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Revision 170 - (hide annotations) (download)
Mon Jun 4 11:21:13 2007 UTC (7 years, 4 months ago) by ph10
File size: 128668 byte(s)
Fix bug in detecting potentially empty groups.

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 165
15 ph10 161 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 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
18     usable with all link sizes.
19    
20 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
21     stack recursion. This gives a massive performance boost under BSD, but just
22 ph10 165 a small improvement under Linux. However, it saves one field in the frame
23 ph10 164 in all cases.
24 ph10 166
25     6. Added more features from the forthcoming Perl 5.10:
26    
27     (a) (?-n) (where n is a string of digits) is a relative subroutine or
28     recursion call. It refers to the nth most recently opened parentheses.
29    
30     (b) (?+n) is also a relative subroutine call; it refers to the nth next
31     to be opened parentheses.
32 ph10 167
33     (c) Conditions that refer to capturing parentheses can be specified
34     relatively, for example, (?(-2)... or (?(+3)...
35 ph10 168
36     (d) \K resets the start of the current match so that everything before
37     is not part of it.
38 ph10 169
39     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
40     PCRE_INFO_JCHANGED.
41 ph10 170
42     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
43     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
44     for detecting groups that can match an empty string.
45 ph10 159
46 ph10 160
47 ph10 155 Version 7.1 24-Apr-07
48 ph10 98 ---------------------
49    
50 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
51 ph10 122 that is more "standard", making use of automake and other Autotools. There
52 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
53     on this.
54 ph10 111
55     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
56     for recursive directory scanning broke on some systems because the files
57     are not scanned in any specific order and on different systems the order
58     was different. A call to "sort" has been inserted into RunGrepTest for the
59     approprate test as a short-term fix. In the longer term there may be an
60 ph10 100 alternative.
61 ph10 111
62 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
63 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
64     people do their own conversions for various reasons). The problems
65     concerned the use of low-level troff macros .br and .in. I have therefore
66     removed all such uses from the man pages (some were redundant, some could
67 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
68     HTML has been updated to handle .nf/.fi and to complain if it encounters
69     .br or .in.
70 ph10 111
71 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
72 ph10 123 arranged for config.h to be included in the distribution, with the name
73 ph10 111 config.h.generic, for the benefit of those who have to compile without
74     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
75    
76     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
77     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
78 ph10 127 makevp.bat for the current PCRE, using the additional files
79 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
80 ph10 111
81     6. A Windows user reported a minor discrepancy with test 2, which turned out
82     to be caused by a trailing space on an input line that had got lost in his
83 ph10 102 copy. The trailing space was an accident, so I've just removed it.
84 ph10 111
85 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
86 ph10 111 that is needed.
87    
88 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
89     as "const" (a) because they are and (b) because it helps the PHP
90     maintainers who have recently made a script to detect big data structures
91 ph10 111 in the php code that should be moved to the .rodata section. I remembered
92     to update Builducptable as well, so it won't revert if ucptable.h is ever
93 ph10 105 re-created.
94 ph10 111
95     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
96 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
97 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
98     support is not required. This saves 1.5-2K of code, which is important in
99 ph10 107 some applications.
100 ph10 111
101 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
102 ph10 111 so as not to refer to the tables, even though these functions will never be
103     called when UTF-8 support is disabled. Otherwise there are problems with a
104     shared library.
105    
106 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
107    
108     (a) It was defining its arguments as char * instead of void *.
109    
110 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
111     a long time ago when I wrote it, but is no longer the case.
112    
113 ph10 118 The emulated memove() is provided for those environments that have neither
114 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
115 ph10 118 is clearly not the case, as these two bugs were recently reported.
116 ph10 123
117 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
118 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
119     pages, and it removes trailing spaces from listed files. It also creates
120     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
121     case, it wraps all the #defines with #ifndefs. This script should be run
122 ph10 111 before "make dist".
123 ph10 123
124 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
125     with Unicode property support.
126 ph10 123
127     (a) For a maximizing quantifier, if the two different cases of the
128     character were of different lengths in their UTF-8 codings (there are
129     some cases like this - I found 11), and the matching function had to
130 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
131     were both the same length.
132 ph10 123
133     (b) When PCRE was configured to use the heap rather than the stack for
134     recursion during matching, it was not correctly preserving the data for
135     the other case of a UTF-8 character when checking ahead for a match
136     while processing a minimizing repeat. If the check also involved
137 ph10 115 matching a wide character, but failed, corruption could cause an
138     erroneous result when trying to check for a repeat of the original
139     character.
140 ph10 123
141 ph10 116 13. Some tidying changes to the testing mechanism:
142 ph10 98
143 ph10 116 (a) The RunTest script now detects the internal link size and whether there
144     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
145 ph10 123 values substituted by "configure". (The RunGrepTest script already did
146     this for UTF-8.) The configure.ac script no longer substitutes the
147     relevant variables.
148    
149 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
150     with length and offset values. This means that the output is different
151     for different internal link sizes. Test 2 is skipped for link sizes
152     other than 2 because of this, bypassing the problem. Unfortunately,
153     there was also a test in test 3 (the locale tests) that used /B and
154 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
155     I have added a new /Z option to pcretest that replaces the length and
156     offset values with spaces. This is now used to make test 3 independent
157 ph10 122 of link size. (Test 2 will be tidied up later.)
158 ph10 123
159     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
160 ph10 122 segmentation fault instead of returning the appropriate error message.
161 ph10 134
162 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
163 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
164     This doesn't seem right; it now treats the CRLF combination as the line
165     ending, and so does not match in that case. It's only a pattern such as ^$
166     that would hit this one: something like ^ABC$ would have failed after \r
167     and then tried again after \r\n.
168    
169 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
170 ph10 134 in an attempt to make files that differ only in their line terminators
171     compare equal. This works on Linux.
172 ph10 142
173 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
174     as it exited. This is now fixed, thanks to valgrind.
175 ph10 142
176 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
177 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
178     was because its rules for how to advance for /g after matching an empty
179 ph10 143 string at the end of a line did not allow for this case. They now check for
180     it specially.
181 ph10 150
182     20. pcretest is supposed to handle patterns and data of any length, by
183     extending its buffers when necessary. It was getting this wrong when the
184 ph10 147 buffer for a data line had to be extended.
185 ph10 150
186 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
187 ph10 150 CRLF as a newline sequence.
188 ph10 152
189 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
190 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
191     I have nevertheless tidied it up.
192 ph10 111
193 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
194 ph10 123
195 ph10 153 24. Added a man page for pcre-config.
196 ph10 152
197 ph10 153
198 nigel 93 Version 7.0 19-Dec-06
199     ---------------------
200    
201     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
202     moving to gcc 4.1.1.
203    
204     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
205     sys/time.h, which is documented as needed for this function. It doesn't
206     seem to matter on Linux, but it showed up on some releases of OS X.
207    
208     3. It seems that there are systems where bytes whose values are greater than
209     127 match isprint() in the "C" locale. The "C" locale should be the
210     default when a C program starts up. In most systems, only ASCII printing
211     characters match isprint(). This difference caused the output from pcretest
212     to vary, making some of the tests fail. I have changed pcretest so that:
213    
214     (a) When it is outputting text in the compiled version of a pattern, bytes
215     other than 32-126 are always shown as hex escapes.
216    
217     (b) When it is outputting text that is a matched part of a subject string,
218     it does the same, unless a different locale has been set for the match
219     (using the /L modifier). In this case, it uses isprint() to decide.
220    
221     4. Fixed a major bug that caused incorrect computation of the amount of memory
222     required for a compiled pattern when options that changed within the
223     pattern affected the logic of the preliminary scan that determines the
224     length. The relevant options are -x, and -i in UTF-8 mode. The result was
225     that the computed length was too small. The symptoms of this bug were
226     either the PCRE error "internal error: code overflow" from pcre_compile(),
227     or a glibc crash with a message such as "pcretest: free(): invalid next
228     size (fast)". Examples of patterns that provoked this bug (shown in
229     pcretest format) are:
230    
231     /(?-x: )/x
232     /(?x)(?-x: \s*#\s*)/
233     /((?i)[\x{c0}])/8
234     /(?i:[\x{c0}])/8
235    
236     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
237     is now done differently.
238    
239     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
240     wrapper classes; (b) implement a new function in the C++ scanner that is
241     more efficient than the old way of doing things because it avoids levels of
242     recursion in the regex matching; (c) add a paragraph to the documentation
243     for the FullMatch() function.
244    
245     6. The escape sequence \n was being treated as whatever was defined as
246     "newline". Not only was this contrary to the documentation, which states
247     that \n is character 10 (hex 0A), but it also went horribly wrong when
248     "newline" was defined as CRLF. This has been fixed.
249    
250     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
251     was being set to -1 for the "end of line" case (supposedly a value that no
252     character can have). Though this value is never used (the check for end of
253     line is "zero bytes in current character"), it caused compiler complaints.
254     I've changed it to 0xffffffff.
255    
256     8. In pcre_version.c, the version string was being built by a sequence of
257     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
258     string (as it is for production releases) called a macro with an empty
259     argument. The C standard says the result of this is undefined. The gcc
260     compiler treats it as an empty string (which was what was wanted) but it is
261     reported that Visual C gives an error. The source has been hacked around to
262     avoid this problem.
263    
264     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
265     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
266     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
267     of them did).
268    
269     10. Originally, pcretest opened its input and output without "b"; then I was
270     told that "b" was needed in some environments, so it was added for release
271     5.0 to both the input and output. (It makes no difference on Unix-like
272     systems.) Later I was told that it is wrong for the input on Windows. I've
273     now abstracted the modes into two macros, to make it easier to fiddle with
274     them, and removed "b" from the input mode under Windows.
275    
276     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
277    
278     12. Added -help and --help to pcretest as an official way of being reminded
279     of the options.
280    
281     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
282     and pcrecpp.cc because they annoy compilers at high warning levels.
283    
284     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
285    
286     15. Fixed an occurrence of == in configure.ac that should have been = (shell
287     scripts are not C programs :-) and which was not noticed because it works
288     on Linux.
289    
290     16. pcretest is supposed to handle any length of pattern and data line (as one
291     line or as a continued sequence of lines) by extending its input buffer if
292     necessary. This feature was broken for very long pattern lines, leading to
293     a string of junk being passed to pcre_compile() if the pattern was longer
294     than about 50K.
295    
296     17. I have done a major re-factoring of the way pcre_compile() computes the
297     amount of memory needed for a compiled pattern. Previously, there was code
298     that made a preliminary scan of the pattern in order to do this. That was
299     OK when PCRE was new, but as the facilities have expanded, it has become
300     harder and harder to keep it in step with the real compile phase, and there
301     have been a number of bugs (see for example, 4 above). I have now found a
302     cunning way of running the real compile function in a "fake" mode that
303     enables it to compute how much memory it would need, while actually only
304     ever using a few hundred bytes of working memory and without too many
305     tests of the mode. This should make future maintenance and development
306     easier. A side effect of this work is that the limit of 200 on the nesting
307     depth of parentheses has been removed (though this was never a serious
308     limitation, I suspect). However, there is a downside: pcre_compile() now
309     runs more slowly than before (30% or more, depending on the pattern). I
310     hope this isn't a big issue. There is no effect on runtime performance.
311    
312     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
313     newline (only possible for the last line of a file) and it was a
314     pattern that set a locale (followed by /Lsomething), pcretest crashed.
315    
316     19. Added additional timing features to pcretest. (1) The -tm option now times
317     matching only, not compiling. (2) Both -t and -tm can be followed, as a
318     separate command line item, by a number that specifies the number of
319     repeats to use when timing. The default is 50000; this gives better
320     precision, but takes uncomfortably long for very large patterns.
321    
322     20. Extended pcre_study() to be more clever in cases where a branch of a
323     subpattern has no definite first character. For example, (a*|b*)[cd] would
324     previously give no result from pcre_study(). Now it recognizes that the
325     first character must be a, b, c, or d.
326    
327     21. There was an incorrect error "recursive call could loop indefinitely" if
328     a subpattern (or the entire pattern) that was being tested for matching an
329     empty string contained only one non-empty item after a nested subpattern.
