in pcre_internal.h, which is used on
331     systems that lack both memmove() and bcopy() - that is, hardly ever -
332     was missing a "static" storage class specifier.
334     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
335     containing an extended class (one that cannot be represented by a bitmap
336     because it contains high-valued characters or Unicode property items, e.g.
337     [\pZ]). Almost always one would set UTF-8 mode when processing such a
338     pattern, but PCRE should not loop if you do not (it no longer does).
339     [Detail: two cases were found: (a) a repeated subpattern containing an
340     extended class; (b) a recursive reference to a subpattern that followed a
341     previous extended class. It wasn't skipping over the extended class
342     correctly when UTF-8 mode was not set.]
344     5. A negated single-character class was not being recognized as fixed-length
345     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
346     compile error "lookbehind assertion is not fixed length".
348     6. The RunPerlTest auxiliary script was showing an unexpected difference
349     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
350     write a Perl script that can interpret lines of an input file either as
351     byte characters or as UTF-8, which is what "perltest" was being required to
352     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
353     can't do is switch easily at run time between having the "use utf8;" pragma
354     or not. In the end, I fudged it by using the RunPerlTest script to insert
355     "use utf8;" explicitly for the UTF-8 tests.
357     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
358     the end of the subject string, contrary to the documentation and to what
359     Perl does. This was true of both matching functions. Now it matches only at
360     the start of the subject and immediately after *internal* newlines.
362     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
363     a pointer to an int instead of a pointer to an unsigned long int. This
364     caused problems on 64-bit systems.
366     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
367     instance of the 'standard' template library not being so standard".
369     10. There was no check on the number of named subpatterns nor the maximum
370     length of a subpattern name. The product of these values is used to compute
371     the size of the memory block for a compiled pattern. By supplying a very
372     long subpattern name and a large number of named subpatterns, the size
373     computation could be caused to overflow. This is now prevented by limiting
374     the length of names to 32 characters, and the number of named subpatterns
375     to 10,000.
377     11. Subpatterns that are repeated with specific counts have to be replicated in
378     the compiled pattern. The size of memory for this was computed from the
379     length of the subpattern and the repeat count. The latter is limited to
380     65535, but there was no limit on the former, meaning that integer overflow
381     could in principle occur. The compiled length of a repeated subpattern is
382     now limited to 30,000 bytes in order to prevent this.
384     12. Added the optional facility to have named substrings with the same name.
386     13. Added the ability to use a named substring as a condition, using the
387     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
388     are numbers (not recommended). Forward references are permitted.
390     14. Added forward references in named backreferences (if you see what I mean).
392     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
393     pattern could run off the end of the subject. For example, the pattern
394     "(?s)(.{1,5})"8 did this with the subject "ab".
396     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
397     PCRE_CASELESS was set when matching characters that were quantified with ?
398     or *.
400     17. A character class other than a single negated character that had a minimum
401     but no maximum quantifier - for example [ab]{6,} - was not handled
402     correctly by pce_dfa_exec(). It would match only one character.
404     18. A valid (though odd) pattern that looked like a POSIX character
405     class but used an invalid character after [ (for example [[,abc,]]) caused
406     pcre_compile() to give the error "Failed: internal error: code overflow" or
407     in some cases to crash with a glibc free() error. This could even happen if
408     the pattern terminated after [[ but there just happened to be a sequence of
409     letters, a binary zero, and a closing ] in the memory that followed.
411     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
412     over the years. Originally (before any Unicode support), just the bottom 8
413     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
414     output from "man perlunicode" includes this:
416     The regular expression compiler produces polymorphic opcodes. That
417     is, the pattern adapts to the data and automatically switches to
418     the Unicode character scheme when presented with Unicode data--or
419     instead uses a traditional byte scheme when presented with byte
420     data.
422     Sadly, a wide octal escape does not cause a switch, and in a string with
423     no other multibyte characters, these octal escapes are treated as before.
424     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
425     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
426     Unicode string.
428     I have not perpetrated such confusion in PCRE. Up till now, it took just
429     the bottom 8 bits, as in old Perl. I have now made octal escapes with
430     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
431     translate to the appropriate multibyte character.
433     29. Applied some refactoring to reduce the number of warnings from Microsoft
434     and Borland compilers. This has included removing the fudge introduced
435     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
436     a warning about an unused variable.
438     21. PCRE has not included VT (character 0x0b) in the set of whitespace
439     characters since release 4.0, because Perl (from release 5.004) does not.
440     [Or at least, is documented not to: some releases seem to be in conflict
441     with the documentation.] However, when a pattern was studied with
442     pcre_study() and all its branches started with \s, PCRE still included VT
443     as a possible starting character. Of course, this did no harm; it just
444     caused an unnecessary match attempt.
446     22. Removed a now-redundant internal flag bit that recorded the fact that case
447     dependency changed within the pattern. This was once needed for "required
448     byte" processing, but is no longer used. This recovers a now-scarce options
449     bit. Also moved the least significant internal flag bit to the most-
450     significant bit of the word, which was not previously used (hangover from
451     the days when it was an int rather than a uint) to free up another bit for
452     the future.
454     23. Added support for CRLF line endings as well as CR and LF. As well as the
455     default being selectable at build time, it can now be changed at runtime
456     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
457     specify that it is scanning data with non-default line endings.
459     24. Changed the definition of CXXLINK to make it agree with the definition of
460     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
462     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
463     recursions. This makes a big different to stack usage for some patterns.
465     26. If a subpattern containing a named recursion or subroutine reference such
466     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
467     the space required for the compiled pattern went wrong and gave too small a
468     value. Depending on the environment, this could lead to "Failed: internal
469     error: code overflow at offset 49" or "glibc detected double free or
470     corruption" errors.
472     27. Applied patches from Google (a) to support the new newline modes and (b) to
473     advance over multibyte UTF-8 characters in GlobalReplace.
475     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
476     difference for some implementation of PCRE in some Windows version.
478     29. Added some extra testing facilities to pcretest:
480     \q<number> in a data line sets the "match limit" value
481     \Q<number> in a data line sets the "match recursion limt" value
482     -S <number> sets the stack size, where <number> is in megabytes
484     The -S option isn't available for Windows.
487 nigel 89 Version 6.6 06-Feb-06
488     ---------------------
490     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
491     in pcreposix.h. I have copied the definition from pcre.h.
493     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
494     because pcre.h is no longer a built file.
496     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
497     not normally included in the compiled code.
500 nigel 87 Version 6.5 01-Feb-06
501     ---------------------
503     1. When using the partial match feature with pcre_dfa_exec(), it was not
504     anchoring the second and subsequent partial matches at the new starting
505     point. This could lead to incorrect results. For example, with the pattern
506     /1234/, partially matching against "123" and then "a4" gave a match.
508     2. Changes to pcregrep:
510     (a) All non-match returns from pcre_exec() were being treated as failures
511     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
512     error message is output. Some extra information is given for the
514     probably the only errors that are likely to be caused by users (by
515     specifying a regex that has nested indefinite repeats, for instance).
516     If there are more than 20 of these errors, pcregrep is abandoned.
518     (b) A binary zero was treated as data while matching, but terminated the
519     output line if it was written out. This has been fixed: binary zeroes
520     are now no different to any other data bytes.
522     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
523     used to set a locale for matching. The --locale=xxxx long option has
524     been added (no short equivalent) to specify a locale explicitly on the
525     pcregrep command, overriding the environment variables.
527     (d) When -B was used with -n, some line numbers in the output were one less
528     than they should have been.
530     (e) Added the -o (--only-matching) option.
532     (f) If -A or -C was used with -c (count only), some lines of context were
533     accidentally printed for the final match.
535     (g) Added the -H (--with-filename) option.
537     (h) The combination of options -rh failed to suppress file names for files
538     that were found from directory arguments.
540     (i) Added the -D (--devices) and -d (--directories) options.
542     (j) Added the -F (--fixed-strings) option.
544     (k) Allow "-" to be used as a file name for -f as well as for a data file.
546     (l) Added the --colo(u)r option.
548     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
549     is not present by default.
551     3. A nasty bug was discovered in the handling of recursive patterns, that is,
552     items such as (?R) or (?1), when the recursion could match a number of
553     alternatives. If it matched one of the alternatives, but subsequently,
554     outside the recursion, there was a failure, the code tried to back up into
555     the recursion. However, because of the way PCRE is implemented, this is not
556     possible, and the result was an incorrect result from the match.
558     In order to prevent this happening, the specification of recursion has
559     been changed so that all such subpatterns are automatically treated as
560     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
562     4. I had overlooked the fact that, in some locales, there are characters for
563     which isalpha() is true but neither isupper() nor islower() are true. In
564     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
565     and ordfeminine) are like this. This affected the treatment of \w and \W
566     when they appeared in character classes, but not when they appeared outside
567     a character class. The bit map for "word" characters is now created
568     separately from the results of isalnum() instead of just taking it from the
569     upper, lower, and digit maps. (Plus the underscore character, of course.)
571     5. The above bug also affected the handling of POSIX character classes such as
572     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
573     permanent tables. Instead, the bit maps for such a class were previously
574     created as the appropriate unions of the upper, lower, and digit bitmaps.
575     Now they are created by subtraction from the [[:word:]] class, which has
576     its own bitmap.
