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Revision 175 - (hide annotations) (download)
Mon Jun 11 13:38:38 2007 UTC (7 years, 6 months ago) by ph10
File size: 129372 byte(s)
Added the Perl 5.10 (?| "branch reset" feature.

1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 ph10 172 Version 7.2 05-June-07
5 ph10 157 ---------------------
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 172
25 ph10 166 6. Added more features from the forthcoming Perl 5.10:
26 ph10 172
27 ph10 166 (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 ph10 172
30 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
31 ph10 172 to be opened parentheses.
32    
33     (c) Conditions that refer to capturing parentheses can be specified
34 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
35 ph10 172
36 ph10 168 (d) \K resets the start of the current match so that everything before
37 ph10 172 is not part of it.
38    
39 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
40 ph10 172
41 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
42 ph10 172 reference syntax.
43 ph10 175
44     (g) (?| introduces a group in which the numbering of parentheses in each
45     alternative starts with the same number.
46 ph10 172
47     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
48     PCRE_INFO_JCHANGED.
49    
50     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
51     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
52 ph10 170 for detecting groups that can match an empty string.
53 ph10 159
54 ph10 172 9. A pattern with a very large number of alternatives (more than several
55     hundred) was running out of internal workspace during the pre-compile
56     phase, where pcre_compile() figures out how much memory will be needed. A
57     bit of new cunning has reduced the workspace needed for groups with
58     alternatives. The 1000-alternative test pattern now uses 12 bytes of
59     workspace instead of running out of the 4096 that are available.
60    
61    
62 ph10 155 Version 7.1 24-Apr-07
63 ph10 98 ---------------------
64    
65 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
66 ph10 122 that is more "standard", making use of automake and other Autotools. There
67 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
68     on this.
69 ph10 111
70     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
71     for recursive directory scanning broke on some systems because the files
72     are not scanned in any specific order and on different systems the order
73     was different. A call to "sort" has been inserted into RunGrepTest for the
74     approprate test as a short-term fix. In the longer term there may be an
75 ph10 100 alternative.
76 ph10 111
77 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
78 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
79     people do their own conversions for various reasons). The problems
80     concerned the use of low-level troff macros .br and .in. I have therefore
81     removed all such uses from the man pages (some were redundant, some could
82 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
83     HTML has been updated to handle .nf/.fi and to complain if it encounters
84     .br or .in.
85 ph10 111
86 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
87 ph10 123 arranged for config.h to be included in the distribution, with the name
88 ph10 111 config.h.generic, for the benefit of those who have to compile without
89     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
90    
91     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
92     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
93 ph10 127 makevp.bat for the current PCRE, using the additional files
94 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
95 ph10 111
96     6. A Windows user reported a minor discrepancy with test 2, which turned out
97     to be caused by a trailing space on an input line that had got lost in his
98 ph10 102 copy. The trailing space was an accident, so I've just removed it.
99 ph10 111
100 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
101 ph10 111 that is needed.
102    
103 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
104     as "const" (a) because they are and (b) because it helps the PHP
105     maintainers who have recently made a script to detect big data structures
106 ph10 111 in the php code that should be moved to the .rodata section. I remembered
107     to update Builducptable as well, so it won't revert if ucptable.h is ever
108 ph10 105 re-created.
109 ph10 111
110     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
111 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
112 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
113     support is not required. This saves 1.5-2K of code, which is important in
114 ph10 107 some applications.
115 ph10 111
116 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
117 ph10 111 so as not to refer to the tables, even though these functions will never be
118     called when UTF-8 support is disabled. Otherwise there are problems with a
119     shared library.
120    
121 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
122    
123     (a) It was defining its arguments as char * instead of void *.
124    
125 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
126     a long time ago when I wrote it, but is no longer the case.
127    
128 ph10 118 The emulated memove() is provided for those environments that have neither
129 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
130 ph10 118 is clearly not the case, as these two bugs were recently reported.
131 ph10 123
132 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
133 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
134     pages, and it removes trailing spaces from listed files. It also creates
135     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
136     case, it wraps all the #defines with #ifndefs. This script should be run
137 ph10 111 before "make dist".
138 ph10 123
139 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
140     with Unicode property support.
141 ph10 123
142     (a) For a maximizing quantifier, if the two different cases of the
143     character were of different lengths in their UTF-8 codings (there are
144     some cases like this - I found 11), and the matching function had to
145 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
146     were both the same length.
147 ph10 123
148     (b) When PCRE was configured to use the heap rather than the stack for
149     recursion during matching, it was not correctly preserving the data for
150     the other case of a UTF-8 character when checking ahead for a match
151     while processing a minimizing repeat. If the check also involved
152 ph10 115 matching a wide character, but failed, corruption could cause an
153     erroneous result when trying to check for a repeat of the original
154     character.
155 ph10 123
156 ph10 116 13. Some tidying changes to the testing mechanism:
157 ph10 98
158 ph10 116 (a) The RunTest script now detects the internal link size and whether there
159     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
160 ph10 123 values substituted by "configure". (The RunGrepTest script already did
161     this for UTF-8.) The configure.ac script no longer substitutes the
162     relevant variables.
163    
164 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
165     with length and offset values. This means that the output is different
166     for different internal link sizes. Test 2 is skipped for link sizes
167     other than 2 because of this, bypassing the problem. Unfortunately,
168     there was also a test in test 3 (the locale tests) that used /B and
169 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
170     I have added a new /Z option to pcretest that replaces the length and
171     offset values with spaces. This is now used to make test 3 independent
172 ph10 122 of link size. (Test 2 will be tidied up later.)
173 ph10 123
174     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
175 ph10 122 segmentation fault instead of returning the appropriate error message.
176 ph10 134
177 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
178 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
179     This doesn't seem right; it now treats the CRLF combination as the line
180     ending, and so does not match in that case. It's only a pattern such as ^$
181     that would hit this one: something like ^ABC$ would have failed after \r
182     and then tried again after \r\n.
183    
184 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
185 ph10 134 in an attempt to make files that differ only in their line terminators
186     compare equal. This works on Linux.
187 ph10 142
188 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
189     as it exited. This is now fixed, thanks to valgrind.
190 ph10 142
191 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
192 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
193     was because its rules for how to advance for /g after matching an empty
194 ph10 143 string at the end of a line did not allow for this case. They now check for
195     it specially.
196 ph10 150
197     20. pcretest is supposed to handle patterns and data of any length, by
198     extending its buffers when necessary. It was getting this wrong when the
199 ph10 147 buffer for a data line had to be extended.
200 ph10 150
201 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
202 ph10 150 CRLF as a newline sequence.
203 ph10 152
204 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
205 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
206     I have nevertheless tidied it up.
207 ph10 111
208 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
209 ph10 123
210 ph10 153 24. Added a man page for pcre-config.
211 ph10 152
212 ph10 153
213 nigel 93 Version 7.0 19-Dec-06
214     ---------------------
215    
216     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
217     moving to gcc 4.1.1.
218    
219     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
220     sys/time.h, which is documented as needed for this function. It doesn't
221     seem to matter on Linux, but it showed up on some releases of OS X.
222    
223     3. It seems that there are systems where bytes whose values are greater than
224     127 match isprint() in the "C" locale. The "C" locale should be the
225     default when a C program starts up. In most systems, only ASCII printing
226     characters match isprint(). This difference caused the output from pcretest
227     to vary, making some of the tests fail. I have changed pcretest so that:
228    
229     (a) When it is outputting text in the compiled version of a pattern, bytes
230     other than 32-126 are always shown as hex escapes.
231    
232     (b) When it is outputting text that is a matched part of a subject string,
233     it does the same, unless a different locale has been set for the match
234     (using the /L modifier). In this case, it uses isprint() to decide.
235    
236     4. Fixed a major bug that caused incorrect computation of the amount of memory
237     required for a compiled pattern when options that changed within the
238     pattern affected the logic of the preliminary scan that determines the
239     length. The relevant options are -x, and -i in UTF-8 mode. The result was
240     that the computed length was too small. The symptoms of this bug were
241     either the PCRE error "internal error: code overflow" from pcre_compile(),
242     or a glibc crash with a message such as "pcretest: free(): invalid next
243     size (fast)". Examples of patterns that provoked this bug (shown in
244     pcretest format) are:
245    
246     /(?-x: )/x
247     /(?x)(?-x: \s*#\s*)/
248     /((?i)[\x{c0}])/8
249     /(?i:[\x{c0}])/8
250    
251     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
252     is now done differently.
253    
254     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
255     wrapper classes; (b) implement a new function in the C++ scanner that is
256     more efficient than the old way of doing things because it avoids levels of
257     recursion in the regex matching; (c) add a paragraph to the documentation
258     for the FullMatch() function.
259    
260     6. The escape sequence \n was being treated as whatever was defined as
261     "newline". Not only was this contrary to the documentation, which states
262     that \n is character 10 (hex 0A), but it also went horribly wrong when
263     "newline" was defined as CRLF. This has been fixed.
264    
265     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
266     was being set to -1 for the "end of line" case (supposedly a value that no
267     character can have). Though this value is never used (the check for end of
268     line is "zero bytes in current character"), it caused compiler complaints.
269     I've changed it to 0xffffffff.
270    
271     8. In pcre_version.c, the version string was being built by a sequence of
272     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
273     string (as it is for production releases) called a macro with an empty
274     argument. The C standard says the result of this is undefined. The gcc
275     compiler treats it as an empty string (which was what was wanted) but it is
276     reported that Visual C gives an error. The source has been hacked around to
277     avoid this problem.
278    
279     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
280     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
281     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
282     of them did).
283    
284     10. Originally, pcretest opened its input and output without "b"; then I was
285     told that "b" was needed in some environments, so it was added for release
286     5.0 to both the input and output. (It makes no difference on Unix-like
287     systems.) Later I was told that it is wrong for the input on Windows. I've
288     now abstracted the modes into two macros, to make it easier to fiddle with
289     them, and removed "b" from the input mode under Windows.
290    
291     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
292    
293     12. Added -help and --help to pcretest as an official way of being reminded
294     of the options.
295    
296     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
297     and pcrecpp.cc because they annoy compilers at high warning levels.
298    
299     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
300    
301     15. Fixed an occurrence of == in configure.ac that should have been = (shell
302     scripts are not C programs :-) and which was not noticed because it works
303     on Linux.
304    
305     16. pcretest is supposed to handle any length of pattern and data line (as one
306     line or as a continued sequence of lines) by extending its input buffer if
307     necessary. This feature was broken for very long pattern lines, leading to
308     a string of junk being passed to pcre_compile() if the pattern was longer
309     than about 50K.
310    
311     17. I have done a major re-factoring of the way pcre_compile() computes the
312     amount of memory needed for a compiled pattern. Previously, there was code
313     that made a preliminary scan of the pattern in order to do this. That was
314     OK when PCRE was new, but as the facilities have expanded, it has become
315     harder and harder to keep it in step with the real compile phase, and there
316     have been a number of bugs (see for example, 4 above). I have now found a
317     cunning way of running the real compile function in a "fake" mode that
318     enables it to compute how much memory it would need, while actually only
319     ever using a few hundred bytes of working memory and without too many
320     tests of the mode. This should make future maintenance and development
321     easier. A side effect of this work is that the limit of 200 on the nesting
322     depth of parentheses has been removed (though this was never a serious
323     limitation, I suspect). However, there is a downside: pcre_compile() now
324     runs more slowly than before (30% or more, depending on the pattern). I
325     hope this isn't a big issue. There is no effect on runtime performance.
326    
327     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
328     newline (only possible for the last line of a file) and it was a
329     pattern that set a locale (followed by /Lsomething), pcretest crashed.
330    
331     19. Added additional timing features to pcretest. (1) The -tm option now times
332     matching only, not compiling. (2) Both -t and -tm can be followed, as a
333     separate command line item, by a number that specifies the number of
334     repeats to use when timing. The default is 50000; this gives better
335     precision, but takes uncomfortably long for very large patterns.
336    
337     20. Extended pcre_study() to be more clever in cases where a branch of a
338     subpattern has no definite first character. For example, (a*|b*)[cd] would
339     previously give no result from pcre_study(). Now it recognizes that the
340     first character must be a, b, c, or d.