330     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
331     incorrectly, because the \d was being skipped in the check.
332    
333     22. The pcretest program now has a new pattern option /B and a command line
334     option -b, which is equivalent to adding /B to every pattern. This causes
335     it to show the compiled bytecode, without the additional information that
336     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
337     is the same as /B/I).
338    
339     23. A new optimization is now able automatically to treat some sequences such
340     as a*b as a*+b. More specifically, if something simple (such as a character
341     or a simple class like \d) has an unlimited quantifier, and is followed by
342     something that cannot possibly match the quantified thing, the quantifier
343     is automatically "possessified".
344    
345     24. A recursive reference to a subpattern whose number was greater than 39
346     went wrong under certain circumstances in UTF-8 mode. This bug could also
347     have affected the operation of pcre_study().
348    
349     25. Realized that a little bit of performance could be had by replacing
350     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
351    
352     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
353    
354     27. Possessive quantifiers such as a++ were previously implemented by turning
355     them into atomic groups such as ($>a+). Now they have their own opcodes,
356     which improves performance. This includes the automatically created ones
357     from 23 above.
358    
359     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
360     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
361     the first matched character to be a colon. This applied both to named and
362     numbered groups.
363    
364     29. The ucpinternal.h header file was missing its idempotency #ifdef.
365    
366     30. I was sent a "project" file called libpcre.a.dev which I understand makes
367     building PCRE on Windows easier, so I have included it in the distribution.
368    
369     31. There is now a check in pcretest against a ridiculously large number being
370     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
371     loop, the loop is abandoned.
372    
373     32. Forward references to subpatterns in conditions such as (?(2)...) where
374     subpattern 2 is defined later cause pcre_compile() to search forwards in
375     the pattern for the relevant set of parentheses. This search went wrong
376     when there were unescaped parentheses in a character class, parentheses
377     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
378    
379     33. "Subroutine" calls and backreferences were previously restricted to
380     referencing subpatterns earlier in the regex. This restriction has now
381     been removed.
382    
383     34. Added a number of extra features that are going to be in Perl 5.10. On the
384     whole, these are just syntactic alternatives for features that PCRE had
385     previously implemented using the Python syntax or my own invention. The
386     other formats are all retained for compatibility.
387    
388     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
389     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
390     also .NET compatible.
391    
392     (b) A recursion or subroutine call to a named group can now be defined as
393     (?&name) as well as (?P>name).
394    
395     (c) A backreference to a named group can now be defined as \k<name> or
396     \k'name' as well as (?P=name). The new forms, as well as being in Perl
397     5.10, are also .NET compatible.
398    
399     (d) A conditional reference to a named group can now use the syntax
400     (?(<name>) or (?('name') as well as (?(name).
401    
402     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
403     groups (named and numbered) that are never evaluated inline, but can be
404     called as "subroutines" from elsewhere. In effect, the DEFINE condition
405     is always false. There may be only one alternative in such a group.
406    
407     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
408     as the simple (?(R). The condition is true only if the most recent
409     recursion is that of the given number or name. It does not search out
410     through the entire recursion stack.
411    
412     (g) The escape \gN or \g{N} has been added, where N is a positive or
413     negative number, specifying an absolute or relative reference.
414    
415     35. Tidied to get rid of some further signed/unsigned compiler warnings and
416     some "unreachable code" warnings.
417    
418     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
419     things, this adds five new scripts.
420    
421     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
422     There were also incompatibilities regarding the handling of \Q..\E inside
423     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
424     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
425    
426     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
427     matches an empty string, and forcibly breaks the loop. There were bugs in
428     this code in non-simple cases. For a pattern such as ^(a()*)* matched
429     against aaaa the result was just "a" rather than "aaaa", for example. Two
430     separate and independent bugs (that affected different cases) have been
431     fixed.
432    
433     39. Refactored the code to abolish the use of different opcodes for small
434     capturing bracket numbers. This is a tidy that I avoided doing when I
435     removed the limit on the number of capturing brackets for 3.5 back in 2001.
436     The new approach is not only tidier, it makes it possible to reduce the
437     memory needed to fix the previous bug (38).
438    
439     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
440     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
441     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
442     mode.
443    
444     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
445     report.
446    
447     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
448     copy construction and assignment in the C++ wrapper.
449    
450     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
451     couple of bugs that could have given wrong results in the "--newline=crlf"
452     case.
453    
454     44. Added a number of casts and did some reorganization of signed/unsigned int
455     variables following suggestions from Dair Grant. Also renamed the variable
456     "this" as "item" because it is a C++ keyword.
457    
458     45. Arranged for dftables to add
459    
460     #include "pcre_internal.h"
461    
462     to pcre_chartables.c because without it, gcc 4.x may remove the array
463     definition from the final binary if PCRE is built into a static library and
464     dead code stripping is activated.
465    
466     46. For an unanchored pattern, if a match attempt fails at the start of a
467     newline sequence, and the newline setting is CRLF or ANY, and the next two
468     characters are CRLF, advance by two characters instead of one.
469    
470    
471 nigel 91 Version 6.7 04-Jul-06
472     ---------------------
473    
474     1. In order to handle tests when input lines are enormously long, pcretest has
475     been re-factored so that it automatically extends its buffers when
476     necessary. The code is crude, but this _is_ just a test program. The
477     default size has been increased from 32K to 50K.
478    
479     2. The code in pcre_study() was using the value of the re argument before
480     testing it for NULL. (Of course, in any sensible call of the function, it
481     won't be NULL.)
482    
483     3. The memmove() emulation function in pcre_internal.h, which is used on
484     systems that lack both memmove() and bcopy() - that is, hardly ever -
485     was missing a "static" storage class specifier.
486    
487     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
488     containing an extended class (one that cannot be represented by a bitmap
489     because it contains high-valued characters or Unicode property items, e.g.
490     [\pZ]). Almost always one would set UTF-8 mode when processing such a
491     pattern, but PCRE should not loop if you do not (it no longer does).
492     [Detail: two cases were found: (a) a repeated subpattern containing an
493     extended class; (b) a recursive reference to a subpattern that followed a
494     previous extended class. It wasn't skipping over the extended class
495     correctly when UTF-8 mode was not set.]
496    
497     5. A negated single-character class was not being recognized as fixed-length
498     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
499     compile error "lookbehind assertion is not fixed length".
500    
501     6. The RunPerlTest auxiliary script was showing an unexpected difference
502     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
503     write a Perl script that can interpret lines of an input file either as
504     byte characters or as UTF-8, which is what "perltest" was being required to
505     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
506     can't do is switch easily at run time between having the "use utf8;" pragma
507     or not. In the end, I fudged it by using the RunPerlTest script to insert
508     "use utf8;" explicitly for the UTF-8 tests.
509    
510     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
511     the end of the subject string, contrary to the documentation and to what
512     Perl does. This was true of both matching functions. Now it matches only at
513     the start of the subject and immediately after *internal* newlines.
514    
515     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
516     a pointer to an int instead of a pointer to an unsigned long int. This
517     caused problems on 64-bit systems.
518    
519     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
520     instance of the 'standard' template library not being so standard".
521    
522     10. There was no check on the number of named subpatterns nor the maximum
523     length of a subpattern name. The product of these values is used to compute
524     the size of the memory block for a compiled pattern. By supplying a very
525     long subpattern name and a large number of named subpatterns, the size
526     computation could be caused to overflow. This is now prevented by limiting
527     the length of names to 32 characters, and the number of named subpatterns
528     to 10,000.
529    
530     11. Subpatterns that are repeated with specific counts have to be replicated in
531     the compiled pattern. The size of memory for this was computed from the
532     length of the subpattern and the repeat count. The latter is limited to
533     65535, but there was no limit on the former, meaning that integer overflow
534     could in principle occur. The compiled length of a repeated subpattern is
535     now limited to 30,000 bytes in order to prevent this.
536    
537     12. Added the optional facility to have named substrings with the same name.
538    
539     13. Added the ability to use a named substring as a condition, using the
540     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
541     are numbers (not recommended). Forward references are permitted.
542    
543     14. Added forward references in named backreferences (if you see what I mean).
544    
545     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
546     pattern could run off the end of the subject. For example, the pattern
547     "(?s)(.{1,5})"8 did this with the subject "ab".
548    
549     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
550     PCRE_CASELESS was set when matching characters that were quantified with ?
551     or *.
552    
553     17. A character class other than a single negated character that had a minimum
554     but no maximum quantifier - for example [ab]{6,} - was not handled
555     correctly by pce_dfa_exec(). It would match only one character.
556    
557     18. A valid (though odd) pattern that looked like a POSIX character
558     class but used an invalid character after [ (for example [[,abc,]]) caused
559     pcre_compile() to give the error "Failed: internal error: code overflow" or
560     in some cases to crash with a glibc free() error. This could even happen if
561     the pattern terminated after [[ but there just happened to be a sequence of
562     letters, a binary zero, and a closing ] in the memory that followed.
563    
564     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
565     over the years. Originally (before any Unicode support), just the bottom 8
566     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
567     output from "man perlunicode" includes this:
568    
569     The regular expression compiler produces polymorphic opcodes. That
570     is, the pattern adapts to the data and automatically switches to
571     the Unicode character scheme when presented with Unicode data--or
572     instead uses a traditional byte scheme when presented with byte
573     data.
574    
575     Sadly, a wide octal escape does not cause a switch, and in a string with
576     no other multibyte characters, these octal escapes are treated as before.
577     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
578     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
579     Unicode string.
580    
581     I have not perpetrated such confusion in PCRE. Up till now, it took just
582     the bottom 8 bits, as in old Perl. I have now made octal escapes with
583     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
584     translate to the appropriate multibyte character.
585    
586     29. Applied some refactoring to reduce the number of warnings from Microsoft
587     and Borland compilers. This has included removing the fudge introduced
588     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
589     a warning about an unused variable.
590    
591     21. PCRE has not included VT (character 0x0b) in the set of whitespace
592     characters since release 4.0, because Perl (from release 5.004) does not.
593     [Or at least, is documented not to: some releases seem to be in conflict
594     with the documentation.] However, when a pattern was studied with
595     pcre_study() and all its branches started with \s, PCRE still included VT
596     as a possible starting character. Of course, this did no harm; it just
597     caused an unnecessary match attempt.
598    
599     22. Removed a now-redundant internal flag bit that recorded the fact that case
600     dependency changed within the pattern. This was once needed for "required
601     byte" processing, but is no longer used. This recovers a now-scarce options
602     bit. Also moved the least significant internal flag bit to the most-
603     significant bit of the word, which was not previously used (hangover from
604     the days when it was an int rather than a uint) to free up another bit for
605     the future.
606    
607     23. Added support for CRLF line endings as well as CR and LF. As well as the
608     default being selectable at build time, it can now be changed at runtime
609     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
610     specify that it is scanning data with non-default line endings.
611    
612     24. Changed the definition of CXXLINK to make it agree with the definition of
613     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
614    
615     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
616     recursions. This makes a big different to stack usage for some patterns.
617    
618     26. If a subpattern containing a named recursion or subroutine reference such
619     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
620     the space required for the compiled pattern went wrong and gave too small a
621     value. Depending on the environment, this could lead to "Failed: internal
622     error: code overflow at offset 49" or "glibc detected double free or
623     corruption" errors.
624    
625     27. Applied patches from Google (a) to support the new newline modes and (b) to
626     advance over multibyte UTF-8 characters in GlobalReplace.
627    
628     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
629     difference for some implementation of PCRE in some Windows version.
630    
631     29. Added some extra testing facilities to pcretest:
632    
633     \q<number> in a data line sets the "match limit" value
634     \Q<number> in a data line sets the "match recursion limt" value
635     -S <number> sets the stack size, where <number> is in megabytes
636    
637     The -S option isn't available for Windows.
638    
639    
640 nigel 89 Version 6.6 06-Feb-06
641     ---------------------
642    
643     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
644     in pcreposix.h. I have copied the definition from pcre.h.
645    
646     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
647     because pcre.h is no longer a built file.
648    
649     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
650     not normally included in the compiled code.
