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Revision 113 - (hide annotations) (download)
Fri Mar 9 10:13:26 2007 UTC (7 years, 9 months ago) by ph10
File size: 122672 byte(s)
Update documentation for forthcoming rename of "maintain" as "maint"

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

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