341    
342     21. There was an incorrect error "recursive call could loop indefinitely" if
343     a subpattern (or the entire pattern) that was being tested for matching an
344     empty string contained only one non-empty item after a nested subpattern.
345     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
346     incorrectly, because the \d was being skipped in the check.
347    
348     22. The pcretest program now has a new pattern option /B and a command line
349     option -b, which is equivalent to adding /B to every pattern. This causes
350     it to show the compiled bytecode, without the additional information that
351     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
352     is the same as /B/I).
353    
354     23. A new optimization is now able automatically to treat some sequences such
355     as a*b as a*+b. More specifically, if something simple (such as a character
356     or a simple class like \d) has an unlimited quantifier, and is followed by
357     something that cannot possibly match the quantified thing, the quantifier
358     is automatically "possessified".
359    
360     24. A recursive reference to a subpattern whose number was greater than 39
361     went wrong under certain circumstances in UTF-8 mode. This bug could also
362     have affected the operation of pcre_study().
363    
364     25. Realized that a little bit of performance could be had by replacing
365     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
366    
367     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
368    
369     27. Possessive quantifiers such as a++ were previously implemented by turning
370     them into atomic groups such as ($>a+). Now they have their own opcodes,
371     which improves performance. This includes the automatically created ones
372     from 23 above.
373    
374     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
375     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
376     the first matched character to be a colon. This applied both to named and
377     numbered groups.
378    
379     29. The ucpinternal.h header file was missing its idempotency #ifdef.
380    
381     30. I was sent a "project" file called libpcre.a.dev which I understand makes
382     building PCRE on Windows easier, so I have included it in the distribution.
383    
384     31. There is now a check in pcretest against a ridiculously large number being
385     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
386     loop, the loop is abandoned.
387    
388     32. Forward references to subpatterns in conditions such as (?(2)...) where
389     subpattern 2 is defined later cause pcre_compile() to search forwards in
390     the pattern for the relevant set of parentheses. This search went wrong
391     when there were unescaped parentheses in a character class, parentheses
392     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
393    
394     33. "Subroutine" calls and backreferences were previously restricted to
395     referencing subpatterns earlier in the regex. This restriction has now
396     been removed.
397    
398     34. Added a number of extra features that are going to be in Perl 5.10. On the
399     whole, these are just syntactic alternatives for features that PCRE had
400     previously implemented using the Python syntax or my own invention. The
401     other formats are all retained for compatibility.
402    
403     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
404     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
405     also .NET compatible.
406    
407     (b) A recursion or subroutine call to a named group can now be defined as
408     (?&name) as well as (?P>name).
409    
410     (c) A backreference to a named group can now be defined as \k<name> or
411     \k'name' as well as (?P=name). The new forms, as well as being in Perl
412     5.10, are also .NET compatible.
413    
414     (d) A conditional reference to a named group can now use the syntax
415     (?(<name>) or (?('name') as well as (?(name).
416    
417     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
418     groups (named and numbered) that are never evaluated inline, but can be
419     called as "subroutines" from elsewhere. In effect, the DEFINE condition
420     is always false. There may be only one alternative in such a group.
421    
422     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
423     as the simple (?(R). The condition is true only if the most recent
424     recursion is that of the given number or name. It does not search out
425     through the entire recursion stack.
426    
427     (g) The escape \gN or \g{N} has been added, where N is a positive or
428     negative number, specifying an absolute or relative reference.
429    
430     35. Tidied to get rid of some further signed/unsigned compiler warnings and
431     some "unreachable code" warnings.
432    
433     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
434     things, this adds five new scripts.
435    
436     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
437     There were also incompatibilities regarding the handling of \Q..\E inside
438     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
439     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
440    
441     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
442     matches an empty string, and forcibly breaks the loop. There were bugs in
443     this code in non-simple cases. For a pattern such as ^(a()*)* matched
444     against aaaa the result was just "a" rather than "aaaa", for example. Two
445     separate and independent bugs (that affected different cases) have been
446     fixed.
447    
448     39. Refactored the code to abolish the use of different opcodes for small
449     capturing bracket numbers. This is a tidy that I avoided doing when I
450     removed the limit on the number of capturing brackets for 3.5 back in 2001.
451     The new approach is not only tidier, it makes it possible to reduce the
452     memory needed to fix the previous bug (38).
453    
454     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
455     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
456     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
457     mode.
458    
459     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
460     report.
461    
462     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
463     copy construction and assignment in the C++ wrapper.
464    
465     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
466     couple of bugs that could have given wrong results in the "--newline=crlf"
467     case.
468    
469     44. Added a number of casts and did some reorganization of signed/unsigned int
470     variables following suggestions from Dair Grant. Also renamed the variable
471     "this" as "item" because it is a C++ keyword.
472    
473     45. Arranged for dftables to add
474    
475     #include "pcre_internal.h"
476    
477     to pcre_chartables.c because without it, gcc 4.x may remove the array
478     definition from the final binary if PCRE is built into a static library and
479     dead code stripping is activated.
480    
481     46. For an unanchored pattern, if a match attempt fails at the start of a
482     newline sequence, and the newline setting is CRLF or ANY, and the next two
483     characters are CRLF, advance by two characters instead of one.
484    
485    
486 nigel 91 Version 6.7 04-Jul-06
487     ---------------------
488    
489     1. In order to handle tests when input lines are enormously long, pcretest has
490     been re-factored so that it automatically extends its buffers when
491     necessary. The code is crude, but this _is_ just a test program. The
492     default size has been increased from 32K to 50K.
493    
494     2. The code in pcre_study() was using the value of the re argument before
495     testing it for NULL. (Of course, in any sensible call of the function, it
496     won't be NULL.)
497    
498     3. The memmove() emulation function in pcre_internal.h, which is used on
499     systems that lack both memmove() and bcopy() - that is, hardly ever -
500     was missing a "static" storage class specifier.
501    
502     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
503     containing an extended class (one that cannot be represented by a bitmap
504     because it contains high-valued characters or Unicode property items, e.g.
505     [\pZ]). Almost always one would set UTF-8 mode when processing such a
506     pattern, but PCRE should not loop if you do not (it no longer does).
507     [Detail: two cases were found: (a) a repeated subpattern containing an
508     extended class; (b) a recursive reference to a subpattern that followed a
509     previous extended class. It wasn't skipping over the extended class
510     correctly when UTF-8 mode was not set.]
511    
512     5. A negated single-character class was not being recognized as fixed-length
513     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
514     compile error "lookbehind assertion is not fixed length".
515    
516     6. The RunPerlTest auxiliary script was showing an unexpected difference
517     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
518     write a Perl script that can interpret lines of an input file either as
519     byte characters or as UTF-8, which is what "perltest" was being required to
520     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
521     can't do is switch easily at run time between having the "use utf8;" pragma
522     or not. In the end, I fudged it by using the RunPerlTest script to insert
523     "use utf8;" explicitly for the UTF-8 tests.
524    
525     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
526     the end of the subject string, contrary to the documentation and to what
527     Perl does. This was true of both matching functions. Now it matches only at
528     the start of the subject and immediately after *internal* newlines.
529    
530     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
531     a pointer to an int instead of a pointer to an unsigned long int. This
532     caused problems on 64-bit systems.
533    
534     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
535     instance of the 'standard' template library not being so standard".
536    
537     10. There was no check on the number of named subpatterns nor the maximum
538     length of a subpattern name. The product of these values is used to compute
539     the size of the memory block for a compiled pattern. By supplying a very
540     long subpattern name and a large number of named subpatterns, the size
541     computation could be caused to overflow. This is now prevented by limiting
542     the length of names to 32 characters, and the number of named subpatterns
543     to 10,000.
544    
545     11. Subpatterns that are repeated with specific counts have to be replicated in
546     the compiled pattern. The size of memory for this was computed from the
547     length of the subpattern and the repeat count. The latter is limited to
548     65535, but there was no limit on the former, meaning that integer overflow
549     could in principle occur. The compiled length of a repeated subpattern is
550     now limited to 30,000 bytes in order to prevent this.
551    
552     12. Added the optional facility to have named substrings with the same name.
553    
554     13. Added the ability to use a named substring as a condition, using the
555     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
556     are numbers (not recommended). Forward references are permitted.
557    
558     14. Added forward references in named backreferences (if you see what I mean).
559    
560     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
561     pattern could run off the end of the subject. For example, the pattern
562     "(?s)(.{1,5})"8 did this with the subject "ab".
563    
564     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
565     PCRE_CASELESS was set when matching characters that were quantified with ?
566     or *.
567    
568     17. A character class other than a single negated character that had a minimum
569     but no maximum quantifier - for example [ab]{6,} - was not handled
570     correctly by pce_dfa_exec(). It would match only one character.
571    
572     18. A valid (though odd) pattern that looked like a POSIX character
573     class but used an invalid character after [ (for example [[,abc,]]) caused
574     pcre_compile() to give the error "Failed: internal error: code overflow" or
575     in some cases to crash with a glibc free() error. This could even happen if
576     the pattern terminated after [[ but there just happened to be a sequence of
577     letters, a binary zero, and a closing ] in the memory that followed.
578    
579     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
580     over the years. Originally (before any Unicode support), just the bottom 8
581     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
582     output from "man perlunicode" includes this:
583    
584     The regular expression compiler produces polymorphic opcodes. That
585     is, the pattern adapts to the data and automatically switches to
586     the Unicode character scheme when presented with Unicode data--or
587     instead uses a traditional byte scheme when presented with byte
588     data.
589    
590     Sadly, a wide octal escape does not cause a switch, and in a string with
591     no other multibyte characters, these octal escapes are treated as before.
592     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
593     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
594     Unicode string.
595    
596     I have not perpetrated such confusion in PCRE. Up till now, it took just
597     the bottom 8 bits, as in old Perl. I have now made octal escapes with
598     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
599     translate to the appropriate multibyte character.
600    
601     29. Applied some refactoring to reduce the number of warnings from Microsoft
602     and Borland compilers. This has included removing the fudge introduced
603     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
604     a warning about an unused variable.
605    
606     21. PCRE has not included VT (character 0x0b) in the set of whitespace
607     characters since release 4.0, because Perl (from release 5.004) does not.
608     [Or at least, is documented not to: some releases seem to be in conflict
609     with the documentation.] However, when a pattern was studied with
610     pcre_study() and all its branches started with \s, PCRE still included VT
611     as a possible starting character. Of course, this did no harm; it just
612     caused an unnecessary match attempt.
613    
614     22. Removed a now-redundant internal flag bit that recorded the fact that case
615     dependency changed within the pattern. This was once needed for "required
616     byte" processing, but is no longer used. This recovers a now-scarce options
617     bit. Also moved the least significant internal flag bit to the most-
618     significant bit of the word, which was not previously used (hangover from
619     the days when it was an int rather than a uint) to free up another bit for
620     the future.
621    
622     23. Added support for CRLF line endings as well as CR and LF. As well as the
623     default being selectable at build time, it can now be changed at runtime
624     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
625     specify that it is scanning data with non-default line endings.
626    
627     24. Changed the definition of CXXLINK to make it agree with the definition of
628     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
629    
630     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
631     recursions. This makes a big different to stack usage for some patterns.
632    
633     26. If a subpattern containing a named recursion or subroutine reference such
634     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
635     the space required for the compiled pattern went wrong and gave too small a
636     value. Depending on the environment, this could lead to "Failed: internal
637     error: code overflow at offset 49" or "glibc detected double free or
638     corruption" errors.
639    
640     27. Applied patches from Google (a) to support the new newline modes and (b) to
641     advance over multibyte UTF-8 characters in GlobalReplace.
642    
643     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
644     difference for some implementation of PCRE in some Windows version.
645    
646     29. Added some extra testing facilities to pcretest:
647    
648     \q<number> in a data line sets the "match limit" value
649     \Q<number> in a data line sets the "match recursion limt" value
650     -S <number> sets the stack size, where <number> is in megabytes
651    
652     The -S option isn't available for Windows.
653    
654    
655 nigel 89 Version 6.6 06-Feb-06
656     ---------------------
657    
658     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
659     in pcreposix.h. I have copied the definition from pcre.h.
660    
661     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
662     because pcre.h is no longer a built file.
