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Revision 161 - (hide annotations) (download)
Thu May 3 10:28:07 2007 UTC (7 years, 6 months ago) by ph10
File size: 127508 byte(s)
Use the pcretest "Z" option so all tests can be run with all link sizes.

1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 ph10 157 Version 7.2 01-May-07
5     ---------------------
6    
7     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
8     which is apparently normally available under Windows.
9 ph10 159
10     2. Re-jig the pcregrep tests with different newline settings in an attempt
11     to make them independent of the local environment's newline setting.
12 ph10 157
13 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
14 ph10 161
15     4. Some of the "internals" tests were previously cut out when the link size
16     was not 2, because the output contained actual offsets. The recent new
17     "Z" feature of pcretest means that these can be cut out, making the tests
18     usable with all link sizes.
19 ph10 159
20 ph10 160
21 ph10 155 Version 7.1 24-Apr-07
22 ph10 98 ---------------------
23    
24 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
25 ph10 122 that is more "standard", making use of automake and other Autotools. There
26 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
27     on this.
28 ph10 111
29     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
30     for recursive directory scanning broke on some systems because the files
31     are not scanned in any specific order and on different systems the order
32     was different. A call to "sort" has been inserted into RunGrepTest for the
33     approprate test as a short-term fix. In the longer term there may be an
34 ph10 100 alternative.
35 ph10 111
36 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
37 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
38     people do their own conversions for various reasons). The problems
39     concerned the use of low-level troff macros .br and .in. I have therefore
40     removed all such uses from the man pages (some were redundant, some could
41 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
42     HTML has been updated to handle .nf/.fi and to complain if it encounters
43     .br or .in.
44 ph10 111
45 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
46 ph10 123 arranged for config.h to be included in the distribution, with the name
47 ph10 111 config.h.generic, for the benefit of those who have to compile without
48     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
49    
50     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
51     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
52 ph10 127 makevp.bat for the current PCRE, using the additional files
53 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
54 ph10 111
55     6. A Windows user reported a minor discrepancy with test 2, which turned out
56     to be caused by a trailing space on an input line that had got lost in his
57 ph10 102 copy. The trailing space was an accident, so I've just removed it.
58 ph10 111
59 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
60 ph10 111 that is needed.
61    
62 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
63     as "const" (a) because they are and (b) because it helps the PHP
64     maintainers who have recently made a script to detect big data structures
65 ph10 111 in the php code that should be moved to the .rodata section. I remembered
66     to update Builducptable as well, so it won't revert if ucptable.h is ever
67 ph10 105 re-created.
68 ph10 111
69     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
70 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
71 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
72     support is not required. This saves 1.5-2K of code, which is important in
73 ph10 107 some applications.
74 ph10 111
75 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
76 ph10 111 so as not to refer to the tables, even though these functions will never be
77     called when UTF-8 support is disabled. Otherwise there are problems with a
78     shared library.
79    
80 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
81    
82     (a) It was defining its arguments as char * instead of void *.
83    
84 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
85     a long time ago when I wrote it, but is no longer the case.
86    
87 ph10 118 The emulated memove() is provided for those environments that have neither
88 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
89 ph10 118 is clearly not the case, as these two bugs were recently reported.
90 ph10 123
91 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
92 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
93     pages, and it removes trailing spaces from listed files. It also creates
94     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
95     case, it wraps all the #defines with #ifndefs. This script should be run
96 ph10 111 before "make dist".
97 ph10 123
98 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
99     with Unicode property support.
100 ph10 123
101     (a) For a maximizing quantifier, if the two different cases of the
102     character were of different lengths in their UTF-8 codings (there are
103     some cases like this - I found 11), and the matching function had to
104 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
105     were both the same length.
106 ph10 123
107     (b) When PCRE was configured to use the heap rather than the stack for
108     recursion during matching, it was not correctly preserving the data for
109     the other case of a UTF-8 character when checking ahead for a match
110     while processing a minimizing repeat. If the check also involved
111 ph10 115 matching a wide character, but failed, corruption could cause an
112     erroneous result when trying to check for a repeat of the original
113     character.
114 ph10 123
115 ph10 116 13. Some tidying changes to the testing mechanism:
116 ph10 98
117 ph10 116 (a) The RunTest script now detects the internal link size and whether there
118     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
119 ph10 123 values substituted by "configure". (The RunGrepTest script already did
120     this for UTF-8.) The configure.ac script no longer substitutes the
121     relevant variables.
122    
123 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
124     with length and offset values. This means that the output is different
125     for different internal link sizes. Test 2 is skipped for link sizes
126     other than 2 because of this, bypassing the problem. Unfortunately,
127     there was also a test in test 3 (the locale tests) that used /B and
128 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
129     I have added a new /Z option to pcretest that replaces the length and
130     offset values with spaces. This is now used to make test 3 independent
131 ph10 122 of link size. (Test 2 will be tidied up later.)
132 ph10 123
133     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
134 ph10 122 segmentation fault instead of returning the appropriate error message.
135 ph10 134
136 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
137 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
138     This doesn't seem right; it now treats the CRLF combination as the line
139     ending, and so does not match in that case. It's only a pattern such as ^$
140     that would hit this one: something like ^ABC$ would have failed after \r
141     and then tried again after \r\n.
142    
143 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
144 ph10 134 in an attempt to make files that differ only in their line terminators
145     compare equal. This works on Linux.
146 ph10 142
147 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
148     as it exited. This is now fixed, thanks to valgrind.
149 ph10 142
150 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
151 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
152     was because its rules for how to advance for /g after matching an empty
153 ph10 143 string at the end of a line did not allow for this case. They now check for
154     it specially.
155 ph10 150
156     20. pcretest is supposed to handle patterns and data of any length, by
157     extending its buffers when necessary. It was getting this wrong when the
158 ph10 147 buffer for a data line had to be extended.
159 ph10 150
160 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
161 ph10 150 CRLF as a newline sequence.
162 ph10 152
163 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
164 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
165     I have nevertheless tidied it up.
166 ph10 111
167 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
168 ph10 123
169 ph10 153 24. Added a man page for pcre-config.
170 ph10 152
171 ph10 153
172 nigel 93 Version 7.0 19-Dec-06
173     ---------------------
174    
175     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
176     moving to gcc 4.1.1.
177    
178     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
179     sys/time.h, which is documented as needed for this function. It doesn't
180     seem to matter on Linux, but it showed up on some releases of OS X.
181    
182     3. It seems that there are systems where bytes whose values are greater than
183     127 match isprint() in the "C" locale. The "C" locale should be the
184     default when a C program starts up. In most systems, only ASCII printing
185     characters match isprint(). This difference caused the output from pcretest
186     to vary, making some of the tests fail. I have changed pcretest so that:
187    
188     (a) When it is outputting text in the compiled version of a pattern, bytes
189     other than 32-126 are always shown as hex escapes.
190    
191     (b) When it is outputting text that is a matched part of a subject string,
192     it does the same, unless a different locale has been set for the match
193     (using the /L modifier). In this case, it uses isprint() to decide.
194    
195     4. Fixed a major bug that caused incorrect computation of the amount of memory
196     required for a compiled pattern when options that changed within the
197     pattern affected the logic of the preliminary scan that determines the
198     length. The relevant options are -x, and -i in UTF-8 mode. The result was
199     that the computed length was too small. The symptoms of this bug were
200     either the PCRE error "internal error: code overflow" from pcre_compile(),
201     or a glibc crash with a message such as "pcretest: free(): invalid next
202     size (fast)". Examples of patterns that provoked this bug (shown in
203     pcretest format) are:
204    
205     /(?-x: )/x
206     /(?x)(?-x: \s*#\s*)/
207     /((?i)[\x{c0}])/8
208     /(?i:[\x{c0}])/8
209    
210     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
211     is now done differently.
212    
213     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
214     wrapper classes; (b) implement a new function in the C++ scanner that is
215     more efficient than the old way of doing things because it avoids levels of
216     recursion in the regex matching; (c) add a paragraph to the documentation
217     for the FullMatch() function.
218    
219     6. The escape sequence \n was being treated as whatever was defined as
220     "newline". Not only was this contrary to the documentation, which states
221     that \n is character 10 (hex 0A), but it also went horribly wrong when
222     "newline" was defined as CRLF. This has been fixed.
223    
224     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
225     was being set to -1 for the "end of line" case (supposedly a value that no
226     character can have). Though this value is never used (the check for end of
227     line is "zero bytes in current character"), it caused compiler complaints.
228     I've changed it to 0xffffffff.
229    
230     8. In pcre_version.c, the version string was being built by a sequence of
231     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
232     string (as it is for production releases) called a macro with an empty
233     argument. The C standard says the result of this is undefined. The gcc
234     compiler treats it as an empty string (which was what was wanted) but it is
235     reported that Visual C gives an error. The source has been hacked around to
236     avoid this problem.
237    
238     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
239     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
240     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
241     of them did).
242    
243     10. Originally, pcretest opened its input and output without "b"; then I was
244     told that "b" was needed in some environments, so it was added for release
245     5.0 to both the input and output. (It makes no difference on Unix-like
246     systems.) Later I was told that it is wrong for the input on Windows. I've
247     now abstracted the modes into two macros, to make it easier to fiddle with
248     them, and removed "b" from the input mode under Windows.
249    
250     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
251    
252     12. Added -help and --help to pcretest as an official way of being reminded
253     of the options.
254    
255     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
256     and pcrecpp.cc because they annoy compilers at high warning levels.
257    
258     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
259    
260     15. Fixed an occurrence of == in configure.ac that should have been = (shell
261     scripts are not C programs :-) and which was not noticed because it works
262     on Linux.
263    
264     16. pcretest is supposed to handle any length of pattern and data line (as one
265     line or as a continued sequence of lines) by extending its input buffer if
266     necessary. This feature was broken for very long pattern lines, leading to
267     a string of junk being passed to pcre_compile() if the pattern was longer
268     than about 50K.
269    
270     17. I have done a major re-factoring of the way pcre_compile() computes the
271     amount of memory needed for a compiled pattern. Previously, there was code
272     that made a preliminary scan of the pattern in order to do this. That was
273     OK when PCRE was new, but as the facilities have expanded, it has become
274     harder and harder to keep it in step with the real compile phase, and there
275     have been a number of bugs (see for example, 4 above). I have now found a
276     cunning way of running the real compile function in a "fake" mode that
277     enables it to compute how much memory it would need, while actually only
278     ever using a few hundred bytes of working memory and without too many
279     tests of the mode. This should make future maintenance and development
280     easier. A side effect of this work is that the limit of 200 on the nesting
281     depth of parentheses has been removed (though this was never a serious
282     limitation, I suspect). However, there is a downside: pcre_compile() now
283     runs more slowly than before (30% or more, depending on the pattern). I
284     hope this isn't a big issue. There is no effect on runtime performance.
285    
286     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
287     newline (only possible for the last line of a file) and it was a
288     pattern that set a locale (followed by /Lsomething), pcretest crashed.
289    
290     19. Added additional timing features to pcretest. (1) The -tm option now times
291     matching only, not compiling. (2) Both -t and -tm can be followed, as a
292     separate command line item, by a number that specifies the number of
293     repeats to use when timing. The default is 50000; this gives better
294     precision, but takes uncomfortably long for very large patterns.
295    
296     20. Extended pcre_study() to be more clever in cases where a branch of a
297     subpattern has no definite first character. For example, (a*|b*)[cd] would
298     previously give no result from pcre_study(). Now it recognizes that the
299     first character must be a, b, c, or d.
300    
301     21. There was an incorrect error "recursive call could loop indefinitely" if
302     a subpattern (or the entire pattern) that was being tested for matching an
303     empty string contained only one non-empty item after a nested subpattern.
304     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
305     incorrectly, because the \d was being skipped in the check.
306    
307     22. The pcretest program now has a new pattern option /B and a command line
308     option -b, which is equivalent to adding /B to every pattern. This causes
309     it to show the compiled bytecode, without the additional information that
310     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
311     is the same as /B/I).
