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Revision 176 - (hide annotations) (download)
Mon Jun 11 13:48:37 2007 UTC (7 years, 10 months ago) by ph10
File size: 129457 byte(s)
Inserted some (unsigned int) casts to kill compiler warnings.

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 172 Version 7.2 05-June-07
5 ph10 157 ---------------------
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.
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.
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.
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
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 ph10 176
61     10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
62 ph10 172
64 ph10 155 Version 7.1 24-Apr-07
65 ph10 98 ---------------------
67 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
68 ph10 122 that is more "standard", making use of automake and other Autotools. There
69 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
70     on this.
71 ph10 111
72     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
73     for recursive directory scanning broke on some systems because the files
74     are not scanned in any specific order and on different systems the order
75     was different. A call to "sort" has been inserted into RunGrepTest for the
76     approprate test as a short-term fix. In the longer term there may be an
77 ph10 100 alternative.
78 ph10 111
79 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
80 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
81     people do their own conversions for various reasons). The problems
82     concerned the use of low-level troff macros .br and .in. I have therefore
83     removed all such uses from the man pages (some were redundant, some could
84 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
85     HTML has been updated to handle .nf/.fi and to complain if it encounters
86     .br or .in.
87 ph10 111
88 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
89 ph10 123 arranged for config.h to be included in the distribution, with the name
90 ph10 111 config.h.generic, for the benefit of those who have to compile without
91     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
93     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
94     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
95 ph10 127 makevp.bat for the current PCRE, using the additional files
96 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
97 ph10 111
98     6. A Windows user reported a minor discrepancy with test 2, which turned out
99     to be caused by a trailing space on an input line that had got lost in his
100 ph10 102 copy. The trailing space was an accident, so I've just removed it.
101 ph10 111
102 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
103 ph10 111 that is needed.
105 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
106     as "const" (a) because they are and (b) because it helps the PHP
107     maintainers who have recently made a script to detect big data structures
108 ph10 111 in the php code that should be moved to the .rodata section. I remembered
109     to update Builducptable as well, so it won't revert if ucptable.h is ever
110 ph10 105 re-created.
111 ph10 111
112     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
113 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
114 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
115     support is not required. This saves 1.5-2K of code, which is important in
116 ph10 107 some applications.
117 ph10 111
118 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
119 ph10 111 so as not to refer to the tables, even though these functions will never be
120     called when UTF-8 support is disabled. Otherwise there are problems with a
121     shared library.
123 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
125     (a) It was defining its arguments as char * instead of void *.
127 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
128     a long time ago when I wrote it, but is no longer the case.
130 ph10 118 The emulated memove() is provided for those environments that have neither
131 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
132 ph10 118 is clearly not the case, as these two bugs were recently reported.
133 ph10 123
134 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
135 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
136     pages, and it removes trailing spaces from listed files. It also creates
137     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
138     case, it wraps all the #defines with #ifndefs. This script should be run
139 ph10 111 before "make dist".
140 ph10 123
141 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
142     with Unicode property support.
143 ph10 123
144     (a) For a maximizing quantifier, if the two different cases of the
145     character were of different lengths in their UTF-8 codings (there are
146     some cases like this - I found 11), and the matching function had to
147 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
148     were both the same length.
149 ph10 123
150     (b) When PCRE was configured to use the heap rather than the stack for
151     recursion during matching, it was not correctly preserving the data for
152     the other case of a UTF-8 character when checking ahead for a match
153     while processing a minimizing repeat. If the check also involved
154 ph10 115 matching a wide character, but failed, corruption could cause an
155     erroneous result when trying to check for a repeat of the original
156     character.
157 ph10 123
158 ph10 116 13. Some tidying changes to the testing mechanism:
159 ph10 98
160 ph10 116 (a) The RunTest script now detects the internal link size and whether there
161     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
162 ph10 123 values substituted by "configure". (The RunGrepTest script already did
163     this for UTF-8.) The configure.ac script no longer substitutes the
164     relevant variables.
166 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
167     with length and offset values. This means that the output is different
168     for different internal link sizes. Test 2 is skipped for link sizes
169     other than 2 because of this, bypassing the problem. Unfortunately,
170     there was also a test in test 3 (the locale tests) that used /B and
171 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
172     I have added a new /Z option to pcretest that replaces the length and
173     offset values with spaces. This is now used to make test 3 independent
174 ph10 122 of link size. (Test 2 will be tidied up later.)
175 ph10 123
176     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
177 ph10 122 segmentation fault instead of returning the appropriate error message.
178 ph10 134
179 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
180 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
181     This doesn't seem right; it now treats the CRLF combination as the line
182     ending, and so does not match in that case. It's only a pattern such as ^$
183     that would hit this one: something like ^ABC$ would have failed after \r
184     and then tried again after \r\n.
186 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
187 ph10 134 in an attempt to make files that differ only in their line terminators
188     compare equal. This works on Linux.
189 ph10 142
190 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
191     as it exited. This is now fixed, thanks to valgrind.
192 ph10 142
193 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
194 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
195     was because its rules for how to advance for /g after matching an empty
196 ph10 143 string at the end of a line did not allow for this case. They now check for
197     it specially.
198 ph10 150
199     20. pcretest is supposed to handle patterns and data of any length, by
200     extending its buffers when necessary. It was getting this wrong when the
201 ph10 147 buffer for a data line had to be extended.
202 ph10 150
203 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
204 ph10 150 CRLF as a newline sequence.
205 ph10 152
206 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
207 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
208     I have nevertheless tidied it up.
209 ph10 111
210 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
211 ph10 123
212 ph10 153 24. Added a man page for pcre-config.
213 ph10 152
214 ph10 153
215 nigel 93 Version 7.0 19-Dec-06
216     ---------------------
218     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
219     moving to gcc 4.1.1.
221     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
222     sys/time.h, which is documented as needed for this function. It doesn't
223     seem to matter on Linux, but it showed up on some releases of OS X.
225     3. It seems that there are systems where bytes whose values are greater than
226     127 match isprint() in the "C" locale. The "C" locale should be the
227     default when a C program starts up. In most systems, only ASCII printing
228     characters match isprint(). This difference caused the output from pcretest
229     to vary, making some of the tests fail. I have changed pcretest so that:
231     (a) When it is outputting text in the compiled version of a pattern, bytes
232     other than 32-126 are always shown as hex escapes.
234     (b) When it is outputting text that is a matched part of a subject string,
235     it does the same, unless a different locale has been set for the match
236     (using the /L modifier). In this case, it uses isprint() to decide.
238     4. Fixed a major bug that caused incorrect computation of the amount of memory
239     required for a compiled pattern when options that changed within the
240     pattern affected the logic of the preliminary scan that determines the
241     length. The relevant options are -x, and -i in UTF-8 mode. The result was
242     that the computed length was too small. The symptoms of this bug were
243     either the PCRE error "internal error: code overflow" from pcre_compile(),
244     or a glibc crash with a message such as "pcretest: free(): invalid next
245     size (fast)". Examples of patterns that provoked this bug (shown in
246     pcretest format) are:
248     /(?-x: )/x
249     /(?x)(?-x: \s*#\s*)/
250     /((?i)[\x{c0}])/8
251     /(?i:[\x{c0}])/8
253     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
254     is now done differently.
256     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
257     wrapper classes; (b) implement a new function in the C++ scanner that is
258     more efficient than the old way of doing things because it avoids levels of
259     recursion in the regex matching; (c) add a paragraph to the documentation
260     for the FullMatch() function.
262     6. The escape sequence \n was being treated as whatever was defined as
263     "newline". Not only was this contrary to the documentation, which states
264     that \n is character 10 (hex 0A), but it also went horribly wrong when
265     "newline" was defined as CRLF. This has been fixed.
267     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
268     was being set to -1 for the "end of line" case (supposedly a value that no
269     character can have). Though this value is never used (the check for end of
270     line is "zero bytes in current character"), it caused compiler complaints.
271     I've changed it to 0xffffffff.
273     8. In pcre_version.c, the version string was being built by a sequence of
274     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
275     string (as it is for production releases) called a macro with an empty
276     argument. The C standard says the result of this is undefined. The gcc
277     compiler treats it as an empty string (which was what was wanted) but it is
278     reported that Visual C gives an error. The source has been hacked around to
279     avoid this problem.
281     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
282     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
283     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
284     of them did).
286     10. Originally, pcretest opened its input and output without "b"; then I was
287     told that "b" was needed in some environments, so it was added for release
288     5.0 to both the input and output. (It makes no difference on Unix-like
289     systems.) Later I was told that it is wrong for the input on Windows. I've
290     now abstracted the modes into two macros, to make it easier to fiddle with
291     them, and removed "b" from the input mode under Windows.
293     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
295     12. Added -help and --help to pcretest as an official way of being reminded
296     of the options.
298     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
299     and pcrecpp.cc because they annoy compilers at high warning levels.
301     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
303     15. Fixed an occurrence of == in configure.ac that should have been = (shell
304     scripts are not C programs :-) and which was not noticed because it works
305     on Linux.
307     16. pcretest is supposed to handle any length of pattern and data line (as one
308     line or as a continued sequence of lines) by extending its input buffer if
309     necessary. This feature was broken for very long pattern lines, leading to
310     a string of junk being passed to pcre_compile() if the pattern was longer
311     than about 50K.
313     17. I have done a major re-factoring of the way pcre_compile() computes the
314     amount of memory needed for a compiled pattern. Previously, there was code
315     that made a preliminary scan of the pattern in order to do this. That was
316     OK when PCRE was new, but as the facilities have expanded, it has become
317     harder and harder to keep it in step with the real compile phase, and there
318     have been a number of bugs (see for example, 4 above). I have now found a
319     cunning way of running the real compile function in a "fake" mode that
320     enables it to compute how much memory it would need, while actually only
321     ever using a few hundred bytes of working memory and without too many
322     tests of the mode. This should make future maintenance and development
323     easier. A side effect of this work is that the limit of 200 on the nesting
324     depth of parentheses has been removed (though this was never a serious
325     limitation, I suspect). However, there is a downside: pcre_compile() now
326     runs more slowly than before (30% or more, depending on the pattern). I
327     hope this isn't a big issue. There is no effect on runtime performance.
329     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
330     newline (only possible for the last line of a file) and it was a
331     pattern that set a locale (followed by /Lsomething), pcretest crashed.
333     19. Added additional timing features to pcretest. (1) The -tm option now times
334     matching only, not compiling. (2) Both -t and -tm can be followed, as a
335     separate command line item, by a number that specifies the number of
336     repeats to use when timing. The default is 50000; this gives better
337     precision, but takes uncomfortably long for very large patterns.
339     20. Extended pcre_study() to be more clever in cases where a branch of a
340     subpattern has no definite first character. For example, (a*|b*)[cd] would
341     previously give no result from pcre_study(). Now it recognizes that the
342     first character must be a, b, c, or d.
344     21. There was an incorrect error "recursive call could loop indefinitely" if
345     a subpattern (or the entire pattern) that was being tested for matching an
346     empty string contained only one non-empty item after a nested subpattern.
347     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
348     incorrectly, because the \d was being skipped in the check.