663    
664     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
665     not normally included in the compiled code.
666    
667    
668 nigel 87 Version 6.5 01-Feb-06
669     ---------------------
670    
671     1. When using the partial match feature with pcre_dfa_exec(), it was not
672     anchoring the second and subsequent partial matches at the new starting
673     point. This could lead to incorrect results. For example, with the pattern
674     /1234/, partially matching against "123" and then "a4" gave a match.
675    
676     2. Changes to pcregrep:
677    
678     (a) All non-match returns from pcre_exec() were being treated as failures
679     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
680     error message is output. Some extra information is given for the
681     PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
682     probably the only errors that are likely to be caused by users (by
683     specifying a regex that has nested indefinite repeats, for instance).
684     If there are more than 20 of these errors, pcregrep is abandoned.
685    
686     (b) A binary zero was treated as data while matching, but terminated the
687     output line if it was written out. This has been fixed: binary zeroes
688     are now no different to any other data bytes.
689    
690     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
691     used to set a locale for matching. The --locale=xxxx long option has
692     been added (no short equivalent) to specify a locale explicitly on the
693     pcregrep command, overriding the environment variables.
694    
695     (d) When -B was used with -n, some line numbers in the output were one less
696     than they should have been.
697    
698     (e) Added the -o (--only-matching) option.
699    
700     (f) If -A or -C was used with -c (count only), some lines of context were
701     accidentally printed for the final match.
702    
703     (g) Added the -H (--with-filename) option.
704    
705     (h) The combination of options -rh failed to suppress file names for files
706     that were found from directory arguments.
707    
708     (i) Added the -D (--devices) and -d (--directories) options.
709    
710     (j) Added the -F (--fixed-strings) option.
711    
712     (k) Allow "-" to be used as a file name for -f as well as for a data file.
713    
714     (l) Added the --colo(u)r option.
715    
716     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
717     is not present by default.
718    
719     3. A nasty bug was discovered in the handling of recursive patterns, that is,
720     items such as (?R) or (?1), when the recursion could match a number of
721     alternatives. If it matched one of the alternatives, but subsequently,
722     outside the recursion, there was a failure, the code tried to back up into
723     the recursion. However, because of the way PCRE is implemented, this is not
724     possible, and the result was an incorrect result from the match.
725    
726     In order to prevent this happening, the specification of recursion has
727     been changed so that all such subpatterns are automatically treated as
728     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
729    
730     4. I had overlooked the fact that, in some locales, there are characters for
731     which isalpha() is true but neither isupper() nor islower() are true. In
732     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
733     and ordfeminine) are like this. This affected the treatment of \w and \W
734     when they appeared in character classes, but not when they appeared outside
735     a character class. The bit map for "word" characters is now created
736     separately from the results of isalnum() instead of just taking it from the
737     upper, lower, and digit maps. (Plus the underscore character, of course.)
738    
739     5. The above bug also affected the handling of POSIX character classes such as
740     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
741     permanent tables. Instead, the bit maps for such a class were previously
742     created as the appropriate unions of the upper, lower, and digit bitmaps.
743     Now they are created by subtraction from the [[:word:]] class, which has
744     its own bitmap.
745    
746     6. The [[:blank:]] character class matches horizontal, but not vertical space.
747     It is created by subtracting the vertical space characters (\x09, \x0a,
748     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
749     subtraction was done in the overall bitmap for a character class, meaning
750     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
751     be recognized. This bug has been fixed.
752    
753     7. Patches from the folks at Google:
754    
755     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
756     real life, but is still worth protecting against".
757    
758     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
759     regular expressions".
760    
761     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
762     have it.
763    
764     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
765     "configure" and the latter not, in order to fix a problem somebody had
766     with compiling the Arg class on HP-UX.
767    
768     (e) Improve the error-handling of the C++ wrapper a little bit.
769    
770     (f) New tests for checking recursion limiting.
771    
772     8. The pcre_memmove() function, which is used only if the environment does not
773     have a standard memmove() function (and is therefore rarely compiled),
774     contained two bugs: (a) use of int instead of size_t, and (b) it was not
775     returning a result (though PCRE never actually uses the result).
776    
777     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
778     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
779     returned instead of calling malloc() with an overflowing number that would
780     most likely cause subsequent chaos.
781    
782     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
783    
784     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
785     with this option is matched, the nmatch and pmatch options of regexec() are
786     ignored.
787    
788     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
789     provided in case anyone wants to the the POSIX interface with UTF-8
790     strings.
791    
792     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
793     C++ linking (needed for some HP-UX environments).
794    
795     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
796     (unused parameter) and in the pcre_printint() function (omitted "default"
797     switch label when the default is to do nothing).
798    
799     15. Added some code to make it possible, when PCRE is compiled as a C++
800     library, to replace subject pointers for pcre_exec() with a smart pointer
801     class, thus making it possible to process discontinuous strings.
802    
803     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
804     much the same function. They were added by different people who were trying
805     to make PCRE easy to compile on non-Unix systems. It has been suggested
806     that PCRE_EXPORT be abolished now that there is more automatic apparatus
807     for compiling on Windows systems. I have therefore replaced it with
808     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
809     defaults to "extern" for C or "extern C" for C++, which works fine on
810     Unix-like systems. It is now possible to override the value of PCRE_DATA_
811     SCOPE with something explicit in config.h. In addition:
812    
813     (a) pcreposix.h still had just "extern" instead of either of these macros;
814     I have replaced it with PCRE_DATA_SCOPE.
815    
816     (b) Functions such as _pcre_xclass(), which are internal to the library,
817     but external in the C sense, all had PCRE_EXPORT in their definitions.
818     This is apparently wrong for the Windows case, so I have removed it.
819     (It makes no difference on Unix-like systems.)
820    
821     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
822     of recursive calls to match(). This is different to MATCH_LIMIT because
823     that limits the total number of calls to match(), not all of which increase
824     the depth of recursion. Limiting the recursion depth limits the amount of
825     stack (or heap if NO_RECURSE is set) that is used. The default can be set
826     when PCRE is compiled, and changed at run time. A patch from Google adds
827     this functionality to the C++ interface.
828    
829     18. Changes to the handling of Unicode character properties:
830    
831     (a) Updated the table to Unicode 4.1.0.
832    
833     (b) Recognize characters that are not in the table as "Cn" (undefined).
834    
835     (c) I revised the way the table is implemented to a much improved format
836     which includes recognition of ranges. It now supports the ranges that
837     are defined in UnicodeData.txt, and it also amalgamates other
838     characters into ranges. This has reduced the number of entries in the
839     table from around 16,000 to around 3,000, thus reducing its size
840     considerably. I realized I did not need to use a tree structure after
841     all - a binary chop search is just as efficient. Having reduced the
842     number of entries, I extended their size from 6 bytes to 8 bytes to
843     allow for more data.
844    
845     (d) Added support for Unicode script names via properties such as \p{Han}.
846    
847     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
848     matching that character.
849    
850     20. When matching a repeated Unicode property with a minimum greater than zero,
851     (for example \pL{2,}), PCRE could look past the end of the subject if it
852     reached it while seeking the minimum number of characters. This could
853     happen only if some of the characters were more than one byte long, because
854     there is a check for at least the minimum number of bytes.
855    
856     21. Refactored the implementation of \p and \P so as to be more general, to
857     allow for more different types of property in future. This has changed the
858     compiled form incompatibly. Anybody with saved compiled patterns that use
859     \p or \P will have to recompile them.
860    
861     22. Added "Any" and "L&" to the supported property types.
862    
863     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
864     but give a compile time error if the value is greater than 0xff.
865    
866     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
867     accidentally not being installed or uninstalled.
868    
869     25. The pcre.h file was built from pcre.h.in, but the only changes that were
870     made were to insert the current release number. This seemed silly, because
871     it made things harder for people building PCRE on systems that don't run
872     "configure". I have turned pcre.h into a distributed file, no longer built
873     by "configure", with the version identification directly included. There is
874     no longer a pcre.h.in file.
875    
876     However, this change necessitated a change to the pcre-config script as
877     well. It is built from pcre-config.in, and one of the substitutions was the
878     release number. I have updated configure.ac so that ./configure now finds
879     the release number by grepping pcre.h.
880    
881     26. Added the ability to run the tests under valgrind.
882    
883    
884 nigel 85 Version 6.4 05-Sep-05
885     ---------------------
886    
887     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
888     "--" to be printed when multiple files were scanned, even when none of the
889     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
890     consider it to be a bug, and have restored the previous behaviour.
891    
892     2. A couple of code tidies to get rid of compiler warnings.
893    
894     3. The pcretest program used to cheat by referring to symbols in the library
895     whose names begin with _pcre_. These are internal symbols that are not
896     really supposed to be visible externally, and in some environments it is
897     possible to suppress them. The cheating is now confined to including
898     certain files from the library's source, which is a bit cleaner.
899    
900     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
901     file's purpose clearer.
902    
903     5. Reorganized pcre_ucp_findchar().
904    
905    
906 nigel 83 Version 6.3 15-Aug-05
907     ---------------------
908    
909     1. The file libpcre.pc.in did not have general read permission in the tarball.
910    
911     2. There were some problems when building without C++ support:
912    
913     (a) If C++ support was not built, "make install" and "make test" still
914     tried to test it.
915    
916     (b) There were problems when the value of CXX was explicitly set. Some
917     changes have been made to try to fix these, and ...
918    
919     (c) --disable-cpp can now be used to explicitly disable C++ support.
920    
921     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
922     backslash in a target when C++ was disabled. This confuses some
923     versions of "make", apparently. Using an intermediate variable solves
924     this. (Same for CPP_LOBJ.)
925    
926     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
927     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
928     necessary on certain architectures.
929    
930     4. Added a setting of -export-symbols-regex to the link command to remove
931     those symbols that are exported in the C sense, but actually are local
932     within the library, and not documented. Their names all begin with
933     "_pcre_". This is not a perfect job, because (a) we have to except some
934     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
935     available (and never for static libraries). I have made a note to try to
936     find a way round (a) in the future.
937    
938    
939 nigel 81 Version 6.2 01-Aug-05
940     ---------------------
941    
942     1. There was no test for integer overflow of quantifier values. A construction
943     such as {1111111111111111} would give undefined results. What is worse, if
944     a minimum quantifier for a parenthesized subpattern overflowed and became
945     negative, the calculation of the memory size went wrong. This could have
946     led to memory overwriting.
947    
948     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
949    
950     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
951     operating environments where this matters.
952    
953     4. Applied Giuseppe Maxia's patch to add additional features for controlling
954     PCRE options from within the C++ wrapper.
955    
956     5. Named capturing subpatterns were not being correctly counted when a pattern
957     was compiled. This caused two problems: (a) If there were more than 100
958     such subpatterns, the calculation of the memory needed for the whole
959     compiled pattern went wrong, leading to an overflow error. (b) Numerical
960     back references of the form \12, where the number was greater than 9, were
961     not recognized as back references, even though there were sufficient
962     previous subpatterns.
963    
964     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
965     versions of gcc, e.g. 2.95.4.
966    
967    
968 nigel 79 Version 6.1 21-Jun-05
969     ---------------------
970    
971     1. There was one reference to the variable "posix" in pcretest.c that was not
972     surrounded by "#if !defined NOPOSIX".
973    
974     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
975     the cross-check on the old pcre_info() function, for the benefit of the
976     cut-down version of PCRE that is currently imported into Exim.
977    
978     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
979     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
980     patterns that start (?i) but I don't think that matters. The use of (?i) is
981     just an example; this all applies to the other options as well.
982    
983     4. Since libtool seems to echo the compile commands it is issuing, the output
984     from "make" can be reduced a bit by putting "@" in front of each libtool
985     compile command.
986    
987     5. Patch from the folks at Google for configure.in to be a bit more thorough
988     in checking for a suitable C++ installation before trying to compile the
989     C++ stuff. This should fix a reported problem when a compiler was present,
990     but no suitable headers.
991    
992     6. The man pages all had just "PCRE" as their title. I have changed them to
993     be the relevant file name. I have also arranged that these names are
994     retained in the file doc/pcre.txt, which is a concatenation in text format
995     of all the man pages except the little individual ones for each function.