578     6. The [[:blank:]] character class matches horizontal, but not vertical space.
579     It is created by subtracting the vertical space characters (\x09, \x0a,
580     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
581     subtraction was done in the overall bitmap for a character class, meaning
582     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
583     be recognized. This bug has been fixed.
585     7. Patches from the folks at Google:
587     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
588     real life, but is still worth protecting against".
590     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
591     regular expressions".
593     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
594     have it.
596     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
597     "configure" and the latter not, in order to fix a problem somebody had
598     with compiling the Arg class on HP-UX.
600     (e) Improve the error-handling of the C++ wrapper a little bit.
602     (f) New tests for checking recursion limiting.
604     8. The pcre_memmove() function, which is used only if the environment does not
605     have a standard memmove() function (and is therefore rarely compiled),
606     contained two bugs: (a) use of int instead of size_t, and (b) it was not
607     returning a result (though PCRE never actually uses the result).
609     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
610     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
611     returned instead of calling malloc() with an overflowing number that would
612     most likely cause subsequent chaos.
614     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
616     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
617     with this option is matched, the nmatch and pmatch options of regexec() are
618     ignored.
620     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
621     provided in case anyone wants to the the POSIX interface with UTF-8
622     strings.
624     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
625     C++ linking (needed for some HP-UX environments).
627     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
628     (unused parameter) and in the pcre_printint() function (omitted "default"
629     switch label when the default is to do nothing).
631     15. Added some code to make it possible, when PCRE is compiled as a C++
632     library, to replace subject pointers for pcre_exec() with a smart pointer
633     class, thus making it possible to process discontinuous strings.
635     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
636     much the same function. They were added by different people who were trying
637     to make PCRE easy to compile on non-Unix systems. It has been suggested
638     that PCRE_EXPORT be abolished now that there is more automatic apparatus
639     for compiling on Windows systems. I have therefore replaced it with
640     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
641     defaults to "extern" for C or "extern C" for C++, which works fine on
642     Unix-like systems. It is now possible to override the value of PCRE_DATA_
643     SCOPE with something explicit in config.h. In addition:
645     (a) pcreposix.h still had just "extern" instead of either of these macros;
646     I have replaced it with PCRE_DATA_SCOPE.
648     (b) Functions such as _pcre_xclass(), which are internal to the library,
649     but external in the C sense, all had PCRE_EXPORT in their definitions.
650     This is apparently wrong for the Windows case, so I have removed it.
651     (It makes no difference on Unix-like systems.)
653     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
654     of recursive calls to match(). This is different to MATCH_LIMIT because
655     that limits the total number of calls to match(), not all of which increase
656     the depth of recursion. Limiting the recursion depth limits the amount of
657     stack (or heap if NO_RECURSE is set) that is used. The default can be set
658     when PCRE is compiled, and changed at run time. A patch from Google adds
659     this functionality to the C++ interface.
661     18. Changes to the handling of Unicode character properties:
663     (a) Updated the table to Unicode 4.1.0.
665     (b) Recognize characters that are not in the table as "Cn" (undefined).
667     (c) I revised the way the table is implemented to a much improved format
668     which includes recognition of ranges. It now supports the ranges that
669     are defined in UnicodeData.txt, and it also amalgamates other
670     characters into ranges. This has reduced the number of entries in the
671     table from around 16,000 to around 3,000, thus reducing its size
672     considerably. I realized I did not need to use a tree structure after
673     all - a binary chop search is just as efficient. Having reduced the
674     number of entries, I extended their size from 6 bytes to 8 bytes to
675     allow for more data.
677     (d) Added support for Unicode script names via properties such as \p{Han}.
679     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
680     matching that character.
682     20. When matching a repeated Unicode property with a minimum greater than zero,
683     (for example \pL{2,}), PCRE could look past the end of the subject if it
684     reached it while seeking the minimum number of characters. This could
685     happen only if some of the characters were more than one byte long, because
686     there is a check for at least the minimum number of bytes.
688     21. Refactored the implementation of \p and \P so as to be more general, to
689     allow for more different types of property in future. This has changed the
690     compiled form incompatibly. Anybody with saved compiled patterns that use
691     \p or \P will have to recompile them.
693     22. Added "Any" and "L&" to the supported property types.
695     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
696     but give a compile time error if the value is greater than 0xff.
698     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
699     accidentally not being installed or uninstalled.
701     25. The pcre.h file was built from pcre.h.in, but the only changes that were
702     made were to insert the current release number. This seemed silly, because
703     it made things harder for people building PCRE on systems that don't run
704     "configure". I have turned pcre.h into a distributed file, no longer built
705     by "configure", with the version identification directly included. There is
706     no longer a pcre.h.in file.
708     However, this change necessitated a change to the pcre-config script as
709     well. It is built from pcre-config.in, and one of the substitutions was the
710     release number. I have updated configure.ac so that ./configure now finds
711     the release number by grepping pcre.h.
713     26. Added the ability to run the tests under valgrind.
716 nigel 85 Version 6.4 05-Sep-05
717     ---------------------
719     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
720     "--" to be printed when multiple files were scanned, even when none of the
721     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
722     consider it to be a bug, and have restored the previous behaviour.
724     2. A couple of code tidies to get rid of compiler warnings.
726     3. The pcretest program used to cheat by referring to symbols in the library
727     whose names begin with _pcre_. These are internal symbols that are not
728     really supposed to be visible externally, and in some environments it is
729     possible to suppress them. The cheating is now confined to including
730     certain files from the library's source, which is a bit cleaner.
732     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
733     file's purpose clearer.
735     5. Reorganized pcre_ucp_findchar().
738 nigel 83 Version 6.3 15-Aug-05
739     ---------------------
741     1. The file libpcre.pc.in did not have general read permission in the tarball.
743     2. There were some problems when building without C++ support:
745     (a) If C++ support was not built, "make install" and "make test" still
746     tried to test it.
748     (b) There were problems when the value of CXX was explicitly set. Some
749     changes have been made to try to fix these, and ...
751     (c) --disable-cpp can now be used to explicitly disable C++ support.
753     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
754     backslash in a target when C++ was disabled. This confuses some
755     versions of "make", apparently. Using an intermediate variable solves
756     this. (Same for CPP_LOBJ.)
758     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
759     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
760     necessary on certain architectures.
762     4. Added a setting of -export-symbols-regex to the link command to remove
763     those symbols that are exported in the C sense, but actually are local
764     within the library, and not documented. Their names all begin with
765     "_pcre_". This is not a perfect job, because (a) we have to except some
766     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
767     available (and never for static libraries). I have made a note to try to
768     find a way round (a) in the future.
771 nigel 81 Version 6.2 01-Aug-05
772     ---------------------
774     1. There was no test for integer overflow of quantifier values. A construction
775     such as {1111111111111111} would give undefined results. What is worse, if
776     a minimum quantifier for a parenthesized subpattern overflowed and became
777     negative, the calculation of the memory size went wrong. This could have
778     led to memory overwriting.
780     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
782     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
783     operating environments where this matters.
785     4. Applied Giuseppe Maxia's patch to add additional features for controlling
786     PCRE options from within the C++ wrapper.
788     5. Named capturing subpatterns were not being correctly counted when a pattern
789     was compiled. This caused two problems: (a) If there were more than 100
790     such subpatterns, the calculation of the memory needed for the whole
791     compiled pattern went wrong, leading to an overflow error. (b) Numerical
792     back references of the form \12, where the number was greater than 9, were
793     not recognized as back references, even though there were sufficient
794     previous subpatterns.
796     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
797     versions of gcc, e.g. 2.95.4.
800 nigel 79 Version 6.1 21-Jun-05
801     ---------------------
803     1. There was one reference to the variable "posix" in pcretest.c that was not
804     surrounded by "#if !defined NOPOSIX".
806     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
807     the cross-check on the old pcre_info() function, for the benefit of the
808     cut-down version of PCRE that is currently imported into Exim.
810     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
811     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
812     patterns that start (?i) but I don't think that matters. The use of (?i) is
813     just an example; this all applies to the other options as well.
815     4. Since libtool seems to echo the compile commands it is issuing, the output
816     from "make" can be reduced a bit by putting "@" in front of each libtool
817     compile command.
819     5. Patch from the folks at Google for configure.in to be a bit more thorough
820     in checking for a suitable C++ installation before trying to compile the
821     C++ stuff. This should fix a reported problem when a compiler was present,
822     but no suitable headers.
824     6. The man pages all had just "PCRE" as their title. I have changed them to
825     be the relevant file name. I have also arranged that these names are
826     retained in the file doc/pcre.txt, which is a concatenation in text format
827     of all the man pages except the little individual ones for each function.
829     7. The NON-UNIX-USE file had not been updated for the different set of source
830     files that come with release 6. I also added a few comments about the C++
831     wrapper.
834 nigel 77 Version 6.0 07-Jun-05
835     ---------------------
837     1. Some minor internal re-organization to help with my DFA experiments.
839     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
840     didn't matter for the library itself when fully configured, but did matter
841     when compiling without UCP support, or within Exim, where the ucp files are
842     not imported.
844     3. Refactoring of the library code to split up the various functions into
845     different source modules. The addition of the new DFA matching code (see
846     below) to a single monolithic source would have made it really too
847     unwieldy, quite apart from causing all the code to be include in a
848     statically linked application, when only some functions are used. This is
849     relevant even without the DFA addition now that patterns can be compiled in
850     one application and matched in another.