350     22. The pcretest program now has a new pattern option /B and a command line
351     option -b, which is equivalent to adding /B to every pattern. This causes
352     it to show the compiled bytecode, without the additional information that
353     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
354     is the same as /B/I).
356     23. A new optimization is now able automatically to treat some sequences such
357     as a*b as a*+b. More specifically, if something simple (such as a character
358     or a simple class like \d) has an unlimited quantifier, and is followed by
359     something that cannot possibly match the quantified thing, the quantifier
360     is automatically "possessified".
362     24. A recursive reference to a subpattern whose number was greater than 39
363     went wrong under certain circumstances in UTF-8 mode. This bug could also
364     have affected the operation of pcre_study().
366     25. Realized that a little bit of performance could be had by replacing
367     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
369     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
371     27. Possessive quantifiers such as a++ were previously implemented by turning
372     them into atomic groups such as ($>a+). Now they have their own opcodes,
373     which improves performance. This includes the automatically created ones
374     from 23 above.
376     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
377     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
378     the first matched character to be a colon. This applied both to named and
379     numbered groups.
381     29. The ucpinternal.h header file was missing its idempotency #ifdef.
383     30. I was sent a "project" file called libpcre.a.dev which I understand makes
384     building PCRE on Windows easier, so I have included it in the distribution.
386     31. There is now a check in pcretest against a ridiculously large number being
387     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
388     loop, the loop is abandoned.
390     32. Forward references to subpatterns in conditions such as (?(2)...) where
391     subpattern 2 is defined later cause pcre_compile() to search forwards in
392     the pattern for the relevant set of parentheses. This search went wrong
393     when there were unescaped parentheses in a character class, parentheses
394     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
396     33. "Subroutine" calls and backreferences were previously restricted to
397     referencing subpatterns earlier in the regex. This restriction has now
398     been removed.
400     34. Added a number of extra features that are going to be in Perl 5.10. On the
401     whole, these are just syntactic alternatives for features that PCRE had
402     previously implemented using the Python syntax or my own invention. The
403     other formats are all retained for compatibility.
405     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
406     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
407     also .NET compatible.
409     (b) A recursion or subroutine call to a named group can now be defined as
410     (?&name) as well as (?P>name).
412     (c) A backreference to a named group can now be defined as \k<name> or
413     \k'name' as well as (?P=name). The new forms, as well as being in Perl
414     5.10, are also .NET compatible.
416     (d) A conditional reference to a named group can now use the syntax
417     (?(<name>) or (?('name') as well as (?(name).
419     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
420     groups (named and numbered) that are never evaluated inline, but can be
421     called as "subroutines" from elsewhere. In effect, the DEFINE condition
422     is always false. There may be only one alternative in such a group.
424     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
425     as the simple (?(R). The condition is true only if the most recent
426     recursion is that of the given number or name. It does not search out
427     through the entire recursion stack.
429     (g) The escape \gN or \g{N} has been added, where N is a positive or
430     negative number, specifying an absolute or relative reference.
432     35. Tidied to get rid of some further signed/unsigned compiler warnings and
433     some "unreachable code" warnings.
435     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
436     things, this adds five new scripts.
438     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
439     There were also incompatibilities regarding the handling of \Q..\E inside
440     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
441     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
443     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
444     matches an empty string, and forcibly breaks the loop. There were bugs in
445     this code in non-simple cases. For a pattern such as ^(a()*)* matched
446     against aaaa the result was just "a" rather than "aaaa", for example. Two
447     separate and independent bugs (that affected different cases) have been
448     fixed.
450     39. Refactored the code to abolish the use of different opcodes for small
451     capturing bracket numbers. This is a tidy that I avoided doing when I
452     removed the limit on the number of capturing brackets for 3.5 back in 2001.
453     The new approach is not only tidier, it makes it possible to reduce the
454     memory needed to fix the previous bug (38).
456     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
457     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
458     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
459     mode.
461     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
462     report.
464     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
465     copy construction and assignment in the C++ wrapper.
467     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
468     couple of bugs that could have given wrong results in the "--newline=crlf"
469     case.
471     44. Added a number of casts and did some reorganization of signed/unsigned int
472     variables following suggestions from Dair Grant. Also renamed the variable
473     "this" as "item" because it is a C++ keyword.
475     45. Arranged for dftables to add
477     #include "pcre_internal.h"
479     to pcre_chartables.c because without it, gcc 4.x may remove the array
480     definition from the final binary if PCRE is built into a static library and
481     dead code stripping is activated.
483     46. For an unanchored pattern, if a match attempt fails at the start of a
484     newline sequence, and the newline setting is CRLF or ANY, and the next two
485     characters are CRLF, advance by two characters instead of one.
488 nigel 91 Version 6.7 04-Jul-06
489     ---------------------
491     1. In order to handle tests when input lines are enormously long, pcretest has
492     been re-factored so that it automatically extends its buffers when
493     necessary. The code is crude, but this _is_ just a test program. The
494     default size has been increased from 32K to 50K.
496     2. The code in pcre_study() was using the value of the re argument before
497     testing it for NULL. (Of course, in any sensible call of the function, it
498     won't be NULL.)
500     3. The memmove() emulation function in pcre_internal.h, which is used on
501     systems that lack both memmove() and bcopy() - that is, hardly ever -
502     was missing a "static" storage class specifier.
504     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
505     containing an extended class (one that cannot be represented by a bitmap
506     because it contains high-valued characters or Unicode property items, e.g.
507     [\pZ]). Almost always one would set UTF-8 mode when processing such a
508     pattern, but PCRE should not loop if you do not (it no longer does).
509     [Detail: two cases were found: (a) a repeated subpattern containing an
510     extended class; (b) a recursive reference to a subpattern that followed a
511     previous extended class. It wasn't skipping over the extended class
512     correctly when UTF-8 mode was not set.]
514     5. A negated single-character class was not being recognized as fixed-length
515     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
516     compile error "lookbehind assertion is not fixed length".
518     6. The RunPerlTest auxiliary script was showing an unexpected difference
519     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
520     write a Perl script that can interpret lines of an input file either as
521     byte characters or as UTF-8, which is what "perltest" was being required to
522     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
523     can't do is switch easily at run time between having the "use utf8;" pragma
524     or not. In the end, I fudged it by using the RunPerlTest script to insert
525     "use utf8;" explicitly for the UTF-8 tests.
527     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
528     the end of the subject string, contrary to the documentation and to what
529     Perl does. This was true of both matching functions. Now it matches only at
530     the start of the subject and immediately after *internal* newlines.
532     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
533     a pointer to an int instead of a pointer to an unsigned long int. This
534     caused problems on 64-bit systems.
536     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
537     instance of the 'standard' template library not being so standard".
539     10. There was no check on the number of named subpatterns nor the maximum
540     length of a subpattern name. The product of these values is used to compute
541     the size of the memory block for a compiled pattern. By supplying a very
542     long subpattern name and a large number of named subpatterns, the size
543     computation could be caused to overflow. This is now prevented by limiting
544     the length of names to 32 characters, and the number of named subpatterns
545     to 10,000.
547     11. Subpatterns that are repeated with specific counts have to be replicated in
548     the compiled pattern. The size of memory for this was computed from the
549     length of the subpattern and the repeat count. The latter is limited to
550     65535, but there was no limit on the former, meaning that integer overflow
551     could in principle occur. The compiled length of a repeated subpattern is
552     now limited to 30,000 bytes in order to prevent this.
554     12. Added the optional facility to have named substrings with the same name.
556     13. Added the ability to use a named substring as a condition, using the
557     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
558     are numbers (not recommended). Forward references are permitted.
560     14. Added forward references in named backreferences (if you see what I mean).
562     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
563     pattern could run off the end of the subject. For example, the pattern
564     "(?s)(.{1,5})"8 did this with the subject "ab".
566     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
567     PCRE_CASELESS was set when matching characters that were quantified with ?
568     or *.
570     17. A character class other than a single negated character that had a minimum
571     but no maximum quantifier - for example [ab]{6,} - was not handled
572     correctly by pce_dfa_exec(). It would match only one character.
574     18. A valid (though odd) pattern that looked like a POSIX character
575     class but used an invalid character after [ (for example [[,abc,]]) caused
576     pcre_compile() to give the error "Failed: internal error: code overflow" or
577     in some cases to crash with a glibc free() error. This could even happen if
578     the pattern terminated after [[ but there just happened to be a sequence of
579     letters, a binary zero, and a closing ] in the memory that followed.
581     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
582     over the years. Originally (before any Unicode support), just the bottom 8
583     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
584     output from "man perlunicode" includes this:
586     The regular expression compiler produces polymorphic opcodes. That
587     is, the pattern adapts to the data and automatically switches to
588     the Unicode character scheme when presented with Unicode data--or
589     instead uses a traditional byte scheme when presented with byte
590     data.
592     Sadly, a wide octal escape does not cause a switch, and in a string with
593     no other multibyte characters, these octal escapes are treated as before.
594     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
595     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
596     Unicode string.
598     I have not perpetrated such confusion in PCRE. Up till now, it took just
599     the bottom 8 bits, as in old Perl. I have now made octal escapes with
600     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
601     translate to the appropriate multibyte character.
603     29. Applied some refactoring to reduce the number of warnings from Microsoft
604     and Borland compilers. This has included removing the fudge introduced
605     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
606     a warning about an unused variable.
608     21. PCRE has not included VT (character 0x0b) in the set of whitespace
609     characters since release 4.0, because Perl (from release 5.004) does not.
610     [Or at least, is documented not to: some releases seem to be in conflict
611     with the documentation.] However, when a pattern was studied with
612     pcre_study() and all its branches started with \s, PCRE still included VT
613     as a possible starting character. Of course, this did no harm; it just
614     caused an unnecessary match attempt.
616     22. Removed a now-redundant internal flag bit that recorded the fact that case
617     dependency changed within the pattern. This was once needed for "required
618     byte" processing, but is no longer used. This recovers a now-scarce options
619     bit. Also moved the least significant internal flag bit to the most-
620     significant bit of the word, which was not previously used (hangover from
621     the days when it was an int rather than a uint) to free up another bit for
622     the future.
624     23. Added support for CRLF line endings as well as CR and LF. As well as the
625     default being selectable at build time, it can now be changed at runtime
626     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
627     specify that it is scanning data with non-default line endings.
629     24. Changed the definition of CXXLINK to make it agree with the definition of
630     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
632     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
633     recursions. This makes a big different to stack usage for some patterns.
635     26. If a subpattern containing a named recursion or subroutine reference such
636     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
637     the space required for the compiled pattern went wrong and gave too small a
638     value. Depending on the environment, this could lead to "Failed: internal
639     error: code overflow at offset 49" or "glibc detected double free or
640     corruption" errors.
642     27. Applied patches from Google (a) to support the new newline modes and (b) to
643     advance over multibyte UTF-8 characters in GlobalReplace.
645     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
646     difference for some implementation of PCRE in some Windows version.
648     29. Added some extra testing facilities to pcretest:
650     \q<number> in a data line sets the "match limit" value
651     \Q<number> in a data line sets the "match recursion limt" value
652     -S <number> sets the stack size, where <number> is in megabytes
654     The -S option isn't available for Windows.
657 nigel 89 Version 6.6 06-Feb-06
658     ---------------------
660     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
661     in pcreposix.h. I have copied the definition from pcre.h.