996    
997     7. The NON-UNIX-USE file had not been updated for the different set of source
998     files that come with release 6. I also added a few comments about the C++
999     wrapper.
1000    
1001    
1002 nigel 77 Version 6.0 07-Jun-05
1003     ---------------------
1004    
1005     1. Some minor internal re-organization to help with my DFA experiments.
1006    
1007     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1008     didn't matter for the library itself when fully configured, but did matter
1009     when compiling without UCP support, or within Exim, where the ucp files are
1010     not imported.
1011    
1012     3. Refactoring of the library code to split up the various functions into
1013     different source modules. The addition of the new DFA matching code (see
1014     below) to a single monolithic source would have made it really too
1015     unwieldy, quite apart from causing all the code to be include in a
1016     statically linked application, when only some functions are used. This is
1017     relevant even without the DFA addition now that patterns can be compiled in
1018     one application and matched in another.
1019    
1020     The downside of splitting up is that there have to be some external
1021     functions and data tables that are used internally in different modules of
1022     the library but which are not part of the API. These have all had their
1023     names changed to start with "_pcre_" so that they are unlikely to clash
1024     with other external names.
1025    
1026     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1027     a different (DFA) algorithm. Although it is slower than the original
1028     function, it does have some advantages for certain types of matching
1029     problem.
1030    
1031     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1032     including restarting after a partial match.
1033    
1034     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1035     defined when compiling for Windows was sent to me. I have put it into the
1036     code, though I have no means of testing or verifying it.
1037    
1038     7. Added the pcre_refcount() auxiliary function.
1039    
1040     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1041     match before or at the first newline in the subject string. In pcretest,
1042     the /f option on a pattern can be used to set this.
1043    
1044     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1045     would behave wrongly. This has been present in PCRE since release 4.0.
1046    
1047     10. A number of changes to the pcregrep command:
1048    
1049     (a) Refactored how -x works; insert ^(...)$ instead of setting
1050     PCRE_ANCHORED and checking the length, in preparation for adding
1051     something similar for -w.
1052    
1053     (b) Added the -w (match as a word) option.
1054    
1055     (c) Refactored the way lines are read and buffered so as to have more
1056     than one at a time available.
1057    
1058     (d) Implemented a pcregrep test script.
1059    
1060     (e) Added the -M (multiline match) option. This allows patterns to match
1061     over several lines of the subject. The buffering ensures that at least
1062     8K, or the rest of the document (whichever is the shorter) is available
1063     for matching (and similarly the previous 8K for lookbehind assertions).
1064    
1065     (f) Changed the --help output so that it now says
1066    
1067     -w, --word-regex(p)
1068    
1069     instead of two lines, one with "regex" and the other with "regexp"
1070     because that confused at least one person since the short forms are the
1071     same. (This required a bit of code, as the output is generated
1072     automatically from a table. It wasn't just a text change.)
1073    
1074     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1075     option but starts with a hyphen. Could be a pattern or a path name
1076     starting with a hyphen, for instance.
1077    
1078     (h) "-" can be given as a file name to represent stdin.
1079    
1080     (i) When file names are being printed, "(standard input)" is used for
1081     the standard input, for compatibility with GNU grep. Previously
1082     "<stdin>" was used.
1083    
1084     (j) The option --label=xxx can be used to supply a name to be used for
1085     stdin when file names are being printed. There is no short form.
1086    
1087     (k) Re-factored the options decoding logic because we are going to add
1088     two more options that take data. Such options can now be given in four
1089     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1090    
1091     (l) Added the -A, -B, and -C options for requesting that lines of context
1092     around matches be printed.
1093    
1094     (m) Added the -L option to print the names of files that do not contain
1095     any matching lines, that is, the complement of -l.
1096    
1097     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1098     continue to scan other files.
1099    
1100     (o) The -s option was incorrectly implemented. For compatibility with other
1101     greps, it now suppresses the error message for a non-existent or non-
1102     accessible file (but not the return code). There is a new option called
1103     -q that suppresses the output of matching lines, which was what -s was
1104     previously doing.
1105    
1106     (p) Added --include and --exclude options to specify files for inclusion
1107     and exclusion when recursing.
1108    
1109     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1110     Hopefully, it now does.
1111    
1112     12. Missing cast in pcre_study().
1113    
1114     13. Added an "uninstall" target to the makefile.
1115    
1116     14. Replaced "extern" in the function prototypes in Makefile.in with
1117     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1118     world, but is set differently for Windows.
1119    
1120     15. Added a second compiling function called pcre_compile2(). The only
1121     difference is that it has an extra argument, which is a pointer to an
1122     integer error code. When there is a compile-time failure, this is set
1123     non-zero, in addition to the error test pointer being set to point to an
1124     error message. The new argument may be NULL if no error number is required
1125     (but then you may as well call pcre_compile(), which is now just a
1126     wrapper). This facility is provided because some applications need a
1127     numeric error indication, but it has also enabled me to tidy up the way
1128     compile-time errors are handled in the POSIX wrapper.
1129    
1130     16. Added VPATH=.libs to the makefile; this should help when building with one
1131     prefix path and installing with another. (Or so I'm told by someone who
1132     knows more about this stuff than I do.)
1133    
1134     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1135     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1136     match everything, including newlines. This is not POSIX-compatible, but
1137     somebody wanted the feature. From pcretest it can be activated by using
1138     both the P and the s flags.
1139    
1140     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1141    
1142     19. libpcre.pc was being incorrectly installed as executable.
1143    
1144     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1145     it now also looks for '\r' so that it will work unmodified on Windows.
1146    
1147     21. Added Google's contributed C++ wrapper to the distribution.
1148    
1149     22. Added some untidy missing memory free() calls in pcretest, to keep
1150     Electric Fence happy when testing.
1151    
1152    
1153    
1154 nigel 75 Version 5.0 13-Sep-04
1155     ---------------------
1156    
1157     1. Internal change: literal characters are no longer packed up into items
1158     containing multiple characters in a single byte-string. Each character
1159     is now matched using a separate opcode. However, there may be more than one
1160     byte in the character in UTF-8 mode.
1161    
1162     2. The pcre_callout_block structure has two new fields: pattern_position and
1163     next_item_length. These contain the offset in the pattern to the next match
1164     item, and its length, respectively.
1165    
1166     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1167     insertion of callouts before each pattern item. Added the /C option to
1168     pcretest to make use of this.
1169    
1170     4. On the advice of a Windows user, the lines
1171    
1172     #if defined(_WIN32) || defined(WIN32)
1173     _setmode( _fileno( stdout ), 0x8000 );
1174     #endif /* defined(_WIN32) || defined(WIN32) */
1175    
1176     have been added to the source of pcretest. This apparently does useful
1177     magic in relation to line terminators.
1178    
1179     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1180     for the benefit of those environments where the "b" makes a difference.
1181    
1182     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1183     to know about it. I have put a hack into configure.in that adds in code
1184     to set GCC=yes if CC=icc. This seems to end up at a point in the
1185     generated configure script that is early enough to affect the setting of
1186     compiler options, which is what is needed, but I have no means of testing
1187     whether it really works. (The user who reported this had patched the
1188     generated configure script, which of course I cannot do.)
1189    
1190     LATER: After change 22 below (new libtool files), the configure script
1191     seems to know about icc (and also ecc). Therefore, I have commented out
1192     this hack in configure.in.
1193    
1194     7. Added support for pkg-config (2 patches were sent in).
1195    
1196     8. Negated POSIX character classes that used a combination of internal tables
1197     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1198     [[:^ascii]]. Typically, they would match almost any characters. The other
1199     POSIX classes were not broken in this way.
1200    
1201     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1202     to find the match, as PCRE was deluded into thinking that the match had to
1203     start at the start point or following a newline. The same bug applied to
1204     patterns with negative forward assertions or any backward assertions
1205     preceding ".*" at the start, unless the pattern required a fixed first
1206     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1207    
1208     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1209     starting at the last subject character, bytes beyond the end of the subject
1210     string were read.
1211    
1212     11. Renamed the variable "class" as "classbits" to make life easier for C++
1213     users. (Previously there was a macro definition, but it apparently wasn't
1214     enough.)
1215    
1216     12. Added the new field "tables" to the extra data so that tables can be passed
1217     in at exec time, or the internal tables can be re-selected. This allows
1218     a compiled regex to be saved and re-used at a later time by a different
1219     program that might have everything at different addresses.
1220    
1221     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1222     -R library as well as a -L library.
1223    
1224     14. The debugging options of pcretest (-d on the command line or D on a
1225     pattern) showed incorrect output for anything following an extended class
1226     that contained multibyte characters and which was followed by a quantifier.
1227    
1228     15. Added optional support for general category Unicode character properties
1229     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1230     support. It adds about 90K to the size of the library. The meanings of the
1231     inbuilt class escapes such as \d and \s have NOT been changed.
1232    
1233     16. Updated pcredemo.c to include calls to free() to release the memory for the
1234     compiled pattern.
1235    
1236     17. The generated file chartables.c was being created in the source directory
1237     instead of in the building directory. This caused the build to fail if the
1238     source directory was different from the building directory, and was
1239     read-only.
1240    
1241     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1242     file. No doubt somebody will tell me if they don't make sense... Also added
1243     Dan Mooney's comments about building on OpenVMS.
1244    
1245     19. Added support for partial matching via the PCRE_PARTIAL option for
1246     pcre_exec() and the \P data escape in pcretest.
1247    
1248     20. Extended pcretest with 3 new pattern features:
1249    
1250     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1251     write the compiled pattern to the file whose name is "rest-of-line".
1252     This is a straight binary dump of the data, with the saved pointer to
1253     the character tables forced to be NULL. The study data, if any, is
1254     written too. After writing, pcretest reads a new pattern.
1255    
1256     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1257     compiled pattern from the given file. There must not be any
1258     occurrences of "<" in the file name (pretty unlikely); if there are,
1259     pcretest will instead treat the initial "<" as a pattern delimiter.
1260     After reading in the pattern, pcretest goes on to read data lines as
1261     usual.
1262    
1263     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1264     and 16-bit fields in a compiled pattern, to simulate a pattern that
1265     was compiled on a host of opposite endianness.
1266    
1267     21. The pcre-exec() function can now cope with patterns that were compiled on
1268     hosts of opposite endianness, with this restriction:
1269    
1270     As for any compiled expression that is saved and used later, the tables
1271     pointer field cannot be preserved; the extra_data field in the arguments
1272     to pcre_exec() should be used to pass in a tables address if a value
1273     other than the default internal tables were used at compile time.
1274    
1275     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1276     now diagnosed as an error. Previously, most of the time, a negative number
1277     would have been treated as zero, but if in addition "ovector" was passed as
1278     NULL, a crash could occur.
1279    
1280     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1281     new versions from the libtool 1.5 distribution (the last one is a copy of
1282     a file called libtool.m4). This seems to have fixed the need to patch
1283     "configure" to support Darwin 1.3 (which I used to do). However, I still
1284     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1285     workstation).
1286    
1287     24. Changed the PCRE licence to be the more standard "BSD" licence.
1288    
1289    
1290 nigel 73 Version 4.5 01-Dec-03
1291     ---------------------
1292    
1293     1. There has been some re-arrangement of the code for the match() function so
1294     that it can be compiled in a version that does not call itself recursively.
1295     Instead, it keeps those local variables that need separate instances for
1296     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1297     needs to "recurse". Keeping track of where control must go is done by means
1298     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1299     hide most of the details from the main code, and operates only if
1300     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1301     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1302     operating.
1303    
1304     To make it easier for callers to provide specially tailored get/free
1305     functions for this usage, two new functions, pcre_stack_malloc, and
1306     pcre_stack_free, are used. They are always called in strict stacking order,
1307     and the size of block requested is always the same.
1308    
1309     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1310     PCRE has been compiled to use the stack or the heap for recursion. The
1311     -C option of pcretest uses this to show which version is compiled.
1312    
1313     A new data escape \S, is added to pcretest; it causes the amounts of store
1314     obtained and freed by both kinds of malloc/free at match time to be added
1315     to the output.
1316    
1317     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1318     what's available on my current Linux desktop machine.
