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Revision 178 - (hide annotations) (download)
Wed Jun 13 08:44:34 2007 UTC (7 years, 10 months ago) by ph10
File size: 129536 byte(s)
Add support for \h, \H, \v, \V.

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 178
47     (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
48 ph10 172
49     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
52     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
53     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
54 ph10 170 for detecting groups that can match an empty string.
55 ph10 159
56 ph10 172 9. A pattern with a very large number of alternatives (more than several
57     hundred) was running out of internal workspace during the pre-compile
58     phase, where pcre_compile() figures out how much memory will be needed. A
59     bit of new cunning has reduced the workspace needed for groups with
60     alternatives. The 1000-alternative test pattern now uses 12 bytes of
61     workspace instead of running out of the 4096 that are available.
62 ph10 176
63     10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
64 ph10 172
66 ph10 155 Version 7.1 24-Apr-07
67 ph10 98 ---------------------
69 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
70 ph10 122 that is more "standard", making use of automake and other Autotools. There
71 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
72     on this.
73 ph10 111
74     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
75     for recursive directory scanning broke on some systems because the files
76     are not scanned in any specific order and on different systems the order
77     was different. A call to "sort" has been inserted into RunGrepTest for the
78     approprate test as a short-term fix. In the longer term there may be an
79 ph10 100 alternative.
80 ph10 111
81 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
82 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
83     people do their own conversions for various reasons). The problems
84     concerned the use of low-level troff macros .br and .in. I have therefore
85     removed all such uses from the man pages (some were redundant, some could
86 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
87     HTML has been updated to handle .nf/.fi and to complain if it encounters
88     .br or .in.
89 ph10 111
90 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
91 ph10 123 arranged for config.h to be included in the distribution, with the name
92 ph10 111 config.h.generic, for the benefit of those who have to compile without
93     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
95     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
96     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
97 ph10 127 makevp.bat for the current PCRE, using the additional files
98 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
99 ph10 111
100     6. A Windows user reported a minor discrepancy with test 2, which turned out
101     to be caused by a trailing space on an input line that had got lost in his
102 ph10 102 copy. The trailing space was an accident, so I've just removed it.
103 ph10 111
104 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
105 ph10 111 that is needed.
107 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
108     as "const" (a) because they are and (b) because it helps the PHP
109     maintainers who have recently made a script to detect big data structures
110 ph10 111 in the php code that should be moved to the .rodata section. I remembered
111     to update Builducptable as well, so it won't revert if ucptable.h is ever
112 ph10 105 re-created.
113 ph10 111
114     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
115 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
116 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
117     support is not required. This saves 1.5-2K of code, which is important in
118 ph10 107 some applications.
119 ph10 111
120 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
121 ph10 111 so as not to refer to the tables, even though these functions will never be
122     called when UTF-8 support is disabled. Otherwise there are problems with a
123     shared library.
125 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
127     (a) It was defining its arguments as char * instead of void *.
129 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
130     a long time ago when I wrote it, but is no longer the case.
132 ph10 118 The emulated memove() is provided for those environments that have neither
133 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
134 ph10 118 is clearly not the case, as these two bugs were recently reported.
135 ph10 123
136 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
137 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
138     pages, and it removes trailing spaces from listed files. It also creates
139     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
140     case, it wraps all the #defines with #ifndefs. This script should be run
141 ph10 111 before "make dist".
142 ph10 123
143 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
144     with Unicode property support.
145 ph10 123
146     (a) For a maximizing quantifier, if the two different cases of the
147     character were of different lengths in their UTF-8 codings (there are
148     some cases like this - I found 11), and the matching function had to
149 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
150     were both the same length.
151 ph10 123
152     (b) When PCRE was configured to use the heap rather than the stack for
153     recursion during matching, it was not correctly preserving the data for
154     the other case of a UTF-8 character when checking ahead for a match
155     while processing a minimizing repeat. If the check also involved
156 ph10 115 matching a wide character, but failed, corruption could cause an
157     erroneous result when trying to check for a repeat of the original
158     character.
159 ph10 123
160 ph10 116 13. Some tidying changes to the testing mechanism:
161 ph10 98
162 ph10 116 (a) The RunTest script now detects the internal link size and whether there
163     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
164 ph10 123 values substituted by "configure". (The RunGrepTest script already did
165     this for UTF-8.) The configure.ac script no longer substitutes the
166     relevant variables.
168 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
169     with length and offset values. This means that the output is different
170     for different internal link sizes. Test 2 is skipped for link sizes
171     other than 2 because of this, bypassing the problem. Unfortunately,
172     there was also a test in test 3 (the locale tests) that used /B and
173 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
174     I have added a new /Z option to pcretest that replaces the length and
175     offset values with spaces. This is now used to make test 3 independent
176 ph10 122 of link size. (Test 2 will be tidied up later.)
177 ph10 123
178     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
179 ph10 122 segmentation fault instead of returning the appropriate error message.
180 ph10 134
181 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
182 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
183     This doesn't seem right; it now treats the CRLF combination as the line
184     ending, and so does not match in that case. It's only a pattern such as ^$
185     that would hit this one: something like ^ABC$ would have failed after \r
186     and then tried again after \r\n.
188 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
189 ph10 134 in an attempt to make files that differ only in their line terminators
190     compare equal. This works on Linux.
191 ph10 142
192 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
193     as it exited. This is now fixed, thanks to valgrind.
194 ph10 142
195 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
196 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
197     was because its rules for how to advance for /g after matching an empty
198 ph10 143 string at the end of a line did not allow for this case. They now check for
199     it specially.
200 ph10 150
201     20. pcretest is supposed to handle patterns and data of any length, by
202     extending its buffers when necessary. It was getting this wrong when the
203 ph10 147 buffer for a data line had to be extended.
204 ph10 150
205 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
206 ph10 150 CRLF as a newline sequence.
207 ph10 152
208 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
209 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
210     I have nevertheless tidied it up.
211 ph10 111
212 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
213 ph10 123
214 ph10 153 24. Added a man page for pcre-config.
215 ph10 152
216 ph10 153
217 nigel 93 Version 7.0 19-Dec-06
218     ---------------------
220     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
221     moving to gcc 4.1.1.
223     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
224     sys/time.h, which is documented as needed for this function. It doesn't
225     seem to matter on Linux, but it showed up on some releases of OS X.
227     3. It seems that there are systems where bytes whose values are greater than
228     127 match isprint() in the "C" locale. The "C" locale should be the
229     default when a C program starts up. In most systems, only ASCII printing
230     characters match isprint(). This difference caused the output from pcretest
231     to vary, making some of the tests fail. I have changed pcretest so that:
233     (a) When it is outputting text in the compiled version of a pattern, bytes
234     other than 32-126 are always shown as hex escapes.
236     (b) When it is outputting text that is a matched part of a subject string,
237     it does the same, unless a different locale has been set for the match
238     (using the /L modifier). In this case, it uses isprint() to decide.
240     4. Fixed a major bug that caused incorrect computation of the amount of memory
241     required for a compiled pattern when options that changed within the
242     pattern affected the logic of the preliminary scan that determines the
243     length. The relevant options are -x, and -i in UTF-8 mode. The result was
244     that the computed length was too small. The symptoms of this bug were
245     either the PCRE error "internal error: code overflow" from pcre_compile(),
246     or a glibc crash with a message such as "pcretest: free(): invalid next
247     size (fast)". Examples of patterns that provoked this bug (shown in
248     pcretest format) are:
250     /(?-x: )/x
251     /(?x)(?-x: \s*#\s*)/
252     /((?i)[\x{c0}])/8
253     /(?i:[\x{c0}])/8
255     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
256     is now done differently.
258     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
259     wrapper classes; (b) implement a new function in the C++ scanner that is
260     more efficient than the old way of doing things because it avoids levels of
261     recursion in the regex matching; (c) add a paragraph to the documentation
262     for the FullMatch() function.
264     6. The escape sequence \n was being treated as whatever was defined as
265     "newline". Not only was this contrary to the documentation, which states
266     that \n is character 10 (hex 0A), but it also went horribly wrong when
267     "newline" was defined as CRLF. This has been fixed.
269     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
270     was being set to -1 for the "end of line" case (supposedly a value that no
271     character can have). Though this value is never used (the check for end of
272     line is "zero bytes in current character"), it caused compiler complaints.
273     I've changed it to 0xffffffff.
275     8. In pcre_version.c, the version string was being built by a sequence of
276     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
277     string (as it is for production releases) called a macro with an empty
278     argument. The C standard says the result of this is undefined. The gcc
279     compiler treats it as an empty string (which was what was wanted) but it is
280     reported that Visual C gives an error. The source has been hacked around to
281     avoid this problem.
283     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
284     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
285     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
286     of them did).
288     10. Originally, pcretest opened its input and output without "b"; then I was
289     told that "b" was needed in some environments, so it was added for release
290     5.0 to both the input and output. (It makes no difference on Unix-like
291     systems.) Later I was told that it is wrong for the input on Windows. I've
292     now abstracted the modes into two macros, to make it easier to fiddle with
293     them, and removed "b" from the input mode under Windows.
295     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
297     12. Added -help and --help to pcretest as an official way of being reminded
298     of the options.
300     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
301     and pcrecpp.cc because they annoy compilers at high warning levels.
303     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
305     15. Fixed an occurrence of == in configure.ac that should have been = (shell
306     scripts are not C programs :-) and which was not noticed because it works
307     on Linux.
309     16. pcretest is supposed to handle any length of pattern and data line (as one
310     line or as a continued sequence of lines) by extending its input buffer if
311     necessary. This feature was broken for very long pattern lines, leading to
312     a string of junk being passed to pcre_compile() if the pattern was longer
313     than about 50K.
315     17. I have done a major re-factoring of the way pcre_compile() computes the
316     amount of memory needed for a compiled pattern. Previously, there was code
317     that made a preliminary scan of the pattern in order to do this. That was
318     OK when PCRE was new, but as the facilities have expanded, it has become
319     harder and harder to keep it in step with the real compile phase, and there
320     have been a number of bugs (see for example, 4 above). I have now found a
321     cunning way of running the real compile function in a "fake" mode that
322     enables it to compute how much memory it would need, while actually only
323     ever using a few hundred bytes of working memory and without too many
324     tests of the mode. This should make future maintenance and development
325     easier. A side effect of this work is that the limit of 200 on the nesting
326     depth of parentheses has been removed (though this was never a serious
327     limitation, I suspect). However, there is a downside: pcre_compile() now
328     runs more slowly than before (30% or more, depending on the pattern). I
329     hope this isn't a big issue. There is no effect on runtime performance.
331     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
332     newline (only possible for the last line of a file) and it was a
333     pattern that set a locale (followed by /Lsomething), pcretest crashed.
335     19. Added additional timing features to pcretest. (1) The -tm option now times
336     matching only, not compiling. (2) Both -t and -tm can be followed, as a
337     separate command line item, by a number that specifies the number of
338     repeats to use when timing. The default is 50000; this gives better
339     precision, but takes uncomfortably long for very large patterns.
341     20. Extended pcre_study() to be more clever in cases where a branch of a
342     subpattern has no definite first character. For example, (a*|b*)[cd] would
343     previously give no result from pcre_study(). Now it recognizes that the
344     first character must be a, b, c, or d.