852     The downside of splitting up is that there have to be some external
853     functions and data tables that are used internally in different modules of
854     the library but which are not part of the API. These have all had their
855     names changed to start with "_pcre_" so that they are unlikely to clash
856     with other external names.
858     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
859     a different (DFA) algorithm. Although it is slower than the original
860     function, it does have some advantages for certain types of matching
861     problem.
863     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
864     including restarting after a partial match.
866     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
867     defined when compiling for Windows was sent to me. I have put it into the
868     code, though I have no means of testing or verifying it.
870     7. Added the pcre_refcount() auxiliary function.
872     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
873     match before or at the first newline in the subject string. In pcretest,
874     the /f option on a pattern can be used to set this.
876     9. A repeated \w when used in UTF-8 mode with characters greater than 256
877     would behave wrongly. This has been present in PCRE since release 4.0.
879     10. A number of changes to the pcregrep command:
881     (a) Refactored how -x works; insert ^(...)$ instead of setting
882     PCRE_ANCHORED and checking the length, in preparation for adding
883     something similar for -w.
885     (b) Added the -w (match as a word) option.
887     (c) Refactored the way lines are read and buffered so as to have more
888     than one at a time available.
890     (d) Implemented a pcregrep test script.
892     (e) Added the -M (multiline match) option. This allows patterns to match
893     over several lines of the subject. The buffering ensures that at least
894     8K, or the rest of the document (whichever is the shorter) is available
895     for matching (and similarly the previous 8K for lookbehind assertions).
897     (f) Changed the --help output so that it now says
899     -w, --word-regex(p)
901     instead of two lines, one with "regex" and the other with "regexp"
902     because that confused at least one person since the short forms are the
903     same. (This required a bit of code, as the output is generated
904     automatically from a table. It wasn't just a text change.)
906     (g) -- can be used to terminate pcregrep options if the next thing isn't an
907     option but starts with a hyphen. Could be a pattern or a path name
908     starting with a hyphen, for instance.
910     (h) "-" can be given as a file name to represent stdin.
912     (i) When file names are being printed, "(standard input)" is used for
913     the standard input, for compatibility with GNU grep. Previously
914     "<stdin>" was used.
916     (j) The option --label=xxx can be used to supply a name to be used for
917     stdin when file names are being printed. There is no short form.
919     (k) Re-factored the options decoding logic because we are going to add
920     two more options that take data. Such options can now be given in four
921     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
923     (l) Added the -A, -B, and -C options for requesting that lines of context
924     around matches be printed.
926     (m) Added the -L option to print the names of files that do not contain
927     any matching lines, that is, the complement of -l.
929     (n) The return code is 2 if any file cannot be opened, but pcregrep does
930     continue to scan other files.
932     (o) The -s option was incorrectly implemented. For compatibility with other
933     greps, it now suppresses the error message for a non-existent or non-
934     accessible file (but not the return code). There is a new option called
935     -q that suppresses the output of matching lines, which was what -s was
936     previously doing.
938     (p) Added --include and --exclude options to specify files for inclusion
939     and exclusion when recursing.
941     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
942     Hopefully, it now does.
944     12. Missing cast in pcre_study().
946     13. Added an "uninstall" target to the makefile.
948     14. Replaced "extern" in the function prototypes in Makefile.in with
949     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
950     world, but is set differently for Windows.
952     15. Added a second compiling function called pcre_compile2(). The only
953     difference is that it has an extra argument, which is a pointer to an
954     integer error code. When there is a compile-time failure, this is set
955     non-zero, in addition to the error test pointer being set to point to an
956     error message. The new argument may be NULL if no error number is required
957     (but then you may as well call pcre_compile(), which is now just a
958     wrapper). This facility is provided because some applications need a
959     numeric error indication, but it has also enabled me to tidy up the way
960     compile-time errors are handled in the POSIX wrapper.
962     16. Added VPATH=.libs to the makefile; this should help when building with one
963     prefix path and installing with another. (Or so I'm told by someone who
964     knows more about this stuff than I do.)
966     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
967     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
968     match everything, including newlines. This is not POSIX-compatible, but
969     somebody wanted the feature. From pcretest it can be activated by using
970     both the P and the s flags.
972     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
974     19. libpcre.pc was being incorrectly installed as executable.
976     20. A couple of places in pcretest check for end-of-line by looking for '\n';
977     it now also looks for '\r' so that it will work unmodified on Windows.
979     21. Added Google's contributed C++ wrapper to the distribution.
981     22. Added some untidy missing memory free() calls in pcretest, to keep
982     Electric Fence happy when testing.
986 nigel 75 Version 5.0 13-Sep-04
987     ---------------------
989     1. Internal change: literal characters are no longer packed up into items
990     containing multiple characters in a single byte-string. Each character
991     is now matched using a separate opcode. However, there may be more than one
992     byte in the character in UTF-8 mode.
994     2. The pcre_callout_block structure has two new fields: pattern_position and
995     next_item_length. These contain the offset in the pattern to the next match
996     item, and its length, respectively.
998     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
999     insertion of callouts before each pattern item. Added the /C option to
1000     pcretest to make use of this.
1002     4. On the advice of a Windows user, the lines
1004     #if defined(_WIN32) || defined(WIN32)
1005     _setmode( _fileno( stdout ), 0x8000 );
1006     #endif /* defined(_WIN32) || defined(WIN32) */
1008     have been added to the source of pcretest. This apparently does useful
1009     magic in relation to line terminators.
1011     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1012     for the benefit of those environments where the "b" makes a difference.
1014     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1015     to know about it. I have put a hack into configure.in that adds in code
1016     to set GCC=yes if CC=icc. This seems to end up at a point in the
1017     generated configure script that is early enough to affect the setting of
1018     compiler options, which is what is needed, but I have no means of testing
1019     whether it really works. (The user who reported this had patched the
1020     generated configure script, which of course I cannot do.)
1022     LATER: After change 22 below (new libtool files), the configure script
1023     seems to know about icc (and also ecc). Therefore, I have commented out
1024     this hack in configure.in.
1026     7. Added support for pkg-config (2 patches were sent in).
1028     8. Negated POSIX character classes that used a combination of internal tables
1029     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1030     [[:^ascii]]. Typically, they would match almost any characters. The other
1031     POSIX classes were not broken in this way.
1033     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1034     to find the match, as PCRE was deluded into thinking that the match had to
1035     start at the start point or following a newline. The same bug applied to
1036     patterns with negative forward assertions or any backward assertions
1037     preceding ".*" at the start, unless the pattern required a fixed first
1038     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1040     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1041     starting at the last subject character, bytes beyond the end of the subject
1042     string were read.
1044     11. Renamed the variable "class" as "classbits" to make life easier for C++
1045     users. (Previously there was a macro definition, but it apparently wasn't
1046     enough.)
1048     12. Added the new field "tables" to the extra data so that tables can be passed
1049     in at exec time, or the internal tables can be re-selected. This allows
1050     a compiled regex to be saved and re-used at a later time by a different
1051     program that might have everything at different addresses.
1053     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1054     -R library as well as a -L library.
1056     14. The debugging options of pcretest (-d on the command line or D on a
1057     pattern) showed incorrect output for anything following an extended class
1058     that contained multibyte characters and which was followed by a quantifier.
1060     15. Added optional support for general category Unicode character properties
1061     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1062     support. It adds about 90K to the size of the library. The meanings of the
1063     inbuilt class escapes such as \d and \s have NOT been changed.
1065     16. Updated pcredemo.c to include calls to free() to release the memory for the
1066     compiled pattern.
1068     17. The generated file chartables.c was being created in the source directory
1069     instead of in the building directory. This caused the build to fail if the
1070     source directory was different from the building directory, and was
1071     read-only.
1073     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1074     file. No doubt somebody will tell me if they don't make sense... Also added
1075     Dan Mooney's comments about building on OpenVMS.
1077     19. Added support for partial matching via the PCRE_PARTIAL option for
1078     pcre_exec() and the \P data escape in pcretest.
1080     20. Extended pcretest with 3 new pattern features:
1082     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1083     write the compiled pattern to the file whose name is "rest-of-line".
1084     This is a straight binary dump of the data, with the saved pointer to
1085     the character tables forced to be NULL. The study data, if any, is
1086     written too. After writing, pcretest reads a new pattern.
1088     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1089     compiled pattern from the given file. There must not be any
1090     occurrences of "<" in the file name (pretty unlikely); if there are,
1091     pcretest will instead treat the initial "<" as a pattern delimiter.
1092     After reading in the pattern, pcretest goes on to read data lines as
1093     usual.
1095     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1096     and 16-bit fields in a compiled pattern, to simulate a pattern that
1097     was compiled on a host of opposite endianness.
1099     21. The pcre-exec() function can now cope with patterns that were compiled on
1100     hosts of opposite endianness, with this restriction:
1102     As for any compiled expression that is saved and used later, the tables
1103     pointer field cannot be preserved; the extra_data field in the arguments
1104     to pcre_exec() should be used to pass in a tables address if a value
1105     other than the default internal tables were used at compile time.