651    
652    
653 nigel 87 Version 6.5 01-Feb-06
654     ---------------------
655    
656     1. When using the partial match feature with pcre_dfa_exec(), it was not
657     anchoring the second and subsequent partial matches at the new starting
658     point. This could lead to incorrect results. For example, with the pattern
659     /1234/, partially matching against "123" and then "a4" gave a match.
660    
661     2. Changes to pcregrep:
662    
663     (a) All non-match returns from pcre_exec() were being treated as failures
664     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
665     error message is output. Some extra information is given for the
666     PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
667     probably the only errors that are likely to be caused by users (by
668     specifying a regex that has nested indefinite repeats, for instance).
669     If there are more than 20 of these errors, pcregrep is abandoned.
670    
671     (b) A binary zero was treated as data while matching, but terminated the
672     output line if it was written out. This has been fixed: binary zeroes
673     are now no different to any other data bytes.
674    
675     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
676     used to set a locale for matching. The --locale=xxxx long option has
677     been added (no short equivalent) to specify a locale explicitly on the
678     pcregrep command, overriding the environment variables.
679    
680     (d) When -B was used with -n, some line numbers in the output were one less
681     than they should have been.
682    
683     (e) Added the -o (--only-matching) option.
684    
685     (f) If -A or -C was used with -c (count only), some lines of context were
686     accidentally printed for the final match.
687    
688     (g) Added the -H (--with-filename) option.
689    
690     (h) The combination of options -rh failed to suppress file names for files
691     that were found from directory arguments.
692    
693     (i) Added the -D (--devices) and -d (--directories) options.
694    
695     (j) Added the -F (--fixed-strings) option.
696    
697     (k) Allow "-" to be used as a file name for -f as well as for a data file.
698    
699     (l) Added the --colo(u)r option.
700    
701     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
702     is not present by default.
703    
704     3. A nasty bug was discovered in the handling of recursive patterns, that is,
705     items such as (?R) or (?1), when the recursion could match a number of
706     alternatives. If it matched one of the alternatives, but subsequently,
707     outside the recursion, there was a failure, the code tried to back up into
708     the recursion. However, because of the way PCRE is implemented, this is not
709     possible, and the result was an incorrect result from the match.
710    
711     In order to prevent this happening, the specification of recursion has
712     been changed so that all such subpatterns are automatically treated as
713     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
714    
715     4. I had overlooked the fact that, in some locales, there are characters for
716     which isalpha() is true but neither isupper() nor islower() are true. In
717     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
718     and ordfeminine) are like this. This affected the treatment of \w and \W
719     when they appeared in character classes, but not when they appeared outside
720     a character class. The bit map for "word" characters is now created
721     separately from the results of isalnum() instead of just taking it from the
722     upper, lower, and digit maps. (Plus the underscore character, of course.)
723    
724     5. The above bug also affected the handling of POSIX character classes such as
725     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
726     permanent tables. Instead, the bit maps for such a class were previously
727     created as the appropriate unions of the upper, lower, and digit bitmaps.
728     Now they are created by subtraction from the [[:word:]] class, which has
729     its own bitmap.
730    
731     6. The [[:blank:]] character class matches horizontal, but not vertical space.
732     It is created by subtracting the vertical space characters (\x09, \x0a,
733     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
734     subtraction was done in the overall bitmap for a character class, meaning
735     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
736     be recognized. This bug has been fixed.
737    
738     7. Patches from the folks at Google:
739    
740     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
741     real life, but is still worth protecting against".
742    
743     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
744     regular expressions".
745    
746     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
747     have it.
748    
749     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
750     "configure" and the latter not, in order to fix a problem somebody had
751     with compiling the Arg class on HP-UX.
752    
753     (e) Improve the error-handling of the C++ wrapper a little bit.
754    
755     (f) New tests for checking recursion limiting.
756    
757     8. The pcre_memmove() function, which is used only if the environment does not
758     have a standard memmove() function (and is therefore rarely compiled),
759     contained two bugs: (a) use of int instead of size_t, and (b) it was not
760     returning a result (though PCRE never actually uses the result).
761    
762     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
763     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
764     returned instead of calling malloc() with an overflowing number that would
765     most likely cause subsequent chaos.
766    
767     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
768    
769     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
770     with this option is matched, the nmatch and pmatch options of regexec() are
771     ignored.
772    
773     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
774     provided in case anyone wants to the the POSIX interface with UTF-8
775     strings.
776    
777     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
778     C++ linking (needed for some HP-UX environments).
779    
780     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
781     (unused parameter) and in the pcre_printint() function (omitted "default"
782     switch label when the default is to do nothing).
783    
784     15. Added some code to make it possible, when PCRE is compiled as a C++
785     library, to replace subject pointers for pcre_exec() with a smart pointer
786     class, thus making it possible to process discontinuous strings.
787    
788     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
789     much the same function. They were added by different people who were trying
790     to make PCRE easy to compile on non-Unix systems. It has been suggested
791     that PCRE_EXPORT be abolished now that there is more automatic apparatus
792     for compiling on Windows systems. I have therefore replaced it with
793     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
794     defaults to "extern" for C or "extern C" for C++, which works fine on
795     Unix-like systems. It is now possible to override the value of PCRE_DATA_
796     SCOPE with something explicit in config.h. In addition:
797    
798     (a) pcreposix.h still had just "extern" instead of either of these macros;
799     I have replaced it with PCRE_DATA_SCOPE.
800    
801     (b) Functions such as _pcre_xclass(), which are internal to the library,
802     but external in the C sense, all had PCRE_EXPORT in their definitions.
803     This is apparently wrong for the Windows case, so I have removed it.
804     (It makes no difference on Unix-like systems.)
805    
806     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
807     of recursive calls to match(). This is different to MATCH_LIMIT because
808     that limits the total number of calls to match(), not all of which increase
809     the depth of recursion. Limiting the recursion depth limits the amount of
810     stack (or heap if NO_RECURSE is set) that is used. The default can be set
811     when PCRE is compiled, and changed at run time. A patch from Google adds
812     this functionality to the C++ interface.
813    
814     18. Changes to the handling of Unicode character properties:
815    
816     (a) Updated the table to Unicode 4.1.0.
817    
818     (b) Recognize characters that are not in the table as "Cn" (undefined).
819    
820     (c) I revised the way the table is implemented to a much improved format
821     which includes recognition of ranges. It now supports the ranges that
822     are defined in UnicodeData.txt, and it also amalgamates other
823     characters into ranges. This has reduced the number of entries in the
824     table from around 16,000 to around 3,000, thus reducing its size
825     considerably. I realized I did not need to use a tree structure after
826     all - a binary chop search is just as efficient. Having reduced the
827     number of entries, I extended their size from 6 bytes to 8 bytes to
828     allow for more data.
829    
830     (d) Added support for Unicode script names via properties such as \p{Han}.
831    
832     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
833     matching that character.
834    
835     20. When matching a repeated Unicode property with a minimum greater than zero,
836     (for example \pL{2,}), PCRE could look past the end of the subject if it
837     reached it while seeking the minimum number of characters. This could
838     happen only if some of the characters were more than one byte long, because
839     there is a check for at least the minimum number of bytes.
840    
841     21. Refactored the implementation of \p and \P so as to be more general, to
842     allow for more different types of property in future. This has changed the
843     compiled form incompatibly. Anybody with saved compiled patterns that use
844     \p or \P will have to recompile them.
845    
846     22. Added "Any" and "L&" to the supported property types.
847    
848     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
849     but give a compile time error if the value is greater than 0xff.
850    
851     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
852     accidentally not being installed or uninstalled.
853    
854     25. The pcre.h file was built from pcre.h.in, but the only changes that were
855     made were to insert the current release number. This seemed silly, because
856     it made things harder for people building PCRE on systems that don't run
857     "configure". I have turned pcre.h into a distributed file, no longer built
858     by "configure", with the version identification directly included. There is
859     no longer a pcre.h.in file.
860    
861     However, this change necessitated a change to the pcre-config script as
862     well. It is built from pcre-config.in, and one of the substitutions was the
863     release number. I have updated configure.ac so that ./configure now finds
864     the release number by grepping pcre.h.
865    
866     26. Added the ability to run the tests under valgrind.
867    
868    
869 nigel 85 Version 6.4 05-Sep-05
870     ---------------------
871    
872     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
873     "--" to be printed when multiple files were scanned, even when none of the
874     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
875     consider it to be a bug, and have restored the previous behaviour.
876    
877     2. A couple of code tidies to get rid of compiler warnings.
878    
879     3. The pcretest program used to cheat by referring to symbols in the library
880     whose names begin with _pcre_. These are internal symbols that are not
881     really supposed to be visible externally, and in some environments it is
882     possible to suppress them. The cheating is now confined to including
883     certain files from the library's source, which is a bit cleaner.
884    
885     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
886     file's purpose clearer.
887    
888     5. Reorganized pcre_ucp_findchar().
889    
890    
891 nigel 83 Version 6.3 15-Aug-05
892     ---------------------
893    
894     1. The file libpcre.pc.in did not have general read permission in the tarball.
895    
896     2. There were some problems when building without C++ support:
897    
898     (a) If C++ support was not built, "make install" and "make test" still
899     tried to test it.
900    
901     (b) There were problems when the value of CXX was explicitly set. Some
902     changes have been made to try to fix these, and ...
903    
904     (c) --disable-cpp can now be used to explicitly disable C++ support.
905    
906     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
907     backslash in a target when C++ was disabled. This confuses some
908     versions of "make", apparently. Using an intermediate variable solves
909     this. (Same for CPP_LOBJ.)
910    
911     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
912     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
913     necessary on certain architectures.
914    
915     4. Added a setting of -export-symbols-regex to the link command to remove
916     those symbols that are exported in the C sense, but actually are local
917     within the library, and not documented. Their names all begin with
918     "_pcre_". This is not a perfect job, because (a) we have to except some
919     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
920     available (and never for static libraries). I have made a note to try to
921     find a way round (a) in the future.
922    
923    
924 nigel 81 Version 6.2 01-Aug-05
925     ---------------------
926    
927     1. There was no test for integer overflow of quantifier values. A construction
928     such as {1111111111111111} would give undefined results. What is worse, if
929     a minimum quantifier for a parenthesized subpattern overflowed and became
930     negative, the calculation of the memory size went wrong. This could have
931     led to memory overwriting.
932    
933     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
934    
935     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
936     operating environments where this matters.
937    
938     4. Applied Giuseppe Maxia's patch to add additional features for controlling
939     PCRE options from within the C++ wrapper.
940    
941     5. Named capturing subpatterns were not being correctly counted when a pattern
942     was compiled. This caused two problems: (a) If there were more than 100
943     such subpatterns, the calculation of the memory needed for the whole
944     compiled pattern went wrong, leading to an overflow error. (b) Numerical
945     back references of the form \12, where the number was greater than 9, were
946     not recognized as back references, even though there were sufficient
947     previous subpatterns.
948    
949     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
950     versions of gcc, e.g. 2.95.4.
951    
952    
953 nigel 79 Version 6.1 21-Jun-05
954     ---------------------
955    
956     1. There was one reference to the variable "posix" in pcretest.c that was not
957     surrounded by "#if !defined NOPOSIX".
958    
959     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
960     the cross-check on the old pcre_info() function, for the benefit of the
961     cut-down version of PCRE that is currently imported into Exim.
962    
963     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
964     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
965     patterns that start (?i) but I don't think that matters. The use of (?i) is
966     just an example; this all applies to the other options as well.
967    
968     4. Since libtool seems to echo the compile commands it is issuing, the output
969     from "make" can be reduced a bit by putting "@" in front of each libtool
970     compile command.
971    
972     5. Patch from the folks at Google for configure.in to be a bit more thorough
973     in checking for a suitable C++ installation before trying to compile the
974     C++ stuff. This should fix a reported problem when a compiler was present,
975     but no suitable headers.
976    
977     6. The man pages all had just "PCRE" as their title. I have changed them to
978     be the relevant file name. I have also arranged that these names are
979     retained in the file doc/pcre.txt, which is a concatenation in text format
980     of all the man pages except the little individual ones for each function.
981    
982     7. The NON-UNIX-USE file had not been updated for the different set of source
983     files that come with release 6. I also added a few comments about the C++
984     wrapper.