312    
313     23. A new optimization is now able automatically to treat some sequences such
314     as a*b as a*+b. More specifically, if something simple (such as a character
315     or a simple class like \d) has an unlimited quantifier, and is followed by
316     something that cannot possibly match the quantified thing, the quantifier
317     is automatically "possessified".
318    
319     24. A recursive reference to a subpattern whose number was greater than 39
320     went wrong under certain circumstances in UTF-8 mode. This bug could also
321     have affected the operation of pcre_study().
322    
323     25. Realized that a little bit of performance could be had by replacing
324     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
325    
326     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
327    
328     27. Possessive quantifiers such as a++ were previously implemented by turning
329     them into atomic groups such as ($>a+). Now they have their own opcodes,
330     which improves performance. This includes the automatically created ones
331     from 23 above.
332    
333     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
334     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
335     the first matched character to be a colon. This applied both to named and
336     numbered groups.
337    
338     29. The ucpinternal.h header file was missing its idempotency #ifdef.
339    
340     30. I was sent a "project" file called libpcre.a.dev which I understand makes
341     building PCRE on Windows easier, so I have included it in the distribution.
342    
343     31. There is now a check in pcretest against a ridiculously large number being
344     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
345     loop, the loop is abandoned.
346    
347     32. Forward references to subpatterns in conditions such as (?(2)...) where
348     subpattern 2 is defined later cause pcre_compile() to search forwards in
349     the pattern for the relevant set of parentheses. This search went wrong
350     when there were unescaped parentheses in a character class, parentheses
351     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
352    
353     33. "Subroutine" calls and backreferences were previously restricted to
354     referencing subpatterns earlier in the regex. This restriction has now
355     been removed.
356    
357     34. Added a number of extra features that are going to be in Perl 5.10. On the
358     whole, these are just syntactic alternatives for features that PCRE had
359     previously implemented using the Python syntax or my own invention. The
360     other formats are all retained for compatibility.
361    
362     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
363     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
364     also .NET compatible.
365    
366     (b) A recursion or subroutine call to a named group can now be defined as
367     (?&name) as well as (?P>name).
368    
369     (c) A backreference to a named group can now be defined as \k<name> or
370     \k'name' as well as (?P=name). The new forms, as well as being in Perl
371     5.10, are also .NET compatible.
372    
373     (d) A conditional reference to a named group can now use the syntax
374     (?(<name>) or (?('name') as well as (?(name).
375    
376     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
377     groups (named and numbered) that are never evaluated inline, but can be
378     called as "subroutines" from elsewhere. In effect, the DEFINE condition
379     is always false. There may be only one alternative in such a group.
380    
381     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
382     as the simple (?(R). The condition is true only if the most recent
383     recursion is that of the given number or name. It does not search out
384     through the entire recursion stack.
385    
386     (g) The escape \gN or \g{N} has been added, where N is a positive or
387     negative number, specifying an absolute or relative reference.
388    
389     35. Tidied to get rid of some further signed/unsigned compiler warnings and
390     some "unreachable code" warnings.
391    
392     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
393     things, this adds five new scripts.
394    
395     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
396     There were also incompatibilities regarding the handling of \Q..\E inside
397     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
398     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
399    
400     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
401     matches an empty string, and forcibly breaks the loop. There were bugs in
402     this code in non-simple cases. For a pattern such as ^(a()*)* matched
403     against aaaa the result was just "a" rather than "aaaa", for example. Two
404     separate and independent bugs (that affected different cases) have been
405     fixed.
406    
407     39. Refactored the code to abolish the use of different opcodes for small
408     capturing bracket numbers. This is a tidy that I avoided doing when I
409     removed the limit on the number of capturing brackets for 3.5 back in 2001.
410     The new approach is not only tidier, it makes it possible to reduce the
411     memory needed to fix the previous bug (38).
412    
413     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
414     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
415     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
416     mode.
417    
418     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
419     report.
420    
421     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
422     copy construction and assignment in the C++ wrapper.
423    
424     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
425     couple of bugs that could have given wrong results in the "--newline=crlf"
426     case.
427    
428     44. Added a number of casts and did some reorganization of signed/unsigned int
429     variables following suggestions from Dair Grant. Also renamed the variable
430     "this" as "item" because it is a C++ keyword.
431    
432     45. Arranged for dftables to add
433    
434     #include "pcre_internal.h"
435    
436     to pcre_chartables.c because without it, gcc 4.x may remove the array
437     definition from the final binary if PCRE is built into a static library and
438     dead code stripping is activated.
439    
440     46. For an unanchored pattern, if a match attempt fails at the start of a
441     newline sequence, and the newline setting is CRLF or ANY, and the next two
442     characters are CRLF, advance by two characters instead of one.
443    
444    
445 nigel 91 Version 6.7 04-Jul-06
446     ---------------------
447    
448     1. In order to handle tests when input lines are enormously long, pcretest has
449     been re-factored so that it automatically extends its buffers when
450     necessary. The code is crude, but this _is_ just a test program. The
451     default size has been increased from 32K to 50K.
452    
453     2. The code in pcre_study() was using the value of the re argument before
454     testing it for NULL. (Of course, in any sensible call of the function, it
455     won't be NULL.)
456    
457     3. The memmove() emulation function in pcre_internal.h, which is used on
458     systems that lack both memmove() and bcopy() - that is, hardly ever -
459     was missing a "static" storage class specifier.
460    
461     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
462     containing an extended class (one that cannot be represented by a bitmap
463     because it contains high-valued characters or Unicode property items, e.g.
464     [\pZ]). Almost always one would set UTF-8 mode when processing such a
465     pattern, but PCRE should not loop if you do not (it no longer does).
466     [Detail: two cases were found: (a) a repeated subpattern containing an
467     extended class; (b) a recursive reference to a subpattern that followed a
468     previous extended class. It wasn't skipping over the extended class
469     correctly when UTF-8 mode was not set.]
470    
471     5. A negated single-character class was not being recognized as fixed-length
472     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
473     compile error "lookbehind assertion is not fixed length".
474    
475     6. The RunPerlTest auxiliary script was showing an unexpected difference
476     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
477     write a Perl script that can interpret lines of an input file either as
478     byte characters or as UTF-8, which is what "perltest" was being required to
479     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
480     can't do is switch easily at run time between having the "use utf8;" pragma
481     or not. In the end, I fudged it by using the RunPerlTest script to insert
482     "use utf8;" explicitly for the UTF-8 tests.
483    
484     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
485     the end of the subject string, contrary to the documentation and to what
486     Perl does. This was true of both matching functions. Now it matches only at
487     the start of the subject and immediately after *internal* newlines.
488    
489     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
490     a pointer to an int instead of a pointer to an unsigned long int. This
491     caused problems on 64-bit systems.
492    
493     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
494     instance of the 'standard' template library not being so standard".
495    
496     10. There was no check on the number of named subpatterns nor the maximum
497     length of a subpattern name. The product of these values is used to compute
498     the size of the memory block for a compiled pattern. By supplying a very
499     long subpattern name and a large number of named subpatterns, the size
500     computation could be caused to overflow. This is now prevented by limiting
501     the length of names to 32 characters, and the number of named subpatterns
502     to 10,000.
503    
504     11. Subpatterns that are repeated with specific counts have to be replicated in
505     the compiled pattern. The size of memory for this was computed from the
506     length of the subpattern and the repeat count. The latter is limited to
507     65535, but there was no limit on the former, meaning that integer overflow
508     could in principle occur. The compiled length of a repeated subpattern is
509     now limited to 30,000 bytes in order to prevent this.
510    
511     12. Added the optional facility to have named substrings with the same name.
512    
513     13. Added the ability to use a named substring as a condition, using the
514     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
515     are numbers (not recommended). Forward references are permitted.
516    
517     14. Added forward references in named backreferences (if you see what I mean).
518    
519     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
520     pattern could run off the end of the subject. For example, the pattern
521     "(?s)(.{1,5})"8 did this with the subject "ab".
522    
523     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
524     PCRE_CASELESS was set when matching characters that were quantified with ?
525     or *.
526    
527     17. A character class other than a single negated character that had a minimum
528     but no maximum quantifier - for example [ab]{6,} - was not handled
529     correctly by pce_dfa_exec(). It would match only one character.
530    
531     18. A valid (though odd) pattern that looked like a POSIX character
532     class but used an invalid character after [ (for example [[,abc,]]) caused
533     pcre_compile() to give the error "Failed: internal error: code overflow" or
534     in some cases to crash with a glibc free() error. This could even happen if
535     the pattern terminated after [[ but there just happened to be a sequence of
536     letters, a binary zero, and a closing ] in the memory that followed.
537    
538     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
539     over the years. Originally (before any Unicode support), just the bottom 8
540     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
541     output from "man perlunicode" includes this:
542    
543     The regular expression compiler produces polymorphic opcodes. That
544     is, the pattern adapts to the data and automatically switches to
545     the Unicode character scheme when presented with Unicode data--or
546     instead uses a traditional byte scheme when presented with byte
547     data.
548    
549     Sadly, a wide octal escape does not cause a switch, and in a string with
550     no other multibyte characters, these octal escapes are treated as before.
551     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
552     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
553     Unicode string.
554    
555     I have not perpetrated such confusion in PCRE. Up till now, it took just
556     the bottom 8 bits, as in old Perl. I have now made octal escapes with
557     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
558     translate to the appropriate multibyte character.
559    
560     29. Applied some refactoring to reduce the number of warnings from Microsoft
561     and Borland compilers. This has included removing the fudge introduced
562     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
563     a warning about an unused variable.
564    
565     21. PCRE has not included VT (character 0x0b) in the set of whitespace
566     characters since release 4.0, because Perl (from release 5.004) does not.
567     [Or at least, is documented not to: some releases seem to be in conflict
568     with the documentation.] However, when a pattern was studied with
569     pcre_study() and all its branches started with \s, PCRE still included VT
570     as a possible starting character. Of course, this did no harm; it just
571     caused an unnecessary match attempt.
572    
573     22. Removed a now-redundant internal flag bit that recorded the fact that case
574     dependency changed within the pattern. This was once needed for "required
575     byte" processing, but is no longer used. This recovers a now-scarce options
576     bit. Also moved the least significant internal flag bit to the most-
577     significant bit of the word, which was not previously used (hangover from
578     the days when it was an int rather than a uint) to free up another bit for
579     the future.
580    
581     23. Added support for CRLF line endings as well as CR and LF. As well as the
582     default being selectable at build time, it can now be changed at runtime
583     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
584     specify that it is scanning data with non-default line endings.
585    
586     24. Changed the definition of CXXLINK to make it agree with the definition of
587     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
588    
589     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
590     recursions. This makes a big different to stack usage for some patterns.
591    
592     26. If a subpattern containing a named recursion or subroutine reference such
593     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
594     the space required for the compiled pattern went wrong and gave too small a
595     value. Depending on the environment, this could lead to "Failed: internal
596     error: code overflow at offset 49" or "glibc detected double free or
597     corruption" errors.
598    
599     27. Applied patches from Google (a) to support the new newline modes and (b) to
600     advance over multibyte UTF-8 characters in GlobalReplace.
601    
602     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
603     difference for some implementation of PCRE in some Windows version.
604    
605     29. Added some extra testing facilities to pcretest:
606    
607     \q<number> in a data line sets the "match limit" value
608     \Q<number> in a data line sets the "match recursion limt" value
609     -S <number> sets the stack size, where <number> is in megabytes
610    
611     The -S option isn't available for Windows.
612    
613    
614 nigel 89 Version 6.6 06-Feb-06
615     ---------------------
616    
617     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
618     in pcreposix.h. I have copied the definition from pcre.h.
619    
620     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
621     because pcre.h is no longer a built file.
622    
623     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
624     not normally included in the compiled code.
625    
626    
627 nigel 87 Version 6.5 01-Feb-06
628     ---------------------
629    
630     1. When using the partial match feature with pcre_dfa_exec(), it was not
631     anchoring the second and subsequent partial matches at the new starting
632     point. This could lead to incorrect results. For example, with the pattern
633     /1234/, partially matching against "123" and then "a4" gave a match.