1107     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1108     now diagnosed as an error. Previously, most of the time, a negative number
1109     would have been treated as zero, but if in addition "ovector" was passed as
1110     NULL, a crash could occur.
1112     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1113     new versions from the libtool 1.5 distribution (the last one is a copy of
1114     a file called libtool.m4). This seems to have fixed the need to patch
1115     "configure" to support Darwin 1.3 (which I used to do). However, I still
1116     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1117     workstation).
1119     24. Changed the PCRE licence to be the more standard "BSD" licence.
1122 nigel 73 Version 4.5 01-Dec-03
1123     ---------------------
1125     1. There has been some re-arrangement of the code for the match() function so
1126     that it can be compiled in a version that does not call itself recursively.
1127     Instead, it keeps those local variables that need separate instances for
1128     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1129     needs to "recurse". Keeping track of where control must go is done by means
1130     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1131     hide most of the details from the main code, and operates only if
1132     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1133     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1134     operating.
1136     To make it easier for callers to provide specially tailored get/free
1137     functions for this usage, two new functions, pcre_stack_malloc, and
1138     pcre_stack_free, are used. They are always called in strict stacking order,
1139     and the size of block requested is always the same.
1141     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1142     PCRE has been compiled to use the stack or the heap for recursion. The
1143     -C option of pcretest uses this to show which version is compiled.
1145     A new data escape \S, is added to pcretest; it causes the amounts of store
1146     obtained and freed by both kinds of malloc/free at match time to be added
1147     to the output.
1149     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1150     what's available on my current Linux desktop machine.
1152     3. When matching a UTF-8 string, the test for a valid string at the start has
1153     been extended. If start_offset is not zero, PCRE now checks that it points
1154     to a byte that is the start of a UTF-8 character. If not, it returns
1155     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1156     this is necessary because there may be backward assertions in the pattern.
1157     When matching the same subject several times, it may save resources to use
1158     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1160     4. The code for checking the validity of UTF-8 strings has been tightened so
1161     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1162     containing "overlong sequences".
1164     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1165     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1166     should have been "&", but it just so happened that all the cases this let
1167     through by mistake were picked up later in the function.
1169     6. I had used a variable called "isblank" - this is a C99 function, causing
1170     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1172     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1173     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1174     so the version is shown; (c) stop "make test" echoing "./RunTest".
1176     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1178     9. The prototype for memmove() for systems that don't have it was using
1179     size_t, but the inclusion of the header that defines size_t was later. I've
1180     moved the #includes for the C headers earlier to avoid this.
1182     10. Added some adjustments to the code to make it easier to compiler on certain
1183     special systems:
1185     (a) Some "const" qualifiers were missing.
1186     (b) Added the macro EXPORT before all exported functions; by default this
1187     is defined to be empty.
1188     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1189     that it reads its output file name as an argument instead of writing
1190     to the standard output and assuming this can be redirected.
1192     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1193     class containing characters with values greater than 255, PCRE compilation
1194     went into a loop.
1196     12. A recursive reference to a subpattern that was within another subpattern
1197     that had a minimum quantifier of zero caused PCRE to crash. For example,
1198     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1199     recursion. If the recursively-called subpattern itself had a zero repeat,
1200     that was OK.
1202     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1203     buffer into which it was copied (for escape processing) was still set at
1204     1024, so long lines caused crashes.
1206     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1207     "internal error: code overflow...". This applied to any character class
1208     that was followed by a possessive quantifier.
1210     15. Modified the Makefile to add libpcre.la as a prerequisite for
1211     libpcreposix.la because I was told this is needed for a parallel build to
1212     work.
1214     16. If a pattern that contained .* following optional items at the start was
1215     studied, the wrong optimizing data was generated, leading to matching
1216     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1217     matching string must start with a or b or c. The correct conclusion for
1218     this pattern is that a match can start with any character.
1221 nigel 71 Version 4.4 13-Aug-03
1222     ---------------------
1224     1. In UTF-8 mode, a character class containing characters with values between
1225     127 and 255 was not handled correctly if the compiled pattern was studied.
1226     In fixing this, I have also improved the studying algorithm for such
1227     classes (slightly).
1229     2. Three internal functions had redundant arguments passed to them. Removal
1230     might give a very teeny performance improvement.
1232     3. Documentation bug: the value of the capture_top field in a callout is *one
1233     more than* the number of the hightest numbered captured substring.
1235     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1236     in incorrectly linking with a previously installed version. They now link
1237     explicitly with libpcre.la.
1239     5. configure.in no longer needs to recognize Cygwin specially.
1241     6. A problem in pcre.in for Windows platforms is fixed.
1243     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1244     pcretest, it used to include the size of the study block as part of its
1245     output. Unfortunately, the structure contains a field that has a different
1246     size on different hardware architectures. This meant that the tests that
1247     showed this size failed. As the block is currently always of a fixed size,
1248     this information isn't actually particularly useful in pcretest output, so
1249     I have just removed it.
1251     8. Three pre-processor statements accidentally did not start in column 1.
1252     Sadly, there are *still* compilers around that complain, even though
1253     standard C has not required this for well over a decade. Sigh.
1255     9. In pcretest, the code for checking callouts passed small integers in the
1256     callout_data field, which is a void * field. However, some picky compilers
1257     complained about the casts involved for this on 64-bit systems. Now
1258     pcretest passes the address of the small integer instead, which should get
1259     rid of the warnings.
1261     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1262     both compile and run time, and gives an error if an invalid UTF-8 sequence
1263     is found. There is a option for disabling this check in cases where the
1264     string is known to be correct and/or the maximum performance is wanted.
1266     11. In response to a bug report, I changed one line in Makefile.in from
1268     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1269     to
1270     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1272     to look similar to other lines, but I have no way of telling whether this
1273     is the right thing to do, as I do not use Windows. No doubt I'll get told
1274     if it's wrong...
1277 nigel 69 Version 4.3 21-May-03
1278     ---------------------
1280     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1281     Makefile.
1283     2. Some refactoring to improve the quality of the code:
1285     (i) The utf8_table... variables are now declared "const".
1287     (ii) The code for \cx, which used the "case flipping" table to upper case
1288     lower case letters, now just substracts 32. This is ASCII-specific,
1289     but the whole concept of \cx is ASCII-specific, so it seems
1290     reasonable.
1292     (iii) PCRE was using its character types table to recognize decimal and
1293     hexadecimal digits in the pattern. This is silly, because it handles
1294     only 0-9, a-f, and A-F, but the character types table is locale-
1295     specific, which means strange things might happen. A private
1296     table is now used for this - though it costs 256 bytes, a table is
1297     much faster than multiple explicit tests. Of course, the standard
1298     character types table is still used for matching digits in subject
1299     strings against \d.
1301     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1302     ending in _t are). So I've renamed it as ESC_tee.
1304     3. The first argument for regexec() in the POSIX wrapper should have been
1305     defined as "const".
1307     4. Changed pcretest to use malloc() for its buffers so that they can be
1308     Electric Fenced for debugging.
1310     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1311     to read one or more bytes before the start of the subject string. Often this
1312     had no effect on PCRE's behaviour, but in some circumstances it could
1313     provoke a segmentation fault.
1315     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1316     to try to read one or more bytes before the start of the subject string.
1318     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1319     UTF-8 support could misbehave in various ways if the subject string
1320     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1321     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1322     back over UTF-8 characters.)
1325 nigel 67 Version 4.2 14-Apr-03
1326     ---------------------
1328     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1330     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1331     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1332     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1333     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1334     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1335     and BUILD_EXEEXT
1336     Note: automatic setting of the BUILD variables is not yet working
1337     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1338     compile-time but not at link-time
1339     [LINK]: use for linking executables only
1340     make different versions for Windows and non-Windows
1341     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1342     libraries
1343     [LINK_FOR_BUILD]: new variable
1344     [OBJEXT]: use throughout
1345     [EXEEXT]: use throughout
1346     <winshared>: new target
1347     <wininstall>: new target
1348     <dftables.o>: use native compiler
1349     <dftables>: use native linker
1350     <install>: handle Windows platform correctly
1351     <clean>: ditto
1352     <check>: ditto
1353     copy DLL to top builddir before testing
1355     As part of these changes, -no-undefined was removed again. This was reported
1356     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1357     in any case.
1359     3. Some tidies to get rid of compiler warnings:
1361     . In the match_data structure, match_limit was an unsigned long int, whereas
1362     match_call_count was an int. I've made them both unsigned long ints.
1364     . In pcretest the fact that a const uschar * doesn't automatically cast to
1365     a void * provoked a warning.
1367     . Turning on some more compiler warnings threw up some "shadow" variables
1368     and a few more missing casts.
1370     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1371     option, a class that contained a single character with a value between 128
1372     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1374     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1375     option, a class that contained several characters, but with at least one
1376     whose value was between 128 and 255 caused PCRE to crash.
1379 nigel 65 Version 4.1 12-Mar-03
1380     ---------------------
1381 nigel 63
1382 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1383     needed, and a string in dftables.c that was longer than standard compilers are
1384     required to support.
1386     2. Compiling with Sun's compiler found a few more places where the code could
1387     be tidied up in order to avoid warnings.
1389     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1390     first of these names is deprecated in the latest Autoconf in favour of the name
1391     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1392     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1393     analogy I have changed it to CFLAGS_FOR_BUILD.
