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Mon Apr 2 10:08:14 2007 UTC (8 years ago) by ph10
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Previous fix for pcretest was buggy. Try again.

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 122 Version 7.1 12-Mar-07
5 ph10 98 ---------------------
7 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
8 ph10 122 that is more "standard", making use of automake and other Autotools. There
9 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
10     on this.
11 ph10 111
12     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
13     for recursive directory scanning broke on some systems because the files
14     are not scanned in any specific order and on different systems the order
15     was different. A call to "sort" has been inserted into RunGrepTest for the
16     approprate test as a short-term fix. In the longer term there may be an
17 ph10 100 alternative.
18 ph10 111
19 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
20 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
21     people do their own conversions for various reasons). The problems
22     concerned the use of low-level troff macros .br and .in. I have therefore
23     removed all such uses from the man pages (some were redundant, some could
24 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
25     HTML has been updated to handle .nf/.fi and to complain if it encounters
26     .br or .in.
27 ph10 111
28 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
29 ph10 123 arranged for config.h to be included in the distribution, with the name
30 ph10 111 config.h.generic, for the benefit of those who have to compile without
31     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
33     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
34     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
35 ph10 127 makevp.bat for the current PCRE, using the additional files
36 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
37 ph10 111
38     6. A Windows user reported a minor discrepancy with test 2, which turned out
39     to be caused by a trailing space on an input line that had got lost in his
40 ph10 102 copy. The trailing space was an accident, so I've just removed it.
41 ph10 111
42 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
43 ph10 111 that is needed.
45 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
46     as "const" (a) because they are and (b) because it helps the PHP
47     maintainers who have recently made a script to detect big data structures
48 ph10 111 in the php code that should be moved to the .rodata section. I remembered
49     to update Builducptable as well, so it won't revert if ucptable.h is ever
50 ph10 105 re-created.
51 ph10 111
52     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
53 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
54 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
55     support is not required. This saves 1.5-2K of code, which is important in
56 ph10 107 some applications.
57 ph10 111
58 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
59 ph10 111 so as not to refer to the tables, even though these functions will never be
60     called when UTF-8 support is disabled. Otherwise there are problems with a
61     shared library.
63 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
65     (a) It was defining its arguments as char * instead of void *.
67 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
68     a long time ago when I wrote it, but is no longer the case.
70 ph10 118 The emulated memove() is provided for those environments that have neither
71 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
72 ph10 118 is clearly not the case, as these two bugs were recently reported.
73 ph10 123
74 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
75 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
76     pages, and it removes trailing spaces from listed files. It also creates
77     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
78     case, it wraps all the #defines with #ifndefs. This script should be run
79 ph10 111 before "make dist".
80 ph10 123
81 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
82     with Unicode property support.
83 ph10 123
84     (a) For a maximizing quantifier, if the two different cases of the
85     character were of different lengths in their UTF-8 codings (there are
86     some cases like this - I found 11), and the matching function had to
87 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
88     were both the same length.
89 ph10 123
90     (b) When PCRE was configured to use the heap rather than the stack for
91     recursion during matching, it was not correctly preserving the data for
92     the other case of a UTF-8 character when checking ahead for a match
93     while processing a minimizing repeat. If the check also involved
94 ph10 115 matching a wide character, but failed, corruption could cause an
95     erroneous result when trying to check for a repeat of the original
96     character.
97 ph10 123
98 ph10 116 13. Some tidying changes to the testing mechanism:
99 ph10 98
100 ph10 116 (a) The RunTest script now detects the internal link size and whether there
101     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
102 ph10 123 values substituted by "configure". (The RunGrepTest script already did
103     this for UTF-8.) The configure.ac script no longer substitutes the
104     relevant variables.
106 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
107     with length and offset values. This means that the output is different
108     for different internal link sizes. Test 2 is skipped for link sizes
109     other than 2 because of this, bypassing the problem. Unfortunately,
110     there was also a test in test 3 (the locale tests) that used /B and
111 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
112     I have added a new /Z option to pcretest that replaces the length and
113     offset values with spaces. This is now used to make test 3 independent
114 ph10 122 of link size. (Test 2 will be tidied up later.)
115 ph10 123
116     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
117 ph10 122 segmentation fault instead of returning the appropriate error message.
118 ph10 134
119 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
120 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
121     This doesn't seem right; it now treats the CRLF combination as the line
122     ending, and so does not match in that case. It's only a pattern such as ^$
123     that would hit this one: something like ^ABC$ would have failed after \r
124     and then tried again after \r\n.
126 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
127 ph10 134 in an attempt to make files that differ only in their line terminators
128     compare equal. This works on Linux.
129 ph10 142
130 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
131     as it exited. This is now fixed, thanks to valgrind.
132 ph10 142
133 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
134 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
135     was because its rules for how to advance for /g after matching an empty
136 ph10 143 string at the end of a line did not allow for this case. They now check for
137     it specially.
138 ph10 111
139 ph10 123
140 nigel 93 Version 7.0 19-Dec-06
141     ---------------------
143     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
144     moving to gcc 4.1.1.
146     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
147     sys/time.h, which is documented as needed for this function. It doesn't
148     seem to matter on Linux, but it showed up on some releases of OS X.
150     3. It seems that there are systems where bytes whose values are greater than
151     127 match isprint() in the "C" locale. The "C" locale should be the
152     default when a C program starts up. In most systems, only ASCII printing
153     characters match isprint(). This difference caused the output from pcretest
154     to vary, making some of the tests fail. I have changed pcretest so that:
156     (a) When it is outputting text in the compiled version of a pattern, bytes
157     other than 32-126 are always shown as hex escapes.
159     (b) When it is outputting text that is a matched part of a subject string,
160     it does the same, unless a different locale has been set for the match
161     (using the /L modifier). In this case, it uses isprint() to decide.
163     4. Fixed a major bug that caused incorrect computation of the amount of memory
164     required for a compiled pattern when options that changed within the
165     pattern affected the logic of the preliminary scan that determines the
166     length. The relevant options are -x, and -i in UTF-8 mode. The result was
167     that the computed length was too small. The symptoms of this bug were
168     either the PCRE error "internal error: code overflow" from pcre_compile(),
169     or a glibc crash with a message such as "pcretest: free(): invalid next
170     size (fast)". Examples of patterns that provoked this bug (shown in
171     pcretest format) are:
173     /(?-x: )/x
174     /(?x)(?-x: \s*#\s*)/
175     /((?i)[\x{c0}])/8
176     /(?i:[\x{c0}])/8
178     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
179     is now done differently.
181     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
182     wrapper classes; (b) implement a new function in the C++ scanner that is
183     more efficient than the old way of doing things because it avoids levels of
184     recursion in the regex matching; (c) add a paragraph to the documentation
185     for the FullMatch() function.
187     6. The escape sequence \n was being treated as whatever was defined as
188     "newline". Not only was this contrary to the documentation, which states
189     that \n is character 10 (hex 0A), but it also went horribly wrong when
190     "newline" was defined as CRLF. This has been fixed.
192     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
193     was being set to -1 for the "end of line" case (supposedly a value that no
194     character can have). Though this value is never used (the check for end of
195     line is "zero bytes in current character"), it caused compiler complaints.
196     I've changed it to 0xffffffff.
198     8. In pcre_version.c, the version string was being built by a sequence of
199     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
200     string (as it is for production releases) called a macro with an empty
201     argument. The C standard says the result of this is undefined. The gcc
202     compiler treats it as an empty string (which was what was wanted) but it is
203     reported that Visual C gives an error. The source has been hacked around to
204     avoid this problem.
206     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
207     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
208     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
209     of them did).
211     10. Originally, pcretest opened its input and output without "b"; then I was
212     told that "b" was needed in some environments, so it was added for release
213     5.0 to both the input and output. (It makes no difference on Unix-like
214     systems.) Later I was told that it is wrong for the input on Windows. I've
215     now abstracted the modes into two macros, to make it easier to fiddle with
216     them, and removed "b" from the input mode under Windows.
218     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
220     12. Added -help and --help to pcretest as an official way of being reminded
221     of the options.
223     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
224     and pcrecpp.cc because they annoy compilers at high warning levels.
226     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
228     15. Fixed an occurrence of == in configure.ac that should have been = (shell
229     scripts are not C programs :-) and which was not noticed because it works
230     on Linux.
232     16. pcretest is supposed to handle any length of pattern and data line (as one
233     line or as a continued sequence of lines) by extending its input buffer if
234     necessary. This feature was broken for very long pattern lines, leading to
235     a string of junk being passed to pcre_compile() if the pattern was longer
236     than about 50K.
238     17. I have done a major re-factoring of the way pcre_compile() computes the
239     amount of memory needed for a compiled pattern. Previously, there was code
240     that made a preliminary scan of the pattern in order to do this. That was
241     OK when PCRE was new, but as the facilities have expanded, it has become
242     harder and harder to keep it in step with the real compile phase, and there
243     have been a number of bugs (see for example, 4 above). I have now found a
244     cunning way of running the real compile function in a "fake" mode that
245     enables it to compute how much memory it would need, while actually only
246     ever using a few hundred bytes of working memory and without too many
247     tests of the mode. This should make future maintenance and development
248     easier. A side effect of this work is that the limit of 200 on the nesting
249     depth of parentheses has been removed (though this was never a serious
250     limitation, I suspect). However, there is a downside: pcre_compile() now
251     runs more slowly than before (30% or more, depending on the pattern). I
252     hope this isn't a big issue. There is no effect on runtime performance.
254     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
255     newline (only possible for the last line of a file) and it was a
256     pattern that set a locale (followed by /Lsomething), pcretest crashed.
258     19. Added additional timing features to pcretest. (1) The -tm option now times
259     matching only, not compiling. (2) Both -t and -tm can be followed, as a
260     separate command line item, by a number that specifies the number of
261     repeats to use when timing. The default is 50000; this gives better
262     precision, but takes uncomfortably long for very large patterns.
264     20. Extended pcre_study() to be more clever in cases where a branch of a
265     subpattern has no definite first character. For example, (a*|b*)[cd] would
266     previously give no result from pcre_study(). Now it recognizes that the
267     first character must be a, b, c, or d.
269     21. There was an incorrect error "recursive call could loop indefinitely" if
270     a subpattern (or the entire pattern) that was being tested for matching an
271     empty string contained only one non-empty item after a nested subpattern.
272     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
273     incorrectly, because the \d was being skipped in the check.
275     22. The pcretest program now has a new pattern option /B and a command line
276     option -b, which is equivalent to adding /B to every pattern. This causes
277     it to show the compiled bytecode, without the additional information that
278     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
279     is the same as /B/I).
281     23. A new optimization is now able automatically to treat some sequences such
282     as a*b as a*+b. More specifically, if something simple (such as a character
283     or a simple class like \d) has an unlimited quantifier, and is followed by
284     something that cannot possibly match the quantified thing, the quantifier
285     is automatically "possessified".
287     24. A recursive reference to a subpattern whose number was greater than 39
288     went wrong under certain circumstances in UTF-8 mode. This bug could also
289     have affected the operation of pcre_study().