346     21. There was an incorrect error "recursive call could loop indefinitely" if
347     a subpattern (or the entire pattern) that was being tested for matching an
348     empty string contained only one non-empty item after a nested subpattern.
349     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
350     incorrectly, because the \d was being skipped in the check.
352     22. The pcretest program now has a new pattern option /B and a command line
353     option -b, which is equivalent to adding /B to every pattern. This causes
354     it to show the compiled bytecode, without the additional information that
355     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
356     is the same as /B/I).
358     23. A new optimization is now able automatically to treat some sequences such
359     as a*b as a*+b. More specifically, if something simple (such as a character
360     or a simple class like \d) has an unlimited quantifier, and is followed by
361     something that cannot possibly match the quantified thing, the quantifier
362     is automatically "possessified".
364     24. A recursive reference to a subpattern whose number was greater than 39
365     went wrong under certain circumstances in UTF-8 mode. This bug could also
366     have affected the operation of pcre_study().
368     25. Realized that a little bit of performance could be had by replacing
369     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
371     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
373     27. Possessive quantifiers such as a++ were previously implemented by turning
374     them into atomic groups such as ($>a+). Now they have their own opcodes,
375     which improves performance. This includes the automatically created ones
376     from 23 above.
378     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
379     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
380     the first matched character to be a colon. This applied both to named and
381     numbered groups.
383     29. The ucpinternal.h header file was missing its idempotency #ifdef.
385     30. I was sent a "project" file called libpcre.a.dev which I understand makes
386     building PCRE on Windows easier, so I have included it in the distribution.
388     31. There is now a check in pcretest against a ridiculously large number being
389     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
390     loop, the loop is abandoned.
392     32. Forward references to subpatterns in conditions such as (?(2)...) where
393     subpattern 2 is defined later cause pcre_compile() to search forwards in
394     the pattern for the relevant set of parentheses. This search went wrong
395     when there were unescaped parentheses in a character class, parentheses
396     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
398     33. "Subroutine" calls and backreferences were previously restricted to
399     referencing subpatterns earlier in the regex. This restriction has now
400     been removed.
402     34. Added a number of extra features that are going to be in Perl 5.10. On the
403     whole, these are just syntactic alternatives for features that PCRE had
404     previously implemented using the Python syntax or my own invention. The
405     other formats are all retained for compatibility.
407     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
408     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
409     also .NET compatible.
411     (b) A recursion or subroutine call to a named group can now be defined as
412     (?&name) as well as (?P>name).
414     (c) A backreference to a named group can now be defined as \k<name> or
415     \k'name' as well as (?P=name). The new forms, as well as being in Perl
416     5.10, are also .NET compatible.
418     (d) A conditional reference to a named group can now use the syntax
419     (?(<name>) or (?('name') as well as (?(name).
421     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
422     groups (named and numbered) that are never evaluated inline, but can be
423     called as "subroutines" from elsewhere. In effect, the DEFINE condition
424     is always false. There may be only one alternative in such a group.
426     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
427     as the simple (?(R). The condition is true only if the most recent
428     recursion is that of the given number or name. It does not search out
429     through the entire recursion stack.
431     (g) The escape \gN or \g{N} has been added, where N is a positive or
432     negative number, specifying an absolute or relative reference.
434     35. Tidied to get rid of some further signed/unsigned compiler warnings and
435     some "unreachable code" warnings.
437     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
438     things, this adds five new scripts.
440     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
441     There were also incompatibilities regarding the handling of \Q..\E inside
442     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
443     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
445     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
446     matches an empty string, and forcibly breaks the loop. There were bugs in
447     this code in non-simple cases. For a pattern such as ^(a()*)* matched
448     against aaaa the result was just "a" rather than "aaaa", for example. Two
449     separate and independent bugs (that affected different cases) have been
450     fixed.
452     39. Refactored the code to abolish the use of different opcodes for small
453     capturing bracket numbers. This is a tidy that I avoided doing when I
454     removed the limit on the number of capturing brackets for 3.5 back in 2001.
455     The new approach is not only tidier, it makes it possible to reduce the
456     memory needed to fix the previous bug (38).
458     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
459     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
460     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
461     mode.
463     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
464     report.
466     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
467     copy construction and assignment in the C++ wrapper.
469     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
470     couple of bugs that could have given wrong results in the "--newline=crlf"
471     case.
473     44. Added a number of casts and did some reorganization of signed/unsigned int
474     variables following suggestions from Dair Grant. Also renamed the variable
475     "this" as "item" because it is a C++ keyword.
477     45. Arranged for dftables to add
479     #include "pcre_internal.h"
481     to pcre_chartables.c because without it, gcc 4.x may remove the array
482     definition from the final binary if PCRE is built into a static library and
483     dead code stripping is activated.
485     46. For an unanchored pattern, if a match attempt fails at the start of a
486     newline sequence, and the newline setting is CRLF or ANY, and the next two
487     characters are CRLF, advance by two characters instead of one.
490 nigel 91 Version 6.7 04-Jul-06
491     ---------------------
493     1. In order to handle tests when input lines are enormously long, pcretest has
494     been re-factored so that it automatically extends its buffers when
495     necessary. The code is crude, but this _is_ just a test program. The
496     default size has been increased from 32K to 50K.
498     2. The code in pcre_study() was using the value of the re argument before
499     testing it for NULL. (Of course, in any sensible call of the function, it
500     won't be NULL.)
502     3. The memmove() emulation function in pcre_internal.h, which is used on
503     systems that lack both memmove() and bcopy() - that is, hardly ever -
504     was missing a "static" storage class specifier.
506     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
507     containing an extended class (one that cannot be represented by a bitmap
508     because it contains high-valued characters or Unicode property items, e.g.
509     [\pZ]). Almost always one would set UTF-8 mode when processing such a
510     pattern, but PCRE should not loop if you do not (it no longer does).
511     [Detail: two cases were found: (a) a repeated subpattern containing an
512     extended class; (b) a recursive reference to a subpattern that followed a
513     previous extended class. It wasn't skipping over the extended class
514     correctly when UTF-8 mode was not set.]
516     5. A negated single-character class was not being recognized as fixed-length
517     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
518     compile error "lookbehind assertion is not fixed length".
520     6. The RunPerlTest auxiliary script was showing an unexpected difference
521     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
522     write a Perl script that can interpret lines of an input file either as
523     byte characters or as UTF-8, which is what "perltest" was being required to
524     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
525     can't do is switch easily at run time between having the "use utf8;" pragma
526     or not. In the end, I fudged it by using the RunPerlTest script to insert
527     "use utf8;" explicitly for the UTF-8 tests.
529     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
530     the end of the subject string, contrary to the documentation and to what
531     Perl does. This was true of both matching functions. Now it matches only at
532     the start of the subject and immediately after *internal* newlines.
534     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
535     a pointer to an int instead of a pointer to an unsigned long int. This
536     caused problems on 64-bit systems.
538     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
539     instance of the 'standard' template library not being so standard".
541     10. There was no check on the number of named subpatterns nor the maximum
542     length of a subpattern name. The product of these values is used to compute
543     the size of the memory block for a compiled pattern. By supplying a very
544     long subpattern name and a large number of named subpatterns, the size
545     computation could be caused to overflow. This is now prevented by limiting
546     the length of names to 32 characters, and the number of named subpatterns
547     to 10,000.
549     11. Subpatterns that are repeated with specific counts have to be replicated in
550     the compiled pattern. The size of memory for this was computed from the
551     length of the subpattern and the repeat count. The latter is limited to
552     65535, but there was no limit on the former, meaning that integer overflow
553     could in principle occur. The compiled length of a repeated subpattern is
554     now limited to 30,000 bytes in order to prevent this.
556     12. Added the optional facility to have named substrings with the same name.
558     13. Added the ability to use a named substring as a condition, using the
559     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
560     are numbers (not recommended). Forward references are permitted.
562     14. Added forward references in named backreferences (if you see what I mean).
564     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
565     pattern could run off the end of the subject. For example, the pattern
566     "(?s)(.{1,5})"8 did this with the subject "ab".
568     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
569     PCRE_CASELESS was set when matching characters that were quantified with ?
570     or *.
572     17. A character class other than a single negated character that had a minimum
573     but no maximum quantifier - for example [ab]{6,} - was not handled
574     correctly by pce_dfa_exec(). It would match only one character.
576     18. A valid (though odd) pattern that looked like a POSIX character
577     class but used an invalid character after [ (for example [[,abc,]]) caused
578     pcre_compile() to give the error "Failed: internal error: code overflow" or
579     in some cases to crash with a glibc free() error. This could even happen if
580     the pattern terminated after [[ but there just happened to be a sequence of
581     letters, a binary zero, and a closing ] in the memory that followed.
583     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
584     over the years. Originally (before any Unicode support), just the bottom 8
585     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
586     output from "man perlunicode" includes this:
588     The regular expression compiler produces polymorphic opcodes. That
589     is, the pattern adapts to the data and automatically switches to
590     the Unicode character scheme when presented with Unicode data--or
591     instead uses a traditional byte scheme when presented with byte
592     data.
594     Sadly, a wide octal escape does not cause a switch, and in a string with
595     no other multibyte characters, these octal escapes are treated as before.
596     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
597     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
598     Unicode string.
600     I have not perpetrated such confusion in PCRE. Up till now, it took just
601     the bottom 8 bits, as in old Perl. I have now made octal escapes with
602     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
603     translate to the appropriate multibyte character.
605     29. Applied some refactoring to reduce the number of warnings from Microsoft
606     and Borland compilers. This has included removing the fudge introduced
607     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
608     a warning about an unused variable.
610     21. PCRE has not included VT (character 0x0b) in the set of whitespace
611     characters since release 4.0, because Perl (from release 5.004) does not.
612     [Or at least, is documented not to: some releases seem to be in conflict
613     with the documentation.] However, when a pattern was studied with
614     pcre_study() and all its branches started with \s, PCRE still included VT
615     as a possible starting character. Of course, this did no harm; it just
616     caused an unnecessary match attempt.
618     22. Removed a now-redundant internal flag bit that recorded the fact that case
619     dependency changed within the pattern. This was once needed for "required
620     byte" processing, but is no longer used. This recovers a now-scarce options
621     bit. Also moved the least significant internal flag bit to the most-
622     significant bit of the word, which was not previously used (hangover from
623     the days when it was an int rather than a uint) to free up another bit for
624     the future.
626     23. Added support for CRLF line endings as well as CR and LF. As well as the
627     default being selectable at build time, it can now be changed at runtime
628     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
629     specify that it is scanning data with non-default line endings.
631     24. Changed the definition of CXXLINK to make it agree with the definition of
632     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
634     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
635     recursions. This makes a big different to stack usage for some patterns.
637     26. If a subpattern containing a named recursion or subroutine reference such
638     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
639     the space required for the compiled pattern went wrong and gave too small a
640     value. Depending on the environment, this could lead to "Failed: internal
641     error: code overflow at offset 49" or "glibc detected double free or
642     corruption" errors.
644     27. Applied patches from Google (a) to support the new newline modes and (b) to
645     advance over multibyte UTF-8 characters in GlobalReplace.
647     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
648     difference for some implementation of PCRE in some Windows version.