1395     4. Added -no-undefined to the linking command in the Makefile, because this is
1396     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1397     linking step for the pcreposix library.
1399     5. PCRE was failing to diagnose the case of two named groups with the same
1400     name.
1402     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1403     literal character that is needed in the subject for a match, and scans along to
1404     ensure that it is present before embarking on the full matching process. This
1405     saves time in cases of nested unlimited repeats that are never going to match.
1406     Problem: the scan can take a lot of time if the subject is very long (e.g.
1407     megabytes), thus penalizing straightforward matches. It is now done only if the
1408     amount of subject to be scanned is less than 1000 bytes.
1410     7. A lesser problem with the same optimization is that it was recording the
1411     first character of an anchored pattern as "needed", thus provoking a search
1412     right along the subject, even when the first match of the pattern was going to
1413     fail. The "needed" character is now not set for anchored patterns, unless it
1414     follows something in the pattern that is of non-fixed length. Thus, it still
1415     fulfils its original purpose of finding quick non-matches in cases of nested
1416     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1419     Version 4.0 17-Feb-03
1420     ---------------------
1422 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1423     extended to the end of string, PCRE compiled incorrect data. This could lead to
1424     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1426     2. Moved to autoconf 2.53 and libtool 1.4.2.
1428     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1429     the special perltest8 script is no longer needed - all the tests can be run
1430     from a single perltest script.
1432     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1433     by \s. It has now been removed in PCRE. This means it isn't recognized as
1434     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1435     class [:space:] *does* include VT, thereby creating a mess.
1437     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1438     space and tab.
1440     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1441     its new features into the main test script, reducing the number of scripts.
1443     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1444     were backward compatible, and made the (?i) apply to the whole pattern, as if
1445     /i were given. Now it behaves more logically, and applies the option setting
1446     only to what follows. PCRE has been changed to follow suit. However, if it
1447     finds options settings right at the start of the pattern, it extracts them into
1448     the global options, as before. Thus, they show up in the info data.
1450     8. Added support for the \Q...\E escape sequence. Characters in between are
1451     treated as literals. This is slightly different from Perl in that $ and @ are
1452     also handled as literals inside the quotes. In Perl, they will cause variable
1453     interpolation. Note the following examples:
1455     Pattern PCRE matches Perl matches
1457     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1458     \Qabc\$xyz\E abc\$xyz abc\$xyz
1459     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1461     For compatibility with Perl, \Q...\E sequences are recognized inside character
1462     classes as well as outside them.
1464     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1465     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1466     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1467     signed/unsigned warnings.
1469     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1470     option for pcretest, so I've replaced it by a simple function that does just
1471     that job.
1473     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1474     "pcregrep -".
1476     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1477     Java package. This provides some syntactic sugar for simple cases of what my
1478     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1479     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1480     item, you can use this simplified notation. Note that only makes sense with
1481     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1482     greediness, whatever the setting of the PCRE_UNGREEDY option.
1484     13. A change of greediness default within a pattern was not taking effect at
1485     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1486     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1487     was abstracted outside.
1489     14. PCRE now supports the \G assertion. It is true when the current matching
1490     position is at the start point of the match. This differs from \A when the
1491     starting offset is non-zero. Used with the /g option of pcretest (or similar
1492     code), it works in the same way as it does for Perl's /g option. If all
1493     alternatives of a regex begin with \G, the expression is anchored to the start
1494     match position, and the "anchored" flag is set in the compiled expression.
1496     15. Some bugs concerning the handling of certain option changes within patterns
1497     have been fixed. These applied to options other than (?ims). For example,
1498     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1499     been the other way round. Some of this was related to change 7 above.
1501     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1502     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1503     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1504     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1506     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1507     mode. Unlike ".", it always matches newline, whatever the setting of
1508     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1509     assertions. Perl allows it, but it doesn't (in general) work because it can't
1510     calculate the length of the lookbehind. At least, that's the case for Perl
1511     5.8.0 - I've been told they are going to document that it doesn't work in
1512     future.
1514     18. Added an error diagnosis for escapes that PCRE does not support: these are
1515     \L, \l, \N, \P, \p, \U, \u, and \X.
1517     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1518     reading past the end of the pattern in cases such as /[abcd/.
1520     20. PCRE was getting more memory than necessary for patterns with classes that
1521     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1523     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1524     compiling PCRE for use with Virtual Pascal.
1526     22. Small fix to the Makefile to make it work properly if the build is done
1527     outside the source tree.
1529     23. Added a new extension: a condition to go with recursion. If a conditional
1530     subpattern starts with (?(R) the "true" branch is used if recursion has
1531     happened, whereas the "false" branch is used only at the top level.
1533     24. When there was a very long string of literal characters (over 255 bytes
1534     without UTF support, over 250 bytes with UTF support), the computation of how
1535     much memory was required could be incorrect, leading to segfaults or other
1536     strange effects.
1538     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1539     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1540     there was a subsequent back reference to those brackets. This meant that, for
1541     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1542     possible to check for precisely this case. All we can do is abandon the
1543     optimization if .* occurs inside capturing brackets when there are any back
1544     references whatsoever. (See below for a better fix that came later.)
1546     26. The handling of the optimization for finding the first character of a
1547     non-anchored pattern, and for finding a character that is required later in the
1548     match were failing in some cases. This didn't break the matching; it just
1549     failed to optimize when it could. The way this is done has been re-implemented.
1551     27. Fixed typo in error message for invalid (?R item (it said "(?p").
1553     28. Added a new feature that provides some of the functionality that Perl
1554     provides with (?{...}). The facility is termed a "callout". The way it is done
1555     in PCRE is for the caller to provide an optional function, by setting
1556     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1557     global variable. By default it is unset, which disables all calling out. To get
1558     the function called, the regex must include (?C) at appropriate points. This
1559     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1560     This provides a means of identifying different callout points. When PCRE
1561     reaches such a point in the regex, if pcre_callout has been set, the external
1562     function is called. It is provided with data in a structure called
1563     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1564     matching continues; if it returns a non-zero value, the match at the current
1565     point fails. However, backtracking will occur if possible. [This was changed
1566     later and other features added - see item 49 below.]
1568     29. pcretest is upgraded to test the callout functionality. It provides a
1569     callout function that displays information. By default, it shows the start of
1570     the match and the current position in the text. There are some new data escapes
1571     to vary what happens:
1573     \C+ in addition, show current contents of captured substrings
1574     \C- do not supply a callout function
1575     \C!n return 1 when callout number n is reached
1576     \C!n!m return 1 when callout number n is reached for the mth time
1578     30. If pcregrep was called with the -l option and just a single file name, it
1579     output "<stdin>" if a match was found, instead of the file name.
1581     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1582     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1583     pcre_exec(). This saves a malloc/free per call. The default value of
1584     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1585     when configuring.
1587     32. The default maximum size of a compiled pattern is 64K. There have been a
1588     few cases of people hitting this limit. The code now uses macros to handle the
1589     storing of links as offsets within the compiled pattern. It defaults to 2-byte
1590     links, but this can be changed to 3 or 4 bytes by --with-link-size when
1591     configuring. Tests 2 and 5 work only with 2-byte links because they output
1592     debugging information about compiled patterns.
1594     33. Internal code re-arrangements:
1596     (a) Moved the debugging function for printing out a compiled regex into
1597     its own source file (printint.c) and used #include to pull it into
1598     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1599     separate copies.
1601     (b) Defined the list of op-code names for debugging as a macro in
1602     internal.h so that it is next to the definition of the opcodes.
1604     (c) Defined a table of op-code lengths for simpler skipping along compiled
1605     code. This is again a macro in internal.h so that it is next to the
1606     definition of the opcodes.
1608     34. Added support for recursive calls to individual subpatterns, along the
1609     lines of Robin Houston's patch (but implemented somewhat differently).
1611     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1612     allow it to read and process whole directories in Win32. This code was
1613     contributed by Lionel Fourquaux; it has not been tested by me.
1615     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1616     used to name a group. Names consist of alphanumerics and underscores, and must
1617     be unique. Back references use the syntax (?P=name) and recursive calls use
1618     (?P>name) which is a PCRE extension to the Python extension. Groups still have
1619     numbers. The function pcre_fullinfo() can be used after compilation to extract
1620     a name/number map. There are three relevant calls:
1622     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1623     PCRE_INFO_NAMECOUNT yields the number of entries
1624     PCRE_INFO_NAMETABLE yields a pointer to the map.
1626     The map is a vector of fixed-size entries. The size of each entry depends on
1627     the length of the longest name used. The first two bytes of each entry are the
1628     group number, most significant byte first. There follows the corresponding
1629     name, zero terminated. The names are in alphabetical order.
1631     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1632     case instead of 255. Making it the same both with and without UTF-8 support
1633     means that the same test output works with both.
1635     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1636     calling malloc() with a zero argument.
1638     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1639     optimization. I've improved things by keeping a bitmap of backreferences with
1640     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1641     fact referenced, the optimization can be applied. It is unlikely that a
1642     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1643     the match to follow \n) will appear inside brackets with a number greater than
1644     31, but if it does, any back reference > 31 suppresses the optimization.
1646     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1647     of disabling numbered capturing parentheses. Any opening parenthesis that is
1648     not followed by ? behaves as if it were followed by ?: but named parentheses
1649     can still be used for capturing (and they will acquire numbers in the usual
1650     way).