663     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
664     because pcre.h is no longer a built file.
666     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
667     not normally included in the compiled code.
670 nigel 87 Version 6.5 01-Feb-06
671     ---------------------
673     1. When using the partial match feature with pcre_dfa_exec(), it was not
674     anchoring the second and subsequent partial matches at the new starting
675     point. This could lead to incorrect results. For example, with the pattern
676     /1234/, partially matching against "123" and then "a4" gave a match.
678     2. Changes to pcregrep:
680     (a) All non-match returns from pcre_exec() were being treated as failures
681     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
682     error message is output. Some extra information is given for the
684     probably the only errors that are likely to be caused by users (by
685     specifying a regex that has nested indefinite repeats, for instance).
686     If there are more than 20 of these errors, pcregrep is abandoned.
688     (b) A binary zero was treated as data while matching, but terminated the
689     output line if it was written out. This has been fixed: binary zeroes
690     are now no different to any other data bytes.
692     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
693     used to set a locale for matching. The --locale=xxxx long option has
694     been added (no short equivalent) to specify a locale explicitly on the
695     pcregrep command, overriding the environment variables.
697     (d) When -B was used with -n, some line numbers in the output were one less
698     than they should have been.
700     (e) Added the -o (--only-matching) option.
702     (f) If -A or -C was used with -c (count only), some lines of context were
703     accidentally printed for the final match.
705     (g) Added the -H (--with-filename) option.
707     (h) The combination of options -rh failed to suppress file names for files
708     that were found from directory arguments.
710     (i) Added the -D (--devices) and -d (--directories) options.
712     (j) Added the -F (--fixed-strings) option.
714     (k) Allow "-" to be used as a file name for -f as well as for a data file.
716     (l) Added the --colo(u)r option.
718     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
719     is not present by default.
721     3. A nasty bug was discovered in the handling of recursive patterns, that is,
722     items such as (?R) or (?1), when the recursion could match a number of
723     alternatives. If it matched one of the alternatives, but subsequently,
724     outside the recursion, there was a failure, the code tried to back up into
725     the recursion. However, because of the way PCRE is implemented, this is not
726     possible, and the result was an incorrect result from the match.
728     In order to prevent this happening, the specification of recursion has
729     been changed so that all such subpatterns are automatically treated as
730     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
732     4. I had overlooked the fact that, in some locales, there are characters for
733     which isalpha() is true but neither isupper() nor islower() are true. In
734     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
735     and ordfeminine) are like this. This affected the treatment of \w and \W
736     when they appeared in character classes, but not when they appeared outside
737     a character class. The bit map for "word" characters is now created
738     separately from the results of isalnum() instead of just taking it from the
739     upper, lower, and digit maps. (Plus the underscore character, of course.)
741     5. The above bug also affected the handling of POSIX character classes such as
742     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
743     permanent tables. Instead, the bit maps for such a class were previously
744     created as the appropriate unions of the upper, lower, and digit bitmaps.
745     Now they are created by subtraction from the [[:word:]] class, which has
746     its own bitmap.
748     6. The [[:blank:]] character class matches horizontal, but not vertical space.
749     It is created by subtracting the vertical space characters (\x09, \x0a,
750     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
751     subtraction was done in the overall bitmap for a character class, meaning
752     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
753     be recognized. This bug has been fixed.
755     7. Patches from the folks at Google:
757     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
758     real life, but is still worth protecting against".
760     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
761     regular expressions".
763     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
764     have it.
766     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
767     "configure" and the latter not, in order to fix a problem somebody had
768     with compiling the Arg class on HP-UX.
770     (e) Improve the error-handling of the C++ wrapper a little bit.
772     (f) New tests for checking recursion limiting.
774     8. The pcre_memmove() function, which is used only if the environment does not
775     have a standard memmove() function (and is therefore rarely compiled),
776     contained two bugs: (a) use of int instead of size_t, and (b) it was not
777     returning a result (though PCRE never actually uses the result).
779     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
780     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
781     returned instead of calling malloc() with an overflowing number that would
782     most likely cause subsequent chaos.
784     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
786     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
787     with this option is matched, the nmatch and pmatch options of regexec() are
788     ignored.
790     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
791     provided in case anyone wants to the the POSIX interface with UTF-8
792     strings.
794     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
795     C++ linking (needed for some HP-UX environments).
797     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
798     (unused parameter) and in the pcre_printint() function (omitted "default"
799     switch label when the default is to do nothing).
801     15. Added some code to make it possible, when PCRE is compiled as a C++
802     library, to replace subject pointers for pcre_exec() with a smart pointer
803     class, thus making it possible to process discontinuous strings.
805     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
806     much the same function. They were added by different people who were trying
807     to make PCRE easy to compile on non-Unix systems. It has been suggested
808     that PCRE_EXPORT be abolished now that there is more automatic apparatus
809     for compiling on Windows systems. I have therefore replaced it with
810     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
811     defaults to "extern" for C or "extern C" for C++, which works fine on
812     Unix-like systems. It is now possible to override the value of PCRE_DATA_
813     SCOPE with something explicit in config.h. In addition:
815     (a) pcreposix.h still had just "extern" instead of either of these macros;
816     I have replaced it with PCRE_DATA_SCOPE.
818     (b) Functions such as _pcre_xclass(), which are internal to the library,
819     but external in the C sense, all had PCRE_EXPORT in their definitions.
820     This is apparently wrong for the Windows case, so I have removed it.
821     (It makes no difference on Unix-like systems.)
823     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
824     of recursive calls to match(). This is different to MATCH_LIMIT because
825     that limits the total number of calls to match(), not all of which increase
826     the depth of recursion. Limiting the recursion depth limits the amount of
827     stack (or heap if NO_RECURSE is set) that is used. The default can be set
828     when PCRE is compiled, and changed at run time. A patch from Google adds
829     this functionality to the C++ interface.
831     18. Changes to the handling of Unicode character properties:
833     (a) Updated the table to Unicode 4.1.0.
835     (b) Recognize characters that are not in the table as "Cn" (undefined).
837     (c) I revised the way the table is implemented to a much improved format
838     which includes recognition of ranges. It now supports the ranges that
839     are defined in UnicodeData.txt, and it also amalgamates other
840     characters into ranges. This has reduced the number of entries in the
841     table from around 16,000 to around 3,000, thus reducing its size
842     considerably. I realized I did not need to use a tree structure after
843     all - a binary chop search is just as efficient. Having reduced the
844     number of entries, I extended their size from 6 bytes to 8 bytes to
845     allow for more data.
847     (d) Added support for Unicode script names via properties such as \p{Han}.
849     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
850     matching that character.
852     20. When matching a repeated Unicode property with a minimum greater than zero,
853     (for example \pL{2,}), PCRE could look past the end of the subject if it
854     reached it while seeking the minimum number of characters. This could
855     happen only if some of the characters were more than one byte long, because
856     there is a check for at least the minimum number of bytes.
858     21. Refactored the implementation of \p and \P so as to be more general, to
859     allow for more different types of property in future. This has changed the
860     compiled form incompatibly. Anybody with saved compiled patterns that use
861     \p or \P will have to recompile them.
863     22. Added "Any" and "L&" to the supported property types.
865     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
866     but give a compile time error if the value is greater than 0xff.
868     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
869     accidentally not being installed or uninstalled.
871     25. The pcre.h file was built from pcre.h.in, but the only changes that were
872     made were to insert the current release number. This seemed silly, because
873     it made things harder for people building PCRE on systems that don't run
874     "configure". I have turned pcre.h into a distributed file, no longer built
875     by "configure", with the version identification directly included. There is
876     no longer a pcre.h.in file.
878     However, this change necessitated a change to the pcre-config script as
879     well. It is built from pcre-config.in, and one of the substitutions was the
880     release number. I have updated configure.ac so that ./configure now finds
881     the release number by grepping pcre.h.
883     26. Added the ability to run the tests under valgrind.
886 nigel 85 Version 6.4 05-Sep-05
887     ---------------------
889     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
890     "--" to be printed when multiple files were scanned, even when none of the
891     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
892     consider it to be a bug, and have restored the previous behaviour.
894     2. A couple of code tidies to get rid of compiler warnings.
896     3. The pcretest program used to cheat by referring to symbols in the library
897     whose names begin with _pcre_. These are internal symbols that are not
898     really supposed to be visible externally, and in some environments it is
899     possible to suppress them. The cheating is now confined to including
900     certain files from the library's source, which is a bit cleaner.
902     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
903     file's purpose clearer.
905     5. Reorganized pcre_ucp_findchar().
908 nigel 83 Version 6.3 15-Aug-05
909     ---------------------
911     1. The file libpcre.pc.in did not have general read permission in the tarball.
913     2. There were some problems when building without C++ support:
915     (a) If C++ support was not built, "make install" and "make test" still
916     tried to test it.
918     (b) There were problems when the value of CXX was explicitly set. Some
919     changes have been made to try to fix these, and ...
921     (c) --disable-cpp can now be used to explicitly disable C++ support.
923     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
924     backslash in a target when C++ was disabled. This confuses some
925     versions of "make", apparently. Using an intermediate variable solves
926     this. (Same for CPP_LOBJ.)
928     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
929     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
930     necessary on certain architectures.
932     4. Added a setting of -export-symbols-regex to the link command to remove
933     those symbols that are exported in the C sense, but actually are local
934     within the library, and not documented. Their names all begin with
935     "_pcre_". This is not a perfect job, because (a) we have to except some
936     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
937     available (and never for static libraries). I have made a note to try to
938     find a way round (a) in the future.
941 nigel 81 Version 6.2 01-Aug-05
942     ---------------------
944     1. There was no test for integer overflow of quantifier values. A construction
945     such as {1111111111111111} would give undefined results. What is worse, if
946     a minimum quantifier for a parenthesized subpattern overflowed and became
947     negative, the calculation of the memory size went wrong. This could have
948     led to memory overwriting.
950     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
952     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
953     operating environments where this matters.
955     4. Applied Giuseppe Maxia's patch to add additional features for controlling
956     PCRE options from within the C++ wrapper.
958     5. Named capturing subpatterns were not being correctly counted when a pattern
959     was compiled. This caused two problems: (a) If there were more than 100
960     such subpatterns, the calculation of the memory needed for the whole
961     compiled pattern went wrong, leading to an overflow error. (b) Numerical
962     back references of the form \12, where the number was greater than 9, were
963     not recognized as back references, even though there were sufficient
964     previous subpatterns.
966     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
967     versions of gcc, e.g. 2.95.4.
970 nigel 79 Version 6.1 21-Jun-05
971     ---------------------
973     1. There was one reference to the variable "posix" in pcretest.c that was not
974     surrounded by "#if !defined NOPOSIX".
976     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
977     the cross-check on the old pcre_info() function, for the benefit of the
978     cut-down version of PCRE that is currently imported into Exim.
980     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
981     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
982     patterns that start (?i) but I don't think that matters. The use of (?i) is
983     just an example; this all applies to the other options as well.
985     4. Since libtool seems to echo the compile commands it is issuing, the output
986     from "make" can be reduced a bit by putting "@" in front of each libtool
987     compile command.