291     25. Realized that a little bit of performance could be had by replacing
292     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
294     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
296     27. Possessive quantifiers such as a++ were previously implemented by turning
297     them into atomic groups such as ($>a+). Now they have their own opcodes,
298     which improves performance. This includes the automatically created ones
299     from 23 above.
301     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
302     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
303     the first matched character to be a colon. This applied both to named and
304     numbered groups.
306     29. The ucpinternal.h header file was missing its idempotency #ifdef.
308     30. I was sent a "project" file called libpcre.a.dev which I understand makes
309     building PCRE on Windows easier, so I have included it in the distribution.
311     31. There is now a check in pcretest against a ridiculously large number being
312     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
313     loop, the loop is abandoned.
315     32. Forward references to subpatterns in conditions such as (?(2)...) where
316     subpattern 2 is defined later cause pcre_compile() to search forwards in
317     the pattern for the relevant set of parentheses. This search went wrong
318     when there were unescaped parentheses in a character class, parentheses
319     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
321     33. "Subroutine" calls and backreferences were previously restricted to
322     referencing subpatterns earlier in the regex. This restriction has now
323     been removed.
325     34. Added a number of extra features that are going to be in Perl 5.10. On the
326     whole, these are just syntactic alternatives for features that PCRE had
327     previously implemented using the Python syntax or my own invention. The
328     other formats are all retained for compatibility.
330     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
331     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
332     also .NET compatible.
334     (b) A recursion or subroutine call to a named group can now be defined as
335     (?&name) as well as (?P>name).
337     (c) A backreference to a named group can now be defined as \k<name> or
338     \k'name' as well as (?P=name). The new forms, as well as being in Perl
339     5.10, are also .NET compatible.
341     (d) A conditional reference to a named group can now use the syntax
342     (?(<name>) or (?('name') as well as (?(name).
344     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
345     groups (named and numbered) that are never evaluated inline, but can be
346     called as "subroutines" from elsewhere. In effect, the DEFINE condition
347     is always false. There may be only one alternative in such a group.
349     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
350     as the simple (?(R). The condition is true only if the most recent
351     recursion is that of the given number or name. It does not search out
352     through the entire recursion stack.
354     (g) The escape \gN or \g{N} has been added, where N is a positive or
355     negative number, specifying an absolute or relative reference.
357     35. Tidied to get rid of some further signed/unsigned compiler warnings and
358     some "unreachable code" warnings.
360     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
361     things, this adds five new scripts.
363     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
364     There were also incompatibilities regarding the handling of \Q..\E inside
365     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
366     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
368     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
369     matches an empty string, and forcibly breaks the loop. There were bugs in
370     this code in non-simple cases. For a pattern such as ^(a()*)* matched
371     against aaaa the result was just "a" rather than "aaaa", for example. Two
372     separate and independent bugs (that affected different cases) have been
373     fixed.
375     39. Refactored the code to abolish the use of different opcodes for small
376     capturing bracket numbers. This is a tidy that I avoided doing when I
377     removed the limit on the number of capturing brackets for 3.5 back in 2001.
378     The new approach is not only tidier, it makes it possible to reduce the
379     memory needed to fix the previous bug (38).
381     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
382     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
383     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
384     mode.
386     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
387     report.
389     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
390     copy construction and assignment in the C++ wrapper.
392     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
393     couple of bugs that could have given wrong results in the "--newline=crlf"
394     case.
396     44. Added a number of casts and did some reorganization of signed/unsigned int
397     variables following suggestions from Dair Grant. Also renamed the variable
398     "this" as "item" because it is a C++ keyword.
400     45. Arranged for dftables to add
402     #include "pcre_internal.h"
404     to pcre_chartables.c because without it, gcc 4.x may remove the array
405     definition from the final binary if PCRE is built into a static library and
406     dead code stripping is activated.
408     46. For an unanchored pattern, if a match attempt fails at the start of a
409     newline sequence, and the newline setting is CRLF or ANY, and the next two
410     characters are CRLF, advance by two characters instead of one.
413 nigel 91 Version 6.7 04-Jul-06
414     ---------------------
416     1. In order to handle tests when input lines are enormously long, pcretest has
417     been re-factored so that it automatically extends its buffers when
418     necessary. The code is crude, but this _is_ just a test program. The
419     default size has been increased from 32K to 50K.
421     2. The code in pcre_study() was using the value of the re argument before
422     testing it for NULL. (Of course, in any sensible call of the function, it
423     won't be NULL.)
425     3. The memmove() emulation function in pcre_internal.h, which is used on
426     systems that lack both memmove() and bcopy() - that is, hardly ever -
427     was missing a "static" storage class specifier.
429     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
430     containing an extended class (one that cannot be represented by a bitmap
431     because it contains high-valued characters or Unicode property items, e.g.
432     [\pZ]). Almost always one would set UTF-8 mode when processing such a
433     pattern, but PCRE should not loop if you do not (it no longer does).
434     [Detail: two cases were found: (a) a repeated subpattern containing an
435     extended class; (b) a recursive reference to a subpattern that followed a
436     previous extended class. It wasn't skipping over the extended class
437     correctly when UTF-8 mode was not set.]
439     5. A negated single-character class was not being recognized as fixed-length
440     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
441     compile error "lookbehind assertion is not fixed length".
443     6. The RunPerlTest auxiliary script was showing an unexpected difference
444     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
445     write a Perl script that can interpret lines of an input file either as
446     byte characters or as UTF-8, which is what "perltest" was being required to
447     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
448     can't do is switch easily at run time between having the "use utf8;" pragma
449     or not. In the end, I fudged it by using the RunPerlTest script to insert
450     "use utf8;" explicitly for the UTF-8 tests.
452     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
453     the end of the subject string, contrary to the documentation and to what
454     Perl does. This was true of both matching functions. Now it matches only at
455     the start of the subject and immediately after *internal* newlines.
457     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
458     a pointer to an int instead of a pointer to an unsigned long int. This
459     caused problems on 64-bit systems.
461     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
462     instance of the 'standard' template library not being so standard".
464     10. There was no check on the number of named subpatterns nor the maximum
465     length of a subpattern name. The product of these values is used to compute
466     the size of the memory block for a compiled pattern. By supplying a very
467     long subpattern name and a large number of named subpatterns, the size
468     computation could be caused to overflow. This is now prevented by limiting
469     the length of names to 32 characters, and the number of named subpatterns
470     to 10,000.
472     11. Subpatterns that are repeated with specific counts have to be replicated in
473     the compiled pattern. The size of memory for this was computed from the
474     length of the subpattern and the repeat count. The latter is limited to
475     65535, but there was no limit on the former, meaning that integer overflow
476     could in principle occur. The compiled length of a repeated subpattern is
477     now limited to 30,000 bytes in order to prevent this.
479     12. Added the optional facility to have named substrings with the same name.
481     13. Added the ability to use a named substring as a condition, using the
482     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
483     are numbers (not recommended). Forward references are permitted.
485     14. Added forward references in named backreferences (if you see what I mean).
487     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
488     pattern could run off the end of the subject. For example, the pattern
489     "(?s)(.{1,5})"8 did this with the subject "ab".
491     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
492     PCRE_CASELESS was set when matching characters that were quantified with ?
493     or *.
495     17. A character class other than a single negated character that had a minimum
496     but no maximum quantifier - for example [ab]{6,} - was not handled
497     correctly by pce_dfa_exec(). It would match only one character.
499     18. A valid (though odd) pattern that looked like a POSIX character
500     class but used an invalid character after [ (for example [[,abc,]]) caused
501     pcre_compile() to give the error "Failed: internal error: code overflow" or
502     in some cases to crash with a glibc free() error. This could even happen if
503     the pattern terminated after [[ but there just happened to be a sequence of
504     letters, a binary zero, and a closing ] in the memory that followed.
506     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
507     over the years. Originally (before any Unicode support), just the bottom 8
508     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
509     output from "man perlunicode" includes this:
511     The regular expression compiler produces polymorphic opcodes. That
512     is, the pattern adapts to the data and automatically switches to
513     the Unicode character scheme when presented with Unicode data--or
514     instead uses a traditional byte scheme when presented with byte
515     data.
517     Sadly, a wide octal escape does not cause a switch, and in a string with
518     no other multibyte characters, these octal escapes are treated as before.
519     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
520     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
521     Unicode string.
523     I have not perpetrated such confusion in PCRE. Up till now, it took just
524     the bottom 8 bits, as in old Perl. I have now made octal escapes with
525     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
526     translate to the appropriate multibyte character.
528     29. Applied some refactoring to reduce the number of warnings from Microsoft
529     and Borland compilers. This has included removing the fudge introduced
530     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
531     a warning about an unused variable.
533     21. PCRE has not included VT (character 0x0b) in the set of whitespace
534     characters since release 4.0, because Perl (from release 5.004) does not.
535     [Or at least, is documented not to: some releases seem to be in conflict
536     with the documentation.] However, when a pattern was studied with
537     pcre_study() and all its branches started with \s, PCRE still included VT
538     as a possible starting character. Of course, this did no harm; it just
539     caused an unnecessary match attempt.
541     22. Removed a now-redundant internal flag bit that recorded the fact that case
542     dependency changed within the pattern. This was once needed for "required
543     byte" processing, but is no longer used. This recovers a now-scarce options
544     bit. Also moved the least significant internal flag bit to the most-
545     significant bit of the word, which was not previously used (hangover from
546     the days when it was an int rather than a uint) to free up another bit for
547     the future.
549     23. Added support for CRLF line endings as well as CR and LF. As well as the
550     default being selectable at build time, it can now be changed at runtime
551     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
552     specify that it is scanning data with non-default line endings.
554     24. Changed the definition of CXXLINK to make it agree with the definition of
555     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
557     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
558     recursions. This makes a big different to stack usage for some patterns.
560     26. If a subpattern containing a named recursion or subroutine reference such
561     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
562     the space required for the compiled pattern went wrong and gave too small a
563     value. Depending on the environment, this could lead to "Failed: internal
564     error: code overflow at offset 49" or "glibc detected double free or
565     corruption" errors.
567     27. Applied patches from Google (a) to support the new newline modes and (b) to
568     advance over multibyte UTF-8 characters in GlobalReplace.
570     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
571     difference for some implementation of PCRE in some Windows version.
573     29. Added some extra testing facilities to pcretest:
575     \q<number> in a data line sets the "match limit" value
576     \Q<number> in a data line sets the "match recursion limt" value
577     -S <number> sets the stack size, where <number> is in megabytes
579     The -S option isn't available for Windows.
582 nigel 89 Version 6.6 06-Feb-06
583     ---------------------
585     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
586     in pcreposix.h. I have copied the definition from pcre.h.
588     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
589     because pcre.h is no longer a built file.
591     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
592     not normally included in the compiled code.
595 nigel 87 Version 6.5 01-Feb-06
596     ---------------------
598     1. When using the partial match feature with pcre_dfa_exec(), it was not
599     anchoring the second and subsequent partial matches at the new starting
600     point. This could lead to incorrect results. For example, with the pattern
601     /1234/, partially matching against "123" and then "a4" gave a match.