1652     41. Redesigned the return codes from the match() function into yes/no/error so
1653     that errors can be passed back from deep inside the nested calls. A malloc
1654     failure while inside a recursive subpattern call now causes the
1655     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1657     42. It is now possible to set a limit on the number of times the match()
1658     function is called in a call to pcre_exec(). This facility makes it possible to
1659     limit the amount of recursion and backtracking, though not in a directly
1660     obvious way, because the match() function is used in a number of different
1661     circumstances. The count starts from zero for each position in the subject
1662     string (for non-anchored patterns). The default limit is, for compatibility, a
1663     large number, namely 10 000 000. You can change this in two ways:
1665     (a) When configuring PCRE before making, you can use --with-match-limit=n
1666     to set a default value for the compiled library.
1668     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1669     a different value is set. See 45 below.
1671     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1673     43. Added a new function pcre_config(int, void *) to enable run-time extraction
1674     of things that can be changed at compile time. The first argument specifies
1675     what is wanted and the second points to where the information is to be placed.
1676     The current list of available information is:
1680     The output is an integer that is set to one if UTF-8 support is available;
1681     otherwise it is set to zero.
1685     The output is an integer that it set to the value of the code that is used for
1686     newline. It is either LF (10) or CR (13).
1690     The output is an integer that contains the number of bytes used for internal
1691     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1695     The output is an integer that contains the threshold above which the POSIX
1696     interface uses malloc() for output vectors. See item 31 above.
1700     The output is an unsigned integer that contains the default limit of the number
1701     of match() calls in a pcre_exec() execution. See 42 above.
1703     44. pcretest has been upgraded by the addition of the -C option. This causes it
1704     to extract all the available output from the new pcre_config() function, and to
1705     output it. The program then exits immediately.
1707     45. A need has arisen to pass over additional data with calls to pcre_exec() in
1708     order to support additional features. One way would have been to define
1709     pcre_exec2() (for example) with extra arguments, but this would not have been
1710     extensible, and would also have required all calls to the original function to
1711     be mapped to the new one. Instead, I have chosen to extend the mechanism that
1712     is used for passing in "extra" data from pcre_study().
1714     The pcre_extra structure is now exposed and defined in pcre.h. It currently
1715     contains the following fields:
1717     flags a bitmap indicating which of the following fields are set
1718     study_data opaque data from pcre_study()
1719     match_limit a way of specifying a limit on match() calls for a specific
1720     call to pcre_exec()
1721     callout_data data for callouts (see 49 below)
1723     The flag bits are also defined in pcre.h, and are
1729     The pcre_study() function now returns one of these new pcre_extra blocks, with
1730     the actual study data pointed to by the study_data field, and the
1731     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1732     before. That is, this change is entirely upwards-compatible and requires no
1733     change to existing code.
1735     If you want to pass in additional data to pcre_exec(), you can either place it
1736     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1737     block.
1739     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1740     data string contains the escape sequence \M, pcretest calls pcre_exec() several
1741     times with different match limits, until it finds the minimum value needed for
1742     pcre_exec() to complete. The value is then output. This can be instructive; for
1743     most simple matches the number is quite small, but for pathological cases it
1744     gets very large very quickly.
1746     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1747     returns the size of the data block pointed to by the study_data field in a
1748     pcre_extra block, that is, the value that was passed as the argument to
1749     pcre_malloc() when PCRE was getting memory in which to place the information
1750     created by pcre_study(). The fourth argument should point to a size_t variable.
1751     pcretest has been extended so that this information is shown after a successful
1752     pcre_study() call when information about the compiled regex is being displayed.
1754     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1755     because what follows is always an absolute path. (Later: it turns out that this
1756     is more than cosmetic for MinGW, because it doesn't like empty path
1757     components.)
1759     49. Some changes have been made to the callout feature (see 28 above):
1761     (i) A callout function now has three choices for what it returns:
1763     0 => success, carry on matching
1764     > 0 => failure at this point, but backtrack if possible
1765     < 0 => serious error, return this value from pcre_exec()
1767     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1768     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1769     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1770     use by callout functions. It will never be used by PCRE itself.
1772     (ii) The pcre_extra structure (see 45 above) has a void * field called
1773     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1774     pcre_callout_block structure has a field of the same name. The contents of
1775     the field passed in the pcre_extra structure are passed to the callout
1776     function in the corresponding field in the callout block. This makes it
1777     easier to use the same callout-containing regex from multiple threads. For
1778     testing, the pcretest program has a new data escape
1780     \C*n pass the number n (may be negative) as callout_data
1782     If the callout function in pcretest receives a non-zero value as
1783     callout_data, it returns that value.
1785     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1786     there were some redundant $(CFLAGS) in commands that are now specified as
1787     $(LINK), which already includes $(CFLAGS).
1789     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1790     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1791     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1792     one-byte characters throughout. Note that case-insensitive matching applies
1793     only to characters whose values are less than 256. PCRE doesn't support the
1794     notion of cases for higher-valued characters.
1796     (i) A character class whose characters are all within 0-255 is handled as
1797     a bit map, and the map is inverted for negative classes. Previously, a
1798     character > 255 always failed to match such a class; however it should
1799     match if the class was a negative one (e.g. [^ab]). This has been fixed.
1801     (ii) A negated character class with a single character < 255 is coded as
1802     "not this character" (OP_NOT). This wasn't working properly when the test
1803     character was multibyte, either singly or repeated.
1805     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1806     mode, for example: \x{100}{2,3}.
1808     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1809     singly or repeated) now correctly test multibyte characters. However,
1810     PCRE doesn't recognize any characters with values greater than 255 as
1811     digits, spaces, or word characters. Such characters always match \D, \S,
1812     and \W, and never match \d, \s, or \w.
1814     (v) Classes may now contain characters and character ranges with values
1815     greater than 255. For example: [ab\x{100}-\x{400}].
1817     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1818     PCRE in UTF-8 mode.
1820     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1821     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1822     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1823     value.)
1825     53. The single man page has become too large. I have therefore split it up into
1826     a number of separate man pages. These also give rise to individual HTML pages;
1827     these are now put in a separate directory, and there is an index.html page that
1828     lists them all. Some hyperlinking between the pages has been installed.
1830     54. Added convenience functions for handling named capturing parentheses.
1832     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1833     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1834     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1835     are faulted.
1837     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1838     calling configure. These values are used when compiling the dftables.c program
1839     which is run to generate the source of the default character tables. They
1840     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1841     you will need to set these values.
1843     57. Updated the building process for Windows DLL, as provided by Fred Cox.
1846     Version 3.9 02-Jan-02
1847 nigel 61 ---------------------
1849     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1851     2. If --disable-static was given, the building process failed when trying to
1852     build pcretest and pcregrep. (For some reason it was using libtool to compile
1853     them, which is not right, as they aren't part of the library.)
1856 nigel 59 Version 3.8 18-Dec-01
1857     ---------------------
1859     1. The experimental UTF-8 code was completely screwed up. It was packing the
1860     bytes in the wrong order. How dumb can you get?
1863 nigel 57 Version 3.7 29-Oct-01
1864     ---------------------
1866     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1867     This caused pcretest, when used on the test data, to segfault. Unfortunately,
1868     this didn't happen under Solaris 8, where I normally test things.
1870 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1871     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1872     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
1873     this fix an hour or so after the initial 3.7 release.)
1874 nigel 57
1875 nigel 59
1876 nigel 55 Version 3.6 23-Oct-01
1877     ---------------------
1879     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1880     offsets passed as NULL with zero offset count.
1882     2. The config.guess and config.sub files had not been updated when I moved to
1883     the latest autoconf.
1886 nigel 53 Version 3.5 15-Aug-01
1887     ---------------------
1888 nigel 5
1889 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
1890     had been forgotten.
1892     2. By using declared but undefined structures, we can avoid using "void"
1893     definitions in pcre.h while keeping the internal definitions of the structures
1894     private.
1896     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
1897     user point of view, this means that both static and shared libraries are built
1898     by default, but this can be individually controlled. More of the work of
1899     handling this static/shared cases is now inside libtool instead of PCRE's make
1900     file.
1902     4. The pcretest utility is now installed along with pcregrep because it is
1903     useful for users (to test regexs) and by doing this, it automatically gets
1904     relinked by libtool. The documentation has been turned into a man page, so
1905     there are now .1, .txt, and .html versions in /doc.
1907     5. Upgrades to pcregrep:
1908     (i) Added long-form option names like gnu grep.
1909     (ii) Added --help to list all options with an explanatory phrase.
1910     (iii) Added -r, --recursive to recurse into sub-directories.
1911     (iv) Added -f, --file to read patterns from a file.
1913     6. pcre_exec() was referring to its "code" argument before testing that
1914     argument for NULL (and giving an error if it was NULL).
1916     7. Upgraded Makefile.in to allow for compiling in a different directory from
1917     the source directory.
1919     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
1920     options bits, the pointer it was passed was to an int instead of to an unsigned
1921     long int. This mattered only on 64-bit systems.
1923     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
1924     generated) instead of pcre.in, which it its source. Also made the same change
1925     in several of the .c files.