634    
635     2. Changes to pcregrep:
636    
637     (a) All non-match returns from pcre_exec() were being treated as failures
638     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
639     error message is output. Some extra information is given for the
640     PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
641     probably the only errors that are likely to be caused by users (by
642     specifying a regex that has nested indefinite repeats, for instance).
643     If there are more than 20 of these errors, pcregrep is abandoned.
644    
645     (b) A binary zero was treated as data while matching, but terminated the
646     output line if it was written out. This has been fixed: binary zeroes
647     are now no different to any other data bytes.
648    
649     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
650     used to set a locale for matching. The --locale=xxxx long option has
651     been added (no short equivalent) to specify a locale explicitly on the
652     pcregrep command, overriding the environment variables.
653    
654     (d) When -B was used with -n, some line numbers in the output were one less
655     than they should have been.
656    
657     (e) Added the -o (--only-matching) option.
658    
659     (f) If -A or -C was used with -c (count only), some lines of context were
660     accidentally printed for the final match.
661    
662     (g) Added the -H (--with-filename) option.
663    
664     (h) The combination of options -rh failed to suppress file names for files
665     that were found from directory arguments.
666    
667     (i) Added the -D (--devices) and -d (--directories) options.
668    
669     (j) Added the -F (--fixed-strings) option.
670    
671     (k) Allow "-" to be used as a file name for -f as well as for a data file.
672    
673     (l) Added the --colo(u)r option.
674    
675     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
676     is not present by default.
677    
678     3. A nasty bug was discovered in the handling of recursive patterns, that is,
679     items such as (?R) or (?1), when the recursion could match a number of
680     alternatives. If it matched one of the alternatives, but subsequently,
681     outside the recursion, there was a failure, the code tried to back up into
682     the recursion. However, because of the way PCRE is implemented, this is not
683     possible, and the result was an incorrect result from the match.
684    
685     In order to prevent this happening, the specification of recursion has
686     been changed so that all such subpatterns are automatically treated as
687     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
688    
689     4. I had overlooked the fact that, in some locales, there are characters for
690     which isalpha() is true but neither isupper() nor islower() are true. In
691     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
692     and ordfeminine) are like this. This affected the treatment of \w and \W
693     when they appeared in character classes, but not when they appeared outside
694     a character class. The bit map for "word" characters is now created
695     separately from the results of isalnum() instead of just taking it from the
696     upper, lower, and digit maps. (Plus the underscore character, of course.)
697    
698     5. The above bug also affected the handling of POSIX character classes such as
699     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
700     permanent tables. Instead, the bit maps for such a class were previously
701     created as the appropriate unions of the upper, lower, and digit bitmaps.
702     Now they are created by subtraction from the [[:word:]] class, which has
703     its own bitmap.
704    
705     6. The [[:blank:]] character class matches horizontal, but not vertical space.
706     It is created by subtracting the vertical space characters (\x09, \x0a,
707     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
708     subtraction was done in the overall bitmap for a character class, meaning
709     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
710     be recognized. This bug has been fixed.
711    
712     7. Patches from the folks at Google:
713    
714     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
715     real life, but is still worth protecting against".
716    
717     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
718     regular expressions".
719    
720     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
721     have it.
722    
723     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
724     "configure" and the latter not, in order to fix a problem somebody had
725     with compiling the Arg class on HP-UX.
726    
727     (e) Improve the error-handling of the C++ wrapper a little bit.
728    
729     (f) New tests for checking recursion limiting.
730    
731     8. The pcre_memmove() function, which is used only if the environment does not
732     have a standard memmove() function (and is therefore rarely compiled),
733     contained two bugs: (a) use of int instead of size_t, and (b) it was not
734     returning a result (though PCRE never actually uses the result).
735    
736     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
737     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
738     returned instead of calling malloc() with an overflowing number that would
739     most likely cause subsequent chaos.
740    
741     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
742    
743     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
744     with this option is matched, the nmatch and pmatch options of regexec() are
745     ignored.
746    
747     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
748     provided in case anyone wants to the the POSIX interface with UTF-8
749     strings.
750    
751     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
752     C++ linking (needed for some HP-UX environments).
753    
754     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
755     (unused parameter) and in the pcre_printint() function (omitted "default"
756     switch label when the default is to do nothing).
757    
758     15. Added some code to make it possible, when PCRE is compiled as a C++
759     library, to replace subject pointers for pcre_exec() with a smart pointer
760     class, thus making it possible to process discontinuous strings.
761    
762     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
763     much the same function. They were added by different people who were trying
764     to make PCRE easy to compile on non-Unix systems. It has been suggested
765     that PCRE_EXPORT be abolished now that there is more automatic apparatus
766     for compiling on Windows systems. I have therefore replaced it with
767     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
768     defaults to "extern" for C or "extern C" for C++, which works fine on
769     Unix-like systems. It is now possible to override the value of PCRE_DATA_
770     SCOPE with something explicit in config.h. In addition:
771    
772     (a) pcreposix.h still had just "extern" instead of either of these macros;
773     I have replaced it with PCRE_DATA_SCOPE.
774    
775     (b) Functions such as _pcre_xclass(), which are internal to the library,
776     but external in the C sense, all had PCRE_EXPORT in their definitions.
777     This is apparently wrong for the Windows case, so I have removed it.
778     (It makes no difference on Unix-like systems.)
779    
780     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
781     of recursive calls to match(). This is different to MATCH_LIMIT because
782     that limits the total number of calls to match(), not all of which increase
783     the depth of recursion. Limiting the recursion depth limits the amount of
784     stack (or heap if NO_RECURSE is set) that is used. The default can be set
785     when PCRE is compiled, and changed at run time. A patch from Google adds
786     this functionality to the C++ interface.
787    
788     18. Changes to the handling of Unicode character properties:
789    
790     (a) Updated the table to Unicode 4.1.0.
791    
792     (b) Recognize characters that are not in the table as "Cn" (undefined).
793    
794     (c) I revised the way the table is implemented to a much improved format
795     which includes recognition of ranges. It now supports the ranges that
796     are defined in UnicodeData.txt, and it also amalgamates other
797     characters into ranges. This has reduced the number of entries in the
798     table from around 16,000 to around 3,000, thus reducing its size
799     considerably. I realized I did not need to use a tree structure after
800     all - a binary chop search is just as efficient. Having reduced the
801     number of entries, I extended their size from 6 bytes to 8 bytes to
802     allow for more data.
803    
804     (d) Added support for Unicode script names via properties such as \p{Han}.
805    
806     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
807     matching that character.
808    
809     20. When matching a repeated Unicode property with a minimum greater than zero,
810     (for example \pL{2,}), PCRE could look past the end of the subject if it
811     reached it while seeking the minimum number of characters. This could
812     happen only if some of the characters were more than one byte long, because
813     there is a check for at least the minimum number of bytes.
814    
815     21. Refactored the implementation of \p and \P so as to be more general, to
816     allow for more different types of property in future. This has changed the
817     compiled form incompatibly. Anybody with saved compiled patterns that use
818     \p or \P will have to recompile them.
819    
820     22. Added "Any" and "L&" to the supported property types.
821    
822     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
823     but give a compile time error if the value is greater than 0xff.
824    
825     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
826     accidentally not being installed or uninstalled.
827    
828     25. The pcre.h file was built from pcre.h.in, but the only changes that were
829     made were to insert the current release number. This seemed silly, because
830     it made things harder for people building PCRE on systems that don't run
831     "configure". I have turned pcre.h into a distributed file, no longer built
832     by "configure", with the version identification directly included. There is
833     no longer a pcre.h.in file.
834    
835     However, this change necessitated a change to the pcre-config script as
836     well. It is built from pcre-config.in, and one of the substitutions was the
837     release number. I have updated configure.ac so that ./configure now finds
838     the release number by grepping pcre.h.
839    
840     26. Added the ability to run the tests under valgrind.
841    
842    
843 nigel 85 Version 6.4 05-Sep-05
844     ---------------------
845    
846     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
847     "--" to be printed when multiple files were scanned, even when none of the
848     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
849     consider it to be a bug, and have restored the previous behaviour.
850    
851     2. A couple of code tidies to get rid of compiler warnings.
852    
853     3. The pcretest program used to cheat by referring to symbols in the library
854     whose names begin with _pcre_. These are internal symbols that are not
855     really supposed to be visible externally, and in some environments it is
856     possible to suppress them. The cheating is now confined to including
857     certain files from the library's source, which is a bit cleaner.
858    
859     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
860     file's purpose clearer.
861    
862     5. Reorganized pcre_ucp_findchar().
863    
864    
865 nigel 83 Version 6.3 15-Aug-05
866     ---------------------
867    
868     1. The file libpcre.pc.in did not have general read permission in the tarball.
869    
870     2. There were some problems when building without C++ support:
871    
872     (a) If C++ support was not built, "make install" and "make test" still
873     tried to test it.
874    
875     (b) There were problems when the value of CXX was explicitly set. Some
876     changes have been made to try to fix these, and ...
877    
878     (c) --disable-cpp can now be used to explicitly disable C++ support.
879    
880     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
881     backslash in a target when C++ was disabled. This confuses some
882     versions of "make", apparently. Using an intermediate variable solves
883     this. (Same for CPP_LOBJ.)
884    
885     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
886     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
887     necessary on certain architectures.
888    
889     4. Added a setting of -export-symbols-regex to the link command to remove
890     those symbols that are exported in the C sense, but actually are local
891     within the library, and not documented. Their names all begin with
892     "_pcre_". This is not a perfect job, because (a) we have to except some
893     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
894     available (and never for static libraries). I have made a note to try to
895     find a way round (a) in the future.
896    
897    
898 nigel 81 Version 6.2 01-Aug-05
899     ---------------------
900    
901     1. There was no test for integer overflow of quantifier values. A construction
902     such as {1111111111111111} would give undefined results. What is worse, if
903     a minimum quantifier for a parenthesized subpattern overflowed and became
904     negative, the calculation of the memory size went wrong. This could have
905     led to memory overwriting.
906    
907     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
908    
909     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
910     operating environments where this matters.
911    
912     4. Applied Giuseppe Maxia's patch to add additional features for controlling
913     PCRE options from within the C++ wrapper.
914    
915     5. Named capturing subpatterns were not being correctly counted when a pattern
916     was compiled. This caused two problems: (a) If there were more than 100
917     such subpatterns, the calculation of the memory needed for the whole
918     compiled pattern went wrong, leading to an overflow error. (b) Numerical
919     back references of the form \12, where the number was greater than 9, were
920     not recognized as back references, even though there were sufficient
921     previous subpatterns.
922    
923     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
924     versions of gcc, e.g. 2.95.4.
925    
926    
927 nigel 79 Version 6.1 21-Jun-05
928     ---------------------
929    
930     1. There was one reference to the variable "posix" in pcretest.c that was not
931     surrounded by "#if !defined NOPOSIX".
932    
933     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
934     the cross-check on the old pcre_info() function, for the benefit of the
935     cut-down version of PCRE that is currently imported into Exim.
936    
937     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
938     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
939     patterns that start (?i) but I don't think that matters. The use of (?i) is
940     just an example; this all applies to the other options as well.
941    
942     4. Since libtool seems to echo the compile commands it is issuing, the output
943     from "make" can be reduced a bit by putting "@" in front of each libtool
944     compile command.
945    
946     5. Patch from the folks at Google for configure.in to be a bit more thorough
947     in checking for a suitable C++ installation before trying to compile the
948     C++ stuff. This should fix a reported problem when a compiler was present,
949     but no suitable headers.
950    
951     6. The man pages all had just "PCRE" as their title. I have changed them to
952     be the relevant file name. I have also arranged that these names are
953     retained in the file doc/pcre.txt, which is a concatenation in text format
954     of all the man pages except the little individual ones for each function.
955    
956     7. The NON-UNIX-USE file had not been updated for the different set of source
957     files that come with release 6. I also added a few comments about the C++
958     wrapper.
959    
960    
961 nigel 77 Version 6.0 07-Jun-05
962     ---------------------
963    
964     1. Some minor internal re-organization to help with my DFA experiments.
965    
966     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
967     didn't matter for the library itself when fully configured, but did matter
968     when compiling without UCP support, or within Exim, where the ucp files are
969     not imported.