650     29. Added some extra testing facilities to pcretest:
652     \q<number> in a data line sets the "match limit" value
653     \Q<number> in a data line sets the "match recursion limt" value
654     -S <number> sets the stack size, where <number> is in megabytes
656     The -S option isn't available for Windows.
659 nigel 89 Version 6.6 06-Feb-06
660     ---------------------
662     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
663     in pcreposix.h. I have copied the definition from pcre.h.
665     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
666     because pcre.h is no longer a built file.
668     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
669     not normally included in the compiled code.
672 nigel 87 Version 6.5 01-Feb-06
673     ---------------------
675     1. When using the partial match feature with pcre_dfa_exec(), it was not
676     anchoring the second and subsequent partial matches at the new starting
677     point. This could lead to incorrect results. For example, with the pattern
678     /1234/, partially matching against "123" and then "a4" gave a match.
680     2. Changes to pcregrep:
682     (a) All non-match returns from pcre_exec() were being treated as failures
683     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
684     error message is output. Some extra information is given for the
686     probably the only errors that are likely to be caused by users (by
687     specifying a regex that has nested indefinite repeats, for instance).
688     If there are more than 20 of these errors, pcregrep is abandoned.
690     (b) A binary zero was treated as data while matching, but terminated the
691     output line if it was written out. This has been fixed: binary zeroes
692     are now no different to any other data bytes.
694     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
695     used to set a locale for matching. The --locale=xxxx long option has
696     been added (no short equivalent) to specify a locale explicitly on the
697     pcregrep command, overriding the environment variables.
699     (d) When -B was used with -n, some line numbers in the output were one less
700     than they should have been.
702     (e) Added the -o (--only-matching) option.
704     (f) If -A or -C was used with -c (count only), some lines of context were
705     accidentally printed for the final match.
707     (g) Added the -H (--with-filename) option.
709     (h) The combination of options -rh failed to suppress file names for files
710     that were found from directory arguments.
712     (i) Added the -D (--devices) and -d (--directories) options.
714     (j) Added the -F (--fixed-strings) option.
716     (k) Allow "-" to be used as a file name for -f as well as for a data file.
718     (l) Added the --colo(u)r option.
720     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
721     is not present by default.
723     3. A nasty bug was discovered in the handling of recursive patterns, that is,
724     items such as (?R) or (?1), when the recursion could match a number of
725     alternatives. If it matched one of the alternatives, but subsequently,
726     outside the recursion, there was a failure, the code tried to back up into
727     the recursion. However, because of the way PCRE is implemented, this is not
728     possible, and the result was an incorrect result from the match.
730     In order to prevent this happening, the specification of recursion has
731     been changed so that all such subpatterns are automatically treated as
732     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
734     4. I had overlooked the fact that, in some locales, there are characters for
735     which isalpha() is true but neither isupper() nor islower() are true. In
736     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
737     and ordfeminine) are like this. This affected the treatment of \w and \W
738     when they appeared in character classes, but not when they appeared outside
739     a character class. The bit map for "word" characters is now created
740     separately from the results of isalnum() instead of just taking it from the
741     upper, lower, and digit maps. (Plus the underscore character, of course.)
743     5. The above bug also affected the handling of POSIX character classes such as
744     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
745     permanent tables. Instead, the bit maps for such a class were previously
746     created as the appropriate unions of the upper, lower, and digit bitmaps.
747     Now they are created by subtraction from the [[:word:]] class, which has
748     its own bitmap.
750     6. The [[:blank:]] character class matches horizontal, but not vertical space.
751     It is created by subtracting the vertical space characters (\x09, \x0a,
752     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
753     subtraction was done in the overall bitmap for a character class, meaning
754     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
755     be recognized. This bug has been fixed.
757     7. Patches from the folks at Google:
759     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
760     real life, but is still worth protecting against".
762     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
763     regular expressions".
765     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
766     have it.
768     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
769     "configure" and the latter not, in order to fix a problem somebody had
770     with compiling the Arg class on HP-UX.
772     (e) Improve the error-handling of the C++ wrapper a little bit.
774     (f) New tests for checking recursion limiting.
776     8. The pcre_memmove() function, which is used only if the environment does not
777     have a standard memmove() function (and is therefore rarely compiled),
778     contained two bugs: (a) use of int instead of size_t, and (b) it was not
779     returning a result (though PCRE never actually uses the result).
781     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
782     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
783     returned instead of calling malloc() with an overflowing number that would
784     most likely cause subsequent chaos.
786     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
788     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
789     with this option is matched, the nmatch and pmatch options of regexec() are
790     ignored.
792     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
793     provided in case anyone wants to the the POSIX interface with UTF-8
794     strings.
796     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
797     C++ linking (needed for some HP-UX environments).
799     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
800     (unused parameter) and in the pcre_printint() function (omitted "default"
801     switch label when the default is to do nothing).
803     15. Added some code to make it possible, when PCRE is compiled as a C++
804     library, to replace subject pointers for pcre_exec() with a smart pointer
805     class, thus making it possible to process discontinuous strings.
807     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
808     much the same function. They were added by different people who were trying
809     to make PCRE easy to compile on non-Unix systems. It has been suggested
810     that PCRE_EXPORT be abolished now that there is more automatic apparatus
811     for compiling on Windows systems. I have therefore replaced it with
812     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
813     defaults to "extern" for C or "extern C" for C++, which works fine on
814     Unix-like systems. It is now possible to override the value of PCRE_DATA_
815     SCOPE with something explicit in config.h. In addition:
817     (a) pcreposix.h still had just "extern" instead of either of these macros;
818     I have replaced it with PCRE_DATA_SCOPE.
820     (b) Functions such as _pcre_xclass(), which are internal to the library,
821     but external in the C sense, all had PCRE_EXPORT in their definitions.
822     This is apparently wrong for the Windows case, so I have removed it.
823     (It makes no difference on Unix-like systems.)
825     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
826     of recursive calls to match(). This is different to MATCH_LIMIT because
827     that limits the total number of calls to match(), not all of which increase
828     the depth of recursion. Limiting the recursion depth limits the amount of
829     stack (or heap if NO_RECURSE is set) that is used. The default can be set
830     when PCRE is compiled, and changed at run time. A patch from Google adds
831     this functionality to the C++ interface.
833     18. Changes to the handling of Unicode character properties:
835     (a) Updated the table to Unicode 4.1.0.
837     (b) Recognize characters that are not in the table as "Cn" (undefined).
839     (c) I revised the way the table is implemented to a much improved format
840     which includes recognition of ranges. It now supports the ranges that
841     are defined in UnicodeData.txt, and it also amalgamates other
842     characters into ranges. This has reduced the number of entries in the
843     table from around 16,000 to around 3,000, thus reducing its size
844     considerably. I realized I did not need to use a tree structure after
845     all - a binary chop search is just as efficient. Having reduced the
846     number of entries, I extended their size from 6 bytes to 8 bytes to
847     allow for more data.
849     (d) Added support for Unicode script names via properties such as \p{Han}.
851     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
852     matching that character.
854     20. When matching a repeated Unicode property with a minimum greater than zero,
855     (for example \pL{2,}), PCRE could look past the end of the subject if it
856     reached it while seeking the minimum number of characters. This could
857     happen only if some of the characters were more than one byte long, because
858     there is a check for at least the minimum number of bytes.
860     21. Refactored the implementation of \p and \P so as to be more general, to
861     allow for more different types of property in future. This has changed the
862     compiled form incompatibly. Anybody with saved compiled patterns that use
863     \p or \P will have to recompile them.
865     22. Added "Any" and "L&" to the supported property types.
867     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
868     but give a compile time error if the value is greater than 0xff.
870     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
871     accidentally not being installed or uninstalled.
873     25. The pcre.h file was built from pcre.h.in, but the only changes that were
874     made were to insert the current release number. This seemed silly, because
875     it made things harder for people building PCRE on systems that don't run
876     "configure". I have turned pcre.h into a distributed file, no longer built
877     by "configure", with the version identification directly included. There is
878     no longer a pcre.h.in file.
880     However, this change necessitated a change to the pcre-config script as
881     well. It is built from pcre-config.in, and one of the substitutions was the
882     release number. I have updated configure.ac so that ./configure now finds
883     the release number by grepping pcre.h.
885     26. Added the ability to run the tests under valgrind.
888 nigel 85 Version 6.4 05-Sep-05
889     ---------------------
891     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
892     "--" to be printed when multiple files were scanned, even when none of the
893     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
894     consider it to be a bug, and have restored the previous behaviour.
896     2. A couple of code tidies to get rid of compiler warnings.
898     3. The pcretest program used to cheat by referring to symbols in the library
899     whose names begin with _pcre_. These are internal symbols that are not
900     really supposed to be visible externally, and in some environments it is
901     possible to suppress them. The cheating is now confined to including
902     certain files from the library's source, which is a bit cleaner.
904     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
905     file's purpose clearer.
907     5. Reorganized pcre_ucp_findchar().
910 nigel 83 Version 6.3 15-Aug-05
911     ---------------------
913     1. The file libpcre.pc.in did not have general read permission in the tarball.
915     2. There were some problems when building without C++ support:
917     (a) If C++ support was not built, "make install" and "make test" still
918     tried to test it.
920     (b) There were problems when the value of CXX was explicitly set. Some
921     changes have been made to try to fix these, and ...
923     (c) --disable-cpp can now be used to explicitly disable C++ support.
925     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
926     backslash in a target when C++ was disabled. This confuses some
927     versions of "make", apparently. Using an intermediate variable solves
928     this. (Same for CPP_LOBJ.)
930     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
931     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
932     necessary on certain architectures.
934     4. Added a setting of -export-symbols-regex to the link command to remove
935     those symbols that are exported in the C sense, but actually are local
936     within the library, and not documented. Their names all begin with
937     "_pcre_". This is not a perfect job, because (a) we have to except some
938     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
939     available (and never for static libraries). I have made a note to try to
940     find a way round (a) in the future.
943 nigel 81 Version 6.2 01-Aug-05
944     ---------------------
946     1. There was no test for integer overflow of quantifier values. A construction
947     such as {1111111111111111} would give undefined results. What is worse, if
948     a minimum quantifier for a parenthesized subpattern overflowed and became
949     negative, the calculation of the memory size went wrong. This could have
950     led to memory overwriting.
952     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
954     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
955     operating environments where this matters.
957     4. Applied Giuseppe Maxia's patch to add additional features for controlling
958     PCRE options from within the C++ wrapper.
960     5. Named capturing subpatterns were not being correctly counted when a pattern
961     was compiled. This caused two problems: (a) If there were more than 100
962     such subpatterns, the calculation of the memory needed for the whole
963     compiled pattern went wrong, leading to an overflow error. (b) Numerical
964     back references of the form \12, where the number was greater than 9, were
965     not recognized as back references, even though there were sufficient
966     previous subpatterns.
968     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
969     versions of gcc, e.g. 2.95.4.
972 nigel 79 Version 6.1 21-Jun-05
973     ---------------------
975     1. There was one reference to the variable "posix" in pcretest.c that was not
976     surrounded by "#if !defined NOPOSIX".
978     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
979     the cross-check on the old pcre_info() function, for the benefit of the
980     cut-down version of PCRE that is currently imported into Exim.
982     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
983     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
984     patterns that start (?i) but I don't think that matters. The use of (?i) is
985     just an example; this all applies to the other options as well.
987     4. Since libtool seems to echo the compile commands it is issuing, the output
988     from "make" can be reduced a bit by putting "@" in front of each libtool
989     compile command.