985    
986    
987 nigel 77 Version 6.0 07-Jun-05
988     ---------------------
989    
990     1. Some minor internal re-organization to help with my DFA experiments.
991    
992     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
993     didn't matter for the library itself when fully configured, but did matter
994     when compiling without UCP support, or within Exim, where the ucp files are
995     not imported.
996    
997     3. Refactoring of the library code to split up the various functions into
998     different source modules. The addition of the new DFA matching code (see
999     below) to a single monolithic source would have made it really too
1000     unwieldy, quite apart from causing all the code to be include in a
1001     statically linked application, when only some functions are used. This is
1002     relevant even without the DFA addition now that patterns can be compiled in
1003     one application and matched in another.
1004    
1005     The downside of splitting up is that there have to be some external
1006     functions and data tables that are used internally in different modules of
1007     the library but which are not part of the API. These have all had their
1008     names changed to start with "_pcre_" so that they are unlikely to clash
1009     with other external names.
1010    
1011     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1012     a different (DFA) algorithm. Although it is slower than the original
1013     function, it does have some advantages for certain types of matching
1014     problem.
1015    
1016     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1017     including restarting after a partial match.
1018    
1019     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1020     defined when compiling for Windows was sent to me. I have put it into the
1021     code, though I have no means of testing or verifying it.
1022    
1023     7. Added the pcre_refcount() auxiliary function.
1024    
1025     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1026     match before or at the first newline in the subject string. In pcretest,
1027     the /f option on a pattern can be used to set this.
1028    
1029     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1030     would behave wrongly. This has been present in PCRE since release 4.0.
1031    
1032     10. A number of changes to the pcregrep command:
1033    
1034     (a) Refactored how -x works; insert ^(...)$ instead of setting
1035     PCRE_ANCHORED and checking the length, in preparation for adding
1036     something similar for -w.
1037    
1038     (b) Added the -w (match as a word) option.
1039    
1040     (c) Refactored the way lines are read and buffered so as to have more
1041     than one at a time available.
1042    
1043     (d) Implemented a pcregrep test script.
1044    
1045     (e) Added the -M (multiline match) option. This allows patterns to match
1046     over several lines of the subject. The buffering ensures that at least
1047     8K, or the rest of the document (whichever is the shorter) is available
1048     for matching (and similarly the previous 8K for lookbehind assertions).
1049    
1050     (f) Changed the --help output so that it now says
1051    
1052     -w, --word-regex(p)
1053    
1054     instead of two lines, one with "regex" and the other with "regexp"
1055     because that confused at least one person since the short forms are the
1056     same. (This required a bit of code, as the output is generated
1057     automatically from a table. It wasn't just a text change.)
1058    
1059     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1060     option but starts with a hyphen. Could be a pattern or a path name
1061     starting with a hyphen, for instance.
1062    
1063     (h) "-" can be given as a file name to represent stdin.
1064    
1065     (i) When file names are being printed, "(standard input)" is used for
1066     the standard input, for compatibility with GNU grep. Previously
1067     "<stdin>" was used.
1068    
1069     (j) The option --label=xxx can be used to supply a name to be used for
1070     stdin when file names are being printed. There is no short form.
1071    
1072     (k) Re-factored the options decoding logic because we are going to add
1073     two more options that take data. Such options can now be given in four
1074     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1075    
1076     (l) Added the -A, -B, and -C options for requesting that lines of context
1077     around matches be printed.
1078    
1079     (m) Added the -L option to print the names of files that do not contain
1080     any matching lines, that is, the complement of -l.
1081    
1082     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1083     continue to scan other files.
1084    
1085     (o) The -s option was incorrectly implemented. For compatibility with other
1086     greps, it now suppresses the error message for a non-existent or non-
1087     accessible file (but not the return code). There is a new option called
1088     -q that suppresses the output of matching lines, which was what -s was
1089     previously doing.
1090    
1091     (p) Added --include and --exclude options to specify files for inclusion
1092     and exclusion when recursing.
1093    
1094     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1095     Hopefully, it now does.
1096    
1097     12. Missing cast in pcre_study().
1098    
1099     13. Added an "uninstall" target to the makefile.
1100    
1101     14. Replaced "extern" in the function prototypes in Makefile.in with
1102     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1103     world, but is set differently for Windows.
1104    
1105     15. Added a second compiling function called pcre_compile2(). The only
1106     difference is that it has an extra argument, which is a pointer to an
1107     integer error code. When there is a compile-time failure, this is set
1108     non-zero, in addition to the error test pointer being set to point to an
1109     error message. The new argument may be NULL if no error number is required
1110     (but then you may as well call pcre_compile(), which is now just a
1111     wrapper). This facility is provided because some applications need a
1112     numeric error indication, but it has also enabled me to tidy up the way
1113     compile-time errors are handled in the POSIX wrapper.
1114    
1115     16. Added VPATH=.libs to the makefile; this should help when building with one
1116     prefix path and installing with another. (Or so I'm told by someone who
1117     knows more about this stuff than I do.)
1118    
1119     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1120     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1121     match everything, including newlines. This is not POSIX-compatible, but
1122     somebody wanted the feature. From pcretest it can be activated by using
1123     both the P and the s flags.
1124    
1125     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1126    
1127     19. libpcre.pc was being incorrectly installed as executable.
1128    
1129     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1130     it now also looks for '\r' so that it will work unmodified on Windows.
1131    
1132     21. Added Google's contributed C++ wrapper to the distribution.
1133    
1134     22. Added some untidy missing memory free() calls in pcretest, to keep
1135     Electric Fence happy when testing.
1136    
1137    
1138    
1139 nigel 75 Version 5.0 13-Sep-04
1140     ---------------------
1141    
1142     1. Internal change: literal characters are no longer packed up into items
1143     containing multiple characters in a single byte-string. Each character
1144     is now matched using a separate opcode. However, there may be more than one
1145     byte in the character in UTF-8 mode.
1146    
1147     2. The pcre_callout_block structure has two new fields: pattern_position and
1148     next_item_length. These contain the offset in the pattern to the next match
1149     item, and its length, respectively.
1150    
1151     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1152     insertion of callouts before each pattern item. Added the /C option to
1153     pcretest to make use of this.
1154    
1155     4. On the advice of a Windows user, the lines
1156    
1157     #if defined(_WIN32) || defined(WIN32)
1158     _setmode( _fileno( stdout ), 0x8000 );
1159     #endif /* defined(_WIN32) || defined(WIN32) */
1160    
1161     have been added to the source of pcretest. This apparently does useful
1162     magic in relation to line terminators.
1163    
1164     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1165     for the benefit of those environments where the "b" makes a difference.
1166    
1167     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1168     to know about it. I have put a hack into configure.in that adds in code
1169     to set GCC=yes if CC=icc. This seems to end up at a point in the
1170     generated configure script that is early enough to affect the setting of
1171     compiler options, which is what is needed, but I have no means of testing
1172     whether it really works. (The user who reported this had patched the
1173     generated configure script, which of course I cannot do.)
1174    
1175     LATER: After change 22 below (new libtool files), the configure script
1176     seems to know about icc (and also ecc). Therefore, I have commented out
1177     this hack in configure.in.
1178    
1179     7. Added support for pkg-config (2 patches were sent in).
1180    
1181     8. Negated POSIX character classes that used a combination of internal tables
1182     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1183     [[:^ascii]]. Typically, they would match almost any characters. The other
1184     POSIX classes were not broken in this way.
1185    
1186     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1187     to find the match, as PCRE was deluded into thinking that the match had to
1188     start at the start point or following a newline. The same bug applied to
1189     patterns with negative forward assertions or any backward assertions
1190     preceding ".*" at the start, unless the pattern required a fixed first
1191     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1192    
1193     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1194     starting at the last subject character, bytes beyond the end of the subject
1195     string were read.
1196    
1197     11. Renamed the variable "class" as "classbits" to make life easier for C++
1198     users. (Previously there was a macro definition, but it apparently wasn't
1199     enough.)
1200    
1201     12. Added the new field "tables" to the extra data so that tables can be passed
1202     in at exec time, or the internal tables can be re-selected. This allows
1203     a compiled regex to be saved and re-used at a later time by a different
1204     program that might have everything at different addresses.
1205    
1206     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1207     -R library as well as a -L library.
1208    
1209     14. The debugging options of pcretest (-d on the command line or D on a
1210     pattern) showed incorrect output for anything following an extended class
1211     that contained multibyte characters and which was followed by a quantifier.
1212    
1213     15. Added optional support for general category Unicode character properties
1214     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1215     support. It adds about 90K to the size of the library. The meanings of the
1216     inbuilt class escapes such as \d and \s have NOT been changed.
1217    
1218     16. Updated pcredemo.c to include calls to free() to release the memory for the
1219     compiled pattern.
1220    
1221     17. The generated file chartables.c was being created in the source directory
1222     instead of in the building directory. This caused the build to fail if the
1223     source directory was different from the building directory, and was
1224     read-only.
1225    
1226     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1227     file. No doubt somebody will tell me if they don't make sense... Also added
1228     Dan Mooney's comments about building on OpenVMS.
1229    
1230     19. Added support for partial matching via the PCRE_PARTIAL option for
1231     pcre_exec() and the \P data escape in pcretest.
1232    
1233     20. Extended pcretest with 3 new pattern features:
1234    
1235     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1236     write the compiled pattern to the file whose name is "rest-of-line".
1237     This is a straight binary dump of the data, with the saved pointer to
1238     the character tables forced to be NULL. The study data, if any, is
1239     written too. After writing, pcretest reads a new pattern.
1240    
1241     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1242     compiled pattern from the given file. There must not be any
1243     occurrences of "<" in the file name (pretty unlikely); if there are,
1244     pcretest will instead treat the initial "<" as a pattern delimiter.
1245     After reading in the pattern, pcretest goes on to read data lines as
1246     usual.
1247    
1248     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1249     and 16-bit fields in a compiled pattern, to simulate a pattern that
1250     was compiled on a host of opposite endianness.
1251    
1252     21. The pcre-exec() function can now cope with patterns that were compiled on
1253     hosts of opposite endianness, with this restriction:
1254    
1255     As for any compiled expression that is saved and used later, the tables
1256     pointer field cannot be preserved; the extra_data field in the arguments
1257     to pcre_exec() should be used to pass in a tables address if a value
1258     other than the default internal tables were used at compile time.
1259    
1260     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1261     now diagnosed as an error. Previously, most of the time, a negative number
1262     would have been treated as zero, but if in addition "ovector" was passed as
1263     NULL, a crash could occur.
1264    
1265     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1266     new versions from the libtool 1.5 distribution (the last one is a copy of
1267     a file called libtool.m4). This seems to have fixed the need to patch
1268     "configure" to support Darwin 1.3 (which I used to do). However, I still
1269     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1270     workstation).
1271    
1272     24. Changed the PCRE licence to be the more standard "BSD" licence.
1273    
1274    
1275 nigel 73 Version 4.5 01-Dec-03
1276     ---------------------
1277    
1278     1. There has been some re-arrangement of the code for the match() function so
1279     that it can be compiled in a version that does not call itself recursively.
1280     Instead, it keeps those local variables that need separate instances for
1281     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1282     needs to "recurse". Keeping track of where control must go is done by means
1283     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1284     hide most of the details from the main code, and operates only if
1285     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1286     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1287     operating.
1288    
1289     To make it easier for callers to provide specially tailored get/free
1290     functions for this usage, two new functions, pcre_stack_malloc, and
1291     pcre_stack_free, are used. They are always called in strict stacking order,
1292     and the size of block requested is always the same.
1293    
1294     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1295     PCRE has been compiled to use the stack or the heap for recursion. The
1296     -C option of pcretest uses this to show which version is compiled.
1297    
1298     A new data escape \S, is added to pcretest; it causes the amounts of store
1299     obtained and freed by both kinds of malloc/free at match time to be added
1300     to the output.
1301    
1302     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1303     what's available on my current Linux desktop machine.
1304    
1305     3. When matching a UTF-8 string, the test for a valid string at the start has
1306     been extended. If start_offset is not zero, PCRE now checks that it points
1307     to a byte that is the start of a UTF-8 character. If not, it returns
1308     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1309     this is necessary because there may be backward assertions in the pattern.