970    
971     3. Refactoring of the library code to split up the various functions into
972     different source modules. The addition of the new DFA matching code (see
973     below) to a single monolithic source would have made it really too
974     unwieldy, quite apart from causing all the code to be include in a
975     statically linked application, when only some functions are used. This is
976     relevant even without the DFA addition now that patterns can be compiled in
977     one application and matched in another.
978    
979     The downside of splitting up is that there have to be some external
980     functions and data tables that are used internally in different modules of
981     the library but which are not part of the API. These have all had their
982     names changed to start with "_pcre_" so that they are unlikely to clash
983     with other external names.
984    
985     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
986     a different (DFA) algorithm. Although it is slower than the original
987     function, it does have some advantages for certain types of matching
988     problem.
989    
990     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
991     including restarting after a partial match.
992    
993     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
994     defined when compiling for Windows was sent to me. I have put it into the
995     code, though I have no means of testing or verifying it.
996    
997     7. Added the pcre_refcount() auxiliary function.
998    
999     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1000     match before or at the first newline in the subject string. In pcretest,
1001     the /f option on a pattern can be used to set this.
1002    
1003     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1004     would behave wrongly. This has been present in PCRE since release 4.0.
1005    
1006     10. A number of changes to the pcregrep command:
1007    
1008     (a) Refactored how -x works; insert ^(...)$ instead of setting
1009     PCRE_ANCHORED and checking the length, in preparation for adding
1010     something similar for -w.
1011    
1012     (b) Added the -w (match as a word) option.
1013    
1014     (c) Refactored the way lines are read and buffered so as to have more
1015     than one at a time available.
1016    
1017     (d) Implemented a pcregrep test script.
1018    
1019     (e) Added the -M (multiline match) option. This allows patterns to match
1020     over several lines of the subject. The buffering ensures that at least
1021     8K, or the rest of the document (whichever is the shorter) is available
1022     for matching (and similarly the previous 8K for lookbehind assertions).
1023    
1024     (f) Changed the --help output so that it now says
1025    
1026     -w, --word-regex(p)
1027    
1028     instead of two lines, one with "regex" and the other with "regexp"
1029     because that confused at least one person since the short forms are the
1030     same. (This required a bit of code, as the output is generated
1031     automatically from a table. It wasn't just a text change.)
1032    
1033     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1034     option but starts with a hyphen. Could be a pattern or a path name
1035     starting with a hyphen, for instance.
1036    
1037     (h) "-" can be given as a file name to represent stdin.
1038    
1039     (i) When file names are being printed, "(standard input)" is used for
1040     the standard input, for compatibility with GNU grep. Previously
1041     "<stdin>" was used.
1042    
1043     (j) The option --label=xxx can be used to supply a name to be used for
1044     stdin when file names are being printed. There is no short form.
1045    
1046     (k) Re-factored the options decoding logic because we are going to add
1047     two more options that take data. Such options can now be given in four
1048     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1049    
1050     (l) Added the -A, -B, and -C options for requesting that lines of context
1051     around matches be printed.
1052    
1053     (m) Added the -L option to print the names of files that do not contain
1054     any matching lines, that is, the complement of -l.
1055    
1056     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1057     continue to scan other files.
1058    
1059     (o) The -s option was incorrectly implemented. For compatibility with other
1060     greps, it now suppresses the error message for a non-existent or non-
1061     accessible file (but not the return code). There is a new option called
1062     -q that suppresses the output of matching lines, which was what -s was
1063     previously doing.
1064    
1065     (p) Added --include and --exclude options to specify files for inclusion
1066     and exclusion when recursing.
1067    
1068     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1069     Hopefully, it now does.
1070    
1071     12. Missing cast in pcre_study().
1072    
1073     13. Added an "uninstall" target to the makefile.
1074    
1075     14. Replaced "extern" in the function prototypes in Makefile.in with
1076     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1077     world, but is set differently for Windows.
1078    
1079     15. Added a second compiling function called pcre_compile2(). The only
1080     difference is that it has an extra argument, which is a pointer to an
1081     integer error code. When there is a compile-time failure, this is set
1082     non-zero, in addition to the error test pointer being set to point to an
1083     error message. The new argument may be NULL if no error number is required
1084     (but then you may as well call pcre_compile(), which is now just a
1085     wrapper). This facility is provided because some applications need a
1086     numeric error indication, but it has also enabled me to tidy up the way
1087     compile-time errors are handled in the POSIX wrapper.
1088    
1089     16. Added VPATH=.libs to the makefile; this should help when building with one
1090     prefix path and installing with another. (Or so I'm told by someone who
1091     knows more about this stuff than I do.)
1092    
1093     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1094     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1095     match everything, including newlines. This is not POSIX-compatible, but
1096     somebody wanted the feature. From pcretest it can be activated by using
1097     both the P and the s flags.
1098    
1099     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1100    
1101     19. libpcre.pc was being incorrectly installed as executable.
1102    
1103     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1104     it now also looks for '\r' so that it will work unmodified on Windows.
1105    
1106     21. Added Google's contributed C++ wrapper to the distribution.
1107    
1108     22. Added some untidy missing memory free() calls in pcretest, to keep
1109     Electric Fence happy when testing.
1110    
1111    
1112    
1113 nigel 75 Version 5.0 13-Sep-04
1114     ---------------------
1115    
1116     1. Internal change: literal characters are no longer packed up into items
1117     containing multiple characters in a single byte-string. Each character
1118     is now matched using a separate opcode. However, there may be more than one
1119     byte in the character in UTF-8 mode.
1120    
1121     2. The pcre_callout_block structure has two new fields: pattern_position and
1122     next_item_length. These contain the offset in the pattern to the next match
1123     item, and its length, respectively.
1124    
1125     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1126     insertion of callouts before each pattern item. Added the /C option to
1127     pcretest to make use of this.
1128    
1129     4. On the advice of a Windows user, the lines
1130    
1131     #if defined(_WIN32) || defined(WIN32)
1132     _setmode( _fileno( stdout ), 0x8000 );
1133     #endif /* defined(_WIN32) || defined(WIN32) */
1134    
1135     have been added to the source of pcretest. This apparently does useful
1136     magic in relation to line terminators.
1137    
1138     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1139     for the benefit of those environments where the "b" makes a difference.
1140    
1141     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1142     to know about it. I have put a hack into configure.in that adds in code
1143     to set GCC=yes if CC=icc. This seems to end up at a point in the
1144     generated configure script that is early enough to affect the setting of
1145     compiler options, which is what is needed, but I have no means of testing
1146     whether it really works. (The user who reported this had patched the
1147     generated configure script, which of course I cannot do.)
1148    
1149     LATER: After change 22 below (new libtool files), the configure script
1150     seems to know about icc (and also ecc). Therefore, I have commented out
1151     this hack in configure.in.
1152    
1153     7. Added support for pkg-config (2 patches were sent in).
1154    
1155     8. Negated POSIX character classes that used a combination of internal tables
1156     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1157     [[:^ascii]]. Typically, they would match almost any characters. The other
1158     POSIX classes were not broken in this way.
1159    
1160     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1161     to find the match, as PCRE was deluded into thinking that the match had to
1162     start at the start point or following a newline. The same bug applied to
1163     patterns with negative forward assertions or any backward assertions
1164     preceding ".*" at the start, unless the pattern required a fixed first
1165     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1166    
1167     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1168     starting at the last subject character, bytes beyond the end of the subject
1169     string were read.
1170    
1171     11. Renamed the variable "class" as "classbits" to make life easier for C++
1172     users. (Previously there was a macro definition, but it apparently wasn't
1173     enough.)
1174    
1175     12. Added the new field "tables" to the extra data so that tables can be passed
1176     in at exec time, or the internal tables can be re-selected. This allows
1177     a compiled regex to be saved and re-used at a later time by a different
1178     program that might have everything at different addresses.
1179    
1180     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1181     -R library as well as a -L library.
1182    
1183     14. The debugging options of pcretest (-d on the command line or D on a
1184     pattern) showed incorrect output for anything following an extended class
1185     that contained multibyte characters and which was followed by a quantifier.
1186    
1187     15. Added optional support for general category Unicode character properties
1188     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1189     support. It adds about 90K to the size of the library. The meanings of the
1190     inbuilt class escapes such as \d and \s have NOT been changed.
1191    
1192     16. Updated pcredemo.c to include calls to free() to release the memory for the
1193     compiled pattern.
1194    
1195     17. The generated file chartables.c was being created in the source directory
1196     instead of in the building directory. This caused the build to fail if the
1197     source directory was different from the building directory, and was
1198     read-only.
1199    
1200     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1201     file. No doubt somebody will tell me if they don't make sense... Also added
1202     Dan Mooney's comments about building on OpenVMS.
1203    
1204     19. Added support for partial matching via the PCRE_PARTIAL option for
1205     pcre_exec() and the \P data escape in pcretest.
1206    
1207     20. Extended pcretest with 3 new pattern features:
1208    
1209     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1210     write the compiled pattern to the file whose name is "rest-of-line".
1211     This is a straight binary dump of the data, with the saved pointer to
1212     the character tables forced to be NULL. The study data, if any, is
1213     written too. After writing, pcretest reads a new pattern.
1214    
1215     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1216     compiled pattern from the given file. There must not be any
1217     occurrences of "<" in the file name (pretty unlikely); if there are,
1218     pcretest will instead treat the initial "<" as a pattern delimiter.
1219     After reading in the pattern, pcretest goes on to read data lines as
1220     usual.
1221    
1222     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1223     and 16-bit fields in a compiled pattern, to simulate a pattern that
1224     was compiled on a host of opposite endianness.
1225    
1226     21. The pcre-exec() function can now cope with patterns that were compiled on
1227     hosts of opposite endianness, with this restriction:
1228    
1229     As for any compiled expression that is saved and used later, the tables
1230     pointer field cannot be preserved; the extra_data field in the arguments
1231     to pcre_exec() should be used to pass in a tables address if a value
1232     other than the default internal tables were used at compile time.
1233    
1234     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1235     now diagnosed as an error. Previously, most of the time, a negative number
1236     would have been treated as zero, but if in addition "ovector" was passed as
1237     NULL, a crash could occur.
1238    
1239     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1240     new versions from the libtool 1.5 distribution (the last one is a copy of
1241     a file called libtool.m4). This seems to have fixed the need to patch
1242     "configure" to support Darwin 1.3 (which I used to do). However, I still
1243     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1244     workstation).
1245    
1246     24. Changed the PCRE licence to be the more standard "BSD" licence.
1247    
1248    
1249 nigel 73 Version 4.5 01-Dec-03
1250     ---------------------
1251    
1252     1. There has been some re-arrangement of the code for the match() function so
1253     that it can be compiled in a version that does not call itself recursively.
1254     Instead, it keeps those local variables that need separate instances for
1255     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1256     needs to "recurse". Keeping track of where control must go is done by means
1257     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1258     hide most of the details from the main code, and operates only if
1259     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1260     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1261     operating.
1262    
1263     To make it easier for callers to provide specially tailored get/free
1264     functions for this usage, two new functions, pcre_stack_malloc, and
1265     pcre_stack_free, are used. They are always called in strict stacking order,
1266     and the size of block requested is always the same.
1267    
1268     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1269     PCRE has been compiled to use the stack or the heap for recursion. The
1270     -C option of pcretest uses this to show which version is compiled.
1271    
1272     A new data escape \S, is added to pcretest; it causes the amounts of store
1273     obtained and freed by both kinds of malloc/free at match time to be added
1274     to the output.
1275    
1276     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1277     what's available on my current Linux desktop machine.
1278    
1279     3. When matching a UTF-8 string, the test for a valid string at the start has
1280     been extended. If start_offset is not zero, PCRE now checks that it points
1281     to a byte that is the start of a UTF-8 character. If not, it returns
1282     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1283     this is necessary because there may be backward assertions in the pattern.
1284     When matching the same subject several times, it may save resources to use
1285     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1286    
1287     4. The code for checking the validity of UTF-8 strings has been tightened so
1288     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1289     containing "overlong sequences".