989     5. Patch from the folks at Google for configure.in to be a bit more thorough
990     in checking for a suitable C++ installation before trying to compile the
991     C++ stuff. This should fix a reported problem when a compiler was present,
992     but no suitable headers.
994     6. The man pages all had just "PCRE" as their title. I have changed them to
995     be the relevant file name. I have also arranged that these names are
996     retained in the file doc/pcre.txt, which is a concatenation in text format
997     of all the man pages except the little individual ones for each function.
999     7. The NON-UNIX-USE file had not been updated for the different set of source
1000     files that come with release 6. I also added a few comments about the C++
1001     wrapper.
1004 nigel 77 Version 6.0 07-Jun-05
1005     ---------------------
1007     1. Some minor internal re-organization to help with my DFA experiments.
1009     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1010     didn't matter for the library itself when fully configured, but did matter
1011     when compiling without UCP support, or within Exim, where the ucp files are
1012     not imported.
1014     3. Refactoring of the library code to split up the various functions into
1015     different source modules. The addition of the new DFA matching code (see
1016     below) to a single monolithic source would have made it really too
1017     unwieldy, quite apart from causing all the code to be include in a
1018     statically linked application, when only some functions are used. This is
1019     relevant even without the DFA addition now that patterns can be compiled in
1020     one application and matched in another.
1022     The downside of splitting up is that there have to be some external
1023     functions and data tables that are used internally in different modules of
1024     the library but which are not part of the API. These have all had their
1025     names changed to start with "_pcre_" so that they are unlikely to clash
1026     with other external names.
1028     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1029     a different (DFA) algorithm. Although it is slower than the original
1030     function, it does have some advantages for certain types of matching
1031     problem.
1033     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1034     including restarting after a partial match.
1036     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1037     defined when compiling for Windows was sent to me. I have put it into the
1038     code, though I have no means of testing or verifying it.
1040     7. Added the pcre_refcount() auxiliary function.
1042     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1043     match before or at the first newline in the subject string. In pcretest,
1044     the /f option on a pattern can be used to set this.
1046     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1047     would behave wrongly. This has been present in PCRE since release 4.0.
1049     10. A number of changes to the pcregrep command:
1051     (a) Refactored how -x works; insert ^(...)$ instead of setting
1052     PCRE_ANCHORED and checking the length, in preparation for adding
1053     something similar for -w.
1055     (b) Added the -w (match as a word) option.
1057     (c) Refactored the way lines are read and buffered so as to have more
1058     than one at a time available.
1060     (d) Implemented a pcregrep test script.
1062     (e) Added the -M (multiline match) option. This allows patterns to match
1063     over several lines of the subject. The buffering ensures that at least
1064     8K, or the rest of the document (whichever is the shorter) is available
1065     for matching (and similarly the previous 8K for lookbehind assertions).
1067     (f) Changed the --help output so that it now says
1069     -w, --word-regex(p)
1071     instead of two lines, one with "regex" and the other with "regexp"
1072     because that confused at least one person since the short forms are the
1073     same. (This required a bit of code, as the output is generated
1074     automatically from a table. It wasn't just a text change.)
1076     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1077     option but starts with a hyphen. Could be a pattern or a path name
1078     starting with a hyphen, for instance.
1080     (h) "-" can be given as a file name to represent stdin.
1082     (i) When file names are being printed, "(standard input)" is used for
1083     the standard input, for compatibility with GNU grep. Previously
1084     "<stdin>" was used.
1086     (j) The option --label=xxx can be used to supply a name to be used for
1087     stdin when file names are being printed. There is no short form.
1089     (k) Re-factored the options decoding logic because we are going to add
1090     two more options that take data. Such options can now be given in four
1091     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1093     (l) Added the -A, -B, and -C options for requesting that lines of context
1094     around matches be printed.
1096     (m) Added the -L option to print the names of files that do not contain
1097     any matching lines, that is, the complement of -l.
1099     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1100     continue to scan other files.
1102     (o) The -s option was incorrectly implemented. For compatibility with other
1103     greps, it now suppresses the error message for a non-existent or non-
1104     accessible file (but not the return code). There is a new option called
1105     -q that suppresses the output of matching lines, which was what -s was
1106     previously doing.
1108     (p) Added --include and --exclude options to specify files for inclusion
1109     and exclusion when recursing.
1111     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1112     Hopefully, it now does.
1114     12. Missing cast in pcre_study().
1116     13. Added an "uninstall" target to the makefile.
1118     14. Replaced "extern" in the function prototypes in Makefile.in with
1119     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1120     world, but is set differently for Windows.
1122     15. Added a second compiling function called pcre_compile2(). The only
1123     difference is that it has an extra argument, which is a pointer to an
1124     integer error code. When there is a compile-time failure, this is set
1125     non-zero, in addition to the error test pointer being set to point to an
1126     error message. The new argument may be NULL if no error number is required
1127     (but then you may as well call pcre_compile(), which is now just a
1128     wrapper). This facility is provided because some applications need a
1129     numeric error indication, but it has also enabled me to tidy up the way
1130     compile-time errors are handled in the POSIX wrapper.
1132     16. Added VPATH=.libs to the makefile; this should help when building with one
1133     prefix path and installing with another. (Or so I'm told by someone who
1134     knows more about this stuff than I do.)
1136     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1137     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1138     match everything, including newlines. This is not POSIX-compatible, but
1139     somebody wanted the feature. From pcretest it can be activated by using
1140     both the P and the s flags.
1142     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1144     19. libpcre.pc was being incorrectly installed as executable.
1146     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1147     it now also looks for '\r' so that it will work unmodified on Windows.
1149     21. Added Google's contributed C++ wrapper to the distribution.
1151     22. Added some untidy missing memory free() calls in pcretest, to keep
1152     Electric Fence happy when testing.
1156 nigel 75 Version 5.0 13-Sep-04
1157     ---------------------
1159     1. Internal change: literal characters are no longer packed up into items
1160     containing multiple characters in a single byte-string. Each character
1161     is now matched using a separate opcode. However, there may be more than one
1162     byte in the character in UTF-8 mode.
1164     2. The pcre_callout_block structure has two new fields: pattern_position and
1165     next_item_length. These contain the offset in the pattern to the next match
1166     item, and its length, respectively.
1168     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1169     insertion of callouts before each pattern item. Added the /C option to
1170     pcretest to make use of this.
1172     4. On the advice of a Windows user, the lines
1174     #if defined(_WIN32) || defined(WIN32)
1175     _setmode( _fileno( stdout ), 0x8000 );
1176     #endif /* defined(_WIN32) || defined(WIN32) */
1178     have been added to the source of pcretest. This apparently does useful
1179     magic in relation to line terminators.
1181     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1182     for the benefit of those environments where the "b" makes a difference.
1184     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1185     to know about it. I have put a hack into configure.in that adds in code
1186     to set GCC=yes if CC=icc. This seems to end up at a point in the
1187     generated configure script that is early enough to affect the setting of
1188     compiler options, which is what is needed, but I have no means of testing
1189     whether it really works. (The user who reported this had patched the
1190     generated configure script, which of course I cannot do.)
1192     LATER: After change 22 below (new libtool files), the configure script
1193     seems to know about icc (and also ecc). Therefore, I have commented out
1194     this hack in configure.in.
1196     7. Added support for pkg-config (2 patches were sent in).
1198     8. Negated POSIX character classes that used a combination of internal tables
1199     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1200     [[:^ascii]]. Typically, they would match almost any characters. The other
1201     POSIX classes were not broken in this way.
1203     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1204     to find the match, as PCRE was deluded into thinking that the match had to
1205     start at the start point or following a newline. The same bug applied to
1206     patterns with negative forward assertions or any backward assertions
1207     preceding ".*" at the start, unless the pattern required a fixed first
1208     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1210     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1211     starting at the last subject character, bytes beyond the end of the subject
1212     string were read.
1214     11. Renamed the variable "class" as "classbits" to make life easier for C++
1215     users. (Previously there was a macro definition, but it apparently wasn't
1216     enough.)
1218     12. Added the new field "tables" to the extra data so that tables can be passed
1219     in at exec time, or the internal tables can be re-selected. This allows
1220     a compiled regex to be saved and re-used at a later time by a different
1221     program that might have everything at different addresses.
1223     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1224     -R library as well as a -L library.
1226     14. The debugging options of pcretest (-d on the command line or D on a
1227     pattern) showed incorrect output for anything following an extended class
1228     that contained multibyte characters and which was followed by a quantifier.
1230     15. Added optional support for general category Unicode character properties
1231     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1232     support. It adds about 90K to the size of the library. The meanings of the
1233     inbuilt class escapes such as \d and \s have NOT been changed.
1235     16. Updated pcredemo.c to include calls to free() to release the memory for the
1236     compiled pattern.
1238     17. The generated file chartables.c was being created in the source directory
1239     instead of in the building directory. This caused the build to fail if the
1240     source directory was different from the building directory, and was
1241     read-only.
1243     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1244     file. No doubt somebody will tell me if they don't make sense... Also added
1245     Dan Mooney's comments about building on OpenVMS.
1247     19. Added support for partial matching via the PCRE_PARTIAL option for
1248     pcre_exec() and the \P data escape in pcretest.
1250     20. Extended pcretest with 3 new pattern features:
1252     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1253     write the compiled pattern to the file whose name is "rest-of-line".
1254     This is a straight binary dump of the data, with the saved pointer to
1255     the character tables forced to be NULL. The study data, if any, is
1256     written too. After writing, pcretest reads a new pattern.
1258     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1259     compiled pattern from the given file. There must not be any
1260     occurrences of "<" in the file name (pretty unlikely); if there are,
1261     pcretest will instead treat the initial "<" as a pattern delimiter.
1262     After reading in the pattern, pcretest goes on to read data lines as
1263     usual.
1265     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1266     and 16-bit fields in a compiled pattern, to simulate a pattern that
1267     was compiled on a host of opposite endianness.
1269     21. The pcre-exec() function can now cope with patterns that were compiled on
1270     hosts of opposite endianness, with this restriction:
1272     As for any compiled expression that is saved and used later, the tables
1273     pointer field cannot be preserved; the extra_data field in the arguments
1274     to pcre_exec() should be used to pass in a tables address if a value
1275     other than the default internal tables were used at compile time.
1277     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1278     now diagnosed as an error. Previously, most of the time, a negative number
1279     would have been treated as zero, but if in addition "ovector" was passed as
1280     NULL, a crash could occur.
1282     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1283     new versions from the libtool 1.5 distribution (the last one is a copy of
1284     a file called libtool.m4). This seems to have fixed the need to patch
1285     "configure" to support Darwin 1.3 (which I used to do). However, I still
1286     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1287     workstation).
1289     24. Changed the PCRE licence to be the more standard "BSD" licence.
1292 nigel 73 Version 4.5 01-Dec-03
1293     ---------------------
1295     1. There has been some re-arrangement of the code for the match() function so
1296     that it can be compiled in a version that does not call itself recursively.
1297     Instead, it keeps those local variables that need separate instances for
1298     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1299     needs to "recurse". Keeping track of where control must go is done by means
1300     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1301     hide most of the details from the main code, and operates only if
1302     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1303     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1304     operating.
1306     To make it easier for callers to provide specially tailored get/free
1307     functions for this usage, two new functions, pcre_stack_malloc, and
1308     pcre_stack_free, are used. They are always called in strict stacking order,
1309     and the size of block requested is always the same.