1310     When matching the same subject several times, it may save resources to use
1311     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1312    
1313     4. The code for checking the validity of UTF-8 strings has been tightened so
1314     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1315     containing "overlong sequences".
1316    
1317     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1318     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1319     should have been "&", but it just so happened that all the cases this let
1320     through by mistake were picked up later in the function.
1321    
1322     6. I had used a variable called "isblank" - this is a C99 function, causing
1323     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1324    
1325     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1326     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1327     so the version is shown; (c) stop "make test" echoing "./RunTest".
1328    
1329     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1330    
1331     9. The prototype for memmove() for systems that don't have it was using
1332     size_t, but the inclusion of the header that defines size_t was later. I've
1333     moved the #includes for the C headers earlier to avoid this.
1334    
1335     10. Added some adjustments to the code to make it easier to compiler on certain
1336     special systems:
1337    
1338     (a) Some "const" qualifiers were missing.
1339     (b) Added the macro EXPORT before all exported functions; by default this
1340     is defined to be empty.
1341     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1342     that it reads its output file name as an argument instead of writing
1343     to the standard output and assuming this can be redirected.
1344    
1345     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1346     class containing characters with values greater than 255, PCRE compilation
1347     went into a loop.
1348    
1349     12. A recursive reference to a subpattern that was within another subpattern
1350     that had a minimum quantifier of zero caused PCRE to crash. For example,
1351     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1352     recursion. If the recursively-called subpattern itself had a zero repeat,
1353     that was OK.
1354    
1355     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1356     buffer into which it was copied (for escape processing) was still set at
1357     1024, so long lines caused crashes.
1358    
1359     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1360     "internal error: code overflow...". This applied to any character class
1361     that was followed by a possessive quantifier.
1362    
1363     15. Modified the Makefile to add libpcre.la as a prerequisite for
1364     libpcreposix.la because I was told this is needed for a parallel build to
1365     work.
1366    
1367     16. If a pattern that contained .* following optional items at the start was
1368     studied, the wrong optimizing data was generated, leading to matching
1369     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1370     matching string must start with a or b or c. The correct conclusion for
1371     this pattern is that a match can start with any character.
1372    
1373    
1374 nigel 71 Version 4.4 13-Aug-03
1375     ---------------------
1376    
1377     1. In UTF-8 mode, a character class containing characters with values between
1378     127 and 255 was not handled correctly if the compiled pattern was studied.
1379     In fixing this, I have also improved the studying algorithm for such
1380     classes (slightly).
1381    
1382     2. Three internal functions had redundant arguments passed to them. Removal
1383     might give a very teeny performance improvement.
1384    
1385     3. Documentation bug: the value of the capture_top field in a callout is *one
1386     more than* the number of the hightest numbered captured substring.
1387    
1388     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1389     in incorrectly linking with a previously installed version. They now link
1390     explicitly with libpcre.la.
1391    
1392     5. configure.in no longer needs to recognize Cygwin specially.
1393    
1394     6. A problem in pcre.in for Windows platforms is fixed.
1395    
1396     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1397     pcretest, it used to include the size of the study block as part of its
1398     output. Unfortunately, the structure contains a field that has a different
1399     size on different hardware architectures. This meant that the tests that
1400     showed this size failed. As the block is currently always of a fixed size,
1401     this information isn't actually particularly useful in pcretest output, so
1402     I have just removed it.
1403    
1404     8. Three pre-processor statements accidentally did not start in column 1.
1405     Sadly, there are *still* compilers around that complain, even though
1406     standard C has not required this for well over a decade. Sigh.
1407    
1408     9. In pcretest, the code for checking callouts passed small integers in the
1409     callout_data field, which is a void * field. However, some picky compilers
1410     complained about the casts involved for this on 64-bit systems. Now
1411     pcretest passes the address of the small integer instead, which should get
1412     rid of the warnings.
1413    
1414     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1415     both compile and run time, and gives an error if an invalid UTF-8 sequence
1416     is found. There is a option for disabling this check in cases where the
1417     string is known to be correct and/or the maximum performance is wanted.
1418    
1419     11. In response to a bug report, I changed one line in Makefile.in from
1420    
1421     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1422     to
1423     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1424    
1425     to look similar to other lines, but I have no way of telling whether this
1426     is the right thing to do, as I do not use Windows. No doubt I'll get told
1427     if it's wrong...
1428    
1429    
1430 nigel 69 Version 4.3 21-May-03
1431     ---------------------
1432    
1433     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1434     Makefile.
1435    
1436     2. Some refactoring to improve the quality of the code:
1437    
1438     (i) The utf8_table... variables are now declared "const".
1439    
1440     (ii) The code for \cx, which used the "case flipping" table to upper case
1441     lower case letters, now just substracts 32. This is ASCII-specific,
1442     but the whole concept of \cx is ASCII-specific, so it seems
1443     reasonable.
1444    
1445     (iii) PCRE was using its character types table to recognize decimal and
1446     hexadecimal digits in the pattern. This is silly, because it handles
1447     only 0-9, a-f, and A-F, but the character types table is locale-
1448     specific, which means strange things might happen. A private
1449     table is now used for this - though it costs 256 bytes, a table is
1450     much faster than multiple explicit tests. Of course, the standard
1451     character types table is still used for matching digits in subject
1452     strings against \d.
1453    
1454     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1455     ending in _t are). So I've renamed it as ESC_tee.
1456    
1457     3. The first argument for regexec() in the POSIX wrapper should have been
1458     defined as "const".
1459    
1460     4. Changed pcretest to use malloc() for its buffers so that they can be
1461     Electric Fenced for debugging.
1462    
1463     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1464     to read one or more bytes before the start of the subject string. Often this
1465     had no effect on PCRE's behaviour, but in some circumstances it could
1466     provoke a segmentation fault.
1467    
1468     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1469     to try to read one or more bytes before the start of the subject string.
1470    
1471     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1472     UTF-8 support could misbehave in various ways if the subject string
1473     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1474     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1475     back over UTF-8 characters.)
1476    
1477    
1478 nigel 67 Version 4.2 14-Apr-03
1479     ---------------------
1480    
1481     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1482    
1483     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1484     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1485     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1486     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1487     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1488     and BUILD_EXEEXT
1489     Note: automatic setting of the BUILD variables is not yet working
1490     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1491     compile-time but not at link-time
1492     [LINK]: use for linking executables only
1493     make different versions for Windows and non-Windows
1494     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1495     libraries
1496     [LINK_FOR_BUILD]: new variable
1497     [OBJEXT]: use throughout
1498     [EXEEXT]: use throughout
1499     <winshared>: new target
1500     <wininstall>: new target
1501     <dftables.o>: use native compiler
1502     <dftables>: use native linker
1503     <install>: handle Windows platform correctly
1504     <clean>: ditto
1505     <check>: ditto
1506     copy DLL to top builddir before testing
1507    
1508     As part of these changes, -no-undefined was removed again. This was reported
1509     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1510     in any case.
1511    
1512     3. Some tidies to get rid of compiler warnings:
1513    
1514     . In the match_data structure, match_limit was an unsigned long int, whereas
1515     match_call_count was an int. I've made them both unsigned long ints.
1516    
1517     . In pcretest the fact that a const uschar * doesn't automatically cast to
1518     a void * provoked a warning.
1519    
1520     . Turning on some more compiler warnings threw up some "shadow" variables
1521     and a few more missing casts.
1522    
1523     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1524     option, a class that contained a single character with a value between 128
1525     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1526    
1527     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1528     option, a class that contained several characters, but with at least one
1529     whose value was between 128 and 255 caused PCRE to crash.
1530    
1531    
1532 nigel 65 Version 4.1 12-Mar-03
1533     ---------------------
1534 nigel 63
1535 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1536     needed, and a string in dftables.c that was longer than standard compilers are
1537     required to support.
1538    
1539     2. Compiling with Sun's compiler found a few more places where the code could
1540     be tidied up in order to avoid warnings.
1541    
1542     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1543     first of these names is deprecated in the latest Autoconf in favour of the name
1544     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1545     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1546     analogy I have changed it to CFLAGS_FOR_BUILD.
1547    
1548     4. Added -no-undefined to the linking command in the Makefile, because this is
1549     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1550     linking step for the pcreposix library.
1551    
1552     5. PCRE was failing to diagnose the case of two named groups with the same
1553     name.
1554    
1555     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1556     literal character that is needed in the subject for a match, and scans along to
1557     ensure that it is present before embarking on the full matching process. This
1558     saves time in cases of nested unlimited repeats that are never going to match.
1559     Problem: the scan can take a lot of time if the subject is very long (e.g.
1560     megabytes), thus penalizing straightforward matches. It is now done only if the
1561     amount of subject to be scanned is less than 1000 bytes.
1562    
1563     7. A lesser problem with the same optimization is that it was recording the
1564     first character of an anchored pattern as "needed", thus provoking a search
1565     right along the subject, even when the first match of the pattern was going to
1566     fail. The "needed" character is now not set for anchored patterns, unless it
1567     follows something in the pattern that is of non-fixed length. Thus, it still
1568     fulfils its original purpose of finding quick non-matches in cases of nested
1569     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1570    
1571    
1572     Version 4.0 17-Feb-03
1573     ---------------------
1574    
1575 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1576     extended to the end of string, PCRE compiled incorrect data. This could lead to
1577     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1578    
1579     2. Moved to autoconf 2.53 and libtool 1.4.2.
1580    
1581     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1582     the special perltest8 script is no longer needed - all the tests can be run
1583     from a single perltest script.
1584    
1585     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1586     by \s. It has now been removed in PCRE. This means it isn't recognized as
1587     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1588     class [:space:] *does* include VT, thereby creating a mess.
1589    
1590     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1591     space and tab.
1592    
1593     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1594     its new features into the main test script, reducing the number of scripts.
1595    
1596     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1597     were backward compatible, and made the (?i) apply to the whole pattern, as if
1598     /i were given. Now it behaves more logically, and applies the option setting
1599     only to what follows. PCRE has been changed to follow suit. However, if it
1600     finds options settings right at the start of the pattern, it extracts them into
1601     the global options, as before. Thus, they show up in the info data.
1602    
1603     8. Added support for the \Q...\E escape sequence. Characters in between are
1604     treated as literals. This is slightly different from Perl in that $ and @ are
1605     also handled as literals inside the quotes. In Perl, they will cause variable
1606     interpolation. Note the following examples:
1607    
1608     Pattern PCRE matches Perl matches
1609    
1610     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1611     \Qabc\$xyz\E abc\$xyz abc\$xyz
1612     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1613    
1614     For compatibility with Perl, \Q...\E sequences are recognized inside character
1615     classes as well as outside them.
1616    
1617     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1618     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1619     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1620     signed/unsigned warnings.
1621    
1622     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1623     option for pcretest, so I've replaced it by a simple function that does just
1624     that job.
1625    
1626     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1627     "pcregrep -".
1628    
1629     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1630     Java package. This provides some syntactic sugar for simple cases of what my
1631     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1632     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1633     item, you can use this simplified notation. Note that only makes sense with
1634     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1635     greediness, whatever the setting of the PCRE_UNGREEDY option.
1636    
1637     13. A change of greediness default within a pattern was not taking effect at
1638     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1639     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1640     was abstracted outside.
1641    
1642     14. PCRE now supports the \G assertion. It is true when the current matching
1643     position is at the start point of the match. This differs from \A when the
1644     starting offset is non-zero. Used with the /g option of pcretest (or similar
1645     code), it works in the same way as it does for Perl's /g option. If all
1646     alternatives of a regex begin with \G, the expression is anchored to the start
1647     match position, and the "anchored" flag is set in the compiled expression.
1648    
1649     15. Some bugs concerning the handling of certain option changes within patterns
1650     have been fixed. These applied to options other than (?ims). For example,
1651     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1652     been the other way round. Some of this was related to change 7 above.
1653    
1654     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1655     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1656     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1657     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1658    
1659     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1660     mode. Unlike ".", it always matches newline, whatever the setting of
1661     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1662     assertions. Perl allows it, but it doesn't (in general) work because it can't
1663     calculate the length of the lookbehind. At least, that's the case for Perl
1664     5.8.0 - I've been told they are going to document that it doesn't work in
1665     future.
