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Revision 91 - (hide annotations) (download)
Sat Feb 24 21:41:34 2007 UTC (8 years, 1 month ago) by nigel
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Load pcre-6.7 into code/trunk.

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 nigel 91 Version 6.7 04-Jul-06
5     ---------------------
7     1. In order to handle tests when input lines are enormously long, pcretest has
8     been re-factored so that it automatically extends its buffers when
9     necessary. The code is crude, but this _is_ just a test program. The
10     default size has been increased from 32K to 50K.
12     2. The code in pcre_study() was using the value of the re argument before
13     testing it for NULL. (Of course, in any sensible call of the function, it
14     won't be NULL.)
16     3. The memmove() emulation function in pcre_internal.h, which is used on
17     systems that lack both memmove() and bcopy() - that is, hardly ever -
18     was missing a "static" storage class specifier.
20     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
21     containing an extended class (one that cannot be represented by a bitmap
22     because it contains high-valued characters or Unicode property items, e.g.
23     [\pZ]). Almost always one would set UTF-8 mode when processing such a
24     pattern, but PCRE should not loop if you do not (it no longer does).
25     [Detail: two cases were found: (a) a repeated subpattern containing an
26     extended class; (b) a recursive reference to a subpattern that followed a
27     previous extended class. It wasn't skipping over the extended class
28     correctly when UTF-8 mode was not set.]
30     5. A negated single-character class was not being recognized as fixed-length
31     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
32     compile error "lookbehind assertion is not fixed length".
34     6. The RunPerlTest auxiliary script was showing an unexpected difference
35     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
36     write a Perl script that can interpret lines of an input file either as
37     byte characters or as UTF-8, which is what "perltest" was being required to
38     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
39     can't do is switch easily at run time between having the "use utf8;" pragma
40     or not. In the end, I fudged it by using the RunPerlTest script to insert
41     "use utf8;" explicitly for the UTF-8 tests.
43     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
44     the end of the subject string, contrary to the documentation and to what
45     Perl does. This was true of both matching functions. Now it matches only at
46     the start of the subject and immediately after *internal* newlines.
48     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
49     a pointer to an int instead of a pointer to an unsigned long int. This
50     caused problems on 64-bit systems.
52     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
53     instance of the 'standard' template library not being so standard".
55     10. There was no check on the number of named subpatterns nor the maximum
56     length of a subpattern name. The product of these values is used to compute
57     the size of the memory block for a compiled pattern. By supplying a very
58     long subpattern name and a large number of named subpatterns, the size
59     computation could be caused to overflow. This is now prevented by limiting
60     the length of names to 32 characters, and the number of named subpatterns
61     to 10,000.
63     11. Subpatterns that are repeated with specific counts have to be replicated in
64     the compiled pattern. The size of memory for this was computed from the
65     length of the subpattern and the repeat count. The latter is limited to
66     65535, but there was no limit on the former, meaning that integer overflow
67     could in principle occur. The compiled length of a repeated subpattern is
68     now limited to 30,000 bytes in order to prevent this.
70     12. Added the optional facility to have named substrings with the same name.
72     13. Added the ability to use a named substring as a condition, using the
73     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
74     are numbers (not recommended). Forward references are permitted.
76     14. Added forward references in named backreferences (if you see what I mean).
78     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
79     pattern could run off the end of the subject. For example, the pattern
80     "(?s)(.{1,5})"8 did this with the subject "ab".
82     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
83     PCRE_CASELESS was set when matching characters that were quantified with ?
84     or *.
86     17. A character class other than a single negated character that had a minimum
87     but no maximum quantifier - for example [ab]{6,} - was not handled
88     correctly by pce_dfa_exec(). It would match only one character.
90     18. A valid (though odd) pattern that looked like a POSIX character
91     class but used an invalid character after [ (for example [[,abc,]]) caused
92     pcre_compile() to give the error "Failed: internal error: code overflow" or
93     in some cases to crash with a glibc free() error. This could even happen if
94     the pattern terminated after [[ but there just happened to be a sequence of
95     letters, a binary zero, and a closing ] in the memory that followed.
97     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
98     over the years. Originally (before any Unicode support), just the bottom 8
99     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
100     output from "man perlunicode" includes this:
102     The regular expression compiler produces polymorphic opcodes. That
103     is, the pattern adapts to the data and automatically switches to
104     the Unicode character scheme when presented with Unicode data--or
105     instead uses a traditional byte scheme when presented with byte
106     data.
108     Sadly, a wide octal escape does not cause a switch, and in a string with
109     no other multibyte characters, these octal escapes are treated as before.
110     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
111     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
112     Unicode string.
114     I have not perpetrated such confusion in PCRE. Up till now, it took just
115     the bottom 8 bits, as in old Perl. I have now made octal escapes with
116     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
117     translate to the appropriate multibyte character.