1290    
1291     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1292     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1293     should have been "&", but it just so happened that all the cases this let
1294     through by mistake were picked up later in the function.
1295    
1296     6. I had used a variable called "isblank" - this is a C99 function, causing
1297     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1298    
1299     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1300     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1301     so the version is shown; (c) stop "make test" echoing "./RunTest".
1302    
1303     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1304    
1305     9. The prototype for memmove() for systems that don't have it was using
1306     size_t, but the inclusion of the header that defines size_t was later. I've
1307     moved the #includes for the C headers earlier to avoid this.
1308    
1309     10. Added some adjustments to the code to make it easier to compiler on certain
1310     special systems:
1311    
1312     (a) Some "const" qualifiers were missing.
1313     (b) Added the macro EXPORT before all exported functions; by default this
1314     is defined to be empty.
1315     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1316     that it reads its output file name as an argument instead of writing
1317     to the standard output and assuming this can be redirected.
1318    
1319     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1320     class containing characters with values greater than 255, PCRE compilation
1321     went into a loop.
1322    
1323     12. A recursive reference to a subpattern that was within another subpattern
1324     that had a minimum quantifier of zero caused PCRE to crash. For example,
1325     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1326     recursion. If the recursively-called subpattern itself had a zero repeat,
1327     that was OK.
1328    
1329     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1330     buffer into which it was copied (for escape processing) was still set at
1331     1024, so long lines caused crashes.
1332    
1333     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1334     "internal error: code overflow...". This applied to any character class
1335     that was followed by a possessive quantifier.
1336    
1337     15. Modified the Makefile to add libpcre.la as a prerequisite for
1338     libpcreposix.la because I was told this is needed for a parallel build to
1339     work.
1340    
1341     16. If a pattern that contained .* following optional items at the start was
1342     studied, the wrong optimizing data was generated, leading to matching
1343     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1344     matching string must start with a or b or c. The correct conclusion for
1345     this pattern is that a match can start with any character.
1346    
1347    
1348 nigel 71 Version 4.4 13-Aug-03
1349     ---------------------
1350    
1351     1. In UTF-8 mode, a character class containing characters with values between
1352     127 and 255 was not handled correctly if the compiled pattern was studied.
1353     In fixing this, I have also improved the studying algorithm for such
1354     classes (slightly).
1355    
1356     2. Three internal functions had redundant arguments passed to them. Removal
1357     might give a very teeny performance improvement.
1358    
1359     3. Documentation bug: the value of the capture_top field in a callout is *one
1360     more than* the number of the hightest numbered captured substring.
1361    
1362     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1363     in incorrectly linking with a previously installed version. They now link
1364     explicitly with libpcre.la.
1365    
1366     5. configure.in no longer needs to recognize Cygwin specially.
1367    
1368     6. A problem in pcre.in for Windows platforms is fixed.
1369    
1370     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1371     pcretest, it used to include the size of the study block as part of its
1372     output. Unfortunately, the structure contains a field that has a different
1373     size on different hardware architectures. This meant that the tests that
1374     showed this size failed. As the block is currently always of a fixed size,
1375     this information isn't actually particularly useful in pcretest output, so
1376     I have just removed it.
1377    
1378     8. Three pre-processor statements accidentally did not start in column 1.
1379     Sadly, there are *still* compilers around that complain, even though
1380     standard C has not required this for well over a decade. Sigh.
1381    
1382     9. In pcretest, the code for checking callouts passed small integers in the
1383     callout_data field, which is a void * field. However, some picky compilers
1384     complained about the casts involved for this on 64-bit systems. Now
1385     pcretest passes the address of the small integer instead, which should get
1386     rid of the warnings.
1387    
1388     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1389     both compile and run time, and gives an error if an invalid UTF-8 sequence
1390     is found. There is a option for disabling this check in cases where the
1391     string is known to be correct and/or the maximum performance is wanted.
1392    
1393     11. In response to a bug report, I changed one line in Makefile.in from
1394    
1395     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1396     to
1397     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1398    
1399     to look similar to other lines, but I have no way of telling whether this
1400     is the right thing to do, as I do not use Windows. No doubt I'll get told
1401     if it's wrong...
1402    
1403    
1404 nigel 69 Version 4.3 21-May-03
1405     ---------------------
1406    
1407     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1408     Makefile.
1409    
1410     2. Some refactoring to improve the quality of the code:
1411    
1412     (i) The utf8_table... variables are now declared "const".
1413    
1414     (ii) The code for \cx, which used the "case flipping" table to upper case
1415     lower case letters, now just substracts 32. This is ASCII-specific,
1416     but the whole concept of \cx is ASCII-specific, so it seems
1417     reasonable.
1418    
1419     (iii) PCRE was using its character types table to recognize decimal and
1420     hexadecimal digits in the pattern. This is silly, because it handles
1421     only 0-9, a-f, and A-F, but the character types table is locale-
1422     specific, which means strange things might happen. A private
1423     table is now used for this - though it costs 256 bytes, a table is
1424     much faster than multiple explicit tests. Of course, the standard
1425     character types table is still used for matching digits in subject
1426     strings against \d.
1427    
1428     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1429     ending in _t are). So I've renamed it as ESC_tee.
1430    
1431     3. The first argument for regexec() in the POSIX wrapper should have been
1432     defined as "const".
1433    
1434     4. Changed pcretest to use malloc() for its buffers so that they can be
1435     Electric Fenced for debugging.
1436    
1437     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1438     to read one or more bytes before the start of the subject string. Often this
1439     had no effect on PCRE's behaviour, but in some circumstances it could
1440     provoke a segmentation fault.
1441    
1442     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1443     to try to read one or more bytes before the start of the subject string.
1444    
1445     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1446     UTF-8 support could misbehave in various ways if the subject string
1447     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1448     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1449     back over UTF-8 characters.)
1450    
1451    
1452 nigel 67 Version 4.2 14-Apr-03
1453     ---------------------
1454    
1455     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1456    
1457     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1458     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1459     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1460     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1461     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1462     and BUILD_EXEEXT
1463     Note: automatic setting of the BUILD variables is not yet working
1464     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1465     compile-time but not at link-time
1466     [LINK]: use for linking executables only
1467     make different versions for Windows and non-Windows
1468     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1469     libraries
1470     [LINK_FOR_BUILD]: new variable
1471     [OBJEXT]: use throughout
1472     [EXEEXT]: use throughout
1473     <winshared>: new target
1474     <wininstall>: new target
1475     <dftables.o>: use native compiler
1476     <dftables>: use native linker
1477     <install>: handle Windows platform correctly
1478     <clean>: ditto
1479     <check>: ditto
1480     copy DLL to top builddir before testing
1481    
1482     As part of these changes, -no-undefined was removed again. This was reported
1483     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1484     in any case.
1485    
1486     3. Some tidies to get rid of compiler warnings:
1487    
1488     . In the match_data structure, match_limit was an unsigned long int, whereas
1489     match_call_count was an int. I've made them both unsigned long ints.
1490    
1491     . In pcretest the fact that a const uschar * doesn't automatically cast to
1492     a void * provoked a warning.
1493    
1494     . Turning on some more compiler warnings threw up some "shadow" variables
1495     and a few more missing casts.
1496    
1497     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1498     option, a class that contained a single character with a value between 128
1499     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1500    
1501     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1502     option, a class that contained several characters, but with at least one
1503     whose value was between 128 and 255 caused PCRE to crash.
1504    
1505    
1506 nigel 65 Version 4.1 12-Mar-03
1507     ---------------------
1508 nigel 63
1509 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1510     needed, and a string in dftables.c that was longer than standard compilers are
1511     required to support.
1512    
1513     2. Compiling with Sun's compiler found a few more places where the code could
1514     be tidied up in order to avoid warnings.
1515    
1516     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1517     first of these names is deprecated in the latest Autoconf in favour of the name
1518     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1519     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1520     analogy I have changed it to CFLAGS_FOR_BUILD.
1521    
1522     4. Added -no-undefined to the linking command in the Makefile, because this is
1523     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1524     linking step for the pcreposix library.
1525    
1526     5. PCRE was failing to diagnose the case of two named groups with the same
1527     name.
1528    
1529     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1530     literal character that is needed in the subject for a match, and scans along to
1531     ensure that it is present before embarking on the full matching process. This
1532     saves time in cases of nested unlimited repeats that are never going to match.
1533     Problem: the scan can take a lot of time if the subject is very long (e.g.
1534     megabytes), thus penalizing straightforward matches. It is now done only if the
1535     amount of subject to be scanned is less than 1000 bytes.
1536    
1537     7. A lesser problem with the same optimization is that it was recording the
1538     first character of an anchored pattern as "needed", thus provoking a search
1539     right along the subject, even when the first match of the pattern was going to
1540     fail. The "needed" character is now not set for anchored patterns, unless it
1541     follows something in the pattern that is of non-fixed length. Thus, it still
1542     fulfils its original purpose of finding quick non-matches in cases of nested
1543     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1544    
1545    
1546     Version 4.0 17-Feb-03
1547     ---------------------
1548    
1549 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1550     extended to the end of string, PCRE compiled incorrect data. This could lead to
1551     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1552    
1553     2. Moved to autoconf 2.53 and libtool 1.4.2.
1554    
1555     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1556     the special perltest8 script is no longer needed - all the tests can be run
1557     from a single perltest script.
1558    
1559     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1560     by \s. It has now been removed in PCRE. This means it isn't recognized as
1561     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1562     class [:space:] *does* include VT, thereby creating a mess.
1563    
1564     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1565     space and tab.
1566    
1567     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1568     its new features into the main test script, reducing the number of scripts.
1569    
1570     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1571     were backward compatible, and made the (?i) apply to the whole pattern, as if
1572     /i were given. Now it behaves more logically, and applies the option setting
1573     only to what follows. PCRE has been changed to follow suit. However, if it
1574     finds options settings right at the start of the pattern, it extracts them into
1575     the global options, as before. Thus, they show up in the info data.
1576    
1577     8. Added support for the \Q...\E escape sequence. Characters in between are
1578     treated as literals. This is slightly different from Perl in that $ and @ are
1579     also handled as literals inside the quotes. In Perl, they will cause variable
1580     interpolation. Note the following examples:
1581    
1582     Pattern PCRE matches Perl matches
1583    
1584     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1585     \Qabc\$xyz\E abc\$xyz abc\$xyz
1586     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1587    
1588     For compatibility with Perl, \Q...\E sequences are recognized inside character
1589     classes as well as outside them.
1590    
1591     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1592     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1593     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1594     signed/unsigned warnings.
1595    
1596     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1597     option for pcretest, so I've replaced it by a simple function that does just
1598     that job.
1599    
1600     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1601     "pcregrep -".
1602    
1603     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1604     Java package. This provides some syntactic sugar for simple cases of what my
1605     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1606     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1607     item, you can use this simplified notation. Note that only makes sense with
1608     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1609     greediness, whatever the setting of the PCRE_UNGREEDY option.
1610    
1611     13. A change of greediness default within a pattern was not taking effect at
1612     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1613     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1614     was abstracted outside.
1615    
1616     14. PCRE now supports the \G assertion. It is true when the current matching
1617     position is at the start point of the match. This differs from \A when the
1618     starting offset is non-zero. Used with the /g option of pcretest (or similar
1619     code), it works in the same way as it does for Perl's /g option. If all
1620     alternatives of a regex begin with \G, the expression is anchored to the start
1621     match position, and the "anchored" flag is set in the compiled expression.
1622    
1623     15. Some bugs concerning the handling of certain option changes within patterns
1624     have been fixed. These applied to options other than (?ims). For example,
1625     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1626     been the other way round. Some of this was related to change 7 above.
1627    
1628     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1629     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1630     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1631     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1632    
1633     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1634     mode. Unlike ".", it always matches newline, whatever the setting of
1635     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1636     assertions. Perl allows it, but it doesn't (in general) work because it can't
1637     calculate the length of the lookbehind. At least, that's the case for Perl
1638     5.8.0 - I've been told they are going to document that it doesn't work in
1639     future.
1640    
1641     18. Added an error diagnosis for escapes that PCRE does not support: these are
1642     \L, \l, \N, \P, \p, \U, \u, and \X.