1311     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1312     PCRE has been compiled to use the stack or the heap for recursion. The
1313     -C option of pcretest uses this to show which version is compiled.
1315     A new data escape \S, is added to pcretest; it causes the amounts of store
1316     obtained and freed by both kinds of malloc/free at match time to be added
1317     to the output.
1319     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1320     what's available on my current Linux desktop machine.
1322     3. When matching a UTF-8 string, the test for a valid string at the start has
1323     been extended. If start_offset is not zero, PCRE now checks that it points
1324     to a byte that is the start of a UTF-8 character. If not, it returns
1325     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1326     this is necessary because there may be backward assertions in the pattern.
1327     When matching the same subject several times, it may save resources to use
1328     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1330     4. The code for checking the validity of UTF-8 strings has been tightened so
1331     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1332     containing "overlong sequences".
1334     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1335     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1336     should have been "&", but it just so happened that all the cases this let
1337     through by mistake were picked up later in the function.
1339     6. I had used a variable called "isblank" - this is a C99 function, causing
1340     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1342     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1343     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1344     so the version is shown; (c) stop "make test" echoing "./RunTest".
1346     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1348     9. The prototype for memmove() for systems that don't have it was using
1349     size_t, but the inclusion of the header that defines size_t was later. I've
1350     moved the #includes for the C headers earlier to avoid this.
1352     10. Added some adjustments to the code to make it easier to compiler on certain
1353     special systems:
1355     (a) Some "const" qualifiers were missing.
1356     (b) Added the macro EXPORT before all exported functions; by default this
1357     is defined to be empty.
1358     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1359     that it reads its output file name as an argument instead of writing
1360     to the standard output and assuming this can be redirected.
1362     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1363     class containing characters with values greater than 255, PCRE compilation
1364     went into a loop.
1366     12. A recursive reference to a subpattern that was within another subpattern
1367     that had a minimum quantifier of zero caused PCRE to crash. For example,
1368     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1369     recursion. If the recursively-called subpattern itself had a zero repeat,
1370     that was OK.
1372     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1373     buffer into which it was copied (for escape processing) was still set at
1374     1024, so long lines caused crashes.
1376     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1377     "internal error: code overflow...". This applied to any character class
1378     that was followed by a possessive quantifier.
1380     15. Modified the Makefile to add libpcre.la as a prerequisite for
1381     libpcreposix.la because I was told this is needed for a parallel build to
1382     work.
1384     16. If a pattern that contained .* following optional items at the start was
1385     studied, the wrong optimizing data was generated, leading to matching
1386     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1387     matching string must start with a or b or c. The correct conclusion for
1388     this pattern is that a match can start with any character.
1391 nigel 71 Version 4.4 13-Aug-03
1392     ---------------------
1394     1. In UTF-8 mode, a character class containing characters with values between
1395     127 and 255 was not handled correctly if the compiled pattern was studied.
1396     In fixing this, I have also improved the studying algorithm for such
1397     classes (slightly).
1399     2. Three internal functions had redundant arguments passed to them. Removal
1400     might give a very teeny performance improvement.
1402     3. Documentation bug: the value of the capture_top field in a callout is *one
1403     more than* the number of the hightest numbered captured substring.
1405     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1406     in incorrectly linking with a previously installed version. They now link
1407     explicitly with libpcre.la.
1409     5. configure.in no longer needs to recognize Cygwin specially.
1411     6. A problem in pcre.in for Windows platforms is fixed.
1413     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1414     pcretest, it used to include the size of the study block as part of its
1415     output. Unfortunately, the structure contains a field that has a different
1416     size on different hardware architectures. This meant that the tests that
1417     showed this size failed. As the block is currently always of a fixed size,
1418     this information isn't actually particularly useful in pcretest output, so
1419     I have just removed it.
1421     8. Three pre-processor statements accidentally did not start in column 1.
1422     Sadly, there are *still* compilers around that complain, even though
1423     standard C has not required this for well over a decade. Sigh.
1425     9. In pcretest, the code for checking callouts passed small integers in the
1426     callout_data field, which is a void * field. However, some picky compilers
1427     complained about the casts involved for this on 64-bit systems. Now
1428     pcretest passes the address of the small integer instead, which should get
1429     rid of the warnings.
1431     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1432     both compile and run time, and gives an error if an invalid UTF-8 sequence
1433     is found. There is a option for disabling this check in cases where the
1434     string is known to be correct and/or the maximum performance is wanted.
1436     11. In response to a bug report, I changed one line in Makefile.in from
1438     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1439     to
1440     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1442     to look similar to other lines, but I have no way of telling whether this
1443     is the right thing to do, as I do not use Windows. No doubt I'll get told
1444     if it's wrong...
1447 nigel 69 Version 4.3 21-May-03
1448     ---------------------
1450     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1451     Makefile.
1453     2. Some refactoring to improve the quality of the code:
1455     (i) The utf8_table... variables are now declared "const".
1457     (ii) The code for \cx, which used the "case flipping" table to upper case
1458     lower case letters, now just substracts 32. This is ASCII-specific,
1459     but the whole concept of \cx is ASCII-specific, so it seems
1460     reasonable.
1462     (iii) PCRE was using its character types table to recognize decimal and
1463     hexadecimal digits in the pattern. This is silly, because it handles
1464     only 0-9, a-f, and A-F, but the character types table is locale-
1465     specific, which means strange things might happen. A private
1466     table is now used for this - though it costs 256 bytes, a table is
1467     much faster than multiple explicit tests. Of course, the standard
1468     character types table is still used for matching digits in subject
1469     strings against \d.
1471     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1472     ending in _t are). So I've renamed it as ESC_tee.
1474     3. The first argument for regexec() in the POSIX wrapper should have been
1475     defined as "const".
1477     4. Changed pcretest to use malloc() for its buffers so that they can be
1478     Electric Fenced for debugging.
1480     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1481     to read one or more bytes before the start of the subject string. Often this
1482     had no effect on PCRE's behaviour, but in some circumstances it could
1483     provoke a segmentation fault.
1485     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1486     to try to read one or more bytes before the start of the subject string.
1488     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1489     UTF-8 support could misbehave in various ways if the subject string
1490     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1491     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1492     back over UTF-8 characters.)
1495 nigel 67 Version 4.2 14-Apr-03
1496     ---------------------
1498     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1500     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1501     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1502     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1503     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1504     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1505     and BUILD_EXEEXT
1506     Note: automatic setting of the BUILD variables is not yet working
1507     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1508     compile-time but not at link-time
1509     [LINK]: use for linking executables only
1510     make different versions for Windows and non-Windows
1511     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1512     libraries
1513     [LINK_FOR_BUILD]: new variable
1514     [OBJEXT]: use throughout
1515     [EXEEXT]: use throughout
1516     <winshared>: new target
1517     <wininstall>: new target
1518     <dftables.o>: use native compiler
1519     <dftables>: use native linker
1520     <install>: handle Windows platform correctly
1521     <clean>: ditto
1522     <check>: ditto
1523     copy DLL to top builddir before testing
1525     As part of these changes, -no-undefined was removed again. This was reported
1526     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1527     in any case.
1529     3. Some tidies to get rid of compiler warnings:
1531     . In the match_data structure, match_limit was an unsigned long int, whereas
1532     match_call_count was an int. I've made them both unsigned long ints.
1534     . In pcretest the fact that a const uschar * doesn't automatically cast to
1535     a void * provoked a warning.
1537     . Turning on some more compiler warnings threw up some "shadow" variables
1538     and a few more missing casts.
1540     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1541     option, a class that contained a single character with a value between 128
1542     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1544     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1545     option, a class that contained several characters, but with at least one
1546     whose value was between 128 and 255 caused PCRE to crash.
1549 nigel 65 Version 4.1 12-Mar-03
1550     ---------------------
1551 nigel 63
1552 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1553     needed, and a string in dftables.c that was longer than standard compilers are
1554     required to support.
1556     2. Compiling with Sun's compiler found a few more places where the code could
1557     be tidied up in order to avoid warnings.
1559     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1560     first of these names is deprecated in the latest Autoconf in favour of the name
1561     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1562     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1563     analogy I have changed it to CFLAGS_FOR_BUILD.
1565     4. Added -no-undefined to the linking command in the Makefile, because this is
1566     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1567     linking step for the pcreposix library.
1569     5. PCRE was failing to diagnose the case of two named groups with the same
1570     name.
1572     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1573     literal character that is needed in the subject for a match, and scans along to
1574     ensure that it is present before embarking on the full matching process. This
1575     saves time in cases of nested unlimited repeats that are never going to match.
1576     Problem: the scan can take a lot of time if the subject is very long (e.g.
1577     megabytes), thus penalizing straightforward matches. It is now done only if the
1578     amount of subject to be scanned is less than 1000 bytes.
1580     7. A lesser problem with the same optimization is that it was recording the
1581     first character of an anchored pattern as "needed", thus provoking a search
1582     right along the subject, even when the first match of the pattern was going to
1583     fail. The "needed" character is now not set for anchored patterns, unless it
1584     follows something in the pattern that is of non-fixed length. Thus, it still
1585     fulfils its original purpose of finding quick non-matches in cases of nested
1586     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1589     Version 4.0 17-Feb-03
1590     ---------------------
1592 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1593     extended to the end of string, PCRE compiled incorrect data. This could lead to
1594     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1596     2. Moved to autoconf 2.53 and libtool 1.4.2.
1598     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1599     the special perltest8 script is no longer needed - all the tests can be run
1600     from a single perltest script.
1602     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1603     by \s. It has now been removed in PCRE. This means it isn't recognized as
1604     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1605     class [:space:] *does* include VT, thereby creating a mess.
1607     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1608     space and tab.
1610     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1611     its new features into the main test script, reducing the number of scripts.
1613     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1614     were backward compatible, and made the (?i) apply to the whole pattern, as if
1615     /i were given. Now it behaves more logically, and applies the option setting
1616     only to what follows. PCRE has been changed to follow suit. However, if it
1617     finds options settings right at the start of the pattern, it extracts them into
1618     the global options, as before. Thus, they show up in the info data.
1620     8. Added support for the \Q...\E escape sequence. Characters in between are
1621     treated as literals. This is slightly different from Perl in that $ and @ are
1622     also handled as literals inside the quotes. In Perl, they will cause variable
1623     interpolation. Note the following examples:
1625     Pattern PCRE matches Perl matches
1627     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1628     \Qabc\$xyz\E abc\$xyz abc\$xyz
1629     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1631     For compatibility with Perl, \Q...\E sequences are recognized inside character
1632     classes as well as outside them.
1634     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1635     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1636     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1637     signed/unsigned warnings.
1639     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1640     option for pcretest, so I've replaced it by a simple function that does just
1641     that job.
1643     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1644     "pcregrep -".
1646     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1647     Java package. This provides some syntactic sugar for simple cases of what my
1648     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1649     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1650     item, you can use this simplified notation. Note that only makes sense with
1651     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1652     greediness, whatever the setting of the PCRE_UNGREEDY option.
1654     13. A change of greediness default within a pattern was not taking effect at
1655     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1656     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1657     was abstracted outside.
