/[pcre]/code/trunk/ChangeLog
ViewVC logotype

Contents of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log


Revision 93 - (hide annotations) (download)
Sat Feb 24 21:41:42 2007 UTC (7 years, 9 months ago) by nigel
File size: 118928 byte(s)
Load pcre-7.0 into code/trunk.

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

webmaster@exim.org
ViewVC Help
Powered by ViewVC 1.1.12