991     5. Patch from the folks at Google for configure.in to be a bit more thorough
992     in checking for a suitable C++ installation before trying to compile the
993     C++ stuff. This should fix a reported problem when a compiler was present,
994     but no suitable headers.
996     6. The man pages all had just "PCRE" as their title. I have changed them to
997     be the relevant file name. I have also arranged that these names are
998     retained in the file doc/pcre.txt, which is a concatenation in text format
999     of all the man pages except the little individual ones for each function.
1001     7. The NON-UNIX-USE file had not been updated for the different set of source
1002     files that come with release 6. I also added a few comments about the C++
1003     wrapper.
1006 nigel 77 Version 6.0 07-Jun-05
1007     ---------------------
1009     1. Some minor internal re-organization to help with my DFA experiments.
1011     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1012     didn't matter for the library itself when fully configured, but did matter
1013     when compiling without UCP support, or within Exim, where the ucp files are
1014     not imported.
1016     3. Refactoring of the library code to split up the various functions into
1017     different source modules. The addition of the new DFA matching code (see
1018     below) to a single monolithic source would have made it really too
1019     unwieldy, quite apart from causing all the code to be include in a
1020     statically linked application, when only some functions are used. This is
1021     relevant even without the DFA addition now that patterns can be compiled in
1022     one application and matched in another.
1024     The downside of splitting up is that there have to be some external
1025     functions and data tables that are used internally in different modules of
1026     the library but which are not part of the API. These have all had their
1027     names changed to start with "_pcre_" so that they are unlikely to clash
1028     with other external names.
1030     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1031     a different (DFA) algorithm. Although it is slower than the original
1032     function, it does have some advantages for certain types of matching
1033     problem.
1035     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1036     including restarting after a partial match.
1038     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1039     defined when compiling for Windows was sent to me. I have put it into the
1040     code, though I have no means of testing or verifying it.
1042     7. Added the pcre_refcount() auxiliary function.
1044     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1045     match before or at the first newline in the subject string. In pcretest,
1046     the /f option on a pattern can be used to set this.
1048     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1049     would behave wrongly. This has been present in PCRE since release 4.0.
1051     10. A number of changes to the pcregrep command:
1053     (a) Refactored how -x works; insert ^(...)$ instead of setting
1054     PCRE_ANCHORED and checking the length, in preparation for adding
1055     something similar for -w.
1057     (b) Added the -w (match as a word) option.
1059     (c) Refactored the way lines are read and buffered so as to have more
1060     than one at a time available.
1062     (d) Implemented a pcregrep test script.
1064     (e) Added the -M (multiline match) option. This allows patterns to match
1065     over several lines of the subject. The buffering ensures that at least
1066     8K, or the rest of the document (whichever is the shorter) is available
1067     for matching (and similarly the previous 8K for lookbehind assertions).
1069     (f) Changed the --help output so that it now says
1071     -w, --word-regex(p)
1073     instead of two lines, one with "regex" and the other with "regexp"
1074     because that confused at least one person since the short forms are the
1075     same. (This required a bit of code, as the output is generated
1076     automatically from a table. It wasn't just a text change.)
1078     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1079     option but starts with a hyphen. Could be a pattern or a path name
1080     starting with a hyphen, for instance.
1082     (h) "-" can be given as a file name to represent stdin.
1084     (i) When file names are being printed, "(standard input)" is used for
1085     the standard input, for compatibility with GNU grep. Previously
1086     "<stdin>" was used.
1088     (j) The option --label=xxx can be used to supply a name to be used for
1089     stdin when file names are being printed. There is no short form.
1091     (k) Re-factored the options decoding logic because we are going to add
1092     two more options that take data. Such options can now be given in four
1093     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1095     (l) Added the -A, -B, and -C options for requesting that lines of context
1096     around matches be printed.
1098     (m) Added the -L option to print the names of files that do not contain
1099     any matching lines, that is, the complement of -l.
1101     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1102     continue to scan other files.
1104     (o) The -s option was incorrectly implemented. For compatibility with other
1105     greps, it now suppresses the error message for a non-existent or non-
1106     accessible file (but not the return code). There is a new option called
1107     -q that suppresses the output of matching lines, which was what -s was
1108     previously doing.
1110     (p) Added --include and --exclude options to specify files for inclusion
1111     and exclusion when recursing.
1113     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1114     Hopefully, it now does.
1116     12. Missing cast in pcre_study().
1118     13. Added an "uninstall" target to the makefile.
1120     14. Replaced "extern" in the function prototypes in Makefile.in with
1121     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1122     world, but is set differently for Windows.
1124     15. Added a second compiling function called pcre_compile2(). The only
1125     difference is that it has an extra argument, which is a pointer to an
1126     integer error code. When there is a compile-time failure, this is set
1127     non-zero, in addition to the error test pointer being set to point to an
1128     error message. The new argument may be NULL if no error number is required
1129     (but then you may as well call pcre_compile(), which is now just a
1130     wrapper). This facility is provided because some applications need a
1131     numeric error indication, but it has also enabled me to tidy up the way
1132     compile-time errors are handled in the POSIX wrapper.
1134     16. Added VPATH=.libs to the makefile; this should help when building with one
1135     prefix path and installing with another. (Or so I'm told by someone who
1136     knows more about this stuff than I do.)
1138     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1139     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1140     match everything, including newlines. This is not POSIX-compatible, but
1141     somebody wanted the feature. From pcretest it can be activated by using
1142     both the P and the s flags.
1144     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1146     19. libpcre.pc was being incorrectly installed as executable.
1148     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1149     it now also looks for '\r' so that it will work unmodified on Windows.
1151     21. Added Google's contributed C++ wrapper to the distribution.
1153     22. Added some untidy missing memory free() calls in pcretest, to keep
1154     Electric Fence happy when testing.
1158 nigel 75 Version 5.0 13-Sep-04
1159     ---------------------
1161     1. Internal change: literal characters are no longer packed up into items
1162     containing multiple characters in a single byte-string. Each character
1163     is now matched using a separate opcode. However, there may be more than one
1164     byte in the character in UTF-8 mode.
1166     2. The pcre_callout_block structure has two new fields: pattern_position and
1167     next_item_length. These contain the offset in the pattern to the next match
1168     item, and its length, respectively.
1170     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1171     insertion of callouts before each pattern item. Added the /C option to
1172     pcretest to make use of this.
1174     4. On the advice of a Windows user, the lines
1176     #if defined(_WIN32) || defined(WIN32)
1177     _setmode( _fileno( stdout ), 0x8000 );
1178     #endif /* defined(_WIN32) || defined(WIN32) */
1180     have been added to the source of pcretest. This apparently does useful
1181     magic in relation to line terminators.
1183     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1184     for the benefit of those environments where the "b" makes a difference.
1186     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1187     to know about it. I have put a hack into configure.in that adds in code
1188     to set GCC=yes if CC=icc. This seems to end up at a point in the
1189     generated configure script that is early enough to affect the setting of
1190     compiler options, which is what is needed, but I have no means of testing
1191     whether it really works. (The user who reported this had patched the
1192     generated configure script, which of course I cannot do.)
1194     LATER: After change 22 below (new libtool files), the configure script
1195     seems to know about icc (and also ecc). Therefore, I have commented out
1196     this hack in configure.in.
1198     7. Added support for pkg-config (2 patches were sent in).
1200     8. Negated POSIX character classes that used a combination of internal tables
1201     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1202     [[:^ascii]]. Typically, they would match almost any characters. The other
1203     POSIX classes were not broken in this way.
1205     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1206     to find the match, as PCRE was deluded into thinking that the match had to
1207     start at the start point or following a newline. The same bug applied to
1208     patterns with negative forward assertions or any backward assertions
1209     preceding ".*" at the start, unless the pattern required a fixed first
1210     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1212     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1213     starting at the last subject character, bytes beyond the end of the subject
1214     string were read.
1216     11. Renamed the variable "class" as "classbits" to make life easier for C++
1217     users. (Previously there was a macro definition, but it apparently wasn't
1218     enough.)
1220     12. Added the new field "tables" to the extra data so that tables can be passed
1221     in at exec time, or the internal tables can be re-selected. This allows
1222     a compiled regex to be saved and re-used at a later time by a different
1223     program that might have everything at different addresses.
1225     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1226     -R library as well as a -L library.
1228     14. The debugging options of pcretest (-d on the command line or D on a
1229     pattern) showed incorrect output for anything following an extended class
1230     that contained multibyte characters and which was followed by a quantifier.
1232     15. Added optional support for general category Unicode character properties
1233     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1234     support. It adds about 90K to the size of the library. The meanings of the
1235     inbuilt class escapes such as \d and \s have NOT been changed.
1237     16. Updated pcredemo.c to include calls to free() to release the memory for the
1238     compiled pattern.
1240     17. The generated file chartables.c was being created in the source directory
1241     instead of in the building directory. This caused the build to fail if the
1242     source directory was different from the building directory, and was
1243     read-only.
1245     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1246     file. No doubt somebody will tell me if they don't make sense... Also added
1247     Dan Mooney's comments about building on OpenVMS.
1249     19. Added support for partial matching via the PCRE_PARTIAL option for
1250     pcre_exec() and the \P data escape in pcretest.
1252     20. Extended pcretest with 3 new pattern features:
1254     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1255     write the compiled pattern to the file whose name is "rest-of-line".
1256     This is a straight binary dump of the data, with the saved pointer to
1257     the character tables forced to be NULL. The study data, if any, is
1258     written too. After writing, pcretest reads a new pattern.
1260     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1261     compiled pattern from the given file. There must not be any
1262     occurrences of "<" in the file name (pretty unlikely); if there are,
1263     pcretest will instead treat the initial "<" as a pattern delimiter.
1264     After reading in the pattern, pcretest goes on to read data lines as
1265     usual.
1267     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1268     and 16-bit fields in a compiled pattern, to simulate a pattern that
1269     was compiled on a host of opposite endianness.
1271     21. The pcre-exec() function can now cope with patterns that were compiled on
1272     hosts of opposite endianness, with this restriction:
1274     As for any compiled expression that is saved and used later, the tables
1275     pointer field cannot be preserved; the extra_data field in the arguments
1276     to pcre_exec() should be used to pass in a tables address if a value
1277     other than the default internal tables were used at compile time.
1279     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1280     now diagnosed as an error. Previously, most of the time, a negative number
1281     would have been treated as zero, but if in addition "ovector" was passed as
1282     NULL, a crash could occur.
1284     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1285     new versions from the libtool 1.5 distribution (the last one is a copy of
1286     a file called libtool.m4). This seems to have fixed the need to patch
1287     "configure" to support Darwin 1.3 (which I used to do). However, I still
1288     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1289     workstation).
1291     24. Changed the PCRE licence to be the more standard "BSD" licence.
1294 nigel 73 Version 4.5 01-Dec-03
1295     ---------------------
1297     1. There has been some re-arrangement of the code for the match() function so
1298     that it can be compiled in a version that does not call itself recursively.
1299     Instead, it keeps those local variables that need separate instances for
1300     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1301     needs to "recurse". Keeping track of where control must go is done by means
1302     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1303     hide most of the details from the main code, and operates only if
1304     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1305     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1306     operating.