1319    
1320     3. When matching a UTF-8 string, the test for a valid string at the start has
1321     been extended. If start_offset is not zero, PCRE now checks that it points
1322     to a byte that is the start of a UTF-8 character. If not, it returns
1323     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1324     this is necessary because there may be backward assertions in the pattern.
1325     When matching the same subject several times, it may save resources to use
1326     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1327    
1328     4. The code for checking the validity of UTF-8 strings has been tightened so
1329     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1330     containing "overlong sequences".
1331    
1332     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1333     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1334     should have been "&", but it just so happened that all the cases this let
1335     through by mistake were picked up later in the function.
1336    
1337     6. I had used a variable called "isblank" - this is a C99 function, causing
1338     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1339    
1340     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1341     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1342     so the version is shown; (c) stop "make test" echoing "./RunTest".
1343    
1344     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1345    
1346     9. The prototype for memmove() for systems that don't have it was using
1347     size_t, but the inclusion of the header that defines size_t was later. I've
1348     moved the #includes for the C headers earlier to avoid this.
1349    
1350     10. Added some adjustments to the code to make it easier to compiler on certain
1351     special systems:
1352    
1353     (a) Some "const" qualifiers were missing.
1354     (b) Added the macro EXPORT before all exported functions; by default this
1355     is defined to be empty.
1356     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1357     that it reads its output file name as an argument instead of writing
1358     to the standard output and assuming this can be redirected.
1359    
1360     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1361     class containing characters with values greater than 255, PCRE compilation
1362     went into a loop.
1363    
1364     12. A recursive reference to a subpattern that was within another subpattern
1365     that had a minimum quantifier of zero caused PCRE to crash. For example,
1366     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1367     recursion. If the recursively-called subpattern itself had a zero repeat,
1368     that was OK.
1369    
1370     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1371     buffer into which it was copied (for escape processing) was still set at
1372     1024, so long lines caused crashes.
1373    
1374     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1375     "internal error: code overflow...". This applied to any character class
1376     that was followed by a possessive quantifier.
1377    
1378     15. Modified the Makefile to add libpcre.la as a prerequisite for
1379     libpcreposix.la because I was told this is needed for a parallel build to
1380     work.
1381    
1382     16. If a pattern that contained .* following optional items at the start was
1383     studied, the wrong optimizing data was generated, leading to matching
1384     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1385     matching string must start with a or b or c. The correct conclusion for
1386     this pattern is that a match can start with any character.
1387    
1388    
1389 nigel 71 Version 4.4 13-Aug-03
1390     ---------------------
1391    
1392     1. In UTF-8 mode, a character class containing characters with values between
1393     127 and 255 was not handled correctly if the compiled pattern was studied.
1394     In fixing this, I have also improved the studying algorithm for such
1395     classes (slightly).
1396    
1397     2. Three internal functions had redundant arguments passed to them. Removal
1398     might give a very teeny performance improvement.
1399    
1400     3. Documentation bug: the value of the capture_top field in a callout is *one
1401     more than* the number of the hightest numbered captured substring.
1402    
1403     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1404     in incorrectly linking with a previously installed version. They now link
1405     explicitly with libpcre.la.
1406    
1407     5. configure.in no longer needs to recognize Cygwin specially.
1408    
1409     6. A problem in pcre.in for Windows platforms is fixed.
1410    
1411     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1412     pcretest, it used to include the size of the study block as part of its
1413     output. Unfortunately, the structure contains a field that has a different
1414     size on different hardware architectures. This meant that the tests that
1415     showed this size failed. As the block is currently always of a fixed size,
1416     this information isn't actually particularly useful in pcretest output, so
1417     I have just removed it.
1418    
1419     8. Three pre-processor statements accidentally did not start in column 1.
1420     Sadly, there are *still* compilers around that complain, even though
1421     standard C has not required this for well over a decade. Sigh.
1422    
1423     9. In pcretest, the code for checking callouts passed small integers in the
1424     callout_data field, which is a void * field. However, some picky compilers
1425     complained about the casts involved for this on 64-bit systems. Now
1426     pcretest passes the address of the small integer instead, which should get
1427     rid of the warnings.
1428    
1429     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1430     both compile and run time, and gives an error if an invalid UTF-8 sequence
1431     is found. There is a option for disabling this check in cases where the
1432     string is known to be correct and/or the maximum performance is wanted.
1433    
1434     11. In response to a bug report, I changed one line in Makefile.in from
1435    
1436     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1437     to
1438     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1439    
1440     to look similar to other lines, but I have no way of telling whether this
1441     is the right thing to do, as I do not use Windows. No doubt I'll get told
1442     if it's wrong...
1443    
1444    
1445 nigel 69 Version 4.3 21-May-03
1446     ---------------------
1447    
1448     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1449     Makefile.
1450    
1451     2. Some refactoring to improve the quality of the code:
1452    
1453     (i) The utf8_table... variables are now declared "const".
1454    
1455     (ii) The code for \cx, which used the "case flipping" table to upper case
1456     lower case letters, now just substracts 32. This is ASCII-specific,
1457     but the whole concept of \cx is ASCII-specific, so it seems
1458     reasonable.
1459    
1460     (iii) PCRE was using its character types table to recognize decimal and
1461     hexadecimal digits in the pattern. This is silly, because it handles
1462     only 0-9, a-f, and A-F, but the character types table is locale-
1463     specific, which means strange things might happen. A private
1464     table is now used for this - though it costs 256 bytes, a table is
1465     much faster than multiple explicit tests. Of course, the standard
1466     character types table is still used for matching digits in subject
1467     strings against \d.
1468    
1469     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1470     ending in _t are). So I've renamed it as ESC_tee.
1471    
1472     3. The first argument for regexec() in the POSIX wrapper should have been
1473     defined as "const".
1474    
1475     4. Changed pcretest to use malloc() for its buffers so that they can be
1476     Electric Fenced for debugging.
1477    
1478     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1479     to read one or more bytes before the start of the subject string. Often this
1480     had no effect on PCRE's behaviour, but in some circumstances it could
1481     provoke a segmentation fault.
1482    
1483     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1484     to try to read one or more bytes before the start of the subject string.
1485    
1486     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1487     UTF-8 support could misbehave in various ways if the subject string
1488     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1489     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1490     back over UTF-8 characters.)
1491    
1492    
1493 nigel 67 Version 4.2 14-Apr-03
1494     ---------------------
1495    
1496     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1497    
1498     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1499     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1500     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1501     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1502     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1503     and BUILD_EXEEXT
1504     Note: automatic setting of the BUILD variables is not yet working
1505     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1506     compile-time but not at link-time
1507     [LINK]: use for linking executables only
1508     make different versions for Windows and non-Windows
1509     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1510     libraries
1511     [LINK_FOR_BUILD]: new variable
1512     [OBJEXT]: use throughout
1513     [EXEEXT]: use throughout
1514     <winshared>: new target
1515     <wininstall>: new target
1516     <dftables.o>: use native compiler
1517     <dftables>: use native linker
1518     <install>: handle Windows platform correctly
1519     <clean>: ditto
1520     <check>: ditto
1521     copy DLL to top builddir before testing
1522    
1523     As part of these changes, -no-undefined was removed again. This was reported
1524     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1525     in any case.
1526    
1527     3. Some tidies to get rid of compiler warnings:
1528    
1529     . In the match_data structure, match_limit was an unsigned long int, whereas
1530     match_call_count was an int. I've made them both unsigned long ints.
1531    
1532     . In pcretest the fact that a const uschar * doesn't automatically cast to
1533     a void * provoked a warning.
1534    
1535     . Turning on some more compiler warnings threw up some "shadow" variables
1536     and a few more missing casts.
1537    
1538     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1539     option, a class that contained a single character with a value between 128
1540     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1541    
1542     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1543     option, a class that contained several characters, but with at least one
1544     whose value was between 128 and 255 caused PCRE to crash.
1545    
1546    
1547 nigel 65 Version 4.1 12-Mar-03
1548     ---------------------
1549 nigel 63
1550 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1551     needed, and a string in dftables.c that was longer than standard compilers are
1552     required to support.
1553    
1554     2. Compiling with Sun's compiler found a few more places where the code could
1555     be tidied up in order to avoid warnings.
1556    
1557     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1558     first of these names is deprecated in the latest Autoconf in favour of the name
1559     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1560     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1561     analogy I have changed it to CFLAGS_FOR_BUILD.
1562    
1563     4. Added -no-undefined to the linking command in the Makefile, because this is
1564     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1565     linking step for the pcreposix library.
1566    
1567     5. PCRE was failing to diagnose the case of two named groups with the same
1568     name.
1569    
1570     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1571     literal character that is needed in the subject for a match, and scans along to
1572     ensure that it is present before embarking on the full matching process. This
1573     saves time in cases of nested unlimited repeats that are never going to match.
1574     Problem: the scan can take a lot of time if the subject is very long (e.g.
1575     megabytes), thus penalizing straightforward matches. It is now done only if the
1576     amount of subject to be scanned is less than 1000 bytes.
1577    
1578     7. A lesser problem with the same optimization is that it was recording the
1579     first character of an anchored pattern as "needed", thus provoking a search
1580     right along the subject, even when the first match of the pattern was going to
1581     fail. The "needed" character is now not set for anchored patterns, unless it
1582     follows something in the pattern that is of non-fixed length. Thus, it still
1583     fulfils its original purpose of finding quick non-matches in cases of nested
1584     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1585    
1586    
1587     Version 4.0 17-Feb-03
1588     ---------------------
1589    
1590 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1591     extended to the end of string, PCRE compiled incorrect data. This could lead to
1592     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1593    
1594     2. Moved to autoconf 2.53 and libtool 1.4.2.
1595    
1596     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1597     the special perltest8 script is no longer needed - all the tests can be run
1598     from a single perltest script.
1599    
1600     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1601     by \s. It has now been removed in PCRE. This means it isn't recognized as
1602     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1603     class [:space:] *does* include VT, thereby creating a mess.
1604    
1605     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1606     space and tab.
1607    
1608     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1609     its new features into the main test script, reducing the number of scripts.
1610    
1611     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1612     were backward compatible, and made the (?i) apply to the whole pattern, as if
1613     /i were given. Now it behaves more logically, and applies the option setting
1614     only to what follows. PCRE has been changed to follow suit. However, if it
1615     finds options settings right at the start of the pattern, it extracts them into
1616     the global options, as before. Thus, they show up in the info data.
1617    
1618     8. Added support for the \Q...\E escape sequence. Characters in between are
1619     treated as literals. This is slightly different from Perl in that $ and @ are
1620     also handled as literals inside the quotes. In Perl, they will cause variable
1621     interpolation. Note the following examples:
1622    
1623     Pattern PCRE matches Perl matches
1624    
1625     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1626     \Qabc\$xyz\E abc\$xyz abc\$xyz
1627     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1628    
1629     For compatibility with Perl, \Q...\E sequences are recognized inside character
1630     classes as well as outside them.
1631    
1632     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1633     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1634     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1635     signed/unsigned warnings.
1636    
1637     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1638     option for pcretest, so I've replaced it by a simple function that does just
1639     that job.
1640    
1641     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1642     "pcregrep -".
1643    
1644     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1645     Java package. This provides some syntactic sugar for simple cases of what my
1646     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1647     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1648     item, you can use this simplified notation. Note that only makes sense with
1649     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1650     greediness, whatever the setting of the PCRE_UNGREEDY option.
1651    
1652     13. A change of greediness default within a pattern was not taking effect at
1653     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1654     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1655     was abstracted outside.
1656    
1657     14. PCRE now supports the \G assertion. It is true when the current matching
1658     position is at the start point of the match. This differs from \A when the
1659     starting offset is non-zero. Used with the /g option of pcretest (or similar
1660     code), it works in the same way as it does for Perl's /g option. If all
1661     alternatives of a regex begin with \G, the expression is anchored to the start
1662     match position, and the "anchored" flag is set in the compiled expression.
1663    
1664     15. Some bugs concerning the handling of certain option changes within patterns
1665     have been fixed. These applied to options other than (?ims). For example,
1666     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1667     been the other way round. Some of this was related to change 7 above.