1659     14. PCRE now supports the \G assertion. It is true when the current matching
1660     position is at the start point of the match. This differs from \A when the
1661     starting offset is non-zero. Used with the /g option of pcretest (or similar
1662     code), it works in the same way as it does for Perl's /g option. If all
1663     alternatives of a regex begin with \G, the expression is anchored to the start
1664     match position, and the "anchored" flag is set in the compiled expression.
1666     15. Some bugs concerning the handling of certain option changes within patterns
1667     have been fixed. These applied to options other than (?ims). For example,
1668     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1669     been the other way round. Some of this was related to change 7 above.
1671     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1672     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1673     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1674     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1676     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1677     mode. Unlike ".", it always matches newline, whatever the setting of
1678     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1679     assertions. Perl allows it, but it doesn't (in general) work because it can't
1680     calculate the length of the lookbehind. At least, that's the case for Perl
1681     5.8.0 - I've been told they are going to document that it doesn't work in
1682     future.
1684     18. Added an error diagnosis for escapes that PCRE does not support: these are
1685     \L, \l, \N, \P, \p, \U, \u, and \X.
1687     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1688     reading past the end of the pattern in cases such as /[abcd/.
1690     20. PCRE was getting more memory than necessary for patterns with classes that
1691     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1693     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1694     compiling PCRE for use with Virtual Pascal.
1696     22. Small fix to the Makefile to make it work properly if the build is done
1697     outside the source tree.
1699     23. Added a new extension: a condition to go with recursion. If a conditional
1700     subpattern starts with (?(R) the "true" branch is used if recursion has
1701     happened, whereas the "false" branch is used only at the top level.
1703     24. When there was a very long string of literal characters (over 255 bytes
1704     without UTF support, over 250 bytes with UTF support), the computation of how
1705     much memory was required could be incorrect, leading to segfaults or other
1706     strange effects.
1708     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1709     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1710     there was a subsequent back reference to those brackets. This meant that, for
1711     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1712     possible to check for precisely this case. All we can do is abandon the
1713     optimization if .* occurs inside capturing brackets when there are any back
1714     references whatsoever. (See below for a better fix that came later.)
1716     26. The handling of the optimization for finding the first character of a
1717     non-anchored pattern, and for finding a character that is required later in the
1718     match were failing in some cases. This didn't break the matching; it just
1719     failed to optimize when it could. The way this is done has been re-implemented.
1721     27. Fixed typo in error message for invalid (?R item (it said "(?p").
1723     28. Added a new feature that provides some of the functionality that Perl
1724     provides with (?{...}). The facility is termed a "callout". The way it is done
1725     in PCRE is for the caller to provide an optional function, by setting
1726     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1727     global variable. By default it is unset, which disables all calling out. To get
1728     the function called, the regex must include (?C) at appropriate points. This
1729     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1730     This provides a means of identifying different callout points. When PCRE
1731     reaches such a point in the regex, if pcre_callout has been set, the external
1732     function is called. It is provided with data in a structure called
1733     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1734     matching continues; if it returns a non-zero value, the match at the current
1735     point fails. However, backtracking will occur if possible. [This was changed
1736     later and other features added - see item 49 below.]
1738     29. pcretest is upgraded to test the callout functionality. It provides a
1739     callout function that displays information. By default, it shows the start of
1740     the match and the current position in the text. There are some new data escapes
1741     to vary what happens:
1743     \C+ in addition, show current contents of captured substrings
1744     \C- do not supply a callout function
1745     \C!n return 1 when callout number n is reached
1746     \C!n!m return 1 when callout number n is reached for the mth time
1748     30. If pcregrep was called with the -l option and just a single file name, it
1749     output "<stdin>" if a match was found, instead of the file name.
1751     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1752     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1753     pcre_exec(). This saves a malloc/free per call. The default value of
1754     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1755     when configuring.
1757     32. The default maximum size of a compiled pattern is 64K. There have been a
1758     few cases of people hitting this limit. The code now uses macros to handle the
1759     storing of links as offsets within the compiled pattern. It defaults to 2-byte
1760     links, but this can be changed to 3 or 4 bytes by --with-link-size when
1761     configuring. Tests 2 and 5 work only with 2-byte links because they output
1762     debugging information about compiled patterns.
1764     33. Internal code re-arrangements:
1766     (a) Moved the debugging function for printing out a compiled regex into
1767     its own source file (printint.c) and used #include to pull it into
1768     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1769     separate copies.
1771     (b) Defined the list of op-code names for debugging as a macro in
1772     internal.h so that it is next to the definition of the opcodes.
1774     (c) Defined a table of op-code lengths for simpler skipping along compiled
1775     code. This is again a macro in internal.h so that it is next to the
1776     definition of the opcodes.
1778     34. Added support for recursive calls to individual subpatterns, along the
1779     lines of Robin Houston's patch (but implemented somewhat differently).
1781     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1782     allow it to read and process whole directories in Win32. This code was
1783     contributed by Lionel Fourquaux; it has not been tested by me.
1785     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1786     used to name a group. Names consist of alphanumerics and underscores, and must
1787     be unique. Back references use the syntax (?P=name) and recursive calls use
1788     (?P>name) which is a PCRE extension to the Python extension. Groups still have
1789     numbers. The function pcre_fullinfo() can be used after compilation to extract
1790     a name/number map. There are three relevant calls:
1792     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1793     PCRE_INFO_NAMECOUNT yields the number of entries
1794     PCRE_INFO_NAMETABLE yields a pointer to the map.
1796     The map is a vector of fixed-size entries. The size of each entry depends on
1797     the length of the longest name used. The first two bytes of each entry are the
1798     group number, most significant byte first. There follows the corresponding
1799     name, zero terminated. The names are in alphabetical order.
1801     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1802     case instead of 255. Making it the same both with and without UTF-8 support
1803     means that the same test output works with both.
1805     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1806     calling malloc() with a zero argument.
1808     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1809     optimization. I've improved things by keeping a bitmap of backreferences with
1810     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1811     fact referenced, the optimization can be applied. It is unlikely that a
1812     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1813     the match to follow \n) will appear inside brackets with a number greater than
1814     31, but if it does, any back reference > 31 suppresses the optimization.
1816     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1817     of disabling numbered capturing parentheses. Any opening parenthesis that is
1818     not followed by ? behaves as if it were followed by ?: but named parentheses
1819     can still be used for capturing (and they will acquire numbers in the usual
1820     way).
1822     41. Redesigned the return codes from the match() function into yes/no/error so
1823     that errors can be passed back from deep inside the nested calls. A malloc
1824     failure while inside a recursive subpattern call now causes the
1825     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1827     42. It is now possible to set a limit on the number of times the match()
1828     function is called in a call to pcre_exec(). This facility makes it possible to
1829     limit the amount of recursion and backtracking, though not in a directly
1830     obvious way, because the match() function is used in a number of different
1831     circumstances. The count starts from zero for each position in the subject
1832     string (for non-anchored patterns). The default limit is, for compatibility, a
1833     large number, namely 10 000 000. You can change this in two ways:
1835     (a) When configuring PCRE before making, you can use --with-match-limit=n
1836     to set a default value for the compiled library.
1838     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1839     a different value is set. See 45 below.
1841     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1843     43. Added a new function pcre_config(int, void *) to enable run-time extraction
1844     of things that can be changed at compile time. The first argument specifies
1845     what is wanted and the second points to where the information is to be placed.
1846     The current list of available information is:
1850     The output is an integer that is set to one if UTF-8 support is available;
1851     otherwise it is set to zero.
1855     The output is an integer that it set to the value of the code that is used for
1856     newline. It is either LF (10) or CR (13).
1860     The output is an integer that contains the number of bytes used for internal
1861     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1865     The output is an integer that contains the threshold above which the POSIX
1866     interface uses malloc() for output vectors. See item 31 above.
1870     The output is an unsigned integer that contains the default limit of the number
1871     of match() calls in a pcre_exec() execution. See 42 above.
1873     44. pcretest has been upgraded by the addition of the -C option. This causes it
1874     to extract all the available output from the new pcre_config() function, and to
1875     output it. The program then exits immediately.
1877     45. A need has arisen to pass over additional data with calls to pcre_exec() in
1878     order to support additional features. One way would have been to define
1879     pcre_exec2() (for example) with extra arguments, but this would not have been
1880     extensible, and would also have required all calls to the original function to
1881     be mapped to the new one. Instead, I have chosen to extend the mechanism that
1882     is used for passing in "extra" data from pcre_study().
1884     The pcre_extra structure is now exposed and defined in pcre.h. It currently
1885     contains the following fields:
1887     flags a bitmap indicating which of the following fields are set
1888     study_data opaque data from pcre_study()
1889     match_limit a way of specifying a limit on match() calls for a specific
1890     call to pcre_exec()
1891     callout_data data for callouts (see 49 below)
1893     The flag bits are also defined in pcre.h, and are
1899     The pcre_study() function now returns one of these new pcre_extra blocks, with
1900     the actual study data pointed to by the study_data field, and the
1901     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1902     before. That is, this change is entirely upwards-compatible and requires no
1903     change to existing code.
1905     If you want to pass in additional data to pcre_exec(), you can either place it
1906     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1907     block.
1909     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1910     data string contains the escape sequence \M, pcretest calls pcre_exec() several
1911     times with different match limits, until it finds the minimum value needed for
1912     pcre_exec() to complete. The value is then output. This can be instructive; for
1913     most simple matches the number is quite small, but for pathological cases it
1914     gets very large very quickly.
1916     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1917     returns the size of the data block pointed to by the study_data field in a
1918     pcre_extra block, that is, the value that was passed as the argument to
1919     pcre_malloc() when PCRE was getting memory in which to place the information
1920     created by pcre_study(). The fourth argument should point to a size_t variable.
1921     pcretest has been extended so that this information is shown after a successful
1922     pcre_study() call when information about the compiled regex is being displayed.
1924     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1925     because what follows is always an absolute path. (Later: it turns out that this
1926     is more than cosmetic for MinGW, because it doesn't like empty path
1927     components.)
1929     49. Some changes have been made to the callout feature (see 28 above):
1931     (i) A callout function now has three choices for what it returns:
1933     0 => success, carry on matching
1934     > 0 => failure at this point, but backtrack if possible
1935     < 0 => serious error, return this value from pcre_exec()
1937     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1938     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1939     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1940     use by callout functions. It will never be used by PCRE itself.
1942     (ii) The pcre_extra structure (see 45 above) has a void * field called
1943     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1944     pcre_callout_block structure has a field of the same name. The contents of
1945     the field passed in the pcre_extra structure are passed to the callout
1946     function in the corresponding field in the callout block. This makes it
1947     easier to use the same callout-containing regex from multiple threads. For
1948     testing, the pcretest program has a new data escape
1950     \C*n pass the number n (may be negative) as callout_data
1952     If the callout function in pcretest receives a non-zero value as
1953     callout_data, it returns that value.
1955     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1956     there were some redundant $(CFLAGS) in commands that are now specified as
1957     $(LINK), which already includes $(CFLAGS).
1959     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1960     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1961     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1962     one-byte characters throughout. Note that case-insensitive matching applies
1963     only to characters whose values are less than 256. PCRE doesn't support the
1964     notion of cases for higher-valued characters.