1308     To make it easier for callers to provide specially tailored get/free
1309     functions for this usage, two new functions, pcre_stack_malloc, and
1310     pcre_stack_free, are used. They are always called in strict stacking order,
1311     and the size of block requested is always the same.
1313     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1314     PCRE has been compiled to use the stack or the heap for recursion. The
1315     -C option of pcretest uses this to show which version is compiled.
1317     A new data escape \S, is added to pcretest; it causes the amounts of store
1318     obtained and freed by both kinds of malloc/free at match time to be added
1319     to the output.
1321     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1322     what's available on my current Linux desktop machine.
1324     3. When matching a UTF-8 string, the test for a valid string at the start has
1325     been extended. If start_offset is not zero, PCRE now checks that it points
1326     to a byte that is the start of a UTF-8 character. If not, it returns
1327     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1328     this is necessary because there may be backward assertions in the pattern.
1329     When matching the same subject several times, it may save resources to use
1330     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1332     4. The code for checking the validity of UTF-8 strings has been tightened so
1333     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1334     containing "overlong sequences".
1336     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1337     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1338     should have been "&", but it just so happened that all the cases this let
1339     through by mistake were picked up later in the function.
1341     6. I had used a variable called "isblank" - this is a C99 function, causing
1342     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1344     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1345     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1346     so the version is shown; (c) stop "make test" echoing "./RunTest".
1348     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1350     9. The prototype for memmove() for systems that don't have it was using
1351     size_t, but the inclusion of the header that defines size_t was later. I've
1352     moved the #includes for the C headers earlier to avoid this.
1354     10. Added some adjustments to the code to make it easier to compiler on certain
1355     special systems:
1357     (a) Some "const" qualifiers were missing.
1358     (b) Added the macro EXPORT before all exported functions; by default this
1359     is defined to be empty.
1360     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1361     that it reads its output file name as an argument instead of writing
1362     to the standard output and assuming this can be redirected.
1364     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1365     class containing characters with values greater than 255, PCRE compilation
1366     went into a loop.
1368     12. A recursive reference to a subpattern that was within another subpattern
1369     that had a minimum quantifier of zero caused PCRE to crash. For example,
1370     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1371     recursion. If the recursively-called subpattern itself had a zero repeat,
1372     that was OK.
1374     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1375     buffer into which it was copied (for escape processing) was still set at
1376     1024, so long lines caused crashes.
1378     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1379     "internal error: code overflow...". This applied to any character class
1380     that was followed by a possessive quantifier.
1382     15. Modified the Makefile to add libpcre.la as a prerequisite for
1383     libpcreposix.la because I was told this is needed for a parallel build to
1384     work.
1386     16. If a pattern that contained .* following optional items at the start was
1387     studied, the wrong optimizing data was generated, leading to matching
1388     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1389     matching string must start with a or b or c. The correct conclusion for
1390     this pattern is that a match can start with any character.
1393 nigel 71 Version 4.4 13-Aug-03
1394     ---------------------
1396     1. In UTF-8 mode, a character class containing characters with values between
1397     127 and 255 was not handled correctly if the compiled pattern was studied.
1398     In fixing this, I have also improved the studying algorithm for such
1399     classes (slightly).
1401     2. Three internal functions had redundant arguments passed to them. Removal
1402     might give a very teeny performance improvement.
1404     3. Documentation bug: the value of the capture_top field in a callout is *one
1405     more than* the number of the hightest numbered captured substring.
1407     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1408     in incorrectly linking with a previously installed version. They now link
1409     explicitly with libpcre.la.
1411     5. configure.in no longer needs to recognize Cygwin specially.
1413     6. A problem in pcre.in for Windows platforms is fixed.
1415     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1416     pcretest, it used to include the size of the study block as part of its
1417     output. Unfortunately, the structure contains a field that has a different
1418     size on different hardware architectures. This meant that the tests that
1419     showed this size failed. As the block is currently always of a fixed size,
1420     this information isn't actually particularly useful in pcretest output, so
1421     I have just removed it.
1423     8. Three pre-processor statements accidentally did not start in column 1.
1424     Sadly, there are *still* compilers around that complain, even though
1425     standard C has not required this for well over a decade. Sigh.
1427     9. In pcretest, the code for checking callouts passed small integers in the
1428     callout_data field, which is a void * field. However, some picky compilers
1429     complained about the casts involved for this on 64-bit systems. Now
1430     pcretest passes the address of the small integer instead, which should get
1431     rid of the warnings.
1433     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1434     both compile and run time, and gives an error if an invalid UTF-8 sequence
1435     is found. There is a option for disabling this check in cases where the
1436     string is known to be correct and/or the maximum performance is wanted.
1438     11. In response to a bug report, I changed one line in Makefile.in from
1440     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1441     to
1442     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1444     to look similar to other lines, but I have no way of telling whether this
1445     is the right thing to do, as I do not use Windows. No doubt I'll get told
1446     if it's wrong...
1449 nigel 69 Version 4.3 21-May-03
1450     ---------------------
1452     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1453     Makefile.
1455     2. Some refactoring to improve the quality of the code:
1457     (i) The utf8_table... variables are now declared "const".
1459     (ii) The code for \cx, which used the "case flipping" table to upper case
1460     lower case letters, now just substracts 32. This is ASCII-specific,
1461     but the whole concept of \cx is ASCII-specific, so it seems
1462     reasonable.
1464     (iii) PCRE was using its character types table to recognize decimal and
1465     hexadecimal digits in the pattern. This is silly, because it handles
1466     only 0-9, a-f, and A-F, but the character types table is locale-
1467     specific, which means strange things might happen. A private
1468     table is now used for this - though it costs 256 bytes, a table is
1469     much faster than multiple explicit tests. Of course, the standard
1470     character types table is still used for matching digits in subject
1471     strings against \d.
1473     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1474     ending in _t are). So I've renamed it as ESC_tee.
1476     3. The first argument for regexec() in the POSIX wrapper should have been
1477     defined as "const".
1479     4. Changed pcretest to use malloc() for its buffers so that they can be
1480     Electric Fenced for debugging.
1482     5. There were several places in the code where, in UTF-8 mode, PCRE would try
1483     to read one or more bytes before the start of the subject string. Often this
1484     had no effect on PCRE's behaviour, but in some circumstances it could
1485     provoke a segmentation fault.
1487     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1488     to try to read one or more bytes before the start of the subject string.
1490     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1491     UTF-8 support could misbehave in various ways if the subject string
1492     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1493     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1494     back over UTF-8 characters.)
1497 nigel 67 Version 4.2 14-Apr-03
1498     ---------------------
1500     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1502     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1503     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1504     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1505     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1506     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1507     and BUILD_EXEEXT
1508     Note: automatic setting of the BUILD variables is not yet working
1509     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1510     compile-time but not at link-time
1511     [LINK]: use for linking executables only
1512     make different versions for Windows and non-Windows
1513     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1514     libraries
1515     [LINK_FOR_BUILD]: new variable
1516     [OBJEXT]: use throughout
1517     [EXEEXT]: use throughout
1518     <winshared>: new target
1519     <wininstall>: new target
1520     <dftables.o>: use native compiler
1521     <dftables>: use native linker
1522     <install>: handle Windows platform correctly
1523     <clean>: ditto
1524     <check>: ditto
1525     copy DLL to top builddir before testing
1527     As part of these changes, -no-undefined was removed again. This was reported
1528     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1529     in any case.
1531     3. Some tidies to get rid of compiler warnings:
1533     . In the match_data structure, match_limit was an unsigned long int, whereas
1534     match_call_count was an int. I've made them both unsigned long ints.
1536     . In pcretest the fact that a const uschar * doesn't automatically cast to
1537     a void * provoked a warning.
1539     . Turning on some more compiler warnings threw up some "shadow" variables
1540     and a few more missing casts.
1542     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1543     option, a class that contained a single character with a value between 128
1544     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1546     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1547     option, a class that contained several characters, but with at least one
1548     whose value was between 128 and 255 caused PCRE to crash.
1551 nigel 65 Version 4.1 12-Mar-03
1552     ---------------------
1553 nigel 63
1554 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1555     needed, and a string in dftables.c that was longer than standard compilers are
1556     required to support.
1558     2. Compiling with Sun's compiler found a few more places where the code could
1559     be tidied up in order to avoid warnings.
1561     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1562     first of these names is deprecated in the latest Autoconf in favour of the name
1563     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1564     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1565     analogy I have changed it to CFLAGS_FOR_BUILD.
1567     4. Added -no-undefined to the linking command in the Makefile, because this is
1568     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1569     linking step for the pcreposix library.
1571     5. PCRE was failing to diagnose the case of two named groups with the same
1572     name.
1574     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1575     literal character that is needed in the subject for a match, and scans along to
1576     ensure that it is present before embarking on the full matching process. This
1577     saves time in cases of nested unlimited repeats that are never going to match.
1578     Problem: the scan can take a lot of time if the subject is very long (e.g.
1579     megabytes), thus penalizing straightforward matches. It is now done only if the
1580     amount of subject to be scanned is less than 1000 bytes.
1582     7. A lesser problem with the same optimization is that it was recording the
1583     first character of an anchored pattern as "needed", thus provoking a search
1584     right along the subject, even when the first match of the pattern was going to
1585     fail. The "needed" character is now not set for anchored patterns, unless it
1586     follows something in the pattern that is of non-fixed length. Thus, it still
1587     fulfils its original purpose of finding quick non-matches in cases of nested
1588     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1591     Version 4.0 17-Feb-03
1592     ---------------------
1594 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1595     extended to the end of string, PCRE compiled incorrect data. This could lead to
1596     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1598     2. Moved to autoconf 2.53 and libtool 1.4.2.
1600     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1601     the special perltest8 script is no longer needed - all the tests can be run
1602     from a single perltest script.
1604     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1605     by \s. It has now been removed in PCRE. This means it isn't recognized as
1606     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1607     class [:space:] *does* include VT, thereby creating a mess.
1609     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1610     space and tab.
1612     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1613     its new features into the main test script, reducing the number of scripts.
1615     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1616     were backward compatible, and made the (?i) apply to the whole pattern, as if
1617     /i were given. Now it behaves more logically, and applies the option setting
1618     only to what follows. PCRE has been changed to follow suit. However, if it
1619     finds options settings right at the start of the pattern, it extracts them into
1620     the global options, as before. Thus, they show up in the info data.
1622     8. Added support for the \Q...\E escape sequence. Characters in between are
1623     treated as literals. This is slightly different from Perl in that $ and @ are
1624     also handled as literals inside the quotes. In Perl, they will cause variable
1625     interpolation. Note the following examples:
1627     Pattern PCRE matches Perl matches
1629     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1630     \Qabc\$xyz\E abc\$xyz abc\$xyz
1631     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1633     For compatibility with Perl, \Q...\E sequences are recognized inside character
1634     classes as well as outside them.
1636     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1637     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1638     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1639     signed/unsigned warnings.
1641     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1642     option for pcretest, so I've replaced it by a simple function that does just
1643     that job.
1645     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1646     "pcregrep -".
1648     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1649     Java package. This provides some syntactic sugar for simple cases of what my
1650     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1651     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1652     item, you can use this simplified notation. Note that only makes sense with
1653     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1654     greediness, whatever the setting of the PCRE_UNGREEDY option.
1656     13. A change of greediness default within a pattern was not taking effect at
1657     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1658     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1659     was abstracted outside.