1927     10. A new release of gcc defines printf() as a macro, which broke pcretest
1928     because it had an ifdef in the middle of a string argument for printf(). Fixed
1929     by using separate calls to printf().
1931     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
1932     script, to force use of CR or LF instead of \n in the source. On non-Unix
1933     systems, the value can be set in config.h.
1935     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
1936     absolute limit. Changed the text of the error message to make this clear, and
1937     likewise updated the man page.
1939     13. The limit of 99 on the number of capturing subpatterns has been removed.
1940     The new limit is 65535, which I hope will not be a "real" limit.
1943 nigel 51 Version 3.4 22-Aug-00
1944     ---------------------
1946     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
1948     2. Diagnose condition (?(0) as an error instead of crashing on matching.
1951 nigel 49 Version 3.3 01-Aug-00
1952     ---------------------
1954     1. If an octal character was given, but the value was greater than \377, it
1955     was not getting masked to the least significant bits, as documented. This could
1956     lead to crashes in some systems.
1958     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
1959     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
1961     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
1962     These just pass their arguments on to (pcre_free)(), but they are provided
1963     because some uses of PCRE bind it to non-C systems that can call its functions,
1964     but cannot call free() or pcre_free() directly.
1966     4. Add "make test" as a synonym for "make check". Corrected some comments in
1967     the Makefile.
1969     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
1970     Makefile.
1972     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
1973     command called pgrep for grepping around the active processes.
1975     7. Added the beginnings of support for UTF-8 character strings.
1977     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
1978     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
1979     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
1980     out for the ar command.)
1983 nigel 47 Version 3.2 12-May-00
1984     ---------------------
1986     This is purely a bug fixing release.
1988     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
1989     of ZA. This was just one example of several cases that could provoke this bug,
1990     which was introduced by change 9 of version 2.00. The code for breaking
1991     infinite loops after an iteration that matches an empty string was't working
1992     correctly.
1994     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
1995     when matched against abbab (for example). After matching an empty string, it
1996     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
1997     caused it to match further down the string than it should.
1999     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2000     was there because it doesn't seem to be needed, and it causes trouble on some
2001     systems, as it is not a Standard C header. It has been removed.
2003     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2004     were reported on the Macintosh. The changes were from
2006     while ((c = *(++ptr)) != 0 && c != '\n');
2007     to
2008     while ((c = *(++ptr)) != 0 && c != '\n') ;
2010     Totally extraordinary, but if that's what it takes...
2012     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2013     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2014     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2015     assumes the way PCRE uses memmove() (always moving upwards).
2017     6. PCRE is being used in one environment where strchr() is not available. There
2018     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2019     faster code anyway.
2022 nigel 45 Version 3.1 09-Feb-00
2023     ---------------------
2025     The only change in this release is the fixing of some bugs in Makefile.in for
2026     the "install" target:
2028     (1) It was failing to install pcreposix.h.
2030     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2033 nigel 43 Version 3.0 01-Feb-00
2034     ---------------------
2035 nigel 41
2036     1. Add support for the /+ modifier to perltest (to output $` like it does in
2037     pcretest).
2039     2. Add support for the /g modifier to perltest.
2041     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2042     matches null strings.
2044     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2045     pattern. Perl treats empty patterns specially - it reuses the most recent
2046     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2047     effect.
2049     5. The POSIX interface was broken in that it was just handing over the POSIX
2050     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2051     required a bigger vector, with some working space on the end. This means that
2052     the POSIX wrapper now has to get and free some memory, and copy the results.
2054 nigel 43 6. Added some simple autoconf support, placing the test data and the
2055     documentation in separate directories, re-organizing some of the
2056     information files, and making it build pcre-config (a GNU standard). Also added
2057     libtool support for building PCRE as a shared library, which is now the
2058     default.
2059 nigel 41
2060 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2061     09 are not valid octal constants. Single digits will be used for minor values
2062     less than 10.
2064     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2065     existing programs that set these in the POSIX interface can use PCRE without
2066     modification.
2068     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2069     return all that pcre_info() returns, plus additional data. The pcre_info()
2070     function is retained for compatibility, but is considered to be obsolete.
2072     10. Added experimental recursion feature (?R) to handle one common case that
2073     Perl 5.6 will be able to do with (?p{...}).
2075     11. Added support for POSIX character classes like [:alpha:], which Perl is
2076     adopting.
2079 nigel 39 Version 2.08 31-Aug-99
2080     ----------------------
2082     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2083     trying to match at the startoffset position, but instead was moving forward to
2084     the next newline as if a previous match had failed.
2086     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2087     and could get into a loop if a null string was matched other than at the start
2088     of the subject.
2090     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2091     be distinguished at compile time, and for completeness also added PCRE_DATE.
2093     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2094     in GnuWin32 environments.
2097 nigel 37 Version 2.07 29-Jul-99
2098     ----------------------
2100     1. The documentation is now supplied in plain text form and HTML as well as in
2101     the form of man page sources.
2103     2. C++ compilers don't like assigning (void *) values to other pointer types.
2104     In particular this affects malloc(). Although there is no problem in Standard
2105     C, I've put in casts to keep C++ compilers happy.
2107     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2108     should be (const char *).
2110     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2111     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2112     However, I haven't made this a standard facility. The documentation doesn't
2113     mention it, and the Makefile doesn't support it.
2115     5. The Makefile now contains an "install" target, with editable destinations at
2116     the top of the file. The pcretest program is not installed.
2118     6. pgrep -V now gives the PCRE version number and date.
2120     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2121     causing the entire string to be ignored, instead of just the last character.
2123     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2124     non-matching string, it can take a very, very long time, even for strings of
2125     quite modest length, because of the nested recursion. PCRE now does better in
2126     some of these cases. It does this by remembering the last required literal
2127     character in the pattern, and pre-searching the subject to ensure it is present
2128     before running the real match. In other words, it applies a heuristic to detect
2129     some types of certain failure quickly, and in the above example, if presented
2130     with a string that has no trailing " it gives "no match" very quickly.
2132     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2133     other alternatives are tried instead.
2136 nigel 35 Version 2.06 09-Jun-99
2137     ----------------------
2139     1. Change pcretest's output for amount of store used to show just the code
2140     space, because the remainder (the data block) varies in size between 32-bit and
2141     64-bit systems.
2143     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2144     start matching at. This allows lookbehinds to work when searching for multiple
2145     occurrences in a string.
2147     3. Added additional options to pcretest for testing multiple occurrences:
2149     /+ outputs the rest of the string that follows a match
2150     /g loops for multiple occurrences, using the new startoffset argument
2151     /G loops for multiple occurrences by passing an incremented pointer
2153     4. PCRE wasn't doing the "first character" optimization for patterns starting
2154     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2155     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2156     the letter 'x'. On long subject strings, this gives a significant speed-up.
2159 nigel 33 Version 2.05 21-Apr-99
2160     ----------------------
2162     1. Changed the type of magic_number from int to long int so that it works
2163     properly on 16-bit systems.
2165     2. Fixed a bug which caused patterns starting with .* not to work correctly
2166     when the subject string contained newline characters. PCRE was assuming
2167     anchoring for such patterns in all cases, which is not correct because .* will
2168     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2169     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2170     must be retried after every newline in the subject.
2173 nigel 31 Version 2.04 18-Feb-99
2174     ----------------------
2176     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2177     computation of the store needed to hold the pattern was incorrect (too large).
2178     If such patterns were nested a few deep, this could multiply and become a real
2179     problem.
2181     2. Added /M option to pcretest to show the memory requirement of a specific
2182     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2184     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2185     compiled in such a way that the backtracking after subsequent failure was
2186     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2187     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2190 nigel 29 Version 2.03 02-Feb-99
2191     ----------------------
2193     1. Fixed typo and small mistake in man page.
2195 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2196     LICENCE file containing the conditions.
2197 nigel 29
2198     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2199     Perl, that is the internal \ allows the delimiter to be included in the
2200     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2201     the final delimiter, add \ to the end of the pattern (to test the error).
2203     4. Added the convenience functions for extracting substrings after a successful
2204     match. Updated pcretest to make it able to test these functions.
2207 nigel 27 Version 2.02 14-Jan-99
2208     ----------------------
2210     1. Initialized the working variables associated with each extraction so that
2211     their saving and restoring doesn't refer to uninitialized store.
2213     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2214     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2215     fix the problem.
2217     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2218     calls, and wasn't printing the correct value for compiling calls. Increased the
2219     default value of LOOPREPEAT, and the number of significant figures in the
2220     times.
2222     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2224     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2225     a building problem on Windows NT with a FAT file system.
2228 nigel 25 Version 2.01 21-Oct-98
2229     ----------------------
2231     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2232     to character tables built by pcre_maketables() in the current locale. If NULL
2233     is passed, the default tables are used.
2236 nigel 23 Version 2.00 24-Sep-98
2237 nigel 21 ----------------------
2239 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2240     it any more.
2242     2. Allow quantification of (?>) groups, and make it work correctly.
2244     3. The first character computation wasn't working for (?>) groups.
2246     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2247     end of the subject) and add 5.005's \z, which really does match only at the
2248     very end of the subject.
2250     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2252     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2253     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2254     localized options. All options to pcre_study() were also removed.