603     2. Changes to pcregrep:
605     (a) All non-match returns from pcre_exec() were being treated as failures
606     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
607     error message is output. Some extra information is given for the
609     probably the only errors that are likely to be caused by users (by
610     specifying a regex that has nested indefinite repeats, for instance).
611     If there are more than 20 of these errors, pcregrep is abandoned.
613     (b) A binary zero was treated as data while matching, but terminated the
614     output line if it was written out. This has been fixed: binary zeroes
615     are now no different to any other data bytes.
617     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
618     used to set a locale for matching. The --locale=xxxx long option has
619     been added (no short equivalent) to specify a locale explicitly on the
620     pcregrep command, overriding the environment variables.
622     (d) When -B was used with -n, some line numbers in the output were one less
623     than they should have been.
625     (e) Added the -o (--only-matching) option.
627     (f) If -A or -C was used with -c (count only), some lines of context were
628     accidentally printed for the final match.
630     (g) Added the -H (--with-filename) option.
632     (h) The combination of options -rh failed to suppress file names for files
633     that were found from directory arguments.
635     (i) Added the -D (--devices) and -d (--directories) options.
637     (j) Added the -F (--fixed-strings) option.
639     (k) Allow "-" to be used as a file name for -f as well as for a data file.
641     (l) Added the --colo(u)r option.
643     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
644     is not present by default.
646     3. A nasty bug was discovered in the handling of recursive patterns, that is,
647     items such as (?R) or (?1), when the recursion could match a number of
648     alternatives. If it matched one of the alternatives, but subsequently,
649     outside the recursion, there was a failure, the code tried to back up into
650     the recursion. However, because of the way PCRE is implemented, this is not
651     possible, and the result was an incorrect result from the match.
653     In order to prevent this happening, the specification of recursion has
654     been changed so that all such subpatterns are automatically treated as
655     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
657     4. I had overlooked the fact that, in some locales, there are characters for
658     which isalpha() is true but neither isupper() nor islower() are true. In
659     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
660     and ordfeminine) are like this. This affected the treatment of \w and \W
661     when they appeared in character classes, but not when they appeared outside
662     a character class. The bit map for "word" characters is now created
663     separately from the results of isalnum() instead of just taking it from the
664     upper, lower, and digit maps. (Plus the underscore character, of course.)
666     5. The above bug also affected the handling of POSIX character classes such as
667     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
668     permanent tables. Instead, the bit maps for such a class were previously
669     created as the appropriate unions of the upper, lower, and digit bitmaps.
670     Now they are created by subtraction from the [[:word:]] class, which has
671     its own bitmap.
673     6. The [[:blank:]] character class matches horizontal, but not vertical space.
674     It is created by subtracting the vertical space characters (\x09, \x0a,
675     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
676     subtraction was done in the overall bitmap for a character class, meaning
677     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
678     be recognized. This bug has been fixed.
680     7. Patches from the folks at Google:
682     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
683     real life, but is still worth protecting against".
685     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
686     regular expressions".
688     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
689     have it.
691     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
692     "configure" and the latter not, in order to fix a problem somebody had
693     with compiling the Arg class on HP-UX.
695     (e) Improve the error-handling of the C++ wrapper a little bit.
697     (f) New tests for checking recursion limiting.
699     8. The pcre_memmove() function, which is used only if the environment does not
700     have a standard memmove() function (and is therefore rarely compiled),
701     contained two bugs: (a) use of int instead of size_t, and (b) it was not
702     returning a result (though PCRE never actually uses the result).
704     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
705     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
706     returned instead of calling malloc() with an overflowing number that would
707     most likely cause subsequent chaos.
709     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
711     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
712     with this option is matched, the nmatch and pmatch options of regexec() are
713     ignored.
715     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
716     provided in case anyone wants to the the POSIX interface with UTF-8
717     strings.
719     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
720     C++ linking (needed for some HP-UX environments).
722     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
723     (unused parameter) and in the pcre_printint() function (omitted "default"
724     switch label when the default is to do nothing).
726     15. Added some code to make it possible, when PCRE is compiled as a C++
727     library, to replace subject pointers for pcre_exec() with a smart pointer
728     class, thus making it possible to process discontinuous strings.
730     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
731     much the same function. They were added by different people who were trying
732     to make PCRE easy to compile on non-Unix systems. It has been suggested
733     that PCRE_EXPORT be abolished now that there is more automatic apparatus
734     for compiling on Windows systems. I have therefore replaced it with
735     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
736     defaults to "extern" for C or "extern C" for C++, which works fine on
737     Unix-like systems. It is now possible to override the value of PCRE_DATA_
738     SCOPE with something explicit in config.h. In addition:
740     (a) pcreposix.h still had just "extern" instead of either of these macros;
741     I have replaced it with PCRE_DATA_SCOPE.
743     (b) Functions such as _pcre_xclass(), which are internal to the library,
744     but external in the C sense, all had PCRE_EXPORT in their definitions.
745     This is apparently wrong for the Windows case, so I have removed it.
746     (It makes no difference on Unix-like systems.)
748     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
749     of recursive calls to match(). This is different to MATCH_LIMIT because
750     that limits the total number of calls to match(), not all of which increase
751     the depth of recursion. Limiting the recursion depth limits the amount of
752     stack (or heap if NO_RECURSE is set) that is used. The default can be set
753     when PCRE is compiled, and changed at run time. A patch from Google adds
754     this functionality to the C++ interface.
756     18. Changes to the handling of Unicode character properties:
758     (a) Updated the table to Unicode 4.1.0.
760     (b) Recognize characters that are not in the table as "Cn" (undefined).
762     (c) I revised the way the table is implemented to a much improved format
763     which includes recognition of ranges. It now supports the ranges that
764     are defined in UnicodeData.txt, and it also amalgamates other
765     characters into ranges. This has reduced the number of entries in the
766     table from around 16,000 to around 3,000, thus reducing its size
767     considerably. I realized I did not need to use a tree structure after
768     all - a binary chop search is just as efficient. Having reduced the
769     number of entries, I extended their size from 6 bytes to 8 bytes to
770     allow for more data.
772     (d) Added support for Unicode script names via properties such as \p{Han}.
774     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
775     matching that character.
777     20. When matching a repeated Unicode property with a minimum greater than zero,
778     (for example \pL{2,}), PCRE could look past the end of the subject if it
779     reached it while seeking the minimum number of characters. This could
780     happen only if some of the characters were more than one byte long, because
781     there is a check for at least the minimum number of bytes.
783     21. Refactored the implementation of \p and \P so as to be more general, to
784     allow for more different types of property in future. This has changed the
785     compiled form incompatibly. Anybody with saved compiled patterns that use
786     \p or \P will have to recompile them.
788     22. Added "Any" and "L&" to the supported property types.
790     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
791     but give a compile time error if the value is greater than 0xff.
793     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
794     accidentally not being installed or uninstalled.
796     25. The pcre.h file was built from pcre.h.in, but the only changes that were
797     made were to insert the current release number. This seemed silly, because
798     it made things harder for people building PCRE on systems that don't run
799     "configure". I have turned pcre.h into a distributed file, no longer built
800     by "configure", with the version identification directly included. There is
801     no longer a pcre.h.in file.
803     However, this change necessitated a change to the pcre-config script as
804     well. It is built from pcre-config.in, and one of the substitutions was the
805     release number. I have updated configure.ac so that ./configure now finds
806     the release number by grepping pcre.h.
808     26. Added the ability to run the tests under valgrind.
811 nigel 85 Version 6.4 05-Sep-05
812     ---------------------
814     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
815     "--" to be printed when multiple files were scanned, even when none of the
816     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
817     consider it to be a bug, and have restored the previous behaviour.
819     2. A couple of code tidies to get rid of compiler warnings.
821     3. The pcretest program used to cheat by referring to symbols in the library
822     whose names begin with _pcre_. These are internal symbols that are not
823     really supposed to be visible externally, and in some environments it is
824     possible to suppress them. The cheating is now confined to including
825     certain files from the library's source, which is a bit cleaner.
827     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
828     file's purpose clearer.
830     5. Reorganized pcre_ucp_findchar().
833 nigel 83 Version 6.3 15-Aug-05
834     ---------------------
836     1. The file libpcre.pc.in did not have general read permission in the tarball.
838     2. There were some problems when building without C++ support:
840     (a) If C++ support was not built, "make install" and "make test" still
841     tried to test it.
843     (b) There were problems when the value of CXX was explicitly set. Some
844     changes have been made to try to fix these, and ...
846     (c) --disable-cpp can now be used to explicitly disable C++ support.
848     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
849     backslash in a target when C++ was disabled. This confuses some
850     versions of "make", apparently. Using an intermediate variable solves
851     this. (Same for CPP_LOBJ.)
853     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
854     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
855     necessary on certain architectures.
857     4. Added a setting of -export-symbols-regex to the link command to remove
858     those symbols that are exported in the C sense, but actually are local
859     within the library, and not documented. Their names all begin with
860     "_pcre_". This is not a perfect job, because (a) we have to except some
861     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
862     available (and never for static libraries). I have made a note to try to
863     find a way round (a) in the future.
866 nigel 81 Version 6.2 01-Aug-05
867     ---------------------
869     1. There was no test for integer overflow of quantifier values. A construction
870     such as {1111111111111111} would give undefined results. What is worse, if
871     a minimum quantifier for a parenthesized subpattern overflowed and became
872     negative, the calculation of the memory size went wrong. This could have
873     led to memory overwriting.
875     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
877     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
878     operating environments where this matters.
880     4. Applied Giuseppe Maxia's patch to add additional features for controlling
881     PCRE options from within the C++ wrapper.
883     5. Named capturing subpatterns were not being correctly counted when a pattern
884     was compiled. This caused two problems: (a) If there were more than 100
885     such subpatterns, the calculation of the memory needed for the whole
886     compiled pattern went wrong, leading to an overflow error. (b) Numerical
887     back references of the form \12, where the number was greater than 9, were
888     not recognized as back references, even though there were sufficient
889     previous subpatterns.
891     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
892     versions of gcc, e.g. 2.95.4.
895 nigel 79 Version 6.1 21-Jun-05
896     ---------------------
898     1. There was one reference to the variable "posix" in pcretest.c that was not
899     surrounded by "#if !defined NOPOSIX".
901     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
902     the cross-check on the old pcre_info() function, for the benefit of the
903     cut-down version of PCRE that is currently imported into Exim.
905     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
906     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
907     patterns that start (?i) but I don't think that matters. The use of (?i) is
908     just an example; this all applies to the other options as well.
910     4. Since libtool seems to echo the compile commands it is issuing, the output
911     from "make" can be reduced a bit by putting "@" in front of each libtool
912     compile command.
914     5. Patch from the folks at Google for configure.in to be a bit more thorough
915     in checking for a suitable C++ installation before trying to compile the
916     C++ stuff. This should fix a reported problem when a compiler was present,
917     but no suitable headers.
919     6. The man pages all had just "PCRE" as their title. I have changed them to
920     be the relevant file name. I have also arranged that these names are
921     retained in the file doc/pcre.txt, which is a concatenation in text format
922     of all the man pages except the little individual ones for each function.
924     7. The NON-UNIX-USE file had not been updated for the different set of source
925     files that come with release 6. I also added a few comments about the C++
926     wrapper.