1661     14. PCRE now supports the \G assertion. It is true when the current matching
1662     position is at the start point of the match. This differs from \A when the
1663     starting offset is non-zero. Used with the /g option of pcretest (or similar
1664     code), it works in the same way as it does for Perl's /g option. If all
1665     alternatives of a regex begin with \G, the expression is anchored to the start
1666     match position, and the "anchored" flag is set in the compiled expression.
1668     15. Some bugs concerning the handling of certain option changes within patterns
1669     have been fixed. These applied to options other than (?ims). For example,
1670     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1671     been the other way round. Some of this was related to change 7 above.
1673     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1674     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1675     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1676     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1678     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1679     mode. Unlike ".", it always matches newline, whatever the setting of
1680     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1681     assertions. Perl allows it, but it doesn't (in general) work because it can't
1682     calculate the length of the lookbehind. At least, that's the case for Perl
1683     5.8.0 - I've been told they are going to document that it doesn't work in
1684     future.
1686     18. Added an error diagnosis for escapes that PCRE does not support: these are
1687     \L, \l, \N, \P, \p, \U, \u, and \X.
1689     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1690     reading past the end of the pattern in cases such as /[abcd/.
1692     20. PCRE was getting more memory than necessary for patterns with classes that
1693     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1695     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1696     compiling PCRE for use with Virtual Pascal.
1698     22. Small fix to the Makefile to make it work properly if the build is done
1699     outside the source tree.
1701     23. Added a new extension: a condition to go with recursion. If a conditional
1702     subpattern starts with (?(R) the "true" branch is used if recursion has
1703     happened, whereas the "false" branch is used only at the top level.
1705     24. When there was a very long string of literal characters (over 255 bytes
1706     without UTF support, over 250 bytes with UTF support), the computation of how
1707     much memory was required could be incorrect, leading to segfaults or other
1708     strange effects.
1710     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1711     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1712     there was a subsequent back reference to those brackets. This meant that, for
1713     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1714     possible to check for precisely this case. All we can do is abandon the
1715     optimization if .* occurs inside capturing brackets when there are any back
1716     references whatsoever. (See below for a better fix that came later.)
1718     26. The handling of the optimization for finding the first character of a
1719     non-anchored pattern, and for finding a character that is required later in the
1720     match were failing in some cases. This didn't break the matching; it just
1721     failed to optimize when it could. The way this is done has been re-implemented.
1723     27. Fixed typo in error message for invalid (?R item (it said "(?p").
1725     28. Added a new feature that provides some of the functionality that Perl
1726     provides with (?{...}). The facility is termed a "callout". The way it is done
1727     in PCRE is for the caller to provide an optional function, by setting
1728     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1729     global variable. By default it is unset, which disables all calling out. To get
1730     the function called, the regex must include (?C) at appropriate points. This
1731     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1732     This provides a means of identifying different callout points. When PCRE
1733     reaches such a point in the regex, if pcre_callout has been set, the external
1734     function is called. It is provided with data in a structure called
1735     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1736     matching continues; if it returns a non-zero value, the match at the current
1737     point fails. However, backtracking will occur if possible. [This was changed
1738     later and other features added - see item 49 below.]
1740     29. pcretest is upgraded to test the callout functionality. It provides a
1741     callout function that displays information. By default, it shows the start of
1742     the match and the current position in the text. There are some new data escapes
1743     to vary what happens:
1745     \C+ in addition, show current contents of captured substrings
1746     \C- do not supply a callout function
1747     \C!n return 1 when callout number n is reached
1748     \C!n!m return 1 when callout number n is reached for the mth time
1750     30. If pcregrep was called with the -l option and just a single file name, it
1751     output "<stdin>" if a match was found, instead of the file name.
1753     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1754     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1755     pcre_exec(). This saves a malloc/free per call. The default value of
1756     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1757     when configuring.
1759     32. The default maximum size of a compiled pattern is 64K. There have been a
1760     few cases of people hitting this limit. The code now uses macros to handle the
1761     storing of links as offsets within the compiled pattern. It defaults to 2-byte
1762     links, but this can be changed to 3 or 4 bytes by --with-link-size when
1763     configuring. Tests 2 and 5 work only with 2-byte links because they output
1764     debugging information about compiled patterns.
1766     33. Internal code re-arrangements:
1768     (a) Moved the debugging function for printing out a compiled regex into
1769     its own source file (printint.c) and used #include to pull it into
1770     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1771     separate copies.
1773     (b) Defined the list of op-code names for debugging as a macro in
1774     internal.h so that it is next to the definition of the opcodes.
1776     (c) Defined a table of op-code lengths for simpler skipping along compiled
1777     code. This is again a macro in internal.h so that it is next to the
1778     definition of the opcodes.
1780     34. Added support for recursive calls to individual subpatterns, along the
1781     lines of Robin Houston's patch (but implemented somewhat differently).
1783     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1784     allow it to read and process whole directories in Win32. This code was
1785     contributed by Lionel Fourquaux; it has not been tested by me.
1787     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1788     used to name a group. Names consist of alphanumerics and underscores, and must
1789     be unique. Back references use the syntax (?P=name) and recursive calls use
1790     (?P>name) which is a PCRE extension to the Python extension. Groups still have
1791     numbers. The function pcre_fullinfo() can be used after compilation to extract
1792     a name/number map. There are three relevant calls:
1794     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1795     PCRE_INFO_NAMECOUNT yields the number of entries
1796     PCRE_INFO_NAMETABLE yields a pointer to the map.
1798     The map is a vector of fixed-size entries. The size of each entry depends on
1799     the length of the longest name used. The first two bytes of each entry are the
1800     group number, most significant byte first. There follows the corresponding
1801     name, zero terminated. The names are in alphabetical order.
1803     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1804     case instead of 255. Making it the same both with and without UTF-8 support
1805     means that the same test output works with both.
1807     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1808     calling malloc() with a zero argument.
1810     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1811     optimization. I've improved things by keeping a bitmap of backreferences with
1812     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1813     fact referenced, the optimization can be applied. It is unlikely that a
1814     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1815     the match to follow \n) will appear inside brackets with a number greater than
1816     31, but if it does, any back reference > 31 suppresses the optimization.
1818     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1819     of disabling numbered capturing parentheses. Any opening parenthesis that is
1820     not followed by ? behaves as if it were followed by ?: but named parentheses
1821     can still be used for capturing (and they will acquire numbers in the usual
1822     way).
1824     41. Redesigned the return codes from the match() function into yes/no/error so
1825     that errors can be passed back from deep inside the nested calls. A malloc
1826     failure while inside a recursive subpattern call now causes the
1827     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1829     42. It is now possible to set a limit on the number of times the match()
1830     function is called in a call to pcre_exec(). This facility makes it possible to
1831     limit the amount of recursion and backtracking, though not in a directly
1832     obvious way, because the match() function is used in a number of different
1833     circumstances. The count starts from zero for each position in the subject
1834     string (for non-anchored patterns). The default limit is, for compatibility, a
1835     large number, namely 10 000 000. You can change this in two ways:
1837     (a) When configuring PCRE before making, you can use --with-match-limit=n
1838     to set a default value for the compiled library.
1840     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1841     a different value is set. See 45 below.
1843     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1845     43. Added a new function pcre_config(int, void *) to enable run-time extraction
1846     of things that can be changed at compile time. The first argument specifies
1847     what is wanted and the second points to where the information is to be placed.
1848     The current list of available information is:
1852     The output is an integer that is set to one if UTF-8 support is available;
1853     otherwise it is set to zero.
1857     The output is an integer that it set to the value of the code that is used for
1858     newline. It is either LF (10) or CR (13).
1862     The output is an integer that contains the number of bytes used for internal
1863     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1867     The output is an integer that contains the threshold above which the POSIX
1868     interface uses malloc() for output vectors. See item 31 above.
1872     The output is an unsigned integer that contains the default limit of the number
1873     of match() calls in a pcre_exec() execution. See 42 above.
1875     44. pcretest has been upgraded by the addition of the -C option. This causes it
1876     to extract all the available output from the new pcre_config() function, and to
1877     output it. The program then exits immediately.
1879     45. A need has arisen to pass over additional data with calls to pcre_exec() in
1880     order to support additional features. One way would have been to define
1881     pcre_exec2() (for example) with extra arguments, but this would not have been
1882     extensible, and would also have required all calls to the original function to
1883     be mapped to the new one. Instead, I have chosen to extend the mechanism that
1884     is used for passing in "extra" data from pcre_study().
1886     The pcre_extra structure is now exposed and defined in pcre.h. It currently
1887     contains the following fields:
1889     flags a bitmap indicating which of the following fields are set
1890     study_data opaque data from pcre_study()
1891     match_limit a way of specifying a limit on match() calls for a specific
1892     call to pcre_exec()
1893     callout_data data for callouts (see 49 below)
1895     The flag bits are also defined in pcre.h, and are
1901     The pcre_study() function now returns one of these new pcre_extra blocks, with
1902     the actual study data pointed to by the study_data field, and the
1903     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1904     before. That is, this change is entirely upwards-compatible and requires no
1905     change to existing code.
1907     If you want to pass in additional data to pcre_exec(), you can either place it
1908     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1909     block.
1911     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1912     data string contains the escape sequence \M, pcretest calls pcre_exec() several
1913     times with different match limits, until it finds the minimum value needed for
1914     pcre_exec() to complete. The value is then output. This can be instructive; for
1915     most simple matches the number is quite small, but for pathological cases it
1916     gets very large very quickly.
1918     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1919     returns the size of the data block pointed to by the study_data field in a
1920     pcre_extra block, that is, the value that was passed as the argument to
1921     pcre_malloc() when PCRE was getting memory in which to place the information
1922     created by pcre_study(). The fourth argument should point to a size_t variable.
1923     pcretest has been extended so that this information is shown after a successful
1924     pcre_study() call when information about the compiled regex is being displayed.
1926     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1927     because what follows is always an absolute path. (Later: it turns out that this
1928     is more than cosmetic for MinGW, because it doesn't like empty path
1929     components.)
1931     49. Some changes have been made to the callout feature (see 28 above):
1933     (i) A callout function now has three choices for what it returns:
1935     0 => success, carry on matching
1936     > 0 => failure at this point, but backtrack if possible
1937     < 0 => serious error, return this value from pcre_exec()
1939     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1940     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1941     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1942     use by callout functions. It will never be used by PCRE itself.
1944     (ii) The pcre_extra structure (see 45 above) has a void * field called
1945     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1946     pcre_callout_block structure has a field of the same name. The contents of
1947     the field passed in the pcre_extra structure are passed to the callout
1948     function in the corresponding field in the callout block. This makes it
1949     easier to use the same callout-containing regex from multiple threads. For
1950     testing, the pcretest program has a new data escape
1952     \C*n pass the number n (may be negative) as callout_data
1954     If the callout function in pcretest receives a non-zero value as
1955     callout_data, it returns that value.
1957     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1958     there were some redundant $(CFLAGS) in commands that are now specified as
1959     $(LINK), which already includes $(CFLAGS).
1961     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1962     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1963     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1964     one-byte characters throughout. Note that case-insensitive matching applies
1965     only to characters whose values are less than 256. PCRE doesn't support the
1966     notion of cases for higher-valued characters.