1666    
1667     18. Added an error diagnosis for escapes that PCRE does not support: these are
1668     \L, \l, \N, \P, \p, \U, \u, and \X.
1669    
1670     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1671     reading past the end of the pattern in cases such as /[abcd/.
1672    
1673     20. PCRE was getting more memory than necessary for patterns with classes that
1674     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1675    
1676     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1677     compiling PCRE for use with Virtual Pascal.
1678    
1679     22. Small fix to the Makefile to make it work properly if the build is done
1680     outside the source tree.
1681    
1682     23. Added a new extension: a condition to go with recursion. If a conditional
1683     subpattern starts with (?(R) the "true" branch is used if recursion has
1684     happened, whereas the "false" branch is used only at the top level.
1685    
1686     24. When there was a very long string of literal characters (over 255 bytes
1687     without UTF support, over 250 bytes with UTF support), the computation of how
1688     much memory was required could be incorrect, leading to segfaults or other
1689     strange effects.
1690    
1691     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1692     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1693     there was a subsequent back reference to those brackets. This meant that, for
1694     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1695     possible to check for precisely this case. All we can do is abandon the
1696     optimization if .* occurs inside capturing brackets when there are any back
1697     references whatsoever. (See below for a better fix that came later.)
1698    
1699     26. The handling of the optimization for finding the first character of a
1700     non-anchored pattern, and for finding a character that is required later in the
1701     match were failing in some cases. This didn't break the matching; it just
1702     failed to optimize when it could. The way this is done has been re-implemented.
1703    
1704     27. Fixed typo in error message for invalid (?R item (it said "(?p").
1705    
1706     28. Added a new feature that provides some of the functionality that Perl
1707     provides with (?{...}). The facility is termed a "callout". The way it is done
1708     in PCRE is for the caller to provide an optional function, by setting
1709     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1710     global variable. By default it is unset, which disables all calling out. To get
1711     the function called, the regex must include (?C) at appropriate points. This
1712     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1713     This provides a means of identifying different callout points. When PCRE
1714     reaches such a point in the regex, if pcre_callout has been set, the external
1715     function is called. It is provided with data in a structure called
1716     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1717     matching continues; if it returns a non-zero value, the match at the current
1718     point fails. However, backtracking will occur if possible. [This was changed
1719     later and other features added - see item 49 below.]
1720    
1721     29. pcretest is upgraded to test the callout functionality. It provides a
1722     callout function that displays information. By default, it shows the start of
1723     the match and the current position in the text. There are some new data escapes
1724     to vary what happens:
1725    
1726     \C+ in addition, show current contents of captured substrings
1727     \C- do not supply a callout function
1728     \C!n return 1 when callout number n is reached
1729     \C!n!m return 1 when callout number n is reached for the mth time
1730    
1731     30. If pcregrep was called with the -l option and just a single file name, it
1732     output "<stdin>" if a match was found, instead of the file name.
1733    
1734     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1735     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1736     pcre_exec(). This saves a malloc/free per call. The default value of
1737     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1738     when configuring.
1739    
1740     32. The default maximum size of a compiled pattern is 64K. There have been a
1741     few cases of people hitting this limit. The code now uses macros to handle the
1742     storing of links as offsets within the compiled pattern. It defaults to 2-byte
1743     links, but this can be changed to 3 or 4 bytes by --with-link-size when
1744     configuring. Tests 2 and 5 work only with 2-byte links because they output
1745     debugging information about compiled patterns.
1746    
1747     33. Internal code re-arrangements:
1748    
1749     (a) Moved the debugging function for printing out a compiled regex into
1750     its own source file (printint.c) and used #include to pull it into
1751     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1752     separate copies.
1753    
1754     (b) Defined the list of op-code names for debugging as a macro in
1755     internal.h so that it is next to the definition of the opcodes.
1756    
1757     (c) Defined a table of op-code lengths for simpler skipping along compiled
1758     code. This is again a macro in internal.h so that it is next to the
1759     definition of the opcodes.
1760    
1761     34. Added support for recursive calls to individual subpatterns, along the
1762     lines of Robin Houston's patch (but implemented somewhat differently).
1763    
1764     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1765     allow it to read and process whole directories in Win32. This code was
1766     contributed by Lionel Fourquaux; it has not been tested by me.
1767    
1768     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1769     used to name a group. Names consist of alphanumerics and underscores, and must
1770     be unique. Back references use the syntax (?P=name) and recursive calls use
1771     (?P>name) which is a PCRE extension to the Python extension. Groups still have
1772     numbers. The function pcre_fullinfo() can be used after compilation to extract
1773     a name/number map. There are three relevant calls:
1774    
1775     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1776     PCRE_INFO_NAMECOUNT yields the number of entries
1777     PCRE_INFO_NAMETABLE yields a pointer to the map.
1778    
1779     The map is a vector of fixed-size entries. The size of each entry depends on
1780     the length of the longest name used. The first two bytes of each entry are the
1781     group number, most significant byte first. There follows the corresponding
1782     name, zero terminated. The names are in alphabetical order.
1783    
1784     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1785     case instead of 255. Making it the same both with and without UTF-8 support
1786     means that the same test output works with both.
1787    
1788     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1789     calling malloc() with a zero argument.
1790    
1791     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1792     optimization. I've improved things by keeping a bitmap of backreferences with
1793     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1794     fact referenced, the optimization can be applied. It is unlikely that a
1795     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1796     the match to follow \n) will appear inside brackets with a number greater than
1797     31, but if it does, any back reference > 31 suppresses the optimization.
1798    
1799     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1800     of disabling numbered capturing parentheses. Any opening parenthesis that is
1801     not followed by ? behaves as if it were followed by ?: but named parentheses
1802     can still be used for capturing (and they will acquire numbers in the usual
1803     way).
1804    
1805     41. Redesigned the return codes from the match() function into yes/no/error so
1806     that errors can be passed back from deep inside the nested calls. A malloc
1807     failure while inside a recursive subpattern call now causes the
1808     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1809    
1810     42. It is now possible to set a limit on the number of times the match()
1811     function is called in a call to pcre_exec(). This facility makes it possible to
1812     limit the amount of recursion and backtracking, though not in a directly
1813     obvious way, because the match() function is used in a number of different
1814     circumstances. The count starts from zero for each position in the subject
1815     string (for non-anchored patterns). The default limit is, for compatibility, a
1816     large number, namely 10 000 000. You can change this in two ways:
1817    
1818     (a) When configuring PCRE before making, you can use --with-match-limit=n
1819     to set a default value for the compiled library.
1820    
1821     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1822     a different value is set. See 45 below.
1823    
1824     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1825    
1826     43. Added a new function pcre_config(int, void *) to enable run-time extraction
1827     of things that can be changed at compile time. The first argument specifies
1828     what is wanted and the second points to where the information is to be placed.
1829     The current list of available information is:
1830    
1831     PCRE_CONFIG_UTF8
1832    
1833     The output is an integer that is set to one if UTF-8 support is available;
1834     otherwise it is set to zero.
1835    
1836     PCRE_CONFIG_NEWLINE
1837    
1838     The output is an integer that it set to the value of the code that is used for
1839     newline. It is either LF (10) or CR (13).
1840    
1841     PCRE_CONFIG_LINK_SIZE
1842    
1843     The output is an integer that contains the number of bytes used for internal
1844     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1845    
1846     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
1847    
1848     The output is an integer that contains the threshold above which the POSIX
1849     interface uses malloc() for output vectors. See item 31 above.
1850    
1851     PCRE_CONFIG_MATCH_LIMIT
1852    
1853     The output is an unsigned integer that contains the default limit of the number
1854     of match() calls in a pcre_exec() execution. See 42 above.
1855    
1856     44. pcretest has been upgraded by the addition of the -C option. This causes it
1857     to extract all the available output from the new pcre_config() function, and to
1858     output it. The program then exits immediately.
1859    
1860     45. A need has arisen to pass over additional data with calls to pcre_exec() in
1861     order to support additional features. One way would have been to define
1862     pcre_exec2() (for example) with extra arguments, but this would not have been
1863     extensible, and would also have required all calls to the original function to
1864     be mapped to the new one. Instead, I have chosen to extend the mechanism that
1865     is used for passing in "extra" data from pcre_study().
1866    
1867     The pcre_extra structure is now exposed and defined in pcre.h. It currently
1868     contains the following fields:
1869    
1870     flags a bitmap indicating which of the following fields are set
1871     study_data opaque data from pcre_study()
1872     match_limit a way of specifying a limit on match() calls for a specific
1873     call to pcre_exec()
1874     callout_data data for callouts (see 49 below)
1875    
1876     The flag bits are also defined in pcre.h, and are
1877    
1878     PCRE_EXTRA_STUDY_DATA
1879     PCRE_EXTRA_MATCH_LIMIT
1880     PCRE_EXTRA_CALLOUT_DATA
1881    
1882     The pcre_study() function now returns one of these new pcre_extra blocks, with
1883     the actual study data pointed to by the study_data field, and the
1884     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1885     before. That is, this change is entirely upwards-compatible and requires no
1886     change to existing code.
1887    
1888     If you want to pass in additional data to pcre_exec(), you can either place it
1889     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1890     block.
1891    
1892     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1893     data string contains the escape sequence \M, pcretest calls pcre_exec() several
1894     times with different match limits, until it finds the minimum value needed for
1895     pcre_exec() to complete. The value is then output. This can be instructive; for
1896     most simple matches the number is quite small, but for pathological cases it
1897     gets very large very quickly.
1898    
1899     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1900     returns the size of the data block pointed to by the study_data field in a
1901     pcre_extra block, that is, the value that was passed as the argument to
1902     pcre_malloc() when PCRE was getting memory in which to place the information
1903     created by pcre_study(). The fourth argument should point to a size_t variable.
1904     pcretest has been extended so that this information is shown after a successful
1905     pcre_study() call when information about the compiled regex is being displayed.
1906    
1907     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1908     because what follows is always an absolute path. (Later: it turns out that this
1909     is more than cosmetic for MinGW, because it doesn't like empty path
1910     components.)
1911    
1912     49. Some changes have been made to the callout feature (see 28 above):
1913    
1914     (i) A callout function now has three choices for what it returns:
1915    
1916     0 => success, carry on matching
1917     > 0 => failure at this point, but backtrack if possible
1918     < 0 => serious error, return this value from pcre_exec()
1919    
1920     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1921     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1922     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1923     use by callout functions. It will never be used by PCRE itself.
1924    
1925     (ii) The pcre_extra structure (see 45 above) has a void * field called
1926     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1927     pcre_callout_block structure has a field of the same name. The contents of
1928     the field passed in the pcre_extra structure are passed to the callout
1929     function in the corresponding field in the callout block. This makes it
1930     easier to use the same callout-containing regex from multiple threads. For
1931     testing, the pcretest program has a new data escape
1932    
1933     \C*n pass the number n (may be negative) as callout_data
1934    
1935     If the callout function in pcretest receives a non-zero value as
1936     callout_data, it returns that value.
1937    
1938     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1939     there were some redundant $(CFLAGS) in commands that are now specified as
1940     $(LINK), which already includes $(CFLAGS).
1941    
1942     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1943     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1944     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1945     one-byte characters throughout. Note that case-insensitive matching applies
1946     only to characters whose values are less than 256. PCRE doesn't support the
1947     notion of cases for higher-valued characters.
1948    
1949     (i) A character class whose characters are all within 0-255 is handled as
1950     a bit map, and the map is inverted for negative classes. Previously, a
1951     character > 255 always failed to match such a class; however it should
1952     match if the class was a negative one (e.g. [^ab]). This has been fixed.
1953    
1954     (ii) A negated character class with a single character < 255 is coded as
1955     "not this character" (OP_NOT). This wasn't working properly when the test
1956     character was multibyte, either singly or repeated.
1957    
1958     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1959     mode, for example: \x{100}{2,3}.
1960    
1961     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1962     singly or repeated) now correctly test multibyte characters. However,
1963     PCRE doesn't recognize any characters with values greater than 255 as
1964     digits, spaces, or word characters. Such characters always match \D, \S,
1965     and \W, and never match \d, \s, or \w.