929 nigel 77 Version 6.0 07-Jun-05
930     ---------------------
932     1. Some minor internal re-organization to help with my DFA experiments.
934     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
935     didn't matter for the library itself when fully configured, but did matter
936     when compiling without UCP support, or within Exim, where the ucp files are
937     not imported.
939     3. Refactoring of the library code to split up the various functions into
940     different source modules. The addition of the new DFA matching code (see
941     below) to a single monolithic source would have made it really too
942     unwieldy, quite apart from causing all the code to be include in a
943     statically linked application, when only some functions are used. This is
944     relevant even without the DFA addition now that patterns can be compiled in
945     one application and matched in another.
947     The downside of splitting up is that there have to be some external
948     functions and data tables that are used internally in different modules of
949     the library but which are not part of the API. These have all had their
950     names changed to start with "_pcre_" so that they are unlikely to clash
951     with other external names.
953     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
954     a different (DFA) algorithm. Although it is slower than the original
955     function, it does have some advantages for certain types of matching
956     problem.
958     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
959     including restarting after a partial match.
961     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
962     defined when compiling for Windows was sent to me. I have put it into the
963     code, though I have no means of testing or verifying it.
965     7. Added the pcre_refcount() auxiliary function.
967     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
968     match before or at the first newline in the subject string. In pcretest,
969     the /f option on a pattern can be used to set this.
971     9. A repeated \w when used in UTF-8 mode with characters greater than 256
972     would behave wrongly. This has been present in PCRE since release 4.0.
974     10. A number of changes to the pcregrep command:
976     (a) Refactored how -x works; insert ^(...)$ instead of setting
977     PCRE_ANCHORED and checking the length, in preparation for adding
978     something similar for -w.
980     (b) Added the -w (match as a word) option.
982     (c) Refactored the way lines are read and buffered so as to have more
983     than one at a time available.
985     (d) Implemented a pcregrep test script.
987     (e) Added the -M (multiline match) option. This allows patterns to match
988     over several lines of the subject. The buffering ensures that at least
989     8K, or the rest of the document (whichever is the shorter) is available
990     for matching (and similarly the previous 8K for lookbehind assertions).
992     (f) Changed the --help output so that it now says
994     -w, --word-regex(p)
996     instead of two lines, one with "regex" and the other with "regexp"
997     because that confused at least one person since the short forms are the
998     same. (This required a bit of code, as the output is generated
999     automatically from a table. It wasn't just a text change.)
1001     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1002     option but starts with a hyphen. Could be a pattern or a path name
1003     starting with a hyphen, for instance.
1005     (h) "-" can be given as a file name to represent stdin.
1007     (i) When file names are being printed, "(standard input)" is used for
1008     the standard input, for compatibility with GNU grep. Previously
1009     "<stdin>" was used.
1011     (j) The option --label=xxx can be used to supply a name to be used for
1012     stdin when file names are being printed. There is no short form.
1014     (k) Re-factored the options decoding logic because we are going to add
1015     two more options that take data. Such options can now be given in four
1016     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1018     (l) Added the -A, -B, and -C options for requesting that lines of context
1019     around matches be printed.
1021     (m) Added the -L option to print the names of files that do not contain
1022     any matching lines, that is, the complement of -l.
1024     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1025     continue to scan other files.
1027     (o) The -s option was incorrectly implemented. For compatibility with other
1028     greps, it now suppresses the error message for a non-existent or non-
1029     accessible file (but not the return code). There is a new option called
1030     -q that suppresses the output of matching lines, which was what -s was
1031     previously doing.
1033     (p) Added --include and --exclude options to specify files for inclusion
1034     and exclusion when recursing.
1036     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1037     Hopefully, it now does.
1039     12. Missing cast in pcre_study().
1041     13. Added an "uninstall" target to the makefile.
1043     14. Replaced "extern" in the function prototypes in Makefile.in with
1044     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1045     world, but is set differently for Windows.
1047     15. Added a second compiling function called pcre_compile2(). The only
1048     difference is that it has an extra argument, which is a pointer to an
1049     integer error code. When there is a compile-time failure, this is set
1050     non-zero, in addition to the error test pointer being set to point to an
1051     error message. The new argument may be NULL if no error number is required
1052     (but then you may as well call pcre_compile(), which is now just a
1053     wrapper). This facility is provided because some applications need a
1054     numeric error indication, but it has also enabled me to tidy up the way
1055     compile-time errors are handled in the POSIX wrapper.
1057     16. Added VPATH=.libs to the makefile; this should help when building with one
1058     prefix path and installing with another. (Or so I'm told by someone who
1059     knows more about this stuff than I do.)
1061     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1062     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1063     match everything, including newlines. This is not POSIX-compatible, but
1064     somebody wanted the feature. From pcretest it can be activated by using
1065     both the P and the s flags.
1067     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1069     19. libpcre.pc was being incorrectly installed as executable.
1071     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1072     it now also looks for '\r' so that it will work unmodified on Windows.
1074     21. Added Google's contributed C++ wrapper to the distribution.
1076     22. Added some untidy missing memory free() calls in pcretest, to keep
1077     Electric Fence happy when testing.
1081 nigel 75 Version 5.0 13-Sep-04
1082     ---------------------
1084     1. Internal change: literal characters are no longer packed up into items
1085     containing multiple characters in a single byte-string. Each character
1086     is now matched using a separate opcode. However, there may be more than one
1087     byte in the character in UTF-8 mode.
1089     2. The pcre_callout_block structure has two new fields: pattern_position and
1090     next_item_length. These contain the offset in the pattern to the next match
1091     item, and its length, respectively.
1093     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1094     insertion of callouts before each pattern item. Added the /C option to
1095     pcretest to make use of this.
1097     4. On the advice of a Windows user, the lines
1099     #if defined(_WIN32) || defined(WIN32)
1100     _setmode( _fileno( stdout ), 0x8000 );
1101     #endif /* defined(_WIN32) || defined(WIN32) */
1103     have been added to the source of pcretest. This apparently does useful
1104     magic in relation to line terminators.
1106     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1107     for the benefit of those environments where the "b" makes a difference.
1109     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1110     to know about it. I have put a hack into configure.in that adds in code
1111     to set GCC=yes if CC=icc. This seems to end up at a point in the
1112     generated configure script that is early enough to affect the setting of
1113     compiler options, which is what is needed, but I have no means of testing
1114     whether it really works. (The user who reported this had patched the
1115     generated configure script, which of course I cannot do.)
1117     LATER: After change 22 below (new libtool files), the configure script
1118     seems to know about icc (and also ecc). Therefore, I have commented out
1119     this hack in configure.in.
1121     7. Added support for pkg-config (2 patches were sent in).
1123     8. Negated POSIX character classes that used a combination of internal tables
1124     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1125     [[:^ascii]]. Typically, they would match almost any characters. The other
1126     POSIX classes were not broken in this way.
1128     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1129     to find the match, as PCRE was deluded into thinking that the match had to
1130     start at the start point or following a newline. The same bug applied to
1131     patterns with negative forward assertions or any backward assertions
1132     preceding ".*" at the start, unless the pattern required a fixed first
1133     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1135     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1136     starting at the last subject character, bytes beyond the end of the subject
1137     string were read.
1139     11. Renamed the variable "class" as "classbits" to make life easier for C++
1140     users. (Previously there was a macro definition, but it apparently wasn't
1141     enough.)
1143     12. Added the new field "tables" to the extra data so that tables can be passed
1144     in at exec time, or the internal tables can be re-selected. This allows
1145     a compiled regex to be saved and re-used at a later time by a different
1146     program that might have everything at different addresses.
1148     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1149     -R library as well as a -L library.
1151     14. The debugging options of pcretest (-d on the command line or D on a
1152     pattern) showed incorrect output for anything following an extended class
1153     that contained multibyte characters and which was followed by a quantifier.
1155     15. Added optional support for general category Unicode character properties
1156     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1157     support. It adds about 90K to the size of the library. The meanings of the
1158     inbuilt class escapes such as \d and \s have NOT been changed.
1160     16. Updated pcredemo.c to include calls to free() to release the memory for the
1161     compiled pattern.
1163     17. The generated file chartables.c was being created in the source directory
1164     instead of in the building directory. This caused the build to fail if the
1165     source directory was different from the building directory, and was
1166     read-only.
1168     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1169     file. No doubt somebody will tell me if they don't make sense... Also added
1170     Dan Mooney's comments about building on OpenVMS.
1172     19. Added support for partial matching via the PCRE_PARTIAL option for
1173     pcre_exec() and the \P data escape in pcretest.
1175     20. Extended pcretest with 3 new pattern features:
1177     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1178     write the compiled pattern to the file whose name is "rest-of-line".
1179     This is a straight binary dump of the data, with the saved pointer to
1180     the character tables forced to be NULL. The study data, if any, is
1181     written too. After writing, pcretest reads a new pattern.
1183     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1184     compiled pattern from the given file. There must not be any
1185     occurrences of "<" in the file name (pretty unlikely); if there are,
1186     pcretest will instead treat the initial "<" as a pattern delimiter.
1187     After reading in the pattern, pcretest goes on to read data lines as
1188     usual.
1190     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1191     and 16-bit fields in a compiled pattern, to simulate a pattern that
1192     was compiled on a host of opposite endianness.
1194     21. The pcre-exec() function can now cope with patterns that were compiled on
1195     hosts of opposite endianness, with this restriction:
1197     As for any compiled expression that is saved and used later, the tables
1198     pointer field cannot be preserved; the extra_data field in the arguments
1199     to pcre_exec() should be used to pass in a tables address if a value
1200     other than the default internal tables were used at compile time.
1202     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1203     now diagnosed as an error. Previously, most of the time, a negative number
1204     would have been treated as zero, but if in addition "ovector" was passed as
1205     NULL, a crash could occur.
1207     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1208     new versions from the libtool 1.5 distribution (the last one is a copy of
1209     a file called libtool.m4). This seems to have fixed the need to patch
1210     "configure" to support Darwin 1.3 (which I used to do). However, I still
1211     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1212     workstation).
1214     24. Changed the PCRE licence to be the more standard "BSD" licence.
1217 nigel 73 Version 4.5 01-Dec-03
1218     ---------------------
1220     1. There has been some re-arrangement of the code for the match() function so
1221     that it can be compiled in a version that does not call itself recursively.
1222     Instead, it keeps those local variables that need separate instances for
1223     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1224     needs to "recurse". Keeping track of where control must go is done by means
1225     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1226     hide most of the details from the main code, and operates only if
1227     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1228     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1229     operating.
1231     To make it easier for callers to provide specially tailored get/free
1232     functions for this usage, two new functions, pcre_stack_malloc, and
1233     pcre_stack_free, are used. They are always called in strict stacking order,
1234     and the size of block requested is always the same.
1236     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1237     PCRE has been compiled to use the stack or the heap for recursion. The
1238     -C option of pcretest uses this to show which version is compiled.
1240     A new data escape \S, is added to pcretest; it causes the amounts of store
1241     obtained and freed by both kinds of malloc/free at match time to be added
1242     to the output.
1244     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1245     what's available on my current Linux desktop machine.