2256     7. Add other new features from 5.005:
2258     $(?<= positive lookbehind
2259     $(?<! negative lookbehind
2260     (?imsx-imsx) added the unsetting capability
2261     such a setting is global if at outer level; local otherwise
2262     (?imsx-imsx:) non-capturing groups with option setting
2263     (?(cond)re|re) conditional pattern matching
2265     A backreference to itself in a repeated group matches the previous
2266     captured string.
2268     8. General tidying up of studying (both automatic and via "study")
2269     consequential on the addition of new assertions.
2271     9. As in 5.005, unlimited repeated groups that could match an empty substring
2272     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2273     runtime if any iteration does actually match an empty substring.
2275     10. Include the RunTest script in the distribution.
2277     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2278     discrepancies, some of which were old and were also with respect to 5.004. They
2279     have now been fixed.
2282     Version 1.09 28-Apr-98
2283     ----------------------
2285 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2286     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2287     program crashes, or just wrong answers. This did not apply to negated classes
2288     containing more than one character, or to minima other than one.
2291 nigel 19 Version 1.08 27-Mar-98
2292     ----------------------
2294     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2296     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2297     latter must appear before anything that relies on it in the pattern.
2300 nigel 17 Version 1.07 16-Feb-98
2301     ----------------------
2303     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2304     repeat of a potentially empty string).
2307 nigel 15 Version 1.06 23-Jan-98
2308     ----------------------
2310     1. Added Markus Oberhumer's little patches for C++.
2312     2. Literal strings longer than 255 characters were broken.
2315 nigel 13 Version 1.05 23-Dec-97
2316     ----------------------
2318     1. Negated character classes containing more than one character were failing if
2319     PCRE_CASELESS was set at run time.
2322 nigel 11 Version 1.04 19-Dec-97
2323     ----------------------
2325     1. Corrected the man page, where some "const" qualifiers had been omitted.
2327     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2328     input syntax.
2330     3. Fixed memory leak which occurred when a regex with back references was
2331     matched with an offsets vector that wasn't big enough. The temporary memory
2332     that is used in this case wasn't being freed if the match failed.
2334     4. Tidied pcretest to ensure it frees memory that it gets.
2336     5. Temporary memory was being obtained in the case where the passed offsets
2337     vector was exactly big enough.
2339     6. Corrected definition of offsetof() from change 5 below.
2341     7. I had screwed up change 6 below and broken the rules for the use of
2342     setjmp(). Now fixed.
2345 nigel 9 Version 1.03 18-Dec-97
2346     ----------------------
2348     1. A erroneous regex with a missing opening parenthesis was correctly
2349     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2350     on some systems.
2352     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2353     it was reported that one broken compiler failed on the former because "code" is
2354     also an independent variable.
2356     3. The erroneous regex a[]b caused an array overrun reference.
2358     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2359     fail on data ending with that character. (It was going on too far, and checking
2360     the next character, typically a binary zero.) This was specific to the
2361     optimized code for single-character negative classes.
2363     5. Added a contributed patch from the TIN world which does the following:
2365     + Add an undef for memmove, in case the the system defines a macro for it.
2367     + Add a definition of offsetof(), in case there isn't one. (I don't know
2368     the reason behind this - offsetof() is part of the ANSI standard - but
2369     it does no harm).
2371     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2372     most of the places where whitespace preceded '#'. I have given up and
2373     allowed the remaining 2 cases to be at the margin.
2375     + Rename some variables in pcre to eliminate shadowing. This seems very
2376     pedantic, but does no harm, of course.
2378     6. Moved the call to setjmp() into its own function, to get rid of warnings
2379     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2381     7. Constructs such as \d{8,} were compiling into the equivalent of
2382 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2383 nigel 9 outcome, but in this particular case used more store than had been allocated,
2384     which caused the bug to be discovered because it threw up an internal error.
2386     8. The debugging code in both pcre and pcretest for outputting the compiled
2387     form of a regex was going wrong in the case of back references followed by
2388     curly-bracketed repeats.
2391 nigel 7 Version 1.02 12-Dec-97
2392     ----------------------
2394     1. Typos in pcre.3 and comments in the source fixed.
2396     2. Applied a contributed patch to get rid of places where it used to remove
2397     'const' from variables, and fixed some signed/unsigned and uninitialized
2398     variable warnings.
2400     3. Added the "runtest" target to Makefile.
2402     4. Set default compiler flag to -O2 rather than just -O.
2405 nigel 5 Version 1.01 19-Nov-97
2406     ----------------------
2408     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2409     like /([ab]*)*/, that is, for classes with more than one character in them.
2411     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2412     as /((?>a*))*/ (a PCRE_EXTRA facility).
2415     Version 1.00 18-Nov-97
2416     ----------------------
2418     1. Added compile-time macros to support systems such as SunOS4 which don't have
2419     memmove() or strerror() but have other things that can be used instead.
2421     2. Arranged that "make clean" removes the executables.
2424 nigel 3 Version 0.99 27-Oct-97
2425     ----------------------
2427     1. Fixed bug in code for optimizing classes with only one character. It was
2428     initializing a 32-byte map regardless, which could cause it to run off the end
2429     of the memory it had got.
2431     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2434     Version 0.98 22-Oct-97
2435     ----------------------
2437     1. Fixed bug in code for handling temporary memory usage when there are more
2438     back references than supplied space in the ovector. This could cause segfaults.
2441     Version 0.97 21-Oct-97
2442     ----------------------
2444     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2446     2. Optimized negated single characters not to use a bit map.
2448     3. Brought error texts together as macro definitions; clarified some of them;
2449     fixed one that was wrong - it said "range out of order" when it meant "invalid
2450     escape sequence".
2452     4. Changed some char * arguments to const char *.
2454     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2456     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2457     pcretest.
2460     Version 0.96 16-Oct-97
2461     ----------------------
2463     1. Added a simple "pgrep" utility to the distribution.
2465     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2466     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2467     where "ddd" means "one or more decimal digits".
2469     3. Fixed serious bug. If a pattern had a back reference, but the call to
2470     pcre_exec() didn't supply a large enough ovector to record the related
2471     identifying subpattern, the match always failed. PCRE now remembers the number
2472     of the largest back reference, and gets some temporary memory in which to save
2473     the offsets during matching if necessary, in order to ensure that
2474     backreferences always work.
2476     4. Increased the compatibility with Perl in a number of ways:
2478     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2479     to request this handling. The option can be set at compile or exec time.
2481     (b) $ matches before a terminating newline by default; an option
2482     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2483     mode). The option can be set at compile or exec time.
2485     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2486     the same as Perl's. If the decimal number it represents is less than 10
2487     or there aren't that many previous left capturing parentheses, an octal
2488     escape is read. Inside a character class, it's always an octal escape,
2489     even if it is a single digit.
2491     (d) An escaped but undefined alphabetic character is taken as a literal,
2492     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2493     escapes.
2495     (e) {0} is now permitted. (The previous item is removed from the compiled
2496     pattern).
2498     5. Changed all the names of code files so that the basic parts are no longer
2499     than 10 characters, and abolished the teeny "globals.c" file.
2501     6. Changed the handling of character classes; they are now done with a 32-byte
2502     bit map always.
2504     7. Added the -d and /D options to pcretest to make it possible to look at the
2505     internals of compilation without having to recompile pcre.
2508     Version 0.95 23-Sep-97
2509     ----------------------
2511     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2512     \x20 at the start of a run of normal characters. These were being treated as
2513     real characters, instead of the source characters being re-checked.
2516     Version 0.94 18-Sep-97
2517     ----------------------
2519     1. The functions are now thread-safe, with the caveat that the global variables
2520     containing pointers to malloc() and free() or alternative functions are the
2521     same for all threads.
2523     2. Get pcre_study() to generate a bitmap of initial characters for non-
2524     anchored patterns when this is possible, and use it if passed to pcre_exec().
2527     Version 0.93 15-Sep-97
2528     ----------------------
2530     1. /(b)|(:+)/ was computing an incorrect first character.
2532     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2533     but not actually doing anything yet.
2535     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2536     as Perl does (e.g. [-az] or [az-]).
2538     4. Set the anchored flag if a branch starts with .* or .*? because that tests
2539     all possible positions.
2541     5. Split up into different modules to avoid including unneeded functions in a
2542     compiled binary. However, compile and exec are still in one module. The "study"
2543     function is split off.
2545     6. The character tables are now in a separate module whose source is generated
2546     by an auxiliary program - but can then be edited by hand if required. There are
2547     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2548     toupper() in the code.
2550     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2551     make them global. Abolish the function for setting them, as the caller can now
2552     set them directly.
2555     Version 0.92 11-Sep-97
2556     ----------------------
2558     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2559     (e.g. /a{1,3}/) was broken (I mis-optimized it).
2561     2. Caseless matching was not working in character classes if the characters in
2562     the pattern were in upper case.
2564     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2566     4. Make PCRE_ANCHORED public and accept as a compile option.
2568     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2569     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2570     pass them.
2572     6. Give an error if bad option bits passed at compile or run time.
2574     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2575     pcretest to cause it to pass that flag.
2577     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2578     options, and the first character, if set.
2580     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2583     Version 0.91 10-Sep-97
2584     ----------------------
2586     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2587     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2589     2. PCRE was looping on encountering an indefinitely repeated back reference to
2590     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2591     Perl does - treats the match as successful.
2593     ****


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