1968     (i) A character class whose characters are all within 0-255 is handled as
1969     a bit map, and the map is inverted for negative classes. Previously, a
1970     character > 255 always failed to match such a class; however it should
1971     match if the class was a negative one (e.g. [^ab]). This has been fixed.
1973     (ii) A negated character class with a single character < 255 is coded as
1974     "not this character" (OP_NOT). This wasn't working properly when the test
1975     character was multibyte, either singly or repeated.
1977     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1978     mode, for example: \x{100}{2,3}.
1980     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1981     singly or repeated) now correctly test multibyte characters. However,
1982     PCRE doesn't recognize any characters with values greater than 255 as
1983     digits, spaces, or word characters. Such characters always match \D, \S,
1984     and \W, and never match \d, \s, or \w.
1986     (v) Classes may now contain characters and character ranges with values
1987     greater than 255. For example: [ab\x{100}-\x{400}].
1989     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1990     PCRE in UTF-8 mode.
1992     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1993     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1994     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1995     value.)
1997     53. The single man page has become too large. I have therefore split it up into
1998     a number of separate man pages. These also give rise to individual HTML pages;
1999     these are now put in a separate directory, and there is an index.html page that
2000     lists them all. Some hyperlinking between the pages has been installed.
2002     54. Added convenience functions for handling named capturing parentheses.
2004     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2005     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2006     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2007     are faulted.
2009     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2010     calling configure. These values are used when compiling the dftables.c program
2011     which is run to generate the source of the default character tables. They
2012     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2013     you will need to set these values.
2015     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2018     Version 3.9 02-Jan-02
2019 nigel 61 ---------------------
2021     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2023     2. If --disable-static was given, the building process failed when trying to
2024     build pcretest and pcregrep. (For some reason it was using libtool to compile
2025     them, which is not right, as they aren't part of the library.)
2028 nigel 59 Version 3.8 18-Dec-01
2029     ---------------------
2031     1. The experimental UTF-8 code was completely screwed up. It was packing the
2032     bytes in the wrong order. How dumb can you get?
2035 nigel 57 Version 3.7 29-Oct-01
2036     ---------------------
2038     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2039     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2040     this didn't happen under Solaris 8, where I normally test things.
2042 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2043     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2044     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2045     this fix an hour or so after the initial 3.7 release.)
2046 nigel 57
2047 nigel 59
2048 nigel 55 Version 3.6 23-Oct-01
2049     ---------------------
2051     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2052     offsets passed as NULL with zero offset count.
2054     2. The config.guess and config.sub files had not been updated when I moved to
2055     the latest autoconf.
2058 nigel 53 Version 3.5 15-Aug-01
2059     ---------------------
2060 nigel 5
2061 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2062     had been forgotten.
2064     2. By using declared but undefined structures, we can avoid using "void"
2065     definitions in pcre.h while keeping the internal definitions of the structures
2066     private.
2068     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2069     user point of view, this means that both static and shared libraries are built
2070     by default, but this can be individually controlled. More of the work of
2071     handling this static/shared cases is now inside libtool instead of PCRE's make
2072     file.
2074     4. The pcretest utility is now installed along with pcregrep because it is
2075     useful for users (to test regexs) and by doing this, it automatically gets
2076     relinked by libtool. The documentation has been turned into a man page, so
2077     there are now .1, .txt, and .html versions in /doc.
2079     5. Upgrades to pcregrep:
2080     (i) Added long-form option names like gnu grep.
2081     (ii) Added --help to list all options with an explanatory phrase.
2082     (iii) Added -r, --recursive to recurse into sub-directories.
2083     (iv) Added -f, --file to read patterns from a file.
2085     6. pcre_exec() was referring to its "code" argument before testing that
2086     argument for NULL (and giving an error if it was NULL).
2088     7. Upgraded Makefile.in to allow for compiling in a different directory from
2089     the source directory.
2091     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2092     options bits, the pointer it was passed was to an int instead of to an unsigned
2093     long int. This mattered only on 64-bit systems.
2095     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2096     generated) instead of pcre.in, which it its source. Also made the same change
2097     in several of the .c files.
2099     10. A new release of gcc defines printf() as a macro, which broke pcretest
2100     because it had an ifdef in the middle of a string argument for printf(). Fixed
2101     by using separate calls to printf().
2103     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2104     script, to force use of CR or LF instead of \n in the source. On non-Unix
2105     systems, the value can be set in config.h.
2107     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2108     absolute limit. Changed the text of the error message to make this clear, and
2109     likewise updated the man page.
2111     13. The limit of 99 on the number of capturing subpatterns has been removed.
2112     The new limit is 65535, which I hope will not be a "real" limit.
2115 nigel 51 Version 3.4 22-Aug-00
2116     ---------------------
2118     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2120     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2123 nigel 49 Version 3.3 01-Aug-00
2124     ---------------------
2126     1. If an octal character was given, but the value was greater than \377, it
2127     was not getting masked to the least significant bits, as documented. This could
2128     lead to crashes in some systems.
2130     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2131     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2133     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2134     These just pass their arguments on to (pcre_free)(), but they are provided
2135     because some uses of PCRE bind it to non-C systems that can call its functions,
2136     but cannot call free() or pcre_free() directly.
2138     4. Add "make test" as a synonym for "make check". Corrected some comments in
2139     the Makefile.
2141     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2142     Makefile.
2144     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2145     command called pgrep for grepping around the active processes.
2147     7. Added the beginnings of support for UTF-8 character strings.
2149     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2150     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2151     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2152     out for the ar command.)
2155 nigel 47 Version 3.2 12-May-00
2156     ---------------------
2158     This is purely a bug fixing release.
2160     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2161     of ZA. This was just one example of several cases that could provoke this bug,
2162     which was introduced by change 9 of version 2.00. The code for breaking
2163     infinite loops after an iteration that matches an empty string was't working
2164     correctly.
2166     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2167     when matched against abbab (for example). After matching an empty string, it
2168     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2169     caused it to match further down the string than it should.
2171     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2172     was there because it doesn't seem to be needed, and it causes trouble on some
2173     systems, as it is not a Standard C header. It has been removed.
2175     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2176     were reported on the Macintosh. The changes were from
2178     while ((c = *(++ptr)) != 0 && c != '\n');
2179     to
2180     while ((c = *(++ptr)) != 0 && c != '\n') ;
2182     Totally extraordinary, but if that's what it takes...
2184     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2185     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2186     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2187     assumes the way PCRE uses memmove() (always moving upwards).
2189     6. PCRE is being used in one environment where strchr() is not available. There
2190     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2191     faster code anyway.
2194 nigel 45 Version 3.1 09-Feb-00
2195     ---------------------
2197     The only change in this release is the fixing of some bugs in Makefile.in for
2198     the "install" target:
2200     (1) It was failing to install pcreposix.h.
2202     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2205 nigel 43 Version 3.0 01-Feb-00
2206     ---------------------
2207 nigel 41
2208     1. Add support for the /+ modifier to perltest (to output $` like it does in
2209     pcretest).
2211     2. Add support for the /g modifier to perltest.
2213     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2214     matches null strings.
2216     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2217     pattern. Perl treats empty patterns specially - it reuses the most recent
2218     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2219     effect.
2221     5. The POSIX interface was broken in that it was just handing over the POSIX
2222     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2223     required a bigger vector, with some working space on the end. This means that
2224     the POSIX wrapper now has to get and free some memory, and copy the results.
2226 nigel 43 6. Added some simple autoconf support, placing the test data and the
2227     documentation in separate directories, re-organizing some of the
2228     information files, and making it build pcre-config (a GNU standard). Also added
2229     libtool support for building PCRE as a shared library, which is now the
2230     default.
2231 nigel 41
2232 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2233     09 are not valid octal constants. Single digits will be used for minor values
2234     less than 10.
2236     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2237     existing programs that set these in the POSIX interface can use PCRE without
2238     modification.
2240     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2241     return all that pcre_info() returns, plus additional data. The pcre_info()
2242     function is retained for compatibility, but is considered to be obsolete.
2244     10. Added experimental recursion feature (?R) to handle one common case that
2245     Perl 5.6 will be able to do with (?p{...}).
2247     11. Added support for POSIX character classes like [:alpha:], which Perl is
2248     adopting.
2251 nigel 39 Version 2.08 31-Aug-99
2252     ----------------------
2254     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2255     trying to match at the startoffset position, but instead was moving forward to
2256     the next newline as if a previous match had failed.
2258     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2259     and could get into a loop if a null string was matched other than at the start
2260     of the subject.
2262     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2263     be distinguished at compile time, and for completeness also added PCRE_DATE.
2265     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2266     in GnuWin32 environments.
2269 nigel 37 Version 2.07 29-Jul-99
2270     ----------------------
2272     1. The documentation is now supplied in plain text form and HTML as well as in
2273     the form of man page sources.
2275     2. C++ compilers don't like assigning (void *) values to other pointer types.
2276     In particular this affects malloc(). Although there is no problem in Standard
2277     C, I've put in casts to keep C++ compilers happy.
2279     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2280     should be (const char *).
2282     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2283     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2284     However, I haven't made this a standard facility. The documentation doesn't
2285     mention it, and the Makefile doesn't support it.
2287     5. The Makefile now contains an "install" target, with editable destinations at
2288     the top of the file. The pcretest program is not installed.
2290     6. pgrep -V now gives the PCRE version number and date.
2292     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2293     causing the entire string to be ignored, instead of just the last character.
2295     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2296     non-matching string, it can take a very, very long time, even for strings of
2297     quite modest length, because of the nested recursion. PCRE now does better in
2298     some of these cases. It does this by remembering the last required literal
2299     character in the pattern, and pre-searching the subject to ensure it is present
2300     before running the real match. In other words, it applies a heuristic to detect
2301     some types of certain failure quickly, and in the above example, if presented
2302     with a string that has no trailing " it gives "no match" very quickly.
2304     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2305     other alternatives are tried instead.
2308 nigel 35 Version 2.06 09-Jun-99
2309     ----------------------
2311     1. Change pcretest's output for amount of store used to show just the code
2312     space, because the remainder (the data block) varies in size between 32-bit and
2313     64-bit systems.
2315     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2316     start matching at. This allows lookbehinds to work when searching for multiple
2317     occurrences in a string.
2319     3. Added additional options to pcretest for testing multiple occurrences:
2321     /+ outputs the rest of the string that follows a match
2322     /g loops for multiple occurrences, using the new startoffset argument
2323     /G loops for multiple occurrences by passing an incremented pointer
2325     4. PCRE wasn't doing the "first character" optimization for patterns starting
2326     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2327     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2328     the letter 'x'. On long subject strings, this gives a significant speed-up.
2331 nigel 33 Version 2.05 21-Apr-99
2332     ----------------------
2334     1. Changed the type of magic_number from int to long int so that it works
2335     properly on 16-bit systems.
2337     2. Fixed a bug which caused patterns starting with .* not to work correctly
2338     when the subject string contained newline characters. PCRE was assuming
2339     anchoring for such patterns in all cases, which is not correct because .* will
2340     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2341     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2342     must be retried after every newline in the subject.
2345 nigel 31 Version 2.04 18-Feb-99
2346     ----------------------
2348     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2349     computation of the store needed to hold the pattern was incorrect (too large).
2350     If such patterns were nested a few deep, this could multiply and become a real
2351     problem.