1966    
1967     (v) Classes may now contain characters and character ranges with values
1968     greater than 255. For example: [ab\x{100}-\x{400}].
1969    
1970     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1971     PCRE in UTF-8 mode.
1972    
1973     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1974     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1975     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1976     value.)
1977    
1978     53. The single man page has become too large. I have therefore split it up into
1979     a number of separate man pages. These also give rise to individual HTML pages;
1980     these are now put in a separate directory, and there is an index.html page that
1981     lists them all. Some hyperlinking between the pages has been installed.
1982    
1983     54. Added convenience functions for handling named capturing parentheses.
1984    
1985     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1986     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1987     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1988     are faulted.
1989    
1990     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1991     calling configure. These values are used when compiling the dftables.c program
1992     which is run to generate the source of the default character tables. They
1993     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1994     you will need to set these values.
1995    
1996     57. Updated the building process for Windows DLL, as provided by Fred Cox.
1997    
1998    
1999     Version 3.9 02-Jan-02
2000 nigel 61 ---------------------
2001    
2002     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2003    
2004     2. If --disable-static was given, the building process failed when trying to
2005     build pcretest and pcregrep. (For some reason it was using libtool to compile
2006     them, which is not right, as they aren't part of the library.)
2007    
2008    
2009 nigel 59 Version 3.8 18-Dec-01
2010     ---------------------
2011    
2012     1. The experimental UTF-8 code was completely screwed up. It was packing the
2013     bytes in the wrong order. How dumb can you get?
2014    
2015    
2016 nigel 57 Version 3.7 29-Oct-01
2017     ---------------------
2018    
2019     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2020     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2021     this didn't happen under Solaris 8, where I normally test things.
2022    
2023 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2024     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2025     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2026     this fix an hour or so after the initial 3.7 release.)
2027 nigel 57
2028 nigel 59
2029 nigel 55 Version 3.6 23-Oct-01
2030     ---------------------
2031    
2032     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2033     offsets passed as NULL with zero offset count.
2034    
2035     2. The config.guess and config.sub files had not been updated when I moved to
2036     the latest autoconf.
2037    
2038    
2039 nigel 53 Version 3.5 15-Aug-01
2040     ---------------------
2041 nigel 5
2042 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2043     had been forgotten.
2044    
2045     2. By using declared but undefined structures, we can avoid using "void"
2046     definitions in pcre.h while keeping the internal definitions of the structures
2047     private.
2048    
2049     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2050     user point of view, this means that both static and shared libraries are built
2051     by default, but this can be individually controlled. More of the work of
2052     handling this static/shared cases is now inside libtool instead of PCRE's make
2053     file.
2054    
2055     4. The pcretest utility is now installed along with pcregrep because it is
2056     useful for users (to test regexs) and by doing this, it automatically gets
2057     relinked by libtool. The documentation has been turned into a man page, so
2058     there are now .1, .txt, and .html versions in /doc.
2059    
2060     5. Upgrades to pcregrep:
2061     (i) Added long-form option names like gnu grep.
2062     (ii) Added --help to list all options with an explanatory phrase.
2063     (iii) Added -r, --recursive to recurse into sub-directories.
2064     (iv) Added -f, --file to read patterns from a file.
2065    
2066     6. pcre_exec() was referring to its "code" argument before testing that
2067     argument for NULL (and giving an error if it was NULL).
2068    
2069     7. Upgraded Makefile.in to allow for compiling in a different directory from
2070     the source directory.
2071    
2072     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2073     options bits, the pointer it was passed was to an int instead of to an unsigned
2074     long int. This mattered only on 64-bit systems.
2075    
2076     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2077     generated) instead of pcre.in, which it its source. Also made the same change
2078     in several of the .c files.
2079    
2080     10. A new release of gcc defines printf() as a macro, which broke pcretest
2081     because it had an ifdef in the middle of a string argument for printf(). Fixed
2082     by using separate calls to printf().
2083    
2084     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2085     script, to force use of CR or LF instead of \n in the source. On non-Unix
2086     systems, the value can be set in config.h.
2087    
2088     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2089     absolute limit. Changed the text of the error message to make this clear, and
2090     likewise updated the man page.
2091    
2092     13. The limit of 99 on the number of capturing subpatterns has been removed.
2093     The new limit is 65535, which I hope will not be a "real" limit.
2094    
2095    
2096 nigel 51 Version 3.4 22-Aug-00
2097     ---------------------
2098    
2099     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2100    
2101     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2102    
2103    
2104 nigel 49 Version 3.3 01-Aug-00
2105     ---------------------
2106    
2107     1. If an octal character was given, but the value was greater than \377, it
2108     was not getting masked to the least significant bits, as documented. This could
2109     lead to crashes in some systems.
2110    
2111     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2112     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2113    
2114     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2115     These just pass their arguments on to (pcre_free)(), but they are provided
2116     because some uses of PCRE bind it to non-C systems that can call its functions,
2117     but cannot call free() or pcre_free() directly.
2118    
2119     4. Add "make test" as a synonym for "make check". Corrected some comments in
2120     the Makefile.
2121    
2122     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2123     Makefile.
2124    
2125     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2126     command called pgrep for grepping around the active processes.
2127    
2128     7. Added the beginnings of support for UTF-8 character strings.
2129    
2130     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2131     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2132     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2133     out for the ar command.)
2134    
2135    
2136 nigel 47 Version 3.2 12-May-00
2137     ---------------------
2138    
2139     This is purely a bug fixing release.
2140    
2141     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2142     of ZA. This was just one example of several cases that could provoke this bug,
2143     which was introduced by change 9 of version 2.00. The code for breaking
2144     infinite loops after an iteration that matches an empty string was't working
2145     correctly.
2146    
2147     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2148     when matched against abbab (for example). After matching an empty string, it
2149     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2150     caused it to match further down the string than it should.
2151    
2152     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2153     was there because it doesn't seem to be needed, and it causes trouble on some
2154     systems, as it is not a Standard C header. It has been removed.
2155    
2156     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2157     were reported on the Macintosh. The changes were from
2158    
2159     while ((c = *(++ptr)) != 0 && c != '\n');
2160     to
2161     while ((c = *(++ptr)) != 0 && c != '\n') ;
2162    
2163     Totally extraordinary, but if that's what it takes...
2164    
2165     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2166     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2167     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2168     assumes the way PCRE uses memmove() (always moving upwards).
2169    
2170     6. PCRE is being used in one environment where strchr() is not available. There
2171     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2172     faster code anyway.
2173    
2174    
2175 nigel 45 Version 3.1 09-Feb-00
2176     ---------------------
2177    
2178     The only change in this release is the fixing of some bugs in Makefile.in for
2179     the "install" target:
2180    
2181     (1) It was failing to install pcreposix.h.
2182    
2183     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2184    
2185    
2186 nigel 43 Version 3.0 01-Feb-00
2187     ---------------------
2188 nigel 41
2189     1. Add support for the /+ modifier to perltest (to output $` like it does in
2190     pcretest).
2191    
2192     2. Add support for the /g modifier to perltest.
2193    
2194     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2195     matches null strings.
2196    
2197     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2198     pattern. Perl treats empty patterns specially - it reuses the most recent
2199     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2200     effect.
2201    
2202     5. The POSIX interface was broken in that it was just handing over the POSIX
2203     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2204     required a bigger vector, with some working space on the end. This means that
2205     the POSIX wrapper now has to get and free some memory, and copy the results.
2206    
2207 nigel 43 6. Added some simple autoconf support, placing the test data and the
2208     documentation in separate directories, re-organizing some of the
2209     information files, and making it build pcre-config (a GNU standard). Also added
2210     libtool support for building PCRE as a shared library, which is now the
2211     default.
2212 nigel 41
2213 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2214     09 are not valid octal constants. Single digits will be used for minor values
2215     less than 10.
2216    
2217     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2218     existing programs that set these in the POSIX interface can use PCRE without
2219     modification.
2220    
2221     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2222     return all that pcre_info() returns, plus additional data. The pcre_info()
2223     function is retained for compatibility, but is considered to be obsolete.
2224    
2225     10. Added experimental recursion feature (?R) to handle one common case that
2226     Perl 5.6 will be able to do with (?p{...}).
2227    
2228     11. Added support for POSIX character classes like [:alpha:], which Perl is
2229     adopting.
2230    
2231    
2232 nigel 39 Version 2.08 31-Aug-99
2233     ----------------------
2234    
2235     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2236     trying to match at the startoffset position, but instead was moving forward to
2237     the next newline as if a previous match had failed.
2238    
2239     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2240     and could get into a loop if a null string was matched other than at the start
2241     of the subject.
2242    
2243     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2244     be distinguished at compile time, and for completeness also added PCRE_DATE.
2245    
2246     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2247     in GnuWin32 environments.
2248    
2249    
2250 nigel 37 Version 2.07 29-Jul-99
2251     ----------------------
2252    
2253     1. The documentation is now supplied in plain text form and HTML as well as in
2254     the form of man page sources.
2255    
2256     2. C++ compilers don't like assigning (void *) values to other pointer types.
2257     In particular this affects malloc(). Although there is no problem in Standard
2258     C, I've put in casts to keep C++ compilers happy.
2259    
2260     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2261     should be (const char *).
2262    
2263     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2264     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2265     However, I haven't made this a standard facility. The documentation doesn't
2266     mention it, and the Makefile doesn't support it.
2267    
2268     5. The Makefile now contains an "install" target, with editable destinations at
2269     the top of the file. The pcretest program is not installed.
2270    
2271     6. pgrep -V now gives the PCRE version number and date.
2272    
2273     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2274     causing the entire string to be ignored, instead of just the last character.
2275    
2276     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2277     non-matching string, it can take a very, very long time, even for strings of
2278     quite modest length, because of the nested recursion. PCRE now does better in
2279     some of these cases. It does this by remembering the last required literal
2280     character in the pattern, and pre-searching the subject to ensure it is present
2281     before running the real match. In other words, it applies a heuristic to detect
2282     some types of certain failure quickly, and in the above example, if presented
2283     with a string that has no trailing " it gives "no match" very quickly.
2284    
2285     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2286     other alternatives are tried instead.
2287    
2288    
2289 nigel 35 Version 2.06 09-Jun-99
2290     ----------------------
2291    
2292     1. Change pcretest's output for amount of store used to show just the code
2293     space, because the remainder (the data block) varies in size between 32-bit and
2294     64-bit systems.
2295    
2296     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2297     start matching at. This allows lookbehinds to work when searching for multiple
2298     occurrences in a string.
2299    
2300     3. Added additional options to pcretest for testing multiple occurrences:
2301    
2302     /+ outputs the rest of the string that follows a match
2303     /g loops for multiple occurrences, using the new startoffset argument
2304     /G loops for multiple occurrences by passing an incremented pointer
2305    
2306     4. PCRE wasn't doing the "first character" optimization for patterns starting
2307     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2308     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2309     the letter 'x'. On long subject strings, this gives a significant speed-up.
2310    
2311    
2312 nigel 33 Version 2.05 21-Apr-99
2313     ----------------------
2314    
2315     1. Changed the type of magic_number from int to long int so that it works
2316     properly on 16-bit systems.
2317    
2318     2. Fixed a bug which caused patterns starting with .* not to work correctly
2319     when the subject string contained newline characters. PCRE was assuming
2320     anchoring for such patterns in all cases, which is not correct because .* will
2321     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2322     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2323     must be retried after every newline in the subject.
2324    
2325    
2326 nigel 31 Version 2.04 18-Feb-99
2327     ----------------------
2328    
2329     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2330     computation of the store needed to hold the pattern was incorrect (too large).
2331     If such patterns were nested a few deep, this could multiply and become a real
2332     problem.
2333    
2334     2. Added /M option to pcretest to show the memory requirement of a specific
2335     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2336    
2337     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2338     compiled in such a way that the backtracking after subsequent failure was
2339     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2340     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2341    
2342    
2343 nigel 29 Version 2.03 02-Feb-99
2344     ----------------------
2345    
2346     1. Fixed typo and small mistake in man page.
2347    
2348 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2349     LICENCE file containing the conditions.