1966     (i) A character class whose characters are all within 0-255 is handled as
1967     a bit map, and the map is inverted for negative classes. Previously, a
1968     character > 255 always failed to match such a class; however it should
1969     match if the class was a negative one (e.g. [^ab]). This has been fixed.
1971     (ii) A negated character class with a single character < 255 is coded as
1972     "not this character" (OP_NOT). This wasn't working properly when the test
1973     character was multibyte, either singly or repeated.
1975     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1976     mode, for example: \x{100}{2,3}.
1978     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1979     singly or repeated) now correctly test multibyte characters. However,
1980     PCRE doesn't recognize any characters with values greater than 255 as
1981     digits, spaces, or word characters. Such characters always match \D, \S,
1982     and \W, and never match \d, \s, or \w.
1984     (v) Classes may now contain characters and character ranges with values
1985     greater than 255. For example: [ab\x{100}-\x{400}].
1987     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1988     PCRE in UTF-8 mode.
1990     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1991     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1992     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1993     value.)
1995     53. The single man page has become too large. I have therefore split it up into
1996     a number of separate man pages. These also give rise to individual HTML pages;
1997     these are now put in a separate directory, and there is an index.html page that
1998     lists them all. Some hyperlinking between the pages has been installed.
2000     54. Added convenience functions for handling named capturing parentheses.
2002     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2003     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2004     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2005     are faulted.
2007     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2008     calling configure. These values are used when compiling the dftables.c program
2009     which is run to generate the source of the default character tables. They
2010     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2011     you will need to set these values.
2013     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2016     Version 3.9 02-Jan-02
2017 nigel 61 ---------------------
2019     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2021     2. If --disable-static was given, the building process failed when trying to
2022     build pcretest and pcregrep. (For some reason it was using libtool to compile
2023     them, which is not right, as they aren't part of the library.)
2026 nigel 59 Version 3.8 18-Dec-01
2027     ---------------------
2029     1. The experimental UTF-8 code was completely screwed up. It was packing the
2030     bytes in the wrong order. How dumb can you get?
2033 nigel 57 Version 3.7 29-Oct-01
2034     ---------------------
2036     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2037     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2038     this didn't happen under Solaris 8, where I normally test things.
2040 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2041     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2042     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2043     this fix an hour or so after the initial 3.7 release.)
2044 nigel 57
2045 nigel 59
2046 nigel 55 Version 3.6 23-Oct-01
2047     ---------------------
2049     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2050     offsets passed as NULL with zero offset count.
2052     2. The config.guess and config.sub files had not been updated when I moved to
2053     the latest autoconf.
2056 nigel 53 Version 3.5 15-Aug-01
2057     ---------------------
2058 nigel 5
2059 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2060     had been forgotten.
2062     2. By using declared but undefined structures, we can avoid using "void"
2063     definitions in pcre.h while keeping the internal definitions of the structures
2064     private.
2066     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2067     user point of view, this means that both static and shared libraries are built
2068     by default, but this can be individually controlled. More of the work of
2069     handling this static/shared cases is now inside libtool instead of PCRE's make
2070     file.
2072     4. The pcretest utility is now installed along with pcregrep because it is
2073     useful for users (to test regexs) and by doing this, it automatically gets
2074     relinked by libtool. The documentation has been turned into a man page, so
2075     there are now .1, .txt, and .html versions in /doc.
2077     5. Upgrades to pcregrep:
2078     (i) Added long-form option names like gnu grep.
2079     (ii) Added --help to list all options with an explanatory phrase.
2080     (iii) Added -r, --recursive to recurse into sub-directories.
2081     (iv) Added -f, --file to read patterns from a file.
2083     6. pcre_exec() was referring to its "code" argument before testing that
2084     argument for NULL (and giving an error if it was NULL).
2086     7. Upgraded Makefile.in to allow for compiling in a different directory from
2087     the source directory.
2089     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2090     options bits, the pointer it was passed was to an int instead of to an unsigned
2091     long int. This mattered only on 64-bit systems.
2093     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2094     generated) instead of pcre.in, which it its source. Also made the same change
2095     in several of the .c files.
2097     10. A new release of gcc defines printf() as a macro, which broke pcretest
2098     because it had an ifdef in the middle of a string argument for printf(). Fixed
2099     by using separate calls to printf().
2101     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2102     script, to force use of CR or LF instead of \n in the source. On non-Unix
2103     systems, the value can be set in config.h.
2105     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2106     absolute limit. Changed the text of the error message to make this clear, and
2107     likewise updated the man page.
2109     13. The limit of 99 on the number of capturing subpatterns has been removed.
2110     The new limit is 65535, which I hope will not be a "real" limit.
2113 nigel 51 Version 3.4 22-Aug-00
2114     ---------------------
2116     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2118     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2121 nigel 49 Version 3.3 01-Aug-00
2122     ---------------------
2124     1. If an octal character was given, but the value was greater than \377, it
2125     was not getting masked to the least significant bits, as documented. This could
2126     lead to crashes in some systems.
2128     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2129     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2131     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2132     These just pass their arguments on to (pcre_free)(), but they are provided
2133     because some uses of PCRE bind it to non-C systems that can call its functions,
2134     but cannot call free() or pcre_free() directly.
2136     4. Add "make test" as a synonym for "make check". Corrected some comments in
2137     the Makefile.
2139     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2140     Makefile.
2142     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2143     command called pgrep for grepping around the active processes.
2145     7. Added the beginnings of support for UTF-8 character strings.
2147     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2148     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2149     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2150     out for the ar command.)
2153 nigel 47 Version 3.2 12-May-00
2154     ---------------------
2156     This is purely a bug fixing release.
2158     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2159     of ZA. This was just one example of several cases that could provoke this bug,
2160     which was introduced by change 9 of version 2.00. The code for breaking
2161     infinite loops after an iteration that matches an empty string was't working
2162     correctly.
2164     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2165     when matched against abbab (for example). After matching an empty string, it
2166     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2167     caused it to match further down the string than it should.
2169     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2170     was there because it doesn't seem to be needed, and it causes trouble on some
2171     systems, as it is not a Standard C header. It has been removed.
2173     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2174     were reported on the Macintosh. The changes were from
2176     while ((c = *(++ptr)) != 0 && c != '\n');
2177     to
2178     while ((c = *(++ptr)) != 0 && c != '\n') ;
2180     Totally extraordinary, but if that's what it takes...
2182     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2183     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2184     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2185     assumes the way PCRE uses memmove() (always moving upwards).
2187     6. PCRE is being used in one environment where strchr() is not available. There
2188     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2189     faster code anyway.
2192 nigel 45 Version 3.1 09-Feb-00
2193     ---------------------
2195     The only change in this release is the fixing of some bugs in Makefile.in for
2196     the "install" target:
2198     (1) It was failing to install pcreposix.h.
2200     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2203 nigel 43 Version 3.0 01-Feb-00
2204     ---------------------
2205 nigel 41
2206     1. Add support for the /+ modifier to perltest (to output $` like it does in
2207     pcretest).
2209     2. Add support for the /g modifier to perltest.
2211     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2212     matches null strings.
2214     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2215     pattern. Perl treats empty patterns specially - it reuses the most recent
2216     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2217     effect.
2219     5. The POSIX interface was broken in that it was just handing over the POSIX
2220     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2221     required a bigger vector, with some working space on the end. This means that
2222     the POSIX wrapper now has to get and free some memory, and copy the results.
2224 nigel 43 6. Added some simple autoconf support, placing the test data and the
2225     documentation in separate directories, re-organizing some of the
2226     information files, and making it build pcre-config (a GNU standard). Also added
2227     libtool support for building PCRE as a shared library, which is now the
2228     default.
2229 nigel 41
2230 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2231     09 are not valid octal constants. Single digits will be used for minor values
2232     less than 10.
2234     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2235     existing programs that set these in the POSIX interface can use PCRE without
2236     modification.
2238     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2239     return all that pcre_info() returns, plus additional data. The pcre_info()
2240     function is retained for compatibility, but is considered to be obsolete.
2242     10. Added experimental recursion feature (?R) to handle one common case that
2243     Perl 5.6 will be able to do with (?p{...}).
2245     11. Added support for POSIX character classes like [:alpha:], which Perl is
2246     adopting.
2249 nigel 39 Version 2.08 31-Aug-99
2250     ----------------------
2252     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2253     trying to match at the startoffset position, but instead was moving forward to
2254     the next newline as if a previous match had failed.
2256     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2257     and could get into a loop if a null string was matched other than at the start
2258     of the subject.
2260     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2261     be distinguished at compile time, and for completeness also added PCRE_DATE.
2263     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2264     in GnuWin32 environments.
2267 nigel 37 Version 2.07 29-Jul-99
2268     ----------------------
2270     1. The documentation is now supplied in plain text form and HTML as well as in
2271     the form of man page sources.
2273     2. C++ compilers don't like assigning (void *) values to other pointer types.
2274     In particular this affects malloc(). Although there is no problem in Standard
2275     C, I've put in casts to keep C++ compilers happy.
2277     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2278     should be (const char *).
2280     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2281     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2282     However, I haven't made this a standard facility. The documentation doesn't
2283     mention it, and the Makefile doesn't support it.
2285     5. The Makefile now contains an "install" target, with editable destinations at
2286     the top of the file. The pcretest program is not installed.
2288     6. pgrep -V now gives the PCRE version number and date.
2290     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2291     causing the entire string to be ignored, instead of just the last character.
2293     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2294     non-matching string, it can take a very, very long time, even for strings of
2295     quite modest length, because of the nested recursion. PCRE now does better in
2296     some of these cases. It does this by remembering the last required literal
2297     character in the pattern, and pre-searching the subject to ensure it is present
2298     before running the real match. In other words, it applies a heuristic to detect
2299     some types of certain failure quickly, and in the above example, if presented
2300     with a string that has no trailing " it gives "no match" very quickly.
2302     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2303     other alternatives are tried instead.
2306 nigel 35 Version 2.06 09-Jun-99
2307     ----------------------
2309     1. Change pcretest's output for amount of store used to show just the code
2310     space, because the remainder (the data block) varies in size between 32-bit and
2311     64-bit systems.
2313     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2314     start matching at. This allows lookbehinds to work when searching for multiple
2315     occurrences in a string.
2317     3. Added additional options to pcretest for testing multiple occurrences:
2319     /+ outputs the rest of the string that follows a match
2320     /g loops for multiple occurrences, using the new startoffset argument
2321     /G loops for multiple occurrences by passing an incremented pointer
2323     4. PCRE wasn't doing the "first character" optimization for patterns starting
2324     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2325     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2326     the letter 'x'. On long subject strings, this gives a significant speed-up.
2329 nigel 33 Version 2.05 21-Apr-99
2330     ----------------------
2332     1. Changed the type of magic_number from int to long int so that it works
2333     properly on 16-bit systems.
2335     2. Fixed a bug which caused patterns starting with .* not to work correctly
2336     when the subject string contained newline characters. PCRE was assuming
2337     anchoring for such patterns in all cases, which is not correct because .* will
2338     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2339     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2340     must be retried after every newline in the subject.
2343 nigel 31 Version 2.04 18-Feb-99
2344     ----------------------
2346     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2347     computation of the store needed to hold the pattern was incorrect (too large).