2353     2. Added /M option to pcretest to show the memory requirement of a specific
2354     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2356     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2357     compiled in such a way that the backtracking after subsequent failure was
2358     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2359     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2362 nigel 29 Version 2.03 02-Feb-99
2363     ----------------------
2365     1. Fixed typo and small mistake in man page.
2367 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2368     LICENCE file containing the conditions.
2369 nigel 29
2370     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2371     Perl, that is the internal \ allows the delimiter to be included in the
2372     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2373     the final delimiter, add \ to the end of the pattern (to test the error).
2375     4. Added the convenience functions for extracting substrings after a successful
2376     match. Updated pcretest to make it able to test these functions.
2379 nigel 27 Version 2.02 14-Jan-99
2380     ----------------------
2382     1. Initialized the working variables associated with each extraction so that
2383     their saving and restoring doesn't refer to uninitialized store.
2385     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2386     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2387     fix the problem.
2389     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2390     calls, and wasn't printing the correct value for compiling calls. Increased the
2391     default value of LOOPREPEAT, and the number of significant figures in the
2392     times.
2394     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2396     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2397     a building problem on Windows NT with a FAT file system.
2400 nigel 25 Version 2.01 21-Oct-98
2401     ----------------------
2403     1. Changed the API for pcre_compile() to allow for the provision of a pointer
2404     to character tables built by pcre_maketables() in the current locale. If NULL
2405     is passed, the default tables are used.
2408 nigel 23 Version 2.00 24-Sep-98
2409 nigel 21 ----------------------
2411 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2412     it any more.
2414     2. Allow quantification of (?>) groups, and make it work correctly.
2416     3. The first character computation wasn't working for (?>) groups.
2418     4. Correct the implementation of \Z (it is permitted to match on the \n at the
2419     end of the subject) and add 5.005's \z, which really does match only at the
2420     very end of the subject.
2422     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2424     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2425     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2426     localized options. All options to pcre_study() were also removed.
2428     7. Add other new features from 5.005:
2430     $(?<= positive lookbehind
2431     $(?<! negative lookbehind
2432     (?imsx-imsx) added the unsetting capability
2433     such a setting is global if at outer level; local otherwise
2434     (?imsx-imsx:) non-capturing groups with option setting
2435     (?(cond)re|re) conditional pattern matching
2437     A backreference to itself in a repeated group matches the previous
2438     captured string.
2440     8. General tidying up of studying (both automatic and via "study")
2441     consequential on the addition of new assertions.
2443     9. As in 5.005, unlimited repeated groups that could match an empty substring
2444     are no longer faulted at compile time. Instead, the loop is forcibly broken at
2445     runtime if any iteration does actually match an empty substring.
2447     10. Include the RunTest script in the distribution.
2449     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2450     discrepancies, some of which were old and were also with respect to 5.004. They
2451     have now been fixed.
2454     Version 1.09 28-Apr-98
2455     ----------------------
2457 nigel 21 1. A negated single character class followed by a quantifier with a minimum
2458     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
2459     program crashes, or just wrong answers. This did not apply to negated classes
2460     containing more than one character, or to minima other than one.
2463 nigel 19 Version 1.08 27-Mar-98
2464     ----------------------
2466     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2468     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2469     latter must appear before anything that relies on it in the pattern.
2472 nigel 17 Version 1.07 16-Feb-98
2473     ----------------------
2475     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2476     repeat of a potentially empty string).
2479 nigel 15 Version 1.06 23-Jan-98
2480     ----------------------
2482     1. Added Markus Oberhumer's little patches for C++.
2484     2. Literal strings longer than 255 characters were broken.
2487 nigel 13 Version 1.05 23-Dec-97
2488     ----------------------
2490     1. Negated character classes containing more than one character were failing if
2491     PCRE_CASELESS was set at run time.
2494 nigel 11 Version 1.04 19-Dec-97
2495     ----------------------
2497     1. Corrected the man page, where some "const" qualifiers had been omitted.
2499     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2500     input syntax.
2502     3. Fixed memory leak which occurred when a regex with back references was
2503     matched with an offsets vector that wasn't big enough. The temporary memory
2504     that is used in this case wasn't being freed if the match failed.
2506     4. Tidied pcretest to ensure it frees memory that it gets.
2508     5. Temporary memory was being obtained in the case where the passed offsets
2509     vector was exactly big enough.
2511     6. Corrected definition of offsetof() from change 5 below.
2513     7. I had screwed up change 6 below and broken the rules for the use of
2514     setjmp(). Now fixed.
2517 nigel 9 Version 1.03 18-Dec-97
2518     ----------------------
2520     1. A erroneous regex with a missing opening parenthesis was correctly
2521     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2522     on some systems.
2524     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2525     it was reported that one broken compiler failed on the former because "code" is
2526     also an independent variable.
2528     3. The erroneous regex a[]b caused an array overrun reference.
2530     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2531     fail on data ending with that character. (It was going on too far, and checking
2532     the next character, typically a binary zero.) This was specific to the
2533     optimized code for single-character negative classes.
2535     5. Added a contributed patch from the TIN world which does the following:
2537     + Add an undef for memmove, in case the the system defines a macro for it.
2539     + Add a definition of offsetof(), in case there isn't one. (I don't know
2540     the reason behind this - offsetof() is part of the ANSI standard - but
2541     it does no harm).
2543     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2544     most of the places where whitespace preceded '#'. I have given up and
2545     allowed the remaining 2 cases to be at the margin.
2547     + Rename some variables in pcre to eliminate shadowing. This seems very
2548     pedantic, but does no harm, of course.
2550     6. Moved the call to setjmp() into its own function, to get rid of warnings
2551     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2553     7. Constructs such as \d{8,} were compiling into the equivalent of
2554 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2555 nigel 9 outcome, but in this particular case used more store than had been allocated,
2556     which caused the bug to be discovered because it threw up an internal error.
2558     8. The debugging code in both pcre and pcretest for outputting the compiled
2559     form of a regex was going wrong in the case of back references followed by
2560     curly-bracketed repeats.
2563 nigel 7 Version 1.02 12-Dec-97
2564     ----------------------
2566     1. Typos in pcre.3 and comments in the source fixed.
2568     2. Applied a contributed patch to get rid of places where it used to remove
2569     'const' from variables, and fixed some signed/unsigned and uninitialized
2570     variable warnings.
2572     3. Added the "runtest" target to Makefile.
2574     4. Set default compiler flag to -O2 rather than just -O.
2577 nigel 5 Version 1.01 19-Nov-97
2578     ----------------------
2580     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2581     like /([ab]*)*/, that is, for classes with more than one character in them.
2583     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2584     as /((?>a*))*/ (a PCRE_EXTRA facility).
2587     Version 1.00 18-Nov-97
2588     ----------------------
2590     1. Added compile-time macros to support systems such as SunOS4 which don't have
2591     memmove() or strerror() but have other things that can be used instead.
2593     2. Arranged that "make clean" removes the executables.
2596 nigel 3 Version 0.99 27-Oct-97
2597     ----------------------
2599     1. Fixed bug in code for optimizing classes with only one character. It was
2600     initializing a 32-byte map regardless, which could cause it to run off the end
2601     of the memory it had got.
2603     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2606     Version 0.98 22-Oct-97
2607     ----------------------
2609     1. Fixed bug in code for handling temporary memory usage when there are more
2610     back references than supplied space in the ovector. This could cause segfaults.
2613     Version 0.97 21-Oct-97
2614     ----------------------
2616     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2618     2. Optimized negated single characters not to use a bit map.
2620     3. Brought error texts together as macro definitions; clarified some of them;
2621     fixed one that was wrong - it said "range out of order" when it meant "invalid
2622     escape sequence".
2624     4. Changed some char * arguments to const char *.
2626     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2628     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2629     pcretest.
2632     Version 0.96 16-Oct-97
2633     ----------------------
2635     1. Added a simple "pgrep" utility to the distribution.
2637     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2638     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2639     where "ddd" means "one or more decimal digits".
2641     3. Fixed serious bug. If a pattern had a back reference, but the call to
2642     pcre_exec() didn't supply a large enough ovector to record the related
2643     identifying subpattern, the match always failed. PCRE now remembers the number
2644     of the largest back reference, and gets some temporary memory in which to save
2645     the offsets during matching if necessary, in order to ensure that
2646     backreferences always work.
2648     4. Increased the compatibility with Perl in a number of ways:
2650     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2651     to request this handling. The option can be set at compile or exec time.
2653     (b) $ matches before a terminating newline by default; an option
2654     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2655     mode). The option can be set at compile or exec time.
2657     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2658     the same as Perl's. If the decimal number it represents is less than 10
2659     or there aren't that many previous left capturing parentheses, an octal
2660     escape is read. Inside a character class, it's always an octal escape,
2661     even if it is a single digit.
2663     (d) An escaped but undefined alphabetic character is taken as a literal,
2664     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2665     escapes.
2667     (e) {0} is now permitted. (The previous item is removed from the compiled
2668     pattern).
2670     5. Changed all the names of code files so that the basic parts are no longer
2671     than 10 characters, and abolished the teeny "globals.c" file.
2673     6. Changed the handling of character classes; they are now done with a 32-byte
2674     bit map always.
2676     7. Added the -d and /D options to pcretest to make it possible to look at the
2677     internals of compilation without having to recompile pcre.
2680     Version 0.95 23-Sep-97
2681     ----------------------
2683     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2684     \x20 at the start of a run of normal characters. These were being treated as
2685     real characters, instead of the source characters being re-checked.
2688     Version 0.94 18-Sep-97
2689     ----------------------
2691     1. The functions are now thread-safe, with the caveat that the global variables
2692     containing pointers to malloc() and free() or alternative functions are the
2693     same for all threads.
2695     2. Get pcre_study() to generate a bitmap of initial characters for non-
2696     anchored patterns when this is possible, and use it if passed to pcre_exec().
2699     Version 0.93 15-Sep-97
2700     ----------------------
2702     1. /(b)|(:+)/ was computing an incorrect first character.
2704     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2705     but not actually doing anything yet.
2707     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2708     as Perl does (e.g. [-az] or [az-]).
2710     4. Set the anchored flag if a branch starts with .* or .*? because that tests
2711     all possible positions.
2713     5. Split up into different modules to avoid including unneeded functions in a
2714     compiled binary. However, compile and exec are still in one module. The "study"
2715     function is split off.
2717     6. The character tables are now in a separate module whose source is generated
2718     by an auxiliary program - but can then be edited by hand if required. There are
2719     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2720     toupper() in the code.
2722     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2723     make them global. Abolish the function for setting them, as the caller can now
2724     set them directly.
2727     Version 0.92 11-Sep-97
2728     ----------------------
2730     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2731     (e.g. /a{1,3}/) was broken (I mis-optimized it).
2733     2. Caseless matching was not working in character classes if the characters in
2734     the pattern were in upper case.
2736     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2738     4. Make PCRE_ANCHORED public and accept as a compile option.
2740     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2741     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2742     pass them.
2744     6. Give an error if bad option bits passed at compile or run time.
2746     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2747     pcretest to cause it to pass that flag.
2749     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2750     options, and the first character, if set.
2752     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2755     Version 0.91 10-Sep-97
2756     ----------------------
2758     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2759     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2761     2. PCRE was looping on encountering an indefinitely repeated back reference to
2762     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2763     Perl does - treats the match as successful.
2765     ****


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