1247     3. When matching a UTF-8 string, the test for a valid string at the start has
1248     been extended. If start_offset is not zero, PCRE now checks that it points
1249     to a byte that is the start of a UTF-8 character. If not, it returns
1250     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1251     this is necessary because there may be backward assertions in the pattern.
1252     When matching the same subject several times, it may save resources to use
1253     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1255     4. The code for checking the validity of UTF-8 strings has been tightened so
1256     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1257     containing "overlong sequences".
1259     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1260     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1261     should have been "&", but it just so happened that all the cases this let
1262     through by mistake were picked up later in the function.
1264     6. I had used a variable called "isblank" - this is a C99 function, causing
1265     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1267     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1268     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1269     so the version is shown; (c) stop "make test" echoing "./RunTest".
1271     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1273     9. The prototype for memmove() for systems that don't have it was using
1274     size_t, but the inclusion of the header that defines size_t was later. I've
1275     moved the #includes for the C headers earlier to avoid this.
1277     10. Added some adjustments to the code to make it easier to compiler on certain
1278     special systems:
1280     (a) Some "const" qualifiers were missing.
1281     (b) Added the macro EXPORT before all exported functions; by default this
1282     is defined to be empty.
1283     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1284     that it reads its output file name as an argument instead of writing
1285     to the standard output and assuming this can be redirected.
1287     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1288     class containing characters with values greater than 255, PCRE compilation
1289     went into a loop.
1291     12. A recursive reference to a subpattern that was within another subpattern
1292     that had a minimum quantifier of zero caused PCRE to crash. For example,
1293     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1294     recursion. If the recursively-called subpattern itself had a zero repeat,
1295     that was OK.
1297     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1298     buffer into which it was copied (for escape processing) was still set at
1299     1024, so long lines caused crashes.
1301     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1302     "internal error: code overflow...". This applied to any character class
1303     that was followed by a possessive quantifier.
1305     15. Modified the Makefile to add libpcre.la as a prerequisite for
1306     libpcreposix.la because I was told this is needed for a parallel build to
1307     work.
1309     16. If a pattern that contained .* following optional items at the start was
1310     studied, the wrong optimizing data was generated, leading to matching
1311     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1312     matching string must start with a or b or c. The correct conclusion for
1313     this pattern is that a match can start with any character.
1316 nigel 71 Version 4.4 13-Aug-03
1317     ---------------------
1319     1. In UTF-8 mode, a character class containing characters with values between
1320     127 and 255 was not handled correctly if the compiled pattern was studied.
1321     In fixing this, I have also improved the studying algorithm for such
1322     classes (slightly).
1324     2. Three internal functions had redundant arguments passed to them. Removal
1325     might give a very teeny performance improvement.
1327     3. Documentation bug: the value of the capture_top field in a callout is *one
1328     more than* the number of the hightest numbered captured substring.
1330     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1331     in incorrectly linking with a previously installed version. They now link
1332     explicitly with libpcre.la.
1334     5. configure.in no longer needs to recognize Cygwin specially.
1336     6. A problem in pcre.in for Windows platforms is fixed.
1338     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1339     pcretest, it used to include the size of the study block as part of its
1340     output. Unfortunately, the structure contains a field that has a different
1341     size on different hardware architectures. This meant that the tests that
1342     showed this size failed. As the block is currently always of a fixed size,
1343     this information isn't actually particularly useful in pcretest output, so
1344     I have just removed it.
1346     8. Three pre-processor statements accidentally did not start in column 1.
1347     Sadly, there are *still* compilers around that complain, even though
1348     standard C has not required this for well over a decade. Sigh.
1350     9. In pcretest, the code for checking callouts passed small integers in the
1351     callout_data field, which is a void * field. However, some picky compilers
1352     complained about the casts involved for this on 64-bit systems. Now
1353     pcretest passes the address of the small integer instead, which should get
1354     rid of the warnings.
1356     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1357     both compile and run time, and gives an error if an invalid UTF-8 sequence
1358     is found. There is a option for disabling this check in cases where the
1359     string is known to be correct and/or the maximum performance is wanted.
1361     11. In response to a bug report, I changed one line in Makefile.in from
1363     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1364     to
1365     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1367     to look similar to other lines, but I have no way of telling whether this
1368     is the right thing to do, as I do not use Windows. No doubt I'll get told
1369     if it's wrong...
1372 nigel 69 Version 4.3 21-May-03
1373     ---------------------
1375     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1376     Makefile.
1378     2. Some refactoring to improve the quality of the code:
1380     (i) The utf8_table... variables are now declared "const".
1382     (ii) The code for \cx, which used the "case flipping" table to upper case
1383     lower case letters, now just substracts 32. This is ASCII-specific,
1384     but the whole concept of \cx is ASCII-specific, so it seems
1385     reasonable.
1387     (iii) PCRE was using its character types table to recognize decimal and
1388     hexadecimal digits in the pattern. This is silly, because it handles
1389     only 0-9, a-f, and A-F, but the character types table is locale-
1390     specific, which means strange things might happen. A private
1391     table is now used for this - though it costs 256 bytes, a table is
1392     much faster than multiple explicit tests. Of course, the standard
1393     character types table is still used for matching digits in subject
1394     strings against \d.
1396     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1397     ending in _t are). So I've renamed it as ESC_tee.
1399     3. The first argument for regexec() in the POSIX wrapper should have been
1400     defined as "const".
1402     4. Changed pcretest to use malloc() for its buffers so that they can be
1403     Electric Fenced for debugging.
1405     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1406     to read one or more bytes before the start of the subject string. Often this
1407     had no effect on PCRE's behaviour, but in some circumstances it could
1408     provoke a segmentation fault.
1410     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1411     to try to read one or more bytes before the start of the subject string.
1413     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1414     UTF-8 support could misbehave in various ways if the subject string
1415     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1416     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1417     back over UTF-8 characters.)
1420 nigel 67 Version 4.2 14-Apr-03
1421     ---------------------
1423     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1425     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1426     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1427     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1428     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1429     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1430     and BUILD_EXEEXT
1431     Note: automatic setting of the BUILD variables is not yet working
1432     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1433     compile-time but not at link-time
1434     [LINK]: use for linking executables only
1435     make different versions for Windows and non-Windows
1436     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1437     libraries
1438     [LINK_FOR_BUILD]: new variable
1439     [OBJEXT]: use throughout
1440     [EXEEXT]: use throughout
1441     <winshared>: new target
1442     <wininstall>: new target
1443     <dftables.o>: use native compiler
1444     <dftables>: use native linker
1445     <install>: handle Windows platform correctly
1446     <clean>: ditto
1447     <check>: ditto
1448     copy DLL to top builddir before testing
1450     As part of these changes, -no-undefined was removed again. This was reported
1451     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1452     in any case.
1454     3. Some tidies to get rid of compiler warnings:
1456     . In the match_data structure, match_limit was an unsigned long int, whereas
1457     match_call_count was an int. I've made them both unsigned long ints.
1459     . In pcretest the fact that a const uschar * doesn't automatically cast to
1460     a void * provoked a warning.
1462     . Turning on some more compiler warnings threw up some "shadow" variables
1463     and a few more missing casts.
1465     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1466     option, a class that contained a single character with a value between 128
1467     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1469     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1470     option, a class that contained several characters, but with at least one
1471     whose value was between 128 and 255 caused PCRE to crash.
1474 nigel 65 Version 4.1 12-Mar-03
1475     ---------------------
1476 nigel 63
1477 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1478     needed, and a string in dftables.c that was longer than standard compilers are
1479     required to support.
1481     2. Compiling with Sun's compiler found a few more places where the code could
1482     be tidied up in order to avoid warnings.
1484     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1485     first of these names is deprecated in the latest Autoconf in favour of the name
1486     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1487     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1488     analogy I have changed it to CFLAGS_FOR_BUILD.
1490     4. Added -no-undefined to the linking command in the Makefile, because this is
1491     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1492     linking step for the pcreposix library.
1494     5. PCRE was failing to diagnose the case of two named groups with the same
1495     name.
1497     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1498     literal character that is needed in the subject for a match, and scans along to
1499     ensure that it is present before embarking on the full matching process. This
1500     saves time in cases of nested unlimited repeats that are never going to match.
1501     Problem: the scan can take a lot of time if the subject is very long (e.g.
1502     megabytes), thus penalizing straightforward matches. It is now done only if the
1503     amount of subject to be scanned is less than 1000 bytes.
1505     7. A lesser problem with the same optimization is that it was recording the
1506     first character of an anchored pattern as "needed", thus provoking a search
1507     right along the subject, even when the first match of the pattern was going to
1508     fail. The "needed" character is now not set for anchored patterns, unless it
1509     follows something in the pattern that is of non-fixed length. Thus, it still
1510     fulfils its original purpose of finding quick non-matches in cases of nested
1511     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1514     Version 4.0 17-Feb-03
1515     ---------------------
1517 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1518     extended to the end of string, PCRE compiled incorrect data. This could lead to
1519     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1521     2. Moved to autoconf 2.53 and libtool 1.4.2.
1523     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1524     the special perltest8 script is no longer needed - all the tests can be run
1525     from a single perltest script.
1527     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1528     by \s. It has now been removed in PCRE. This means it isn't recognized as
1529     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1530     class [:space:] *does* include VT, thereby creating a mess.
1532     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1533     space and tab.
1535     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1536     its new features into the main test script, reducing the number of scripts.
1538     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1539     were backward compatible, and made the (?i) apply to the whole pattern, as if
1540     /i were given. Now it behaves more logically, and applies the option setting
1541     only to what follows. PCRE has been changed to follow suit. However, if it
1542     finds options settings right at the start of the pattern, it extracts them into
1543     the global options, as before. Thus, they show up in the info data.
1545     8. Added support for the \Q...\E escape sequence. Characters in between are
1546     treated as literals. This is slightly different from Perl in that $ and @ are
1547     also handled as literals inside the quotes. In Perl, they will cause variable
1548     interpolation. Note the following examples:
1550     Pattern PCRE matches Perl matches
1552     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1553     \Qabc\$xyz\E abc\$xyz abc\$xyz
1554     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1556     For compatibility with Perl, \Q...\E sequences are recognized inside character
1557     classes as well as outside them.
1559     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1560     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1561     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1562     signed/unsigned warnings.
1564     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1565     option for pcretest, so I've replaced it by a simple function that does just
1566     that job.
1568     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1569     "pcregrep -".
1571     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1572     Java package. This provides some syntactic sugar for simple cases of what my
1573     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1574     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1575     item, you can use this simplified notation. Note that only makes sense with
1576     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1577     greediness, whatever the setting of the PCRE_UNGREEDY option.
1579     13. A change of greediness default within a pattern was not taking effect at
1580     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1581     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1582     was abstracted outside.
1584     14. PCRE now supports the \G assertion. It is true when the current matching
1585     position is at the start point of the match. This differs from \A when the
1586     starting offset is non-zero. Used with the /g option of pcretest (or similar
1587     code), it works in the same way as it does for Perl's /g option. If all
1588     alternatives of a regex begin with \G, the expression is anchored to the start
1589     match position, and the "anchored" flag is set in the compiled expression.