2348     If such patterns were nested a few deep, this could multiply and become a real
2349     problem.
2351     2. Added /M option to pcretest to show the memory requirement of a specific
2352     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2354     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2355     compiled in such a way that the backtracking after subsequent failure was
2356     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2357     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2360 nigel 29 Version 2.03 02-Feb-99
2361     ----------------------
2363     1. Fixed typo and small mistake in man page.
2365 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2366     LICENCE file containing the conditions.
2367 nigel 29
2368     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2369     Perl, that is the internal \ allows the delimiter to be included in the
2370     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2371     the final delimiter, add \ to the end of the pattern (to test the error).
2373     4. Added the convenience functions for extracting substrings after a successful
2374     match. Updated pcretest to make it able to test these functions.
2377 nigel 27 Version 2.02 14-Jan-99
2378     ----------------------
2380     1. Initialized the working variables associated with each extraction so that
2381     their saving and restoring doesn't refer to uninitialized store.
2383     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2384     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2385     fix the problem.
2387     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2388     calls, and wasn't printing the correct value for compiling calls. Increased the
2389     default value of LOOPREPEAT, and the number of significant figures in the
2390     times.
2392     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2394     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2395     a building problem on Windows NT with a FAT file system.
2398 nigel 25 Version 2.01 21-Oct-98
2399     ----------------------
2401     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2402     to character tables built by pcre_maketables() in the current locale. If NULL
2403     is passed, the default tables are used.
2406 nigel 23 Version 2.00 24-Sep-98
2407 nigel 21 ----------------------
2409 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2410     it any more.
2412     2. Allow quantification of (?>) groups, and make it work correctly.
2414     3. The first character computation wasn't working for (?>) groups.
2416     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2417     end of the subject) and add 5.005's \z, which really does match only at the
2418     very end of the subject.
2420     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2422     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2423     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2424     localized options. All options to pcre_study() were also removed.
2426     7. Add other new features from 5.005:
2428     $(?<= positive lookbehind
2429     $(?<! negative lookbehind
2430     (?imsx-imsx) added the unsetting capability
2431     such a setting is global if at outer level; local otherwise
2432     (?imsx-imsx:) non-capturing groups with option setting
2433     (?(cond)re|re) conditional pattern matching
2435     A backreference to itself in a repeated group matches the previous
2436     captured string.
2438     8. General tidying up of studying (both automatic and via "study")
2439     consequential on the addition of new assertions.
2441     9. As in 5.005, unlimited repeated groups that could match an empty substring
2442     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2443     runtime if any iteration does actually match an empty substring.
2445     10. Include the RunTest script in the distribution.
2447     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2448     discrepancies, some of which were old and were also with respect to 5.004. They
2449     have now been fixed.
2452     Version 1.09 28-Apr-98
2453     ----------------------
2455 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2456     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2457     program crashes, or just wrong answers. This did not apply to negated classes
2458     containing more than one character, or to minima other than one.
2461 nigel 19 Version 1.08 27-Mar-98
2462     ----------------------
2464     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2466     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2467     latter must appear before anything that relies on it in the pattern.
2470 nigel 17 Version 1.07 16-Feb-98
2471     ----------------------
2473     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2474     repeat of a potentially empty string).
2477 nigel 15 Version 1.06 23-Jan-98
2478     ----------------------
2480     1. Added Markus Oberhumer's little patches for C++.
2482     2. Literal strings longer than 255 characters were broken.
2485 nigel 13 Version 1.05 23-Dec-97
2486     ----------------------
2488     1. Negated character classes containing more than one character were failing if
2489     PCRE_CASELESS was set at run time.
2492 nigel 11 Version 1.04 19-Dec-97
2493     ----------------------
2495     1. Corrected the man page, where some "const" qualifiers had been omitted.
2497     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2498     input syntax.
2500     3. Fixed memory leak which occurred when a regex with back references was
2501     matched with an offsets vector that wasn't big enough. The temporary memory
2502     that is used in this case wasn't being freed if the match failed.
2504     4. Tidied pcretest to ensure it frees memory that it gets.
2506     5. Temporary memory was being obtained in the case where the passed offsets
2507     vector was exactly big enough.
2509     6. Corrected definition of offsetof() from change 5 below.
2511     7. I had screwed up change 6 below and broken the rules for the use of
2512     setjmp(). Now fixed.
2515 nigel 9 Version 1.03 18-Dec-97
2516     ----------------------
2518     1. A erroneous regex with a missing opening parenthesis was correctly
2519     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2520     on some systems.
2522     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2523     it was reported that one broken compiler failed on the former because "code" is
2524     also an independent variable.
2526     3. The erroneous regex a[]b caused an array overrun reference.
2528     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2529     fail on data ending with that character. (It was going on too far, and checking
2530     the next character, typically a binary zero.) This was specific to the
2531     optimized code for single-character negative classes.
2533     5. Added a contributed patch from the TIN world which does the following:
2535     + Add an undef for memmove, in case the the system defines a macro for it.
2537     + Add a definition of offsetof(), in case there isn't one. (I don't know
2538     the reason behind this - offsetof() is part of the ANSI standard - but
2539     it does no harm).
2541     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2542     most of the places where whitespace preceded '#'. I have given up and
2543     allowed the remaining 2 cases to be at the margin.
2545     + Rename some variables in pcre to eliminate shadowing. This seems very
2546     pedantic, but does no harm, of course.
2548     6. Moved the call to setjmp() into its own function, to get rid of warnings
2549     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2551     7. Constructs such as \d{8,} were compiling into the equivalent of
2552 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2553 nigel 9 outcome, but in this particular case used more store than had been allocated,
2554     which caused the bug to be discovered because it threw up an internal error.
2556     8. The debugging code in both pcre and pcretest for outputting the compiled
2557     form of a regex was going wrong in the case of back references followed by
2558     curly-bracketed repeats.
2561 nigel 7 Version 1.02 12-Dec-97
2562     ----------------------
2564     1. Typos in pcre.3 and comments in the source fixed.
2566     2. Applied a contributed patch to get rid of places where it used to remove
2567     'const' from variables, and fixed some signed/unsigned and uninitialized
2568     variable warnings.
2570     3. Added the "runtest" target to Makefile.
2572     4. Set default compiler flag to -O2 rather than just -O.
2575 nigel 5 Version 1.01 19-Nov-97
2576     ----------------------
2578     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2579     like /([ab]*)*/, that is, for classes with more than one character in them.
2581     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2582     as /((?>a*))*/ (a PCRE_EXTRA facility).
2585     Version 1.00 18-Nov-97
2586     ----------------------
2588     1. Added compile-time macros to support systems such as SunOS4 which don't have
2589     memmove() or strerror() but have other things that can be used instead.
2591     2. Arranged that "make clean" removes the executables.
2594 nigel 3 Version 0.99 27-Oct-97
2595     ----------------------
2597     1. Fixed bug in code for optimizing classes with only one character. It was
2598     initializing a 32-byte map regardless, which could cause it to run off the end
2599     of the memory it had got.
2601     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2604     Version 0.98 22-Oct-97
2605     ----------------------
2607     1. Fixed bug in code for handling temporary memory usage when there are more
2608     back references than supplied space in the ovector. This could cause segfaults.
2611     Version 0.97 21-Oct-97
2612     ----------------------
2614     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2616     2. Optimized negated single characters not to use a bit map.
2618     3. Brought error texts together as macro definitions; clarified some of them;
2619     fixed one that was wrong - it said "range out of order" when it meant "invalid
2620     escape sequence".
2622     4. Changed some char * arguments to const char *.
2624     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2626     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2627     pcretest.
2630     Version 0.96 16-Oct-97
2631     ----------------------
2633     1. Added a simple "pgrep" utility to the distribution.
2635     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2636     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2637     where "ddd" means "one or more decimal digits".
2639     3. Fixed serious bug. If a pattern had a back reference, but the call to
2640     pcre_exec() didn't supply a large enough ovector to record the related
2641     identifying subpattern, the match always failed. PCRE now remembers the number
2642     of the largest back reference, and gets some temporary memory in which to save
2643     the offsets during matching if necessary, in order to ensure that
2644     backreferences always work.
2646     4. Increased the compatibility with Perl in a number of ways:
2648     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2649     to request this handling. The option can be set at compile or exec time.
2651     (b) $ matches before a terminating newline by default; an option
2652     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2653     mode). The option can be set at compile or exec time.
2655     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2656     the same as Perl's. If the decimal number it represents is less than 10
2657     or there aren't that many previous left capturing parentheses, an octal
2658     escape is read. Inside a character class, it's always an octal escape,
2659     even if it is a single digit.
2661     (d) An escaped but undefined alphabetic character is taken as a literal,
2662     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2663     escapes.
2665     (e) {0} is now permitted. (The previous item is removed from the compiled
2666     pattern).
2668     5. Changed all the names of code files so that the basic parts are no longer
2669     than 10 characters, and abolished the teeny "globals.c" file.
2671     6. Changed the handling of character classes; they are now done with a 32-byte
2672     bit map always.
2674     7. Added the -d and /D options to pcretest to make it possible to look at the
2675     internals of compilation without having to recompile pcre.
2678     Version 0.95 23-Sep-97
2679     ----------------------
2681     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2682     \x20 at the start of a run of normal characters. These were being treated as
2683     real characters, instead of the source characters being re-checked.
2686     Version 0.94 18-Sep-97
2687     ----------------------
2689     1. The functions are now thread-safe, with the caveat that the global variables
2690     containing pointers to malloc() and free() or alternative functions are the
2691     same for all threads.
2693     2. Get pcre_study() to generate a bitmap of initial characters for non-
2694     anchored patterns when this is possible, and use it if passed to pcre_exec().
2697     Version 0.93 15-Sep-97
2698     ----------------------
2700     1. /(b)|(:+)/ was computing an incorrect first character.
2702     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2703     but not actually doing anything yet.
2705     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2706     as Perl does (e.g. [-az] or [az-]).
2708     4. Set the anchored flag if a branch starts with .* or .*? because that tests
2709     all possible positions.
2711     5. Split up into different modules to avoid including unneeded functions in a
2712     compiled binary. However, compile and exec are still in one module. The "study"
2713     function is split off.
2715     6. The character tables are now in a separate module whose source is generated
2716     by an auxiliary program - but can then be edited by hand if required. There are
2717     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2718     toupper() in the code.
2720     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2721     make them global. Abolish the function for setting them, as the caller can now
2722     set them directly.
2725     Version 0.92 11-Sep-97
2726     ----------------------
2728     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2729     (e.g. /a{1,3}/) was broken (I mis-optimized it).
2731     2. Caseless matching was not working in character classes if the characters in
2732     the pattern were in upper case.
2734     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2736     4. Make PCRE_ANCHORED public and accept as a compile option.
2738     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2739     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2740     pass them.
2742     6. Give an error if bad option bits passed at compile or run time.
2744     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2745     pcretest to cause it to pass that flag.
2747     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2748     options, and the first character, if set.
2750     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2753     Version 0.91 10-Sep-97
2754     ----------------------
2756     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2757     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2759     2. PCRE was looping on encountering an indefinitely repeated back reference to
2760     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2761     Perl does - treats the match as successful.
2763     ****


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