1643    
1644     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1645     reading past the end of the pattern in cases such as /[abcd/.
1646    
1647     20. PCRE was getting more memory than necessary for patterns with classes that
1648     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1649    
1650     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1651     compiling PCRE for use with Virtual Pascal.
1652    
1653     22. Small fix to the Makefile to make it work properly if the build is done
1654     outside the source tree.
1655    
1656     23. Added a new extension: a condition to go with recursion. If a conditional
1657     subpattern starts with (?(R) the "true" branch is used if recursion has
1658     happened, whereas the "false" branch is used only at the top level.
1659    
1660     24. When there was a very long string of literal characters (over 255 bytes
1661     without UTF support, over 250 bytes with UTF support), the computation of how
1662     much memory was required could be incorrect, leading to segfaults or other
1663     strange effects.
1664    
1665     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1666     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1667     there was a subsequent back reference to those brackets. This meant that, for
1668     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1669     possible to check for precisely this case. All we can do is abandon the
1670     optimization if .* occurs inside capturing brackets when there are any back
1671     references whatsoever. (See below for a better fix that came later.)
1672    
1673     26. The handling of the optimization for finding the first character of a
1674     non-anchored pattern, and for finding a character that is required later in the
1675     match were failing in some cases. This didn't break the matching; it just
1676     failed to optimize when it could. The way this is done has been re-implemented.
1677    
1678     27. Fixed typo in error message for invalid (?R item (it said "(?p").
1679    
1680     28. Added a new feature that provides some of the functionality that Perl
1681     provides with (?{...}). The facility is termed a "callout". The way it is done
1682     in PCRE is for the caller to provide an optional function, by setting
1683     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1684     global variable. By default it is unset, which disables all calling out. To get
1685     the function called, the regex must include (?C) at appropriate points. This
1686     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1687     This provides a means of identifying different callout points. When PCRE
1688     reaches such a point in the regex, if pcre_callout has been set, the external
1689     function is called. It is provided with data in a structure called
1690     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1691     matching continues; if it returns a non-zero value, the match at the current
1692     point fails. However, backtracking will occur if possible. [This was changed
1693     later and other features added - see item 49 below.]
1694    
1695     29. pcretest is upgraded to test the callout functionality. It provides a
1696     callout function that displays information. By default, it shows the start of
1697     the match and the current position in the text. There are some new data escapes
1698     to vary what happens:
1699    
1700     \C+ in addition, show current contents of captured substrings
1701     \C- do not supply a callout function
1702     \C!n return 1 when callout number n is reached
1703     \C!n!m return 1 when callout number n is reached for the mth time
1704    
1705     30. If pcregrep was called with the -l option and just a single file name, it
1706     output "<stdin>" if a match was found, instead of the file name.
1707    
1708     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1709     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1710     pcre_exec(). This saves a malloc/free per call. The default value of
1711     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1712     when configuring.
1713    
1714     32. The default maximum size of a compiled pattern is 64K. There have been a
1715     few cases of people hitting this limit. The code now uses macros to handle the
1716     storing of links as offsets within the compiled pattern. It defaults to 2-byte
1717     links, but this can be changed to 3 or 4 bytes by --with-link-size when
1718     configuring. Tests 2 and 5 work only with 2-byte links because they output
1719     debugging information about compiled patterns.
1720    
1721     33. Internal code re-arrangements:
1722    
1723     (a) Moved the debugging function for printing out a compiled regex into
1724     its own source file (printint.c) and used #include to pull it into
1725     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1726     separate copies.
1727    
1728     (b) Defined the list of op-code names for debugging as a macro in
1729     internal.h so that it is next to the definition of the opcodes.
1730    
1731     (c) Defined a table of op-code lengths for simpler skipping along compiled
1732     code. This is again a macro in internal.h so that it is next to the
1733     definition of the opcodes.
1734    
1735     34. Added support for recursive calls to individual subpatterns, along the
1736     lines of Robin Houston's patch (but implemented somewhat differently).
1737    
1738     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1739     allow it to read and process whole directories in Win32. This code was
1740     contributed by Lionel Fourquaux; it has not been tested by me.
1741    
1742     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1743     used to name a group. Names consist of alphanumerics and underscores, and must
1744     be unique. Back references use the syntax (?P=name) and recursive calls use
1745     (?P>name) which is a PCRE extension to the Python extension. Groups still have
1746     numbers. The function pcre_fullinfo() can be used after compilation to extract
1747     a name/number map. There are three relevant calls:
1748    
1749     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1750     PCRE_INFO_NAMECOUNT yields the number of entries
1751     PCRE_INFO_NAMETABLE yields a pointer to the map.
1752    
1753     The map is a vector of fixed-size entries. The size of each entry depends on
1754     the length of the longest name used. The first two bytes of each entry are the
1755     group number, most significant byte first. There follows the corresponding
1756     name, zero terminated. The names are in alphabetical order.
1757    
1758     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1759     case instead of 255. Making it the same both with and without UTF-8 support
1760     means that the same test output works with both.
1761    
1762     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1763     calling malloc() with a zero argument.
1764    
1765     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1766     optimization. I've improved things by keeping a bitmap of backreferences with
1767     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1768     fact referenced, the optimization can be applied. It is unlikely that a
1769     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1770     the match to follow \n) will appear inside brackets with a number greater than
1771     31, but if it does, any back reference > 31 suppresses the optimization.
1772    
1773     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1774     of disabling numbered capturing parentheses. Any opening parenthesis that is
1775     not followed by ? behaves as if it were followed by ?: but named parentheses
1776     can still be used for capturing (and they will acquire numbers in the usual
1777     way).
1778    
1779     41. Redesigned the return codes from the match() function into yes/no/error so
1780     that errors can be passed back from deep inside the nested calls. A malloc
1781     failure while inside a recursive subpattern call now causes the
1782     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1783    
1784     42. It is now possible to set a limit on the number of times the match()
1785     function is called in a call to pcre_exec(). This facility makes it possible to
1786     limit the amount of recursion and backtracking, though not in a directly
1787     obvious way, because the match() function is used in a number of different
1788     circumstances. The count starts from zero for each position in the subject
1789     string (for non-anchored patterns). The default limit is, for compatibility, a
1790     large number, namely 10 000 000. You can change this in two ways:
1791    
1792     (a) When configuring PCRE before making, you can use --with-match-limit=n
1793     to set a default value for the compiled library.
1794    
1795     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1796     a different value is set. See 45 below.
1797    
1798     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1799    
1800     43. Added a new function pcre_config(int, void *) to enable run-time extraction
1801     of things that can be changed at compile time. The first argument specifies
1802     what is wanted and the second points to where the information is to be placed.
1803     The current list of available information is:
1804    
1805     PCRE_CONFIG_UTF8
1806    
1807     The output is an integer that is set to one if UTF-8 support is available;
1808     otherwise it is set to zero.
1809    
1810     PCRE_CONFIG_NEWLINE
1811    
1812     The output is an integer that it set to the value of the code that is used for
1813     newline. It is either LF (10) or CR (13).
1814    
1815     PCRE_CONFIG_LINK_SIZE
1816    
1817     The output is an integer that contains the number of bytes used for internal
1818     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1819    
1820     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
1821    
1822     The output is an integer that contains the threshold above which the POSIX
1823     interface uses malloc() for output vectors. See item 31 above.
1824    
1825     PCRE_CONFIG_MATCH_LIMIT
1826    
1827     The output is an unsigned integer that contains the default limit of the number
1828     of match() calls in a pcre_exec() execution. See 42 above.
1829    
1830     44. pcretest has been upgraded by the addition of the -C option. This causes it
1831     to extract all the available output from the new pcre_config() function, and to
1832     output it. The program then exits immediately.
1833    
1834     45. A need has arisen to pass over additional data with calls to pcre_exec() in
1835     order to support additional features. One way would have been to define
1836     pcre_exec2() (for example) with extra arguments, but this would not have been
1837     extensible, and would also have required all calls to the original function to
1838     be mapped to the new one. Instead, I have chosen to extend the mechanism that
1839     is used for passing in "extra" data from pcre_study().
1840    
1841     The pcre_extra structure is now exposed and defined in pcre.h. It currently
1842     contains the following fields:
1843    
1844     flags a bitmap indicating which of the following fields are set
1845     study_data opaque data from pcre_study()
1846     match_limit a way of specifying a limit on match() calls for a specific
1847     call to pcre_exec()
1848     callout_data data for callouts (see 49 below)
1849    
1850     The flag bits are also defined in pcre.h, and are
1851    
1852     PCRE_EXTRA_STUDY_DATA
1853     PCRE_EXTRA_MATCH_LIMIT
1854     PCRE_EXTRA_CALLOUT_DATA
1855    
1856     The pcre_study() function now returns one of these new pcre_extra blocks, with
1857     the actual study data pointed to by the study_data field, and the
1858     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1859     before. That is, this change is entirely upwards-compatible and requires no
1860     change to existing code.
1861    
1862     If you want to pass in additional data to pcre_exec(), you can either place it
1863     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1864     block.
1865    
1866     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1867     data string contains the escape sequence \M, pcretest calls pcre_exec() several
1868     times with different match limits, until it finds the minimum value needed for
1869     pcre_exec() to complete. The value is then output. This can be instructive; for
1870     most simple matches the number is quite small, but for pathological cases it
1871     gets very large very quickly.
1872    
1873     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1874     returns the size of the data block pointed to by the study_data field in a
1875     pcre_extra block, that is, the value that was passed as the argument to
1876     pcre_malloc() when PCRE was getting memory in which to place the information
1877     created by pcre_study(). The fourth argument should point to a size_t variable.
1878     pcretest has been extended so that this information is shown after a successful
1879     pcre_study() call when information about the compiled regex is being displayed.
1880    
1881     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1882     because what follows is always an absolute path. (Later: it turns out that this
1883     is more than cosmetic for MinGW, because it doesn't like empty path
1884     components.)
1885    
1886     49. Some changes have been made to the callout feature (see 28 above):
1887    
1888     (i) A callout function now has three choices for what it returns:
1889    
1890     0 => success, carry on matching
1891     > 0 => failure at this point, but backtrack if possible
1892     < 0 => serious error, return this value from pcre_exec()
1893    
1894     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1895     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1896     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1897     use by callout functions. It will never be used by PCRE itself.
1898    
1899     (ii) The pcre_extra structure (see 45 above) has a void * field called
1900     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1901     pcre_callout_block structure has a field of the same name. The contents of
1902     the field passed in the pcre_extra structure are passed to the callout
1903     function in the corresponding field in the callout block. This makes it
1904     easier to use the same callout-containing regex from multiple threads. For
1905     testing, the pcretest program has a new data escape
1906    
1907     \C*n pass the number n (may be negative) as callout_data
1908    
1909     If the callout function in pcretest receives a non-zero value as
1910     callout_data, it returns that value.
1911    
1912     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1913     there were some redundant $(CFLAGS) in commands that are now specified as
1914     $(LINK), which already includes $(CFLAGS).
1915    
1916     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1917     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1918     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1919     one-byte characters throughout. Note that case-insensitive matching applies
1920     only to characters whose values are less than 256. PCRE doesn't support the
1921     notion of cases for higher-valued characters.
1922    
1923     (i) A character class whose characters are all within 0-255 is handled as
1924     a bit map, and the map is inverted for negative classes. Previously, a
1925     character > 255 always failed to match such a class; however it should
1926     match if the class was a negative one (e.g. [^ab]). This has been fixed.
1927    
1928     (ii) A negated character class with a single character < 255 is coded as
1929     "not this character" (OP_NOT). This wasn't working properly when the test
1930     character was multibyte, either singly or repeated.
1931    
1932     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1933     mode, for example: \x{100}{2,3}.
1934    
1935     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1936     singly or repeated) now correctly test multibyte characters. However,
1937     PCRE doesn't recognize any characters with values greater than 255 as
1938     digits, spaces, or word characters. Such characters always match \D, \S,
1939     and \W, and never match \d, \s, or \w.
1940    
1941     (v) Classes may now contain characters and character ranges with values
1942     greater than 255. For example: [ab\x{100}-\x{400}].