2350 nigel 29
2351     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2352     Perl, that is the internal \ allows the delimiter to be included in the
2353     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2354     the final delimiter, add \ to the end of the pattern (to test the error).
2355    
2356     4. Added the convenience functions for extracting substrings after a successful
2357     match. Updated pcretest to make it able to test these functions.
2358    
2359    
2360 nigel 27 Version 2.02 14-Jan-99
2361     ----------------------
2362    
2363     1. Initialized the working variables associated with each extraction so that
2364     their saving and restoring doesn't refer to uninitialized store.
2365    
2366     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2367     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2368     fix the problem.
2369    
2370     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2371     calls, and wasn't printing the correct value for compiling calls. Increased the
2372     default value of LOOPREPEAT, and the number of significant figures in the
2373     times.
2374    
2375     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2376    
2377     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2378     a building problem on Windows NT with a FAT file system.
2379    
2380    
2381 nigel 25 Version 2.01 21-Oct-98
2382     ----------------------
2383    
2384     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2385     to character tables built by pcre_maketables() in the current locale. If NULL
2386     is passed, the default tables are used.
2387    
2388    
2389 nigel 23 Version 2.00 24-Sep-98
2390 nigel 21 ----------------------
2391    
2392 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2393     it any more.
2394    
2395     2. Allow quantification of (?>) groups, and make it work correctly.
2396    
2397     3. The first character computation wasn't working for (?>) groups.
2398    
2399     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2400     end of the subject) and add 5.005's \z, which really does match only at the
2401     very end of the subject.
2402    
2403     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2404    
2405     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2406     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2407     localized options. All options to pcre_study() were also removed.
2408    
2409     7. Add other new features from 5.005:
2410    
2411     $(?<= positive lookbehind
2412     $(?<! negative lookbehind
2413     (?imsx-imsx) added the unsetting capability
2414     such a setting is global if at outer level; local otherwise
2415     (?imsx-imsx:) non-capturing groups with option setting
2416     (?(cond)re|re) conditional pattern matching
2417    
2418     A backreference to itself in a repeated group matches the previous
2419     captured string.
2420    
2421     8. General tidying up of studying (both automatic and via "study")
2422     consequential on the addition of new assertions.
2423    
2424     9. As in 5.005, unlimited repeated groups that could match an empty substring
2425     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2426     runtime if any iteration does actually match an empty substring.
2427    
2428     10. Include the RunTest script in the distribution.
2429    
2430     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2431     discrepancies, some of which were old and were also with respect to 5.004. They
2432     have now been fixed.
2433    
2434    
2435     Version 1.09 28-Apr-98
2436     ----------------------
2437    
2438 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2439     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2440     program crashes, or just wrong answers. This did not apply to negated classes
2441     containing more than one character, or to minima other than one.
2442    
2443    
2444 nigel 19 Version 1.08 27-Mar-98
2445     ----------------------
2446    
2447     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2448    
2449     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2450     latter must appear before anything that relies on it in the pattern.
2451    
2452    
2453 nigel 17 Version 1.07 16-Feb-98
2454     ----------------------
2455    
2456     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2457     repeat of a potentially empty string).
2458    
2459    
2460 nigel 15 Version 1.06 23-Jan-98
2461     ----------------------
2462    
2463     1. Added Markus Oberhumer's little patches for C++.
2464    
2465     2. Literal strings longer than 255 characters were broken.
2466    
2467    
2468 nigel 13 Version 1.05 23-Dec-97
2469     ----------------------
2470    
2471     1. Negated character classes containing more than one character were failing if
2472     PCRE_CASELESS was set at run time.
2473    
2474    
2475 nigel 11 Version 1.04 19-Dec-97
2476     ----------------------
2477    
2478     1. Corrected the man page, where some "const" qualifiers had been omitted.
2479    
2480     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2481     input syntax.
2482    
2483     3. Fixed memory leak which occurred when a regex with back references was
2484     matched with an offsets vector that wasn't big enough. The temporary memory
2485     that is used in this case wasn't being freed if the match failed.
2486    
2487     4. Tidied pcretest to ensure it frees memory that it gets.
2488    
2489     5. Temporary memory was being obtained in the case where the passed offsets
2490     vector was exactly big enough.
2491    
2492     6. Corrected definition of offsetof() from change 5 below.
2493    
2494     7. I had screwed up change 6 below and broken the rules for the use of
2495     setjmp(). Now fixed.
2496    
2497    
2498 nigel 9 Version 1.03 18-Dec-97
2499     ----------------------
2500    
2501     1. A erroneous regex with a missing opening parenthesis was correctly
2502     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2503     on some systems.
2504    
2505     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2506     it was reported that one broken compiler failed on the former because "code" is
2507     also an independent variable.
2508    
2509     3. The erroneous regex a[]b caused an array overrun reference.
2510    
2511     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2512     fail on data ending with that character. (It was going on too far, and checking
2513     the next character, typically a binary zero.) This was specific to the
2514     optimized code for single-character negative classes.
2515    
2516     5. Added a contributed patch from the TIN world which does the following:
2517    
2518     + Add an undef for memmove, in case the the system defines a macro for it.
2519    
2520     + Add a definition of offsetof(), in case there isn't one. (I don't know
2521     the reason behind this - offsetof() is part of the ANSI standard - but
2522     it does no harm).
2523    
2524     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2525     most of the places where whitespace preceded '#'. I have given up and
2526     allowed the remaining 2 cases to be at the margin.
2527    
2528     + Rename some variables in pcre to eliminate shadowing. This seems very
2529     pedantic, but does no harm, of course.
2530    
2531     6. Moved the call to setjmp() into its own function, to get rid of warnings
2532     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2533    
2534     7. Constructs such as \d{8,} were compiling into the equivalent of
2535 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2536 nigel 9 outcome, but in this particular case used more store than had been allocated,
2537     which caused the bug to be discovered because it threw up an internal error.
2538    
2539     8. The debugging code in both pcre and pcretest for outputting the compiled
2540     form of a regex was going wrong in the case of back references followed by
2541     curly-bracketed repeats.
2542    
2543    
2544 nigel 7 Version 1.02 12-Dec-97
2545     ----------------------
2546    
2547     1. Typos in pcre.3 and comments in the source fixed.
2548    
2549     2. Applied a contributed patch to get rid of places where it used to remove
2550     'const' from variables, and fixed some signed/unsigned and uninitialized
2551     variable warnings.
2552    
2553     3. Added the "runtest" target to Makefile.
2554    
2555     4. Set default compiler flag to -O2 rather than just -O.
2556    
2557    
2558 nigel 5 Version 1.01 19-Nov-97
2559     ----------------------
2560    
2561     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2562     like /([ab]*)*/, that is, for classes with more than one character in them.
2563    
2564     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2565     as /((?>a*))*/ (a PCRE_EXTRA facility).
2566    
2567    
2568     Version 1.00 18-Nov-97
2569     ----------------------
2570    
2571     1. Added compile-time macros to support systems such as SunOS4 which don't have
2572     memmove() or strerror() but have other things that can be used instead.
2573    
2574     2. Arranged that "make clean" removes the executables.
2575    
2576    
2577 nigel 3 Version 0.99 27-Oct-97
2578     ----------------------
2579    
2580     1. Fixed bug in code for optimizing classes with only one character. It was
2581     initializing a 32-byte map regardless, which could cause it to run off the end
2582     of the memory it had got.
2583    
2584     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2585    
2586    
2587     Version 0.98 22-Oct-97
2588     ----------------------
2589    
2590     1. Fixed bug in code for handling temporary memory usage when there are more
2591     back references than supplied space in the ovector. This could cause segfaults.
2592    
2593    
2594     Version 0.97 21-Oct-97
2595     ----------------------
2596    
2597     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2598    
2599     2. Optimized negated single characters not to use a bit map.
2600    
2601     3. Brought error texts together as macro definitions; clarified some of them;
2602     fixed one that was wrong - it said "range out of order" when it meant "invalid
2603     escape sequence".
2604    
2605     4. Changed some char * arguments to const char *.
2606    
2607     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2608    
2609     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2610     pcretest.
2611    
2612    
2613     Version 0.96 16-Oct-97
2614     ----------------------
2615    
2616     1. Added a simple "pgrep" utility to the distribution.
2617    
2618     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2619     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2620     where "ddd" means "one or more decimal digits".
2621    
2622     3. Fixed serious bug. If a pattern had a back reference, but the call to
2623     pcre_exec() didn't supply a large enough ovector to record the related
2624     identifying subpattern, the match always failed. PCRE now remembers the number
2625     of the largest back reference, and gets some temporary memory in which to save
2626     the offsets during matching if necessary, in order to ensure that
2627     backreferences always work.
2628    
2629     4. Increased the compatibility with Perl in a number of ways:
2630    
2631     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2632     to request this handling. The option can be set at compile or exec time.
2633    
2634     (b) $ matches before a terminating newline by default; an option
2635     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2636     mode). The option can be set at compile or exec time.
2637    
2638     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2639     the same as Perl's. If the decimal number it represents is less than 10
2640     or there aren't that many previous left capturing parentheses, an octal
2641     escape is read. Inside a character class, it's always an octal escape,
2642     even if it is a single digit.
2643    
2644     (d) An escaped but undefined alphabetic character is taken as a literal,
2645     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2646     escapes.
2647    
2648     (e) {0} is now permitted. (The previous item is removed from the compiled
2649     pattern).
2650    
2651     5. Changed all the names of code files so that the basic parts are no longer
2652     than 10 characters, and abolished the teeny "globals.c" file.
2653    
2654     6. Changed the handling of character classes; they are now done with a 32-byte
2655     bit map always.
2656    
2657     7. Added the -d and /D options to pcretest to make it possible to look at the
2658     internals of compilation without having to recompile pcre.
2659    
2660    
2661     Version 0.95 23-Sep-97
2662     ----------------------
2663    
2664     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2665     \x20 at the start of a run of normal characters. These were being treated as
2666     real characters, instead of the source characters being re-checked.
2667    
2668    
2669     Version 0.94 18-Sep-97
2670     ----------------------
2671    
2672     1. The functions are now thread-safe, with the caveat that the global variables
2673     containing pointers to malloc() and free() or alternative functions are the
2674     same for all threads.
2675    
2676     2. Get pcre_study() to generate a bitmap of initial characters for non-
2677     anchored patterns when this is possible, and use it if passed to pcre_exec().
2678    
2679    
2680     Version 0.93 15-Sep-97
2681     ----------------------
2682    
2683     1. /(b)|(:+)/ was computing an incorrect first character.
2684    
2685     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2686     but not actually doing anything yet.
2687    
2688     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2689     as Perl does (e.g. [-az] or [az-]).
2690    
2691     4. Set the anchored flag if a branch starts with .* or .*? because that tests
2692     all possible positions.
2693    
2694     5. Split up into different modules to avoid including unneeded functions in a
2695     compiled binary. However, compile and exec are still in one module. The "study"
2696     function is split off.
2697    
2698     6. The character tables are now in a separate module whose source is generated
2699     by an auxiliary program - but can then be edited by hand if required. There are
2700     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2701     toupper() in the code.
2702    
2703     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2704     make them global. Abolish the function for setting them, as the caller can now
2705     set them directly.
2706    
2707    
2708     Version 0.92 11-Sep-97
2709     ----------------------
2710    
2711     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2712     (e.g. /a{1,3}/) was broken (I mis-optimized it).
2713    
2714     2. Caseless matching was not working in character classes if the characters in
2715     the pattern were in upper case.
2716    
2717     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2718    
2719     4. Make PCRE_ANCHORED public and accept as a compile option.
2720    
2721     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2722     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2723     pass them.
2724    
2725     6. Give an error if bad option bits passed at compile or run time.
2726    
2727     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2728     pcretest to cause it to pass that flag.
2729    
2730     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2731     options, and the first character, if set.
2732    
2733     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2734    
2735    
2736     Version 0.91 10-Sep-97
2737     ----------------------
2738    
2739     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2740     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2741    
2742     2. PCRE was looping on encountering an indefinitely repeated back reference to
2743     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2744     Perl does - treats the match as successful.
2745    
2746     ****

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