1668    
1669     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1670     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1671     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1672     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1673    
1674     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1675     mode. Unlike ".", it always matches newline, whatever the setting of
1676     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1677     assertions. Perl allows it, but it doesn't (in general) work because it can't
1678     calculate the length of the lookbehind. At least, that's the case for Perl
1679     5.8.0 - I've been told they are going to document that it doesn't work in
1680     future.
1681    
1682     18. Added an error diagnosis for escapes that PCRE does not support: these are
1683     \L, \l, \N, \P, \p, \U, \u, and \X.
1684    
1685     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1686     reading past the end of the pattern in cases such as /[abcd/.
1687    
1688     20. PCRE was getting more memory than necessary for patterns with classes that
1689     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1690    
1691     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1692     compiling PCRE for use with Virtual Pascal.
1693    
1694     22. Small fix to the Makefile to make it work properly if the build is done
1695     outside the source tree.
1696    
1697     23. Added a new extension: a condition to go with recursion. If a conditional
1698     subpattern starts with (?(R) the "true" branch is used if recursion has
1699     happened, whereas the "false" branch is used only at the top level.
1700    
1701     24. When there was a very long string of literal characters (over 255 bytes
1702     without UTF support, over 250 bytes with UTF support), the computation of how
1703     much memory was required could be incorrect, leading to segfaults or other
1704     strange effects.
1705    
1706     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1707     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1708     there was a subsequent back reference to those brackets. This meant that, for
1709     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1710     possible to check for precisely this case. All we can do is abandon the
1711     optimization if .* occurs inside capturing brackets when there are any back
1712     references whatsoever. (See below for a better fix that came later.)
1713    
1714     26. The handling of the optimization for finding the first character of a
1715     non-anchored pattern, and for finding a character that is required later in the
1716     match were failing in some cases. This didn't break the matching; it just
1717     failed to optimize when it could. The way this is done has been re-implemented.
1718    
1719     27. Fixed typo in error message for invalid (?R item (it said "(?p").
1720    
1721     28. Added a new feature that provides some of the functionality that Perl
1722     provides with (?{...}). The facility is termed a "callout". The way it is done
1723     in PCRE is for the caller to provide an optional function, by setting
1724     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1725     global variable. By default it is unset, which disables all calling out. To get
1726     the function called, the regex must include (?C) at appropriate points. This
1727     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1728     This provides a means of identifying different callout points. When PCRE
1729     reaches such a point in the regex, if pcre_callout has been set, the external
1730     function is called. It is provided with data in a structure called
1731     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1732     matching continues; if it returns a non-zero value, the match at the current
1733     point fails. However, backtracking will occur if possible. [This was changed
1734     later and other features added - see item 49 below.]
1735    
1736     29. pcretest is upgraded to test the callout functionality. It provides a
1737     callout function that displays information. By default, it shows the start of
1738     the match and the current position in the text. There are some new data escapes
1739     to vary what happens:
1740    
1741     \C+ in addition, show current contents of captured substrings
1742     \C- do not supply a callout function
1743     \C!n return 1 when callout number n is reached
1744     \C!n!m return 1 when callout number n is reached for the mth time
1745    
1746     30. If pcregrep was called with the -l option and just a single file name, it
1747     output "<stdin>" if a match was found, instead of the file name.
1748    
1749     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1750     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1751     pcre_exec(). This saves a malloc/free per call. The default value of
1752     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1753     when configuring.
1754    
1755     32. The default maximum size of a compiled pattern is 64K. There have been a
1756     few cases of people hitting this limit. The code now uses macros to handle the
1757     storing of links as offsets within the compiled pattern. It defaults to 2-byte
1758     links, but this can be changed to 3 or 4 bytes by --with-link-size when
1759     configuring. Tests 2 and 5 work only with 2-byte links because they output
1760     debugging information about compiled patterns.
1761    
1762     33. Internal code re-arrangements:
1763    
1764     (a) Moved the debugging function for printing out a compiled regex into
1765     its own source file (printint.c) and used #include to pull it into
1766     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1767     separate copies.
1768    
1769     (b) Defined the list of op-code names for debugging as a macro in
1770     internal.h so that it is next to the definition of the opcodes.
1771    
1772     (c) Defined a table of op-code lengths for simpler skipping along compiled
1773     code. This is again a macro in internal.h so that it is next to the
1774     definition of the opcodes.
1775    
1776     34. Added support for recursive calls to individual subpatterns, along the
1777     lines of Robin Houston's patch (but implemented somewhat differently).
1778    
1779     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1780     allow it to read and process whole directories in Win32. This code was
1781     contributed by Lionel Fourquaux; it has not been tested by me.
1782    
1783     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1784     used to name a group. Names consist of alphanumerics and underscores, and must
1785     be unique. Back references use the syntax (?P=name) and recursive calls use
1786     (?P>name) which is a PCRE extension to the Python extension. Groups still have
1787     numbers. The function pcre_fullinfo() can be used after compilation to extract
1788     a name/number map. There are three relevant calls:
1789    
1790     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1791     PCRE_INFO_NAMECOUNT yields the number of entries
1792     PCRE_INFO_NAMETABLE yields a pointer to the map.
1793    
1794     The map is a vector of fixed-size entries. The size of each entry depends on
1795     the length of the longest name used. The first two bytes of each entry are the
1796     group number, most significant byte first. There follows the corresponding
1797     name, zero terminated. The names are in alphabetical order.
1798    
1799     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1800     case instead of 255. Making it the same both with and without UTF-8 support
1801     means that the same test output works with both.
1802    
1803     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1804     calling malloc() with a zero argument.
1805    
1806     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1807     optimization. I've improved things by keeping a bitmap of backreferences with
1808     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1809     fact referenced, the optimization can be applied. It is unlikely that a
1810     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1811     the match to follow \n) will appear inside brackets with a number greater than
1812     31, but if it does, any back reference > 31 suppresses the optimization.
1813    
1814     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1815     of disabling numbered capturing parentheses. Any opening parenthesis that is
1816     not followed by ? behaves as if it were followed by ?: but named parentheses
1817     can still be used for capturing (and they will acquire numbers in the usual
1818     way).
1819    
1820     41. Redesigned the return codes from the match() function into yes/no/error so
1821     that errors can be passed back from deep inside the nested calls. A malloc
1822     failure while inside a recursive subpattern call now causes the
1823     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1824    
1825     42. It is now possible to set a limit on the number of times the match()
1826     function is called in a call to pcre_exec(). This facility makes it possible to
1827     limit the amount of recursion and backtracking, though not in a directly
1828     obvious way, because the match() function is used in a number of different
1829     circumstances. The count starts from zero for each position in the subject
1830     string (for non-anchored patterns). The default limit is, for compatibility, a
1831     large number, namely 10 000 000. You can change this in two ways:
1832    
1833     (a) When configuring PCRE before making, you can use --with-match-limit=n
1834     to set a default value for the compiled library.
1835    
1836     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1837     a different value is set. See 45 below.
1838    
1839     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1840    
1841     43. Added a new function pcre_config(int, void *) to enable run-time extraction
1842     of things that can be changed at compile time. The first argument specifies
1843     what is wanted and the second points to where the information is to be placed.
1844     The current list of available information is:
1845    
1846     PCRE_CONFIG_UTF8
1847    
1848     The output is an integer that is set to one if UTF-8 support is available;
1849     otherwise it is set to zero.
1850    
1851     PCRE_CONFIG_NEWLINE
1852    
1853     The output is an integer that it set to the value of the code that is used for
1854     newline. It is either LF (10) or CR (13).
1855    
1856     PCRE_CONFIG_LINK_SIZE
1857    
1858     The output is an integer that contains the number of bytes used for internal
1859     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1860    
1861     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
1862    
1863     The output is an integer that contains the threshold above which the POSIX
1864     interface uses malloc() for output vectors. See item 31 above.
1865    
1866     PCRE_CONFIG_MATCH_LIMIT
1867    
1868     The output is an unsigned integer that contains the default limit of the number
1869     of match() calls in a pcre_exec() execution. See 42 above.
1870    
1871     44. pcretest has been upgraded by the addition of the -C option. This causes it
1872     to extract all the available output from the new pcre_config() function, and to
1873     output it. The program then exits immediately.
1874    
1875     45. A need has arisen to pass over additional data with calls to pcre_exec() in
1876     order to support additional features. One way would have been to define
1877     pcre_exec2() (for example) with extra arguments, but this would not have been
1878     extensible, and would also have required all calls to the original function to
1879     be mapped to the new one. Instead, I have chosen to extend the mechanism that
1880     is used for passing in "extra" data from pcre_study().
1881    
1882     The pcre_extra structure is now exposed and defined in pcre.h. It currently
1883     contains the following fields:
1884    
1885     flags a bitmap indicating which of the following fields are set
1886     study_data opaque data from pcre_study()
1887     match_limit a way of specifying a limit on match() calls for a specific
1888     call to pcre_exec()
1889     callout_data data for callouts (see 49 below)
1890    
1891     The flag bits are also defined in pcre.h, and are
1892    
1893     PCRE_EXTRA_STUDY_DATA
1894     PCRE_EXTRA_MATCH_LIMIT
1895     PCRE_EXTRA_CALLOUT_DATA
1896    
1897     The pcre_study() function now returns one of these new pcre_extra blocks, with
1898     the actual study data pointed to by the study_data field, and the
1899     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1900     before. That is, this change is entirely upwards-compatible and requires no
1901     change to existing code.
1902    
1903     If you want to pass in additional data to pcre_exec(), you can either place it
1904     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1905     block.
1906    
1907     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1908     data string contains the escape sequence \M, pcretest calls pcre_exec() several
1909     times with different match limits, until it finds the minimum value needed for
1910     pcre_exec() to complete. The value is then output. This can be instructive; for
1911     most simple matches the number is quite small, but for pathological cases it
1912     gets very large very quickly.
1913    
1914     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1915     returns the size of the data block pointed to by the study_data field in a
1916     pcre_extra block, that is, the value that was passed as the argument to
1917     pcre_malloc() when PCRE was getting memory in which to place the information
1918     created by pcre_study(). The fourth argument should point to a size_t variable.
1919     pcretest has been extended so that this information is shown after a successful
1920     pcre_study() call when information about the compiled regex is being displayed.
1921    
1922     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1923     because what follows is always an absolute path. (Later: it turns out that this
1924     is more than cosmetic for MinGW, because it doesn't like empty path
1925     components.)
1926    
1927     49. Some changes have been made to the callout feature (see 28 above):
1928    
1929     (i) A callout function now has three choices for what it returns:
1930    
1931     0 => success, carry on matching
1932     > 0 => failure at this point, but backtrack if possible
1933     < 0 => serious error, return this value from pcre_exec()
1934    
1935     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1936     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1937     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1938     use by callout functions. It will never be used by PCRE itself.
1939    
1940     (ii) The pcre_extra structure (see 45 above) has a void * field called
1941     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1942     pcre_callout_block structure has a field of the same name. The contents of
1943     the field passed in the pcre_extra structure are passed to the callout
1944     function in the corresponding field in the callout block. This makes it
1945     easier to use the same callout-containing regex from multiple threads. For
1946     testing, the pcretest program has a new data escape
1947    
1948     \C*n pass the number n (may be negative) as callout_data
1949    
1950     If the callout function in pcretest receives a non-zero value as
1951     callout_data, it returns that value.
1952    
1953     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1954     there were some redundant $(CFLAGS) in commands that are now specified as
1955     $(LINK), which already includes $(CFLAGS).
1956    
1957     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1958     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1959     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1960     one-byte characters throughout. Note that case-insensitive matching applies
1961     only to characters whose values are less than 256. PCRE doesn't support the
1962     notion of cases for higher-valued characters.
1963    
1964     (i) A character class whose characters are all within 0-255 is handled as
1965     a bit map, and the map is inverted for negative classes. Previously, a
1966     character > 255 always failed to match such a class; however it should
1967     match if the class was a negative one (e.g. [^ab]). This has been fixed.
1968    
1969     (ii) A negated character class with a single character < 255 is coded as
1970     "not this character" (OP_NOT). This wasn't working properly when the test
1971     character was multibyte, either singly or repeated.
1972    
1973     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1974     mode, for example: \x{100}{2,3}.
