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

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