1591     15. Some bugs concerning the handling of certain option changes within patterns
1592     have been fixed. These applied to options other than (?ims). For example,
1593     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1594     been the other way round. Some of this was related to change 7 above.
1596     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1597     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1598     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1599     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1601     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1602     mode. Unlike ".", it always matches newline, whatever the setting of
1603     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1604     assertions. Perl allows it, but it doesn't (in general) work because it can't
1605     calculate the length of the lookbehind. At least, that's the case for Perl
1606     5.8.0 - I've been told they are going to document that it doesn't work in
1607     future.
1609     18. Added an error diagnosis for escapes that PCRE does not support: these are
1610     \L, \l, \N, \P, \p, \U, \u, and \X.
1612     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1613     reading past the end of the pattern in cases such as /[abcd/.
1615     20. PCRE was getting more memory than necessary for patterns with classes that
1616     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1618     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1619     compiling PCRE for use with Virtual Pascal.
1621     22. Small fix to the Makefile to make it work properly if the build is done
1622     outside the source tree.
1624     23. Added a new extension: a condition to go with recursion. If a conditional
1625     subpattern starts with (?(R) the "true" branch is used if recursion has
1626     happened, whereas the "false" branch is used only at the top level.
1628     24. When there was a very long string of literal characters (over 255 bytes
1629     without UTF support, over 250 bytes with UTF support), the computation of how
1630     much memory was required could be incorrect, leading to segfaults or other
1631     strange effects.
1633     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1634     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1635     there was a subsequent back reference to those brackets. This meant that, for
1636     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1637     possible to check for precisely this case. All we can do is abandon the
1638     optimization if .* occurs inside capturing brackets when there are any back
1639     references whatsoever. (See below for a better fix that came later.)
1641     26. The handling of the optimization for finding the first character of a
1642     non-anchored pattern, and for finding a character that is required later in the
1643     match were failing in some cases. This didn't break the matching; it just
1644     failed to optimize when it could. The way this is done has been re-implemented.
1646     27. Fixed typo in error message for invalid (?R item (it said "(?p").
1648     28. Added a new feature that provides some of the functionality that Perl
1649     provides with (?{...}). The facility is termed a "callout". The way it is done
1650     in PCRE is for the caller to provide an optional function, by setting
1651     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1652     global variable. By default it is unset, which disables all calling out. To get
1653     the function called, the regex must include (?C) at appropriate points. This
1654     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1655     This provides a means of identifying different callout points. When PCRE
1656     reaches such a point in the regex, if pcre_callout has been set, the external
1657     function is called. It is provided with data in a structure called
1658     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1659     matching continues; if it returns a non-zero value, the match at the current
1660     point fails. However, backtracking will occur if possible. [This was changed
1661     later and other features added - see item 49 below.]
1663     29. pcretest is upgraded to test the callout functionality. It provides a
1664     callout function that displays information. By default, it shows the start of
1665     the match and the current position in the text. There are some new data escapes
1666     to vary what happens:
1668     \C+ in addition, show current contents of captured substrings
1669     \C- do not supply a callout function
1670     \C!n return 1 when callout number n is reached
1671     \C!n!m return 1 when callout number n is reached for the mth time
1673     30. If pcregrep was called with the -l option and just a single file name, it
1674     output "<stdin>" if a match was found, instead of the file name.
1676     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1677     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1678     pcre_exec(). This saves a malloc/free per call. The default value of
1679     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1680     when configuring.
1682     32. The default maximum size of a compiled pattern is 64K. There have been a
1683     few cases of people hitting this limit. The code now uses macros to handle the
1684     storing of links as offsets within the compiled pattern. It defaults to 2-byte
1685     links, but this can be changed to 3 or 4 bytes by --with-link-size when
1686     configuring. Tests 2 and 5 work only with 2-byte links because they output
1687     debugging information about compiled patterns.
1689     33. Internal code re-arrangements:
1691     (a) Moved the debugging function for printing out a compiled regex into
1692     its own source file (printint.c) and used #include to pull it into
1693     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1694     separate copies.
1696     (b) Defined the list of op-code names for debugging as a macro in
1697     internal.h so that it is next to the definition of the opcodes.
1699     (c) Defined a table of op-code lengths for simpler skipping along compiled
1700     code. This is again a macro in internal.h so that it is next to the
1701     definition of the opcodes.
1703     34. Added support for recursive calls to individual subpatterns, along the
1704     lines of Robin Houston's patch (but implemented somewhat differently).
1706     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1707     allow it to read and process whole directories in Win32. This code was
1708     contributed by Lionel Fourquaux; it has not been tested by me.
1710     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1711     used to name a group. Names consist of alphanumerics and underscores, and must
1712     be unique. Back references use the syntax (?P=name) and recursive calls use
1713     (?P>name) which is a PCRE extension to the Python extension. Groups still have
1714     numbers. The function pcre_fullinfo() can be used after compilation to extract
1715     a name/number map. There are three relevant calls:
1717     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1718     PCRE_INFO_NAMECOUNT yields the number of entries
1719     PCRE_INFO_NAMETABLE yields a pointer to the map.
1721     The map is a vector of fixed-size entries. The size of each entry depends on
1722     the length of the longest name used. The first two bytes of each entry are the
1723     group number, most significant byte first. There follows the corresponding
1724     name, zero terminated. The names are in alphabetical order.
1726     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1727     case instead of 255. Making it the same both with and without UTF-8 support
1728     means that the same test output works with both.
1730     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1731     calling malloc() with a zero argument.
1733     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1734     optimization. I've improved things by keeping a bitmap of backreferences with
1735     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1736     fact referenced, the optimization can be applied. It is unlikely that a
1737     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1738     the match to follow \n) will appear inside brackets with a number greater than
1739     31, but if it does, any back reference > 31 suppresses the optimization.
1741     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1742     of disabling numbered capturing parentheses. Any opening parenthesis that is
1743     not followed by ? behaves as if it were followed by ?: but named parentheses
1744     can still be used for capturing (and they will acquire numbers in the usual
1745     way).
1747     41. Redesigned the return codes from the match() function into yes/no/error so
1748     that errors can be passed back from deep inside the nested calls. A malloc
1749     failure while inside a recursive subpattern call now causes the
1750     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1752     42. It is now possible to set a limit on the number of times the match()
1753     function is called in a call to pcre_exec(). This facility makes it possible to
1754     limit the amount of recursion and backtracking, though not in a directly
1755     obvious way, because the match() function is used in a number of different
1756     circumstances. The count starts from zero for each position in the subject
1757     string (for non-anchored patterns). The default limit is, for compatibility, a
1758     large number, namely 10 000 000. You can change this in two ways:
1760     (a) When configuring PCRE before making, you can use --with-match-limit=n
1761     to set a default value for the compiled library.
1763     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1764     a different value is set. See 45 below.
1766     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1768     43. Added a new function pcre_config(int, void *) to enable run-time extraction
1769     of things that can be changed at compile time. The first argument specifies
1770     what is wanted and the second points to where the information is to be placed.
1771     The current list of available information is:
1775     The output is an integer that is set to one if UTF-8 support is available;
1776     otherwise it is set to zero.
1780     The output is an integer that it set to the value of the code that is used for
1781     newline. It is either LF (10) or CR (13).
1785     The output is an integer that contains the number of bytes used for internal
1786     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1790     The output is an integer that contains the threshold above which the POSIX
1791     interface uses malloc() for output vectors. See item 31 above.
1795     The output is an unsigned integer that contains the default limit of the number
1796     of match() calls in a pcre_exec() execution. See 42 above.
1798     44. pcretest has been upgraded by the addition of the -C option. This causes it
1799     to extract all the available output from the new pcre_config() function, and to
1800     output it. The program then exits immediately.
1802     45. A need has arisen to pass over additional data with calls to pcre_exec() in
1803     order to support additional features. One way would have been to define
1804     pcre_exec2() (for example) with extra arguments, but this would not have been
1805     extensible, and would also have required all calls to the original function to
1806     be mapped to the new one. Instead, I have chosen to extend the mechanism that
1807     is used for passing in "extra" data from pcre_study().
1809     The pcre_extra structure is now exposed and defined in pcre.h. It currently
1810     contains the following fields:
1812     flags a bitmap indicating which of the following fields are set
1813     study_data opaque data from pcre_study()
1814     match_limit a way of specifying a limit on match() calls for a specific
1815     call to pcre_exec()
1816     callout_data data for callouts (see 49 below)
1818     The flag bits are also defined in pcre.h, and are
1824     The pcre_study() function now returns one of these new pcre_extra blocks, with
1825     the actual study data pointed to by the study_data field, and the
1826     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1827     before. That is, this change is entirely upwards-compatible and requires no
1828     change to existing code.
1830     If you want to pass in additional data to pcre_exec(), you can either place it
1831     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1832     block.
1834     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1835     data string contains the escape sequence \M, pcretest calls pcre_exec() several
1836     times with different match limits, until it finds the minimum value needed for
1837     pcre_exec() to complete. The value is then output. This can be instructive; for
1838     most simple matches the number is quite small, but for pathological cases it
1839     gets very large very quickly.
1841     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1842     returns the size of the data block pointed to by the study_data field in a
1843     pcre_extra block, that is, the value that was passed as the argument to
1844     pcre_malloc() when PCRE was getting memory in which to place the information
1845     created by pcre_study(). The fourth argument should point to a size_t variable.
1846     pcretest has been extended so that this information is shown after a successful
1847     pcre_study() call when information about the compiled regex is being displayed.
1849     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1850     because what follows is always an absolute path. (Later: it turns out that this
1851     is more than cosmetic for MinGW, because it doesn't like empty path
1852     components.)
1854     49. Some changes have been made to the callout feature (see 28 above):
1856     (i) A callout function now has three choices for what it returns:
1858     0 => success, carry on matching
1859     > 0 => failure at this point, but backtrack if possible
1860     < 0 => serious error, return this value from pcre_exec()
1862     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1863     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1864     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1865     use by callout functions. It will never be used by PCRE itself.
1867     (ii) The pcre_extra structure (see 45 above) has a void * field called
1868     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1869     pcre_callout_block structure has a field of the same name. The contents of
1870     the field passed in the pcre_extra structure are passed to the callout
1871     function in the corresponding field in the callout block. This makes it
1872     easier to use the same callout-containing regex from multiple threads. For
1873     testing, the pcretest program has a new data escape
1875     \C*n pass the number n (may be negative) as callout_data
1877     If the callout function in pcretest receives a non-zero value as
1878     callout_data, it returns that value.
1880     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1881     there were some redundant $(CFLAGS) in commands that are now specified as
1882     $(LINK), which already includes $(CFLAGS).
1884     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1885     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1886     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1887     one-byte characters throughout. Note that case-insensitive matching applies
1888     only to characters whose values are less than 256. PCRE doesn't support the
1889     notion of cases for higher-valued characters.
1891     (i) A character class whose characters are all within 0-255 is handled as
1892     a bit map, and the map is inverted for negative classes. Previously, a
1893     character > 255 always failed to match such a class; however it should
1894     match if the class was a negative one (e.g. [^ab]). This has been fixed.