1975    
1976     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1977     singly or repeated) now correctly test multibyte characters. However,
1978     PCRE doesn't recognize any characters with values greater than 255 as
1979     digits, spaces, or word characters. Such characters always match \D, \S,
1980     and \W, and never match \d, \s, or \w.
1981    
1982     (v) Classes may now contain characters and character ranges with values
1983     greater than 255. For example: [ab\x{100}-\x{400}].
1984    
1985     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1986     PCRE in UTF-8 mode.
1987    
1988     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1989     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1990     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1991     value.)
1992    
1993     53. The single man page has become too large. I have therefore split it up into
1994     a number of separate man pages. These also give rise to individual HTML pages;
1995     these are now put in a separate directory, and there is an index.html page that
1996     lists them all. Some hyperlinking between the pages has been installed.
1997    
1998     54. Added convenience functions for handling named capturing parentheses.
1999    
2000     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2001     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2002     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2003     are faulted.
2004    
2005     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2006     calling configure. These values are used when compiling the dftables.c program
2007     which is run to generate the source of the default character tables. They
2008     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2009     you will need to set these values.
2010    
2011     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2012    
2013    
2014     Version 3.9 02-Jan-02
2015 nigel 61 ---------------------
2016    
2017     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2018    
2019     2. If --disable-static was given, the building process failed when trying to
2020     build pcretest and pcregrep. (For some reason it was using libtool to compile
2021     them, which is not right, as they aren't part of the library.)
2022    
2023    
2024 nigel 59 Version 3.8 18-Dec-01
2025     ---------------------
2026    
2027     1. The experimental UTF-8 code was completely screwed up. It was packing the
2028     bytes in the wrong order. How dumb can you get?
2029    
2030    
2031 nigel 57 Version 3.7 29-Oct-01
2032     ---------------------
2033    
2034     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2035     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2036     this didn't happen under Solaris 8, where I normally test things.
2037    
2038 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2039     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2040     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2041     this fix an hour or so after the initial 3.7 release.)
2042 nigel 57
2043 nigel 59
2044 nigel 55 Version 3.6 23-Oct-01
2045     ---------------------
2046    
2047     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2048     offsets passed as NULL with zero offset count.
2049    
2050     2. The config.guess and config.sub files had not been updated when I moved to
2051     the latest autoconf.
2052    
2053    
2054 nigel 53 Version 3.5 15-Aug-01
2055     ---------------------
2056 nigel 5
2057 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2058     had been forgotten.
2059    
2060     2. By using declared but undefined structures, we can avoid using "void"
2061     definitions in pcre.h while keeping the internal definitions of the structures
2062     private.
2063    
2064     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2065     user point of view, this means that both static and shared libraries are built
2066     by default, but this can be individually controlled. More of the work of
2067     handling this static/shared cases is now inside libtool instead of PCRE's make
2068     file.
2069    
2070     4. The pcretest utility is now installed along with pcregrep because it is
2071     useful for users (to test regexs) and by doing this, it automatically gets
2072     relinked by libtool. The documentation has been turned into a man page, so
2073     there are now .1, .txt, and .html versions in /doc.
2074    
2075     5. Upgrades to pcregrep:
2076     (i) Added long-form option names like gnu grep.
2077     (ii) Added --help to list all options with an explanatory phrase.
2078     (iii) Added -r, --recursive to recurse into sub-directories.
2079     (iv) Added -f, --file to read patterns from a file.
2080    
2081     6. pcre_exec() was referring to its "code" argument before testing that
2082     argument for NULL (and giving an error if it was NULL).
2083    
2084     7. Upgraded Makefile.in to allow for compiling in a different directory from
2085     the source directory.
2086    
2087     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2088     options bits, the pointer it was passed was to an int instead of to an unsigned
2089     long int. This mattered only on 64-bit systems.
2090    
2091     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2092     generated) instead of pcre.in, which it its source. Also made the same change
2093     in several of the .c files.
2094    
2095     10. A new release of gcc defines printf() as a macro, which broke pcretest
2096     because it had an ifdef in the middle of a string argument for printf(). Fixed
2097     by using separate calls to printf().
2098    
2099     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2100     script, to force use of CR or LF instead of \n in the source. On non-Unix
2101     systems, the value can be set in config.h.
2102    
2103     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2104     absolute limit. Changed the text of the error message to make this clear, and
2105     likewise updated the man page.
2106    
2107     13. The limit of 99 on the number of capturing subpatterns has been removed.
2108     The new limit is 65535, which I hope will not be a "real" limit.
2109    
2110    
2111 nigel 51 Version 3.4 22-Aug-00
2112     ---------------------
2113    
2114     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2115    
2116     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2117    
2118    
2119 nigel 49 Version 3.3 01-Aug-00
2120     ---------------------
2121    
2122     1. If an octal character was given, but the value was greater than \377, it
2123     was not getting masked to the least significant bits, as documented. This could
2124     lead to crashes in some systems.
2125    
2126     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2127     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2128    
2129     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2130     These just pass their arguments on to (pcre_free)(), but they are provided
2131     because some uses of PCRE bind it to non-C systems that can call its functions,
2132     but cannot call free() or pcre_free() directly.
2133    
2134     4. Add "make test" as a synonym for "make check". Corrected some comments in
2135     the Makefile.
2136    
2137     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2138     Makefile.
2139    
2140     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2141     command called pgrep for grepping around the active processes.
2142    
2143     7. Added the beginnings of support for UTF-8 character strings.
2144    
2145     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2146     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2147     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2148     out for the ar command.)
2149    
2150    
2151 nigel 47 Version 3.2 12-May-00
2152     ---------------------
2153    
2154     This is purely a bug fixing release.
2155    
2156     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2157     of ZA. This was just one example of several cases that could provoke this bug,
2158     which was introduced by change 9 of version 2.00. The code for breaking
2159     infinite loops after an iteration that matches an empty string was't working
2160     correctly.
2161    
2162     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2163     when matched against abbab (for example). After matching an empty string, it
2164     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2165     caused it to match further down the string than it should.
2166    
2167     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2168     was there because it doesn't seem to be needed, and it causes trouble on some
2169     systems, as it is not a Standard C header. It has been removed.
2170    
2171     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2172     were reported on the Macintosh. The changes were from
2173    
2174     while ((c = *(++ptr)) != 0 && c != '\n');
2175     to
2176     while ((c = *(++ptr)) != 0 && c != '\n') ;
2177    
2178     Totally extraordinary, but if that's what it takes...
2179    
2180     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2181     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2182     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2183     assumes the way PCRE uses memmove() (always moving upwards).
2184    
2185     6. PCRE is being used in one environment where strchr() is not available. There
2186     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2187     faster code anyway.
2188    
2189    
2190 nigel 45 Version 3.1 09-Feb-00
2191     ---------------------
2192    
2193     The only change in this release is the fixing of some bugs in Makefile.in for
2194     the "install" target:
2195    
2196     (1) It was failing to install pcreposix.h.
2197    
2198     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2199    
2200    
2201 nigel 43 Version 3.0 01-Feb-00
2202     ---------------------
2203 nigel 41
2204     1. Add support for the /+ modifier to perltest (to output $` like it does in
2205     pcretest).
2206    
2207     2. Add support for the /g modifier to perltest.
2208    
2209     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2210     matches null strings.
2211    
2212     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2213     pattern. Perl treats empty patterns specially - it reuses the most recent
2214     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2215     effect.
2216    
2217     5. The POSIX interface was broken in that it was just handing over the POSIX
2218     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2219     required a bigger vector, with some working space on the end. This means that
2220     the POSIX wrapper now has to get and free some memory, and copy the results.
2221    
2222 nigel 43 6. Added some simple autoconf support, placing the test data and the
2223     documentation in separate directories, re-organizing some of the
2224     information files, and making it build pcre-config (a GNU standard). Also added
2225     libtool support for building PCRE as a shared library, which is now the
2226     default.
2227 nigel 41
2228 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2229     09 are not valid octal constants. Single digits will be used for minor values
2230     less than 10.
2231    
2232     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2233     existing programs that set these in the POSIX interface can use PCRE without
2234     modification.
2235    
2236     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2237     return all that pcre_info() returns, plus additional data. The pcre_info()
2238     function is retained for compatibility, but is considered to be obsolete.
2239    
2240     10. Added experimental recursion feature (?R) to handle one common case that
2241     Perl 5.6 will be able to do with (?p{...}).
2242    
2243     11. Added support for POSIX character classes like [:alpha:], which Perl is
2244     adopting.
2245    
2246    
2247 nigel 39 Version 2.08 31-Aug-99
2248     ----------------------
2249    
2250     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2251     trying to match at the startoffset position, but instead was moving forward to
2252     the next newline as if a previous match had failed.
2253    
2254     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2255     and could get into a loop if a null string was matched other than at the start
2256     of the subject.
2257    
2258     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2259     be distinguished at compile time, and for completeness also added PCRE_DATE.
2260    
2261     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2262     in GnuWin32 environments.
2263    
2264    
2265 nigel 37 Version 2.07 29-Jul-99
2266     ----------------------
2267    
2268     1. The documentation is now supplied in plain text form and HTML as well as in
2269     the form of man page sources.
2270    
2271     2. C++ compilers don't like assigning (void *) values to other pointer types.
2272     In particular this affects malloc(). Although there is no problem in Standard
2273     C, I've put in casts to keep C++ compilers happy.
2274    
2275     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2276     should be (const char *).
2277    
2278     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2279     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2280     However, I haven't made this a standard facility. The documentation doesn't
2281     mention it, and the Makefile doesn't support it.
2282    
2283     5. The Makefile now contains an "install" target, with editable destinations at
2284     the top of the file. The pcretest program is not installed.
2285    
2286     6. pgrep -V now gives the PCRE version number and date.
2287    
2288     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2289     causing the entire string to be ignored, instead of just the last character.
2290    
2291     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2292     non-matching string, it can take a very, very long time, even for strings of
2293     quite modest length, because of the nested recursion. PCRE now does better in
2294     some of these cases. It does this by remembering the last required literal
2295     character in the pattern, and pre-searching the subject to ensure it is present
2296     before running the real match. In other words, it applies a heuristic to detect
2297     some types of certain failure quickly, and in the above example, if presented
2298     with a string that has no trailing " it gives "no match" very quickly.
2299    
2300     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2301     other alternatives are tried instead.
2302    
2303    
2304 nigel 35 Version 2.06 09-Jun-99
2305     ----------------------
2306    
2307     1. Change pcretest's output for amount of store used to show just the code
2308     space, because the remainder (the data block) varies in size between 32-bit and
2309     64-bit systems.
2310    
2311     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2312     start matching at. This allows lookbehinds to work when searching for multiple
2313     occurrences in a string.
2314    
2315     3. Added additional options to pcretest for testing multiple occurrences:
2316    
2317     /+ outputs the rest of the string that follows a match
2318     /g loops for multiple occurrences, using the new startoffset argument
2319     /G loops for multiple occurrences by passing an incremented pointer
2320    
2321     4. PCRE wasn't doing the "first character" optimization for patterns starting
2322     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2323     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2324     the letter 'x'. On long subject strings, this gives a significant speed-up.
2325    
2326    
2327 nigel 33 Version 2.05 21-Apr-99
2328     ----------------------
2329    
2330     1. Changed the type of magic_number from int to long int so that it works
2331     properly on 16-bit systems.
2332    
2333     2. Fixed a bug which caused patterns starting with .* not to work correctly
2334     when the subject string contained newline characters. PCRE was assuming
2335     anchoring for such patterns in all cases, which is not correct because .* will
2336     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2337     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2338     must be retried after every newline in the subject.
2339    
2340    
2341 nigel 31 Version 2.04 18-Feb-99
2342     ----------------------
2343    
2344     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2345     computation of the store needed to hold the pattern was incorrect (too large).
2346     If such patterns were nested a few deep, this could multiply and become a real
2347     problem.
2348    
2349     2. Added /M option to pcretest to show the memory requirement of a specific
2350     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2351    
2352     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2353     compiled in such a way that the backtracking after subsequent failure was
2354     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2355     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2356    
2357    
2358 nigel 29 Version 2.03 02-Feb-99
2359     ----------------------
2360    
2361     1. Fixed typo and small mistake in man page.