1943    
1944     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1945     PCRE in UTF-8 mode.
1946    
1947     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1948     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1949     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1950     value.)
1951    
1952     53. The single man page has become too large. I have therefore split it up into
1953     a number of separate man pages. These also give rise to individual HTML pages;
1954     these are now put in a separate directory, and there is an index.html page that
1955     lists them all. Some hyperlinking between the pages has been installed.
1956    
1957     54. Added convenience functions for handling named capturing parentheses.
1958    
1959     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1960     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1961     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1962     are faulted.
1963    
1964     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1965     calling configure. These values are used when compiling the dftables.c program
1966     which is run to generate the source of the default character tables. They
1967     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1968     you will need to set these values.
1969    
1970     57. Updated the building process for Windows DLL, as provided by Fred Cox.
1971    
1972    
1973     Version 3.9 02-Jan-02
1974 nigel 61 ---------------------
1975    
1976     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1977    
1978     2. If --disable-static was given, the building process failed when trying to
1979     build pcretest and pcregrep. (For some reason it was using libtool to compile
1980     them, which is not right, as they aren't part of the library.)
1981    
1982    
1983 nigel 59 Version 3.8 18-Dec-01
1984     ---------------------
1985    
1986     1. The experimental UTF-8 code was completely screwed up. It was packing the
1987     bytes in the wrong order. How dumb can you get?
1988    
1989    
1990 nigel 57 Version 3.7 29-Oct-01
1991     ---------------------
1992    
1993     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1994     This caused pcretest, when used on the test data, to segfault. Unfortunately,
1995     this didn't happen under Solaris 8, where I normally test things.
1996    
1997 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1998     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1999     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2000     this fix an hour or so after the initial 3.7 release.)
2001 nigel 57
2002 nigel 59
2003 nigel 55 Version 3.6 23-Oct-01
2004     ---------------------
2005    
2006     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2007     offsets passed as NULL with zero offset count.
2008    
2009     2. The config.guess and config.sub files had not been updated when I moved to
2010     the latest autoconf.
2011    
2012    
2013 nigel 53 Version 3.5 15-Aug-01
2014     ---------------------
2015 nigel 5
2016 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2017     had been forgotten.
2018    
2019     2. By using declared but undefined structures, we can avoid using "void"
2020     definitions in pcre.h while keeping the internal definitions of the structures
2021     private.
2022    
2023     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2024     user point of view, this means that both static and shared libraries are built
2025     by default, but this can be individually controlled. More of the work of
2026     handling this static/shared cases is now inside libtool instead of PCRE's make
2027     file.
2028    
2029     4. The pcretest utility is now installed along with pcregrep because it is
2030     useful for users (to test regexs) and by doing this, it automatically gets
2031     relinked by libtool. The documentation has been turned into a man page, so
2032     there are now .1, .txt, and .html versions in /doc.
2033    
2034     5. Upgrades to pcregrep:
2035     (i) Added long-form option names like gnu grep.
2036     (ii) Added --help to list all options with an explanatory phrase.
2037     (iii) Added -r, --recursive to recurse into sub-directories.
2038     (iv) Added -f, --file to read patterns from a file.
2039    
2040     6. pcre_exec() was referring to its "code" argument before testing that
2041     argument for NULL (and giving an error if it was NULL).
2042    
2043     7. Upgraded Makefile.in to allow for compiling in a different directory from
2044     the source directory.
2045    
2046     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2047     options bits, the pointer it was passed was to an int instead of to an unsigned
2048     long int. This mattered only on 64-bit systems.
2049    
2050     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2051     generated) instead of pcre.in, which it its source. Also made the same change
2052     in several of the .c files.
2053    
2054     10. A new release of gcc defines printf() as a macro, which broke pcretest
2055     because it had an ifdef in the middle of a string argument for printf(). Fixed
2056     by using separate calls to printf().
2057    
2058     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2059     script, to force use of CR or LF instead of \n in the source. On non-Unix
2060     systems, the value can be set in config.h.
2061    
2062     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2063     absolute limit. Changed the text of the error message to make this clear, and
2064     likewise updated the man page.
2065    
2066     13. The limit of 99 on the number of capturing subpatterns has been removed.
2067     The new limit is 65535, which I hope will not be a "real" limit.
2068    
2069    
2070 nigel 51 Version 3.4 22-Aug-00
2071     ---------------------
2072    
2073     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2074    
2075     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2076    
2077    
2078 nigel 49 Version 3.3 01-Aug-00
2079     ---------------------
2080    
2081     1. If an octal character was given, but the value was greater than \377, it
2082     was not getting masked to the least significant bits, as documented. This could
2083     lead to crashes in some systems.
2084    
2085     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2086     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2087    
2088     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2089     These just pass their arguments on to (pcre_free)(), but they are provided
2090     because some uses of PCRE bind it to non-C systems that can call its functions,
2091     but cannot call free() or pcre_free() directly.
2092    
2093     4. Add "make test" as a synonym for "make check". Corrected some comments in
2094     the Makefile.
2095    
2096     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2097     Makefile.
2098    
2099     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2100     command called pgrep for grepping around the active processes.
2101    
2102     7. Added the beginnings of support for UTF-8 character strings.
2103    
2104     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2105     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2106     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2107     out for the ar command.)
2108    
2109    
2110 nigel 47 Version 3.2 12-May-00
2111     ---------------------
2112    
2113     This is purely a bug fixing release.
2114    
2115     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2116     of ZA. This was just one example of several cases that could provoke this bug,
2117     which was introduced by change 9 of version 2.00. The code for breaking
2118     infinite loops after an iteration that matches an empty string was't working
2119     correctly.
2120    
2121     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2122     when matched against abbab (for example). After matching an empty string, it
2123     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2124     caused it to match further down the string than it should.
2125    
2126     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2127     was there because it doesn't seem to be needed, and it causes trouble on some
2128     systems, as it is not a Standard C header. It has been removed.
2129    
2130     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2131     were reported on the Macintosh. The changes were from
2132    
2133     while ((c = *(++ptr)) != 0 && c != '\n');
2134     to
2135     while ((c = *(++ptr)) != 0 && c != '\n') ;
2136    
2137     Totally extraordinary, but if that's what it takes...
2138    
2139     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2140     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2141     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2142     assumes the way PCRE uses memmove() (always moving upwards).
2143    
2144     6. PCRE is being used in one environment where strchr() is not available. There
2145     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2146     faster code anyway.
2147    
2148    
2149 nigel 45 Version 3.1 09-Feb-00
2150     ---------------------
2151    
2152     The only change in this release is the fixing of some bugs in Makefile.in for
2153     the "install" target:
2154    
2155     (1) It was failing to install pcreposix.h.
2156    
2157     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2158    
2159    
2160 nigel 43 Version 3.0 01-Feb-00
2161     ---------------------
2162 nigel 41
2163     1. Add support for the /+ modifier to perltest (to output $` like it does in
2164     pcretest).
2165    
2166     2. Add support for the /g modifier to perltest.
2167    
2168     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2169     matches null strings.
2170    
2171     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2172     pattern. Perl treats empty patterns specially - it reuses the most recent
2173     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2174     effect.
2175    
2176     5. The POSIX interface was broken in that it was just handing over the POSIX
2177     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2178     required a bigger vector, with some working space on the end. This means that
2179     the POSIX wrapper now has to get and free some memory, and copy the results.
2180    
2181 nigel 43 6. Added some simple autoconf support, placing the test data and the
2182     documentation in separate directories, re-organizing some of the
2183     information files, and making it build pcre-config (a GNU standard). Also added
2184     libtool support for building PCRE as a shared library, which is now the
2185     default.
2186 nigel 41
2187 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2188     09 are not valid octal constants. Single digits will be used for minor values
2189     less than 10.
2190    
2191     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2192     existing programs that set these in the POSIX interface can use PCRE without
2193     modification.
2194    
2195     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2196     return all that pcre_info() returns, plus additional data. The pcre_info()
2197     function is retained for compatibility, but is considered to be obsolete.
2198    
2199     10. Added experimental recursion feature (?R) to handle one common case that
2200     Perl 5.6 will be able to do with (?p{...}).
2201    
2202     11. Added support for POSIX character classes like [:alpha:], which Perl is
2203     adopting.
2204    
2205    
2206 nigel 39 Version 2.08 31-Aug-99
2207     ----------------------
2208    
2209     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2210     trying to match at the startoffset position, but instead was moving forward to
2211     the next newline as if a previous match had failed.
2212    
2213     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2214     and could get into a loop if a null string was matched other than at the start
2215     of the subject.
2216    
2217     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2218     be distinguished at compile time, and for completeness also added PCRE_DATE.
2219    
2220     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2221     in GnuWin32 environments.
2222    
2223    
2224 nigel 37 Version 2.07 29-Jul-99
2225     ----------------------
2226    
2227     1. The documentation is now supplied in plain text form and HTML as well as in
2228     the form of man page sources.
2229    
2230     2. C++ compilers don't like assigning (void *) values to other pointer types.
2231     In particular this affects malloc(). Although there is no problem in Standard
2232     C, I've put in casts to keep C++ compilers happy.
2233    
2234     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2235     should be (const char *).
2236    
2237     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2238     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2239     However, I haven't made this a standard facility. The documentation doesn't
2240     mention it, and the Makefile doesn't support it.
2241    
2242     5. The Makefile now contains an "install" target, with editable destinations at
2243     the top of the file. The pcretest program is not installed.
2244    
2245     6. pgrep -V now gives the PCRE version number and date.
2246    
2247     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2248     causing the entire string to be ignored, instead of just the last character.
2249    
2250     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2251     non-matching string, it can take a very, very long time, even for strings of
2252     quite modest length, because of the nested recursion. PCRE now does better in
2253     some of these cases. It does this by remembering the last required literal
2254     character in the pattern, and pre-searching the subject to ensure it is present
2255     before running the real match. In other words, it applies a heuristic to detect
2256     some types of certain failure quickly, and in the above example, if presented
2257     with a string that has no trailing " it gives "no match" very quickly.
2258    
2259     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2260     other alternatives are tried instead.
2261    
2262    
2263 nigel 35 Version 2.06 09-Jun-99
2264     ----------------------
2265    
2266     1. Change pcretest's output for amount of store used to show just the code
2267     space, because the remainder (the data block) varies in size between 32-bit and
2268     64-bit systems.
2269    
2270     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2271     start matching at. This allows lookbehinds to work when searching for multiple
2272     occurrences in a string.
2273    
2274     3. Added additional options to pcretest for testing multiple occurrences:
2275    
2276     /+ outputs the rest of the string that follows a match
2277     /g loops for multiple occurrences, using the new startoffset argument
2278     /G loops for multiple occurrences by passing an incremented pointer
2279    
2280     4. PCRE wasn't doing the "first character" optimization for patterns starting
2281     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2282     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2283     the letter 'x'. On long subject strings, this gives a significant speed-up.
2284    
2285    
2286 nigel 33 Version 2.05 21-Apr-99
2287     ----------------------
2288    
2289     1. Changed the type of magic_number from int to long int so that it works
2290     properly on 16-bit systems.
2291    
2292     2. Fixed a bug which caused patterns starting with .* not to work correctly
2293     when the subject string contained newline characters. PCRE was assuming
2294     anchoring for such patterns in all cases, which is not correct because .* will
2295     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2296     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2297     must be retried after every newline in the subject.
2298    
2299    
2300 nigel 31 Version 2.04 18-Feb-99
2301     ----------------------
2302    
2303     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2304     computation of the store needed to hold the pattern was incorrect (too large).
2305     If such patterns were nested a few deep, this could multiply and become a real
2306     problem.
2307    
2308     2. Added /M option to pcretest to show the memory requirement of a specific
2309     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2310    
2311     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2312     compiled in such a way that the backtracking after subsequent failure was
2313     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2314     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2315    
2316    
2317 nigel 29 Version 2.03 02-Feb-99
2318     ----------------------
2319    
2320     1. Fixed typo and small mistake in man page.
2321    
2322 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2323     LICENCE file containing the conditions.