1896     (ii) A negated character class with a single character < 255 is coded as
1897     "not this character" (OP_NOT). This wasn't working properly when the test
1898     character was multibyte, either singly or repeated.
1900     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1901     mode, for example: \x{100}{2,3}.
1903     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1904     singly or repeated) now correctly test multibyte characters. However,
1905     PCRE doesn't recognize any characters with values greater than 255 as
1906     digits, spaces, or word characters. Such characters always match \D, \S,
1907     and \W, and never match \d, \s, or \w.
1909     (v) Classes may now contain characters and character ranges with values
1910     greater than 255. For example: [ab\x{100}-\x{400}].
1912     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1913     PCRE in UTF-8 mode.
1915     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1916     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1917     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1918     value.)
1920     53. The single man page has become too large. I have therefore split it up into
1921     a number of separate man pages. These also give rise to individual HTML pages;
1922     these are now put in a separate directory, and there is an index.html page that
1923     lists them all. Some hyperlinking between the pages has been installed.
1925     54. Added convenience functions for handling named capturing parentheses.
1927     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1928     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1929     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1930     are faulted.
1932     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1933     calling configure. These values are used when compiling the dftables.c program
1934     which is run to generate the source of the default character tables. They
1935     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1936     you will need to set these values.
1938     57. Updated the building process for Windows DLL, as provided by Fred Cox.
1941     Version 3.9 02-Jan-02
1942 nigel 61 ---------------------
1944     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1946     2. If --disable-static was given, the building process failed when trying to
1947     build pcretest and pcregrep. (For some reason it was using libtool to compile
1948     them, which is not right, as they aren't part of the library.)
1951 nigel 59 Version 3.8 18-Dec-01
1952     ---------------------
1954     1. The experimental UTF-8 code was completely screwed up. It was packing the
1955     bytes in the wrong order. How dumb can you get?
1958 nigel 57 Version 3.7 29-Oct-01
1959     ---------------------
1961     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1962     This caused pcretest, when used on the test data, to segfault. Unfortunately,
1963     this didn't happen under Solaris 8, where I normally test things.
1965 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1966     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1967     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
1968     this fix an hour or so after the initial 3.7 release.)
1969 nigel 57
1970 nigel 59
1971 nigel 55 Version 3.6 23-Oct-01
1972     ---------------------
1974     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1975     offsets passed as NULL with zero offset count.
1977     2. The config.guess and config.sub files had not been updated when I moved to
1978     the latest autoconf.
1981 nigel 53 Version 3.5 15-Aug-01
1982     ---------------------
1983 nigel 5
1984 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
1985     had been forgotten.
1987     2. By using declared but undefined structures, we can avoid using "void"
1988     definitions in pcre.h while keeping the internal definitions of the structures
1989     private.
1991     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
1992     user point of view, this means that both static and shared libraries are built
1993     by default, but this can be individually controlled. More of the work of
1994     handling this static/shared cases is now inside libtool instead of PCRE's make
1995     file.
1997     4. The pcretest utility is now installed along with pcregrep because it is
1998     useful for users (to test regexs) and by doing this, it automatically gets
1999     relinked by libtool. The documentation has been turned into a man page, so
2000     there are now .1, .txt, and .html versions in /doc.
2002     5. Upgrades to pcregrep:
2003     (i) Added long-form option names like gnu grep.
2004     (ii) Added --help to list all options with an explanatory phrase.
2005     (iii) Added -r, --recursive to recurse into sub-directories.
2006     (iv) Added -f, --file to read patterns from a file.
2008     6. pcre_exec() was referring to its "code" argument before testing that
2009     argument for NULL (and giving an error if it was NULL).
2011     7. Upgraded Makefile.in to allow for compiling in a different directory from
2012     the source directory.
2014     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2015     options bits, the pointer it was passed was to an int instead of to an unsigned
2016     long int. This mattered only on 64-bit systems.
2018     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2019     generated) instead of pcre.in, which it its source. Also made the same change
2020     in several of the .c files.
2022     10. A new release of gcc defines printf() as a macro, which broke pcretest
2023     because it had an ifdef in the middle of a string argument for printf(). Fixed
2024     by using separate calls to printf().
2026     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2027     script, to force use of CR or LF instead of \n in the source. On non-Unix
2028     systems, the value can be set in config.h.
2030     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2031     absolute limit. Changed the text of the error message to make this clear, and
2032     likewise updated the man page.
2034     13. The limit of 99 on the number of capturing subpatterns has been removed.
2035     The new limit is 65535, which I hope will not be a "real" limit.
2038 nigel 51 Version 3.4 22-Aug-00
2039     ---------------------
2041     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2043     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2046 nigel 49 Version 3.3 01-Aug-00
2047     ---------------------
2049     1. If an octal character was given, but the value was greater than \377, it
2050     was not getting masked to the least significant bits, as documented. This could
2051     lead to crashes in some systems.
2053     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2054     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2056     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2057     These just pass their arguments on to (pcre_free)(), but they are provided
2058     because some uses of PCRE bind it to non-C systems that can call its functions,
2059     but cannot call free() or pcre_free() directly.
2061     4. Add "make test" as a synonym for "make check". Corrected some comments in
2062     the Makefile.
2064     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2065     Makefile.
2067     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2068     command called pgrep for grepping around the active processes.
2070     7. Added the beginnings of support for UTF-8 character strings.
2072     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2073     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2074     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2075     out for the ar command.)
2078 nigel 47 Version 3.2 12-May-00
2079     ---------------------
2081     This is purely a bug fixing release.
2083     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2084     of ZA. This was just one example of several cases that could provoke this bug,
2085     which was introduced by change 9 of version 2.00. The code for breaking
2086     infinite loops after an iteration that matches an empty string was't working
2087     correctly.
2089     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2090     when matched against abbab (for example). After matching an empty string, it
2091     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2092     caused it to match further down the string than it should.
2094     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2095     was there because it doesn't seem to be needed, and it causes trouble on some
2096     systems, as it is not a Standard C header. It has been removed.
2098     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2099     were reported on the Macintosh. The changes were from
2101     while ((c = *(++ptr)) != 0 && c != '\n');
2102     to
2103     while ((c = *(++ptr)) != 0 && c != '\n') ;
2105     Totally extraordinary, but if that's what it takes...
2107     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2108     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2109     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2110     assumes the way PCRE uses memmove() (always moving upwards).
2112     6. PCRE is being used in one environment where strchr() is not available. There
2113     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2114     faster code anyway.
2117 nigel 45 Version 3.1 09-Feb-00
2118     ---------------------
2120     The only change in this release is the fixing of some bugs in Makefile.in for
2121     the "install" target:
2123     (1) It was failing to install pcreposix.h.
2125     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2128 nigel 43 Version 3.0 01-Feb-00
2129     ---------------------
2130 nigel 41
2131     1. Add support for the /+ modifier to perltest (to output $` like it does in
2132     pcretest).
2134     2. Add support for the /g modifier to perltest.
2136     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2137     matches null strings.
2139     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2140     pattern. Perl treats empty patterns specially - it reuses the most recent
2141     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2142     effect.
2144     5. The POSIX interface was broken in that it was just handing over the POSIX
2145     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2146     required a bigger vector, with some working space on the end. This means that
2147     the POSIX wrapper now has to get and free some memory, and copy the results.
2149 nigel 43 6. Added some simple autoconf support, placing the test data and the
2150     documentation in separate directories, re-organizing some of the
2151     information files, and making it build pcre-config (a GNU standard). Also added
2152     libtool support for building PCRE as a shared library, which is now the
2153     default.
2154 nigel 41
2155 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2156     09 are not valid octal constants. Single digits will be used for minor values
2157     less than 10.
2159     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2160     existing programs that set these in the POSIX interface can use PCRE without
2161     modification.
2163     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2164     return all that pcre_info() returns, plus additional data. The pcre_info()
2165     function is retained for compatibility, but is considered to be obsolete.
2167     10. Added experimental recursion feature (?R) to handle one common case that
2168     Perl 5.6 will be able to do with (?p{...}).
2170     11. Added support for POSIX character classes like [:alpha:], which Perl is
2171     adopting.
2174 nigel 39 Version 2.08 31-Aug-99
2175     ----------------------
2177     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2178     trying to match at the startoffset position, but instead was moving forward to
2179     the next newline as if a previous match had failed.
2181     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2182     and could get into a loop if a null string was matched other than at the start
2183     of the subject.
2185     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2186     be distinguished at compile time, and for completeness also added PCRE_DATE.
2188     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2189     in GnuWin32 environments.
2192 nigel 37 Version 2.07 29-Jul-99
2193     ----------------------
2195     1. The documentation is now supplied in plain text form and HTML as well as in
2196     the form of man page sources.
2198     2. C++ compilers don't like assigning (void *) values to other pointer types.
2199     In particular this affects malloc(). Although there is no problem in Standard
2200     C, I've put in casts to keep C++ compilers happy.
2202     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2203     should be (const char *).
2205     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2206     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2207     However, I haven't made this a standard facility. The documentation doesn't
2208     mention it, and the Makefile doesn't support it.
2210     5. The Makefile now contains an "install" target, with editable destinations at
2211     the top of the file. The pcretest program is not installed.
2213     6. pgrep -V now gives the PCRE version number and date.
2215     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2216     causing the entire string to be ignored, instead of just the last character.
2218     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2219     non-matching string, it can take a very, very long time, even for strings of
2220     quite modest length, because of the nested recursion. PCRE now does better in
2221     some of these cases. It does this by remembering the last required literal
2222     character in the pattern, and pre-searching the subject to ensure it is present
2223     before running the real match. In other words, it applies a heuristic to detect
2224     some types of certain failure quickly, and in the above example, if presented
2225     with a string that has no trailing " it gives "no match" very quickly.
2227     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2228     other alternatives are tried instead.
2231 nigel 35 Version 2.06 09-Jun-99
2232     ----------------------
2234     1. Change pcretest's output for amount of store used to show just the code
2235     space, because the remainder (the data block) varies in size between 32-bit and
2236     64-bit systems.
2238     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2239     start matching at. This allows lookbehinds to work when searching for multiple
2240     occurrences in a string.
2242     3. Added additional options to pcretest for testing multiple occurrences:
2244     /+ outputs the rest of the string that follows a match
2245     /g loops for multiple occurrences, using the new startoffset argument
2246     /G loops for multiple occurrences by passing an incremented pointer
2248     4. PCRE wasn't doing the "first character" optimization for patterns starting
2249     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2250     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2251     the letter 'x'. On long subject strings, this gives a significant speed-up.
2254 nigel 33 Version 2.05 21-Apr-99
2255     ----------------------
2257     1. Changed the type of magic_number from int to long int so that it works
2258     properly on 16-bit systems.
2260     2. Fixed a bug which caused patterns starting with .* not to work correctly
2261     when the subject string contained newline characters. PCRE was assuming
2262     anchoring for such patterns in all cases, which is not correct because .* will
2263     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2264     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2265     must be retried after every newline in the subject.
2268 nigel 31 Version 2.04 18-Feb-99
2269     ----------------------
2271     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2272     computation of the store needed to hold the pattern was incorrect (too large).
2273     If such patterns were nested a few deep, this could multiply and become a real
2274     problem.