2362    
2363 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2364     LICENCE file containing the conditions.
2365 nigel 29
2366     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2367     Perl, that is the internal \ allows the delimiter to be included in the
2368     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2369     the final delimiter, add \ to the end of the pattern (to test the error).
2370    
2371     4. Added the convenience functions for extracting substrings after a successful
2372     match. Updated pcretest to make it able to test these functions.
2373    
2374    
2375 nigel 27 Version 2.02 14-Jan-99
2376     ----------------------
2377    
2378     1. Initialized the working variables associated with each extraction so that
2379     their saving and restoring doesn't refer to uninitialized store.
2380    
2381     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2382     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2383     fix the problem.
2384    
2385     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2386     calls, and wasn't printing the correct value for compiling calls. Increased the
2387     default value of LOOPREPEAT, and the number of significant figures in the
2388     times.
2389    
2390     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2391    
2392     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2393     a building problem on Windows NT with a FAT file system.
2394    
2395    
2396 nigel 25 Version 2.01 21-Oct-98
2397     ----------------------
2398    
2399     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2400     to character tables built by pcre_maketables() in the current locale. If NULL
2401     is passed, the default tables are used.
2402    
2403    
2404 nigel 23 Version 2.00 24-Sep-98
2405 nigel 21 ----------------------
2406    
2407 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2408     it any more.
2409    
2410     2. Allow quantification of (?>) groups, and make it work correctly.
2411    
2412     3. The first character computation wasn't working for (?>) groups.
2413    
2414     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2415     end of the subject) and add 5.005's \z, which really does match only at the
2416     very end of the subject.
2417    
2418     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2419    
2420     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2421     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2422     localized options. All options to pcre_study() were also removed.
2423    
2424     7. Add other new features from 5.005:
2425    
2426     $(?<= positive lookbehind
2427     $(?<! negative lookbehind
2428     (?imsx-imsx) added the unsetting capability
2429     such a setting is global if at outer level; local otherwise
2430     (?imsx-imsx:) non-capturing groups with option setting
2431     (?(cond)re|re) conditional pattern matching
2432    
2433     A backreference to itself in a repeated group matches the previous
2434     captured string.
2435    
2436     8. General tidying up of studying (both automatic and via "study")
2437     consequential on the addition of new assertions.
2438    
2439     9. As in 5.005, unlimited repeated groups that could match an empty substring
2440     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2441     runtime if any iteration does actually match an empty substring.
2442    
2443     10. Include the RunTest script in the distribution.
2444    
2445     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2446     discrepancies, some of which were old and were also with respect to 5.004. They
2447     have now been fixed.
2448    
2449    
2450     Version 1.09 28-Apr-98
2451     ----------------------
2452    
2453 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2454     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2455     program crashes, or just wrong answers. This did not apply to negated classes
2456     containing more than one character, or to minima other than one.
2457    
2458    
2459 nigel 19 Version 1.08 27-Mar-98
2460     ----------------------
2461    
2462     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2463    
2464     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2465     latter must appear before anything that relies on it in the pattern.
2466    
2467    
2468 nigel 17 Version 1.07 16-Feb-98
2469     ----------------------
2470    
2471     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2472     repeat of a potentially empty string).
2473    
2474    
2475 nigel 15 Version 1.06 23-Jan-98
2476     ----------------------
2477    
2478     1. Added Markus Oberhumer's little patches for C++.
2479    
2480     2. Literal strings longer than 255 characters were broken.
2481    
2482    
2483 nigel 13 Version 1.05 23-Dec-97
2484     ----------------------
2485    
2486     1. Negated character classes containing more than one character were failing if
2487     PCRE_CASELESS was set at run time.
2488    
2489    
2490 nigel 11 Version 1.04 19-Dec-97
2491     ----------------------
2492    
2493     1. Corrected the man page, where some "const" qualifiers had been omitted.
2494    
2495     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2496     input syntax.
2497    
2498     3. Fixed memory leak which occurred when a regex with back references was
2499     matched with an offsets vector that wasn't big enough. The temporary memory
2500     that is used in this case wasn't being freed if the match failed.
2501    
2502     4. Tidied pcretest to ensure it frees memory that it gets.
2503    
2504     5. Temporary memory was being obtained in the case where the passed offsets
2505     vector was exactly big enough.
2506    
2507     6. Corrected definition of offsetof() from change 5 below.
2508    
2509     7. I had screwed up change 6 below and broken the rules for the use of
2510     setjmp(). Now fixed.
2511    
2512    
2513 nigel 9 Version 1.03 18-Dec-97
2514     ----------------------
2515    
2516     1. A erroneous regex with a missing opening parenthesis was correctly
2517     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2518     on some systems.
2519    
2520     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2521     it was reported that one broken compiler failed on the former because "code" is
2522     also an independent variable.
2523    
2524     3. The erroneous regex a[]b caused an array overrun reference.
2525    
2526     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2527     fail on data ending with that character. (It was going on too far, and checking
2528     the next character, typically a binary zero.) This was specific to the
2529     optimized code for single-character negative classes.
2530    
2531     5. Added a contributed patch from the TIN world which does the following:
2532    
2533     + Add an undef for memmove, in case the the system defines a macro for it.
2534    
2535     + Add a definition of offsetof(), in case there isn't one. (I don't know
2536     the reason behind this - offsetof() is part of the ANSI standard - but
2537     it does no harm).
2538    
2539     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2540     most of the places where whitespace preceded '#'. I have given up and
2541     allowed the remaining 2 cases to be at the margin.
2542    
2543     + Rename some variables in pcre to eliminate shadowing. This seems very
2544     pedantic, but does no harm, of course.
2545    
2546     6. Moved the call to setjmp() into its own function, to get rid of warnings
2547     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2548    
2549     7. Constructs such as \d{8,} were compiling into the equivalent of
2550 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2551 nigel 9 outcome, but in this particular case used more store than had been allocated,
2552     which caused the bug to be discovered because it threw up an internal error.
2553    
2554     8. The debugging code in both pcre and pcretest for outputting the compiled
2555     form of a regex was going wrong in the case of back references followed by
2556     curly-bracketed repeats.
2557    
2558    
2559 nigel 7 Version 1.02 12-Dec-97
2560     ----------------------
2561    
2562     1. Typos in pcre.3 and comments in the source fixed.
2563    
2564     2. Applied a contributed patch to get rid of places where it used to remove
2565     'const' from variables, and fixed some signed/unsigned and uninitialized
2566     variable warnings.
2567    
2568     3. Added the "runtest" target to Makefile.
2569    
2570     4. Set default compiler flag to -O2 rather than just -O.
2571    
2572    
2573 nigel 5 Version 1.01 19-Nov-97
2574     ----------------------
2575    
2576     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2577     like /([ab]*)*/, that is, for classes with more than one character in them.
2578    
2579     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2580     as /((?>a*))*/ (a PCRE_EXTRA facility).
2581    
2582    
2583     Version 1.00 18-Nov-97
2584     ----------------------
2585    
2586     1. Added compile-time macros to support systems such as SunOS4 which don't have
2587     memmove() or strerror() but have other things that can be used instead.
2588    
2589     2. Arranged that "make clean" removes the executables.
2590    
2591    
2592 nigel 3 Version 0.99 27-Oct-97
2593     ----------------------
2594    
2595     1. Fixed bug in code for optimizing classes with only one character. It was
2596     initializing a 32-byte map regardless, which could cause it to run off the end
2597     of the memory it had got.
2598    
2599     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2600    
2601    
2602     Version 0.98 22-Oct-97
2603     ----------------------
2604    
2605     1. Fixed bug in code for handling temporary memory usage when there are more
2606     back references than supplied space in the ovector. This could cause segfaults.
2607    
2608    
2609     Version 0.97 21-Oct-97
2610     ----------------------
2611    
2612     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2613    
2614     2. Optimized negated single characters not to use a bit map.
2615    
2616     3. Brought error texts together as macro definitions; clarified some of them;
2617     fixed one that was wrong - it said "range out of order" when it meant "invalid
2618     escape sequence".
2619    
2620     4. Changed some char * arguments to const char *.
2621    
2622     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2623    
2624     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2625     pcretest.
2626    
2627    
2628     Version 0.96 16-Oct-97
2629     ----------------------
2630    
2631     1. Added a simple "pgrep" utility to the distribution.
2632    
2633     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2634     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2635     where "ddd" means "one or more decimal digits".
2636    
2637     3. Fixed serious bug. If a pattern had a back reference, but the call to
2638     pcre_exec() didn't supply a large enough ovector to record the related
2639     identifying subpattern, the match always failed. PCRE now remembers the number
2640     of the largest back reference, and gets some temporary memory in which to save
2641     the offsets during matching if necessary, in order to ensure that
2642     backreferences always work.
2643    
2644     4. Increased the compatibility with Perl in a number of ways:
2645    
2646     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2647     to request this handling. The option can be set at compile or exec time.
2648    
2649     (b) $ matches before a terminating newline by default; an option
2650     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2651     mode). The option can be set at compile or exec time.
2652    
2653     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2654     the same as Perl's. If the decimal number it represents is less than 10
2655     or there aren't that many previous left capturing parentheses, an octal
2656     escape is read. Inside a character class, it's always an octal escape,
2657     even if it is a single digit.
2658    
2659     (d) An escaped but undefined alphabetic character is taken as a literal,
2660     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2661     escapes.
2662    
2663     (e) {0} is now permitted. (The previous item is removed from the compiled
2664     pattern).
2665    
2666     5. Changed all the names of code files so that the basic parts are no longer
2667     than 10 characters, and abolished the teeny "globals.c" file.
2668    
2669     6. Changed the handling of character classes; they are now done with a 32-byte
2670     bit map always.
2671    
2672     7. Added the -d and /D options to pcretest to make it possible to look at the
2673     internals of compilation without having to recompile pcre.
2674    
2675    
2676     Version 0.95 23-Sep-97
2677     ----------------------
2678    
2679     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2680     \x20 at the start of a run of normal characters. These were being treated as
2681     real characters, instead of the source characters being re-checked.
2682    
2683    
2684     Version 0.94 18-Sep-97
2685     ----------------------
2686    
2687     1. The functions are now thread-safe, with the caveat that the global variables
2688     containing pointers to malloc() and free() or alternative functions are the
2689     same for all threads.
2690    
2691     2. Get pcre_study() to generate a bitmap of initial characters for non-
2692     anchored patterns when this is possible, and use it if passed to pcre_exec().
2693    
2694    
2695     Version 0.93 15-Sep-97
2696     ----------------------
2697    
2698     1. /(b)|(:+)/ was computing an incorrect first character.
2699    
2700     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2701     but not actually doing anything yet.
2702    
2703     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2704     as Perl does (e.g. [-az] or [az-]).
2705    
2706     4. Set the anchored flag if a branch starts with .* or .*? because that tests
2707     all possible positions.
2708    
2709     5. Split up into different modules to avoid including unneeded functions in a
2710     compiled binary. However, compile and exec are still in one module. The "study"
2711     function is split off.
2712    
2713     6. The character tables are now in a separate module whose source is generated
2714     by an auxiliary program - but can then be edited by hand if required. There are
2715     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2716     toupper() in the code.
2717    
2718     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2719     make them global. Abolish the function for setting them, as the caller can now
2720     set them directly.
2721    
2722    
2723     Version 0.92 11-Sep-97
2724     ----------------------
2725    
2726     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2727     (e.g. /a{1,3}/) was broken (I mis-optimized it).
2728    
2729     2. Caseless matching was not working in character classes if the characters in
2730     the pattern were in upper case.
2731    
2732     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2733    
2734     4. Make PCRE_ANCHORED public and accept as a compile option.
2735    
2736     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2737     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2738     pass them.
2739    
2740     6. Give an error if bad option bits passed at compile or run time.
2741    
2742     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2743     pcretest to cause it to pass that flag.
2744    
2745     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2746     options, and the first character, if set.
2747    
2748     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2749    
2750    
2751     Version 0.91 10-Sep-97
2752     ----------------------
2753    
2754     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2755     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2756    
2757     2. PCRE was looping on encountering an indefinitely repeated back reference to
2758     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2759     Perl does - treats the match as successful.
2760    
2761     ****

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