2324 nigel 29
2325     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2326     Perl, that is the internal \ allows the delimiter to be included in the
2327     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2328     the final delimiter, add \ to the end of the pattern (to test the error).
2329    
2330     4. Added the convenience functions for extracting substrings after a successful
2331     match. Updated pcretest to make it able to test these functions.
2332    
2333    
2334 nigel 27 Version 2.02 14-Jan-99
2335     ----------------------
2336    
2337     1. Initialized the working variables associated with each extraction so that
2338     their saving and restoring doesn't refer to uninitialized store.
2339    
2340     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2341     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2342     fix the problem.
2343    
2344     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2345     calls, and wasn't printing the correct value for compiling calls. Increased the
2346     default value of LOOPREPEAT, and the number of significant figures in the
2347     times.
2348    
2349     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2350    
2351     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2352     a building problem on Windows NT with a FAT file system.
2353    
2354    
2355 nigel 25 Version 2.01 21-Oct-98
2356     ----------------------
2357    
2358     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2359     to character tables built by pcre_maketables() in the current locale. If NULL
2360     is passed, the default tables are used.
2361    
2362    
2363 nigel 23 Version 2.00 24-Sep-98
2364 nigel 21 ----------------------
2365    
2366 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2367     it any more.
2368    
2369     2. Allow quantification of (?>) groups, and make it work correctly.
2370    
2371     3. The first character computation wasn't working for (?>) groups.
2372    
2373     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2374     end of the subject) and add 5.005's \z, which really does match only at the
2375     very end of the subject.
2376    
2377     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2378    
2379     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2380     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2381     localized options. All options to pcre_study() were also removed.
2382    
2383     7. Add other new features from 5.005:
2384    
2385     $(?<= positive lookbehind
2386     $(?<! negative lookbehind
2387     (?imsx-imsx) added the unsetting capability
2388     such a setting is global if at outer level; local otherwise
2389     (?imsx-imsx:) non-capturing groups with option setting
2390     (?(cond)re|re) conditional pattern matching
2391    
2392     A backreference to itself in a repeated group matches the previous
2393     captured string.
2394    
2395     8. General tidying up of studying (both automatic and via "study")
2396     consequential on the addition of new assertions.
2397    
2398     9. As in 5.005, unlimited repeated groups that could match an empty substring
2399     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2400     runtime if any iteration does actually match an empty substring.
2401    
2402     10. Include the RunTest script in the distribution.
2403    
2404     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2405     discrepancies, some of which were old and were also with respect to 5.004. They
2406     have now been fixed.
2407    
2408    
2409     Version 1.09 28-Apr-98
2410     ----------------------
2411    
2412 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2413     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2414     program crashes, or just wrong answers. This did not apply to negated classes
2415     containing more than one character, or to minima other than one.
2416    
2417    
2418 nigel 19 Version 1.08 27-Mar-98
2419     ----------------------
2420    
2421     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2422    
2423     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2424     latter must appear before anything that relies on it in the pattern.
2425    
2426    
2427 nigel 17 Version 1.07 16-Feb-98
2428     ----------------------
2429    
2430     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2431     repeat of a potentially empty string).
2432    
2433    
2434 nigel 15 Version 1.06 23-Jan-98
2435     ----------------------
2436    
2437     1. Added Markus Oberhumer's little patches for C++.
2438    
2439     2. Literal strings longer than 255 characters were broken.
2440    
2441    
2442 nigel 13 Version 1.05 23-Dec-97
2443     ----------------------
2444    
2445     1. Negated character classes containing more than one character were failing if
2446     PCRE_CASELESS was set at run time.
2447    
2448    
2449 nigel 11 Version 1.04 19-Dec-97
2450     ----------------------
2451    
2452     1. Corrected the man page, where some "const" qualifiers had been omitted.
2453    
2454     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2455     input syntax.
2456    
2457     3. Fixed memory leak which occurred when a regex with back references was
2458     matched with an offsets vector that wasn't big enough. The temporary memory
2459     that is used in this case wasn't being freed if the match failed.
2460    
2461     4. Tidied pcretest to ensure it frees memory that it gets.
2462    
2463     5. Temporary memory was being obtained in the case where the passed offsets
2464     vector was exactly big enough.
2465    
2466     6. Corrected definition of offsetof() from change 5 below.
2467    
2468     7. I had screwed up change 6 below and broken the rules for the use of
2469     setjmp(). Now fixed.
2470    
2471    
2472 nigel 9 Version 1.03 18-Dec-97
2473     ----------------------
2474    
2475     1. A erroneous regex with a missing opening parenthesis was correctly
2476     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2477     on some systems.
2478    
2479     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2480     it was reported that one broken compiler failed on the former because "code" is
2481     also an independent variable.
2482    
2483     3. The erroneous regex a[]b caused an array overrun reference.
2484    
2485     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2486     fail on data ending with that character. (It was going on too far, and checking
2487     the next character, typically a binary zero.) This was specific to the
2488     optimized code for single-character negative classes.
2489    
2490     5. Added a contributed patch from the TIN world which does the following:
2491    
2492     + Add an undef for memmove, in case the the system defines a macro for it.
2493    
2494     + Add a definition of offsetof(), in case there isn't one. (I don't know
2495     the reason behind this - offsetof() is part of the ANSI standard - but
2496     it does no harm).
2497    
2498     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2499     most of the places where whitespace preceded '#'. I have given up and
2500     allowed the remaining 2 cases to be at the margin.
2501    
2502     + Rename some variables in pcre to eliminate shadowing. This seems very
2503     pedantic, but does no harm, of course.
2504    
2505     6. Moved the call to setjmp() into its own function, to get rid of warnings
2506     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2507    
2508     7. Constructs such as \d{8,} were compiling into the equivalent of
2509 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2510 nigel 9 outcome, but in this particular case used more store than had been allocated,
2511     which caused the bug to be discovered because it threw up an internal error.
2512    
2513     8. The debugging code in both pcre and pcretest for outputting the compiled
2514     form of a regex was going wrong in the case of back references followed by
2515     curly-bracketed repeats.
2516    
2517    
2518 nigel 7 Version 1.02 12-Dec-97
2519     ----------------------
2520    
2521     1. Typos in pcre.3 and comments in the source fixed.
2522    
2523     2. Applied a contributed patch to get rid of places where it used to remove
2524     'const' from variables, and fixed some signed/unsigned and uninitialized
2525     variable warnings.
2526    
2527     3. Added the "runtest" target to Makefile.
2528    
2529     4. Set default compiler flag to -O2 rather than just -O.
2530    
2531    
2532 nigel 5 Version 1.01 19-Nov-97
2533     ----------------------
2534    
2535     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2536     like /([ab]*)*/, that is, for classes with more than one character in them.
2537    
2538     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2539     as /((?>a*))*/ (a PCRE_EXTRA facility).
2540    
2541    
2542     Version 1.00 18-Nov-97
2543     ----------------------
2544    
2545     1. Added compile-time macros to support systems such as SunOS4 which don't have
2546     memmove() or strerror() but have other things that can be used instead.
2547    
2548     2. Arranged that "make clean" removes the executables.
2549    
2550    
2551 nigel 3 Version 0.99 27-Oct-97
2552     ----------------------
2553    
2554     1. Fixed bug in code for optimizing classes with only one character. It was
2555     initializing a 32-byte map regardless, which could cause it to run off the end
2556     of the memory it had got.
2557    
2558     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2559    
2560    
2561     Version 0.98 22-Oct-97
2562     ----------------------
2563    
2564     1. Fixed bug in code for handling temporary memory usage when there are more
2565     back references than supplied space in the ovector. This could cause segfaults.
2566    
2567    
2568     Version 0.97 21-Oct-97
2569     ----------------------
2570    
2571     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2572    
2573     2. Optimized negated single characters not to use a bit map.
2574    
2575     3. Brought error texts together as macro definitions; clarified some of them;
2576     fixed one that was wrong - it said "range out of order" when it meant "invalid
2577     escape sequence".
2578    
2579     4. Changed some char * arguments to const char *.
2580    
2581     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2582    
2583     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2584     pcretest.
2585    
2586    
2587     Version 0.96 16-Oct-97
2588     ----------------------
2589    
2590     1. Added a simple "pgrep" utility to the distribution.
2591    
2592     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2593     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2594     where "ddd" means "one or more decimal digits".
2595    
2596     3. Fixed serious bug. If a pattern had a back reference, but the call to
2597     pcre_exec() didn't supply a large enough ovector to record the related
2598     identifying subpattern, the match always failed. PCRE now remembers the number
2599     of the largest back reference, and gets some temporary memory in which to save
2600     the offsets during matching if necessary, in order to ensure that
2601     backreferences always work.
2602    
2603     4. Increased the compatibility with Perl in a number of ways:
2604    
2605     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2606     to request this handling. The option can be set at compile or exec time.
2607    
2608     (b) $ matches before a terminating newline by default; an option
2609     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2610     mode). The option can be set at compile or exec time.
2611    
2612     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2613     the same as Perl's. If the decimal number it represents is less than 10
2614     or there aren't that many previous left capturing parentheses, an octal
2615     escape is read. Inside a character class, it's always an octal escape,
2616     even if it is a single digit.
2617    
2618     (d) An escaped but undefined alphabetic character is taken as a literal,
2619     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2620     escapes.
2621    
2622     (e) {0} is now permitted. (The previous item is removed from the compiled
2623     pattern).
2624    
2625     5. Changed all the names of code files so that the basic parts are no longer
2626     than 10 characters, and abolished the teeny "globals.c" file.
2627    
2628     6. Changed the handling of character classes; they are now done with a 32-byte
2629     bit map always.
2630    
2631     7. Added the -d and /D options to pcretest to make it possible to look at the
2632     internals of compilation without having to recompile pcre.
2633    
2634    
2635     Version 0.95 23-Sep-97
2636     ----------------------
2637    
2638     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2639     \x20 at the start of a run of normal characters. These were being treated as
2640     real characters, instead of the source characters being re-checked.
2641    
2642    
2643     Version 0.94 18-Sep-97
2644     ----------------------
2645    
2646     1. The functions are now thread-safe, with the caveat that the global variables
2647     containing pointers to malloc() and free() or alternative functions are the
2648     same for all threads.
2649    
2650     2. Get pcre_study() to generate a bitmap of initial characters for non-
2651     anchored patterns when this is possible, and use it if passed to pcre_exec().
2652    
2653    
2654     Version 0.93 15-Sep-97
2655     ----------------------
2656    
2657     1. /(b)|(:+)/ was computing an incorrect first character.
2658    
2659     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2660     but not actually doing anything yet.
2661    
2662     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2663     as Perl does (e.g. [-az] or [az-]).
2664    
2665     4. Set the anchored flag if a branch starts with .* or .*? because that tests
2666     all possible positions.
2667    
2668     5. Split up into different modules to avoid including unneeded functions in a
2669     compiled binary. However, compile and exec are still in one module. The "study"
2670     function is split off.
2671    
2672     6. The character tables are now in a separate module whose source is generated
2673     by an auxiliary program - but can then be edited by hand if required. There are
2674     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2675     toupper() in the code.
2676    
2677     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2678     make them global. Abolish the function for setting them, as the caller can now
2679     set them directly.
2680    
2681    
2682     Version 0.92 11-Sep-97
2683     ----------------------
2684    
2685     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2686     (e.g. /a{1,3}/) was broken (I mis-optimized it).
2687    
2688     2. Caseless matching was not working in character classes if the characters in
2689     the pattern were in upper case.
2690    
2691     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2692    
2693     4. Make PCRE_ANCHORED public and accept as a compile option.
2694    
2695     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2696     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2697     pass them.
2698    
2699     6. Give an error if bad option bits passed at compile or run time.
2700    
2701     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2702     pcretest to cause it to pass that flag.
2703    
2704     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2705     options, and the first character, if set.
2706    
2707     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2708    
2709    
2710     Version 0.91 10-Sep-97
2711     ----------------------
2712    
2713     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2714     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2715    
2716     2. PCRE was looping on encountering an indefinitely repeated back reference to
2717     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2718     Perl does - treats the match as successful.
2719    
2720     ****

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