2276     2. Added /M option to pcretest to show the memory requirement of a specific
2277     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2279     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2280     compiled in such a way that the backtracking after subsequent failure was
2281     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2282     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2285 nigel 29 Version 2.03 02-Feb-99
2286     ----------------------
2288     1. Fixed typo and small mistake in man page.
2290 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2291     LICENCE file containing the conditions.
2292 nigel 29
2293     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2294     Perl, that is the internal \ allows the delimiter to be included in the
2295     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2296     the final delimiter, add \ to the end of the pattern (to test the error).
2298     4. Added the convenience functions for extracting substrings after a successful
2299     match. Updated pcretest to make it able to test these functions.
2302 nigel 27 Version 2.02 14-Jan-99
2303     ----------------------
2305     1. Initialized the working variables associated with each extraction so that
2306     their saving and restoring doesn't refer to uninitialized store.
2308     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2309     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2310     fix the problem.
2312     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2313     calls, and wasn't printing the correct value for compiling calls. Increased the
2314     default value of LOOPREPEAT, and the number of significant figures in the
2315     times.
2317     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2319     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2320     a building problem on Windows NT with a FAT file system.
2323 nigel 25 Version 2.01 21-Oct-98
2324     ----------------------
2326     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2327     to character tables built by pcre_maketables() in the current locale. If NULL
2328     is passed, the default tables are used.
2331 nigel 23 Version 2.00 24-Sep-98
2332 nigel 21 ----------------------
2334 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2335     it any more.
2337     2. Allow quantification of (?>) groups, and make it work correctly.
2339     3. The first character computation wasn't working for (?>) groups.
2341     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2342     end of the subject) and add 5.005's \z, which really does match only at the
2343     very end of the subject.
2345     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2347     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2348     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2349     localized options. All options to pcre_study() were also removed.
2351     7. Add other new features from 5.005:
2353     $(?<= positive lookbehind
2354     $(?<! negative lookbehind
2355     (?imsx-imsx) added the unsetting capability
2356     such a setting is global if at outer level; local otherwise
2357     (?imsx-imsx:) non-capturing groups with option setting
2358     (?(cond)re|re) conditional pattern matching
2360     A backreference to itself in a repeated group matches the previous
2361     captured string.
2363     8. General tidying up of studying (both automatic and via "study")
2364     consequential on the addition of new assertions.
2366     9. As in 5.005, unlimited repeated groups that could match an empty substring
2367     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2368     runtime if any iteration does actually match an empty substring.
2370     10. Include the RunTest script in the distribution.
2372     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2373     discrepancies, some of which were old and were also with respect to 5.004. They
2374     have now been fixed.
2377     Version 1.09 28-Apr-98
2378     ----------------------
2380 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2381     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2382     program crashes, or just wrong answers. This did not apply to negated classes
2383     containing more than one character, or to minima other than one.
2386 nigel 19 Version 1.08 27-Mar-98
2387     ----------------------
2389     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2391     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2392     latter must appear before anything that relies on it in the pattern.
2395 nigel 17 Version 1.07 16-Feb-98
2396     ----------------------
2398     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2399     repeat of a potentially empty string).
2402 nigel 15 Version 1.06 23-Jan-98
2403     ----------------------
2405     1. Added Markus Oberhumer's little patches for C++.
2407     2. Literal strings longer than 255 characters were broken.
2410 nigel 13 Version 1.05 23-Dec-97
2411     ----------------------
2413     1. Negated character classes containing more than one character were failing if
2414     PCRE_CASELESS was set at run time.
2417 nigel 11 Version 1.04 19-Dec-97
2418     ----------------------
2420     1. Corrected the man page, where some "const" qualifiers had been omitted.
2422     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2423     input syntax.
2425     3. Fixed memory leak which occurred when a regex with back references was
2426     matched with an offsets vector that wasn't big enough. The temporary memory
2427     that is used in this case wasn't being freed if the match failed.
2429     4. Tidied pcretest to ensure it frees memory that it gets.
2431     5. Temporary memory was being obtained in the case where the passed offsets
2432     vector was exactly big enough.
2434     6. Corrected definition of offsetof() from change 5 below.
2436     7. I had screwed up change 6 below and broken the rules for the use of
2437     setjmp(). Now fixed.
2440 nigel 9 Version 1.03 18-Dec-97
2441     ----------------------
2443     1. A erroneous regex with a missing opening parenthesis was correctly
2444     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2445     on some systems.
2447     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2448     it was reported that one broken compiler failed on the former because "code" is
2449     also an independent variable.
2451     3. The erroneous regex a[]b caused an array overrun reference.
2453     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2454     fail on data ending with that character. (It was going on too far, and checking
2455     the next character, typically a binary zero.) This was specific to the
2456     optimized code for single-character negative classes.
2458     5. Added a contributed patch from the TIN world which does the following:
2460     + Add an undef for memmove, in case the the system defines a macro for it.
2462     + Add a definition of offsetof(), in case there isn't one. (I don't know
2463     the reason behind this - offsetof() is part of the ANSI standard - but
2464     it does no harm).
2466     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2467     most of the places where whitespace preceded '#'. I have given up and
2468     allowed the remaining 2 cases to be at the margin.
2470     + Rename some variables in pcre to eliminate shadowing. This seems very
2471     pedantic, but does no harm, of course.
2473     6. Moved the call to setjmp() into its own function, to get rid of warnings
2474     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2476     7. Constructs such as \d{8,} were compiling into the equivalent of
2477 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2478 nigel 9 outcome, but in this particular case used more store than had been allocated,
2479     which caused the bug to be discovered because it threw up an internal error.
2481     8. The debugging code in both pcre and pcretest for outputting the compiled
2482     form of a regex was going wrong in the case of back references followed by
2483     curly-bracketed repeats.
2486 nigel 7 Version 1.02 12-Dec-97
2487     ----------------------
2489     1. Typos in pcre.3 and comments in the source fixed.
2491     2. Applied a contributed patch to get rid of places where it used to remove
2492     'const' from variables, and fixed some signed/unsigned and uninitialized
2493     variable warnings.
2495     3. Added the "runtest" target to Makefile.
2497     4. Set default compiler flag to -O2 rather than just -O.
2500 nigel 5 Version 1.01 19-Nov-97
2501     ----------------------
2503     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2504     like /([ab]*)*/, that is, for classes with more than one character in them.
2506     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2507     as /((?>a*))*/ (a PCRE_EXTRA facility).
2510     Version 1.00 18-Nov-97
2511     ----------------------
2513     1. Added compile-time macros to support systems such as SunOS4 which don't have
2514     memmove() or strerror() but have other things that can be used instead.
2516     2. Arranged that "make clean" removes the executables.
2519 nigel 3 Version 0.99 27-Oct-97
2520     ----------------------
2522     1. Fixed bug in code for optimizing classes with only one character. It was
2523     initializing a 32-byte map regardless, which could cause it to run off the end
2524     of the memory it had got.
2526     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2529     Version 0.98 22-Oct-97
2530     ----------------------
2532     1. Fixed bug in code for handling temporary memory usage when there are more
2533     back references than supplied space in the ovector. This could cause segfaults.
2536     Version 0.97 21-Oct-97
2537     ----------------------
2539     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2541     2. Optimized negated single characters not to use a bit map.
2543     3. Brought error texts together as macro definitions; clarified some of them;
2544     fixed one that was wrong - it said "range out of order" when it meant "invalid
2545     escape sequence".
2547     4. Changed some char * arguments to const char *.
2549     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2551     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2552     pcretest.
2555     Version 0.96 16-Oct-97
2556     ----------------------
2558     1. Added a simple "pgrep" utility to the distribution.
2560     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2561     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2562     where "ddd" means "one or more decimal digits".
2564     3. Fixed serious bug. If a pattern had a back reference, but the call to
2565     pcre_exec() didn't supply a large enough ovector to record the related
2566     identifying subpattern, the match always failed. PCRE now remembers the number
2567     of the largest back reference, and gets some temporary memory in which to save
2568     the offsets during matching if necessary, in order to ensure that
2569     backreferences always work.
2571     4. Increased the compatibility with Perl in a number of ways:
2573     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2574     to request this handling. The option can be set at compile or exec time.
2576     (b) $ matches before a terminating newline by default; an option
2577     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2578     mode). The option can be set at compile or exec time.
2580     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2581     the same as Perl's. If the decimal number it represents is less than 10
2582     or there aren't that many previous left capturing parentheses, an octal
2583     escape is read. Inside a character class, it's always an octal escape,
2584     even if it is a single digit.
2586     (d) An escaped but undefined alphabetic character is taken as a literal,
2587     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2588     escapes.
2590     (e) {0} is now permitted. (The previous item is removed from the compiled
2591     pattern).
2593     5. Changed all the names of code files so that the basic parts are no longer
2594     than 10 characters, and abolished the teeny "globals.c" file.
2596     6. Changed the handling of character classes; they are now done with a 32-byte
2597     bit map always.
2599     7. Added the -d and /D options to pcretest to make it possible to look at the
2600     internals of compilation without having to recompile pcre.
2603     Version 0.95 23-Sep-97
2604     ----------------------
2606     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2607     \x20 at the start of a run of normal characters. These were being treated as
2608     real characters, instead of the source characters being re-checked.
2611     Version 0.94 18-Sep-97
2612     ----------------------
2614     1. The functions are now thread-safe, with the caveat that the global variables
2615     containing pointers to malloc() and free() or alternative functions are the
2616     same for all threads.
2618     2. Get pcre_study() to generate a bitmap of initial characters for non-
2619     anchored patterns when this is possible, and use it if passed to pcre_exec().
2622     Version 0.93 15-Sep-97
2623     ----------------------
2625     1. /(b)|(:+)/ was computing an incorrect first character.
2627     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2628     but not actually doing anything yet.
2630     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2631     as Perl does (e.g. [-az] or [az-]).
2633     4. Set the anchored flag if a branch starts with .* or .*? because that tests
2634     all possible positions.
2636     5. Split up into different modules to avoid including unneeded functions in a
2637     compiled binary. However, compile and exec are still in one module. The "study"
2638     function is split off.
2640     6. The character tables are now in a separate module whose source is generated
2641     by an auxiliary program - but can then be edited by hand if required. There are
2642     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2643     toupper() in the code.
2645     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2646     make them global. Abolish the function for setting them, as the caller can now
2647     set them directly.
2650     Version 0.92 11-Sep-97
2651     ----------------------
2653     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2654     (e.g. /a{1,3}/) was broken (I mis-optimized it).
2656     2. Caseless matching was not working in character classes if the characters in
2657     the pattern were in upper case.
2659     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2661     4. Make PCRE_ANCHORED public and accept as a compile option.
2663     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2664     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2665     pass them.
2667     6. Give an error if bad option bits passed at compile or run time.
2669     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2670     pcretest to cause it to pass that flag.
2672     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2673     options, and the first character, if set.
2675     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2678     Version 0.91 10-Sep-97
2679     ----------------------
2681     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2682     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2684     2. PCRE was looping on encountering an indefinitely repeated back reference to
2685     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2686     Perl does - treats the match as successful.
2688     ****


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