119     29. Applied some refactoring to reduce the number of warnings from Microsoft
120     and Borland compilers. This has included removing the fudge introduced
121     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
122     a warning about an unused variable.
124     21. PCRE has not included VT (character 0x0b) in the set of whitespace
125     characters since release 4.0, because Perl (from release 5.004) does not.
126     [Or at least, is documented not to: some releases seem to be in conflict
127     with the documentation.] However, when a pattern was studied with
128     pcre_study() and all its branches started with \s, PCRE still included VT
129     as a possible starting character. Of course, this did no harm; it just
130     caused an unnecessary match attempt.
132     22. Removed a now-redundant internal flag bit that recorded the fact that case
133     dependency changed within the pattern. This was once needed for "required
134     byte" processing, but is no longer used. This recovers a now-scarce options
135     bit. Also moved the least significant internal flag bit to the most-
136     significant bit of the word, which was not previously used (hangover from
137     the days when it was an int rather than a uint) to free up another bit for
138     the future.
140     23. Added support for CRLF line endings as well as CR and LF. As well as the
141     default being selectable at build time, it can now be changed at runtime
142     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
143     specify that it is scanning data with non-default line endings.
145     24. Changed the definition of CXXLINK to make it agree with the definition of
146     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
148     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
149     recursions. This makes a big different to stack usage for some patterns.
151     26. If a subpattern containing a named recursion or subroutine reference such
152     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
153     the space required for the compiled pattern went wrong and gave too small a
154     value. Depending on the environment, this could lead to "Failed: internal
155     error: code overflow at offset 49" or "glibc detected double free or
156     corruption" errors.
158     27. Applied patches from Google (a) to support the new newline modes and (b) to
159     advance over multibyte UTF-8 characters in GlobalReplace.
161     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
162     difference for some implementation of PCRE in some Windows version.
164     29. Added some extra testing facilities to pcretest:
166     \q<number> in a data line sets the "match limit" value
167     \Q<number> in a data line sets the "match recursion limt" value
168     -S <number> sets the stack size, where <number> is in megabytes
170     The -S option isn't available for Windows.
173 nigel 89 Version 6.6 06-Feb-06
174     ---------------------
176     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
177     in pcreposix.h. I have copied the definition from pcre.h.
179     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
180     because pcre.h is no longer a built file.
182     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
183     not normally included in the compiled code.
186 nigel 87 Version 6.5 01-Feb-06
187     ---------------------
189     1. When using the partial match feature with pcre_dfa_exec(), it was not
190     anchoring the second and subsequent partial matches at the new starting
191     point. This could lead to incorrect results. For example, with the pattern
192     /1234/, partially matching against "123" and then "a4" gave a match.
194     2. Changes to pcregrep:
196     (a) All non-match returns from pcre_exec() were being treated as failures
197     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
198     error message is output. Some extra information is given for the
200     probably the only errors that are likely to be caused by users (by
201     specifying a regex that has nested indefinite repeats, for instance).
202     If there are more than 20 of these errors, pcregrep is abandoned.
204     (b) A binary zero was treated as data while matching, but terminated the
205     output line if it was written out. This has been fixed: binary zeroes
206     are now no different to any other data bytes.
208     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
209     used to set a locale for matching. The --locale=xxxx long option has
210     been added (no short equivalent) to specify a locale explicitly on the
211     pcregrep command, overriding the environment variables.
213     (d) When -B was used with -n, some line numbers in the output were one less
214     than they should have been.
216     (e) Added the -o (--only-matching) option.
218     (f) If -A or -C was used with -c (count only), some lines of context were
219     accidentally printed for the final match.
221     (g) Added the -H (--with-filename) option.
223     (h) The combination of options -rh failed to suppress file names for files
224     that were found from directory arguments.
226     (i) Added the -D (--devices) and -d (--directories) options.
228     (j) Added the -F (--fixed-strings) option.
230     (k) Allow "-" to be used as a file name for -f as well as for a data file.
232     (l) Added the --colo(u)r option.
234     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
235     is not present by default.
237     3. A nasty bug was discovered in the handling of recursive patterns, that is,
238     items such as (?R) or (?1), when the recursion could match a number of
239     alternatives. If it matched one of the alternatives, but subsequently,
240     outside the recursion, there was a failure, the code tried to back up into
241     the recursion. However, because of the way PCRE is implemented, this is not
242     possible, and the result was an incorrect result from the match.
244     In order to prevent this happening, the specification of recursion has
245     been changed so that all such subpatterns are automatically treated as
246     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
248     4. I had overlooked the fact that, in some locales, there are characters for
249     which isalpha() is true but neither isupper() nor islower() are true. In
250     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
251     and ordfeminine) are like this. This affected the treatment of \w and \W
252     when they appeared in character classes, but not when they appeared outside
253     a character class. The bit map for "word" characters is now created
254     separately from the results of isalnum() instead of just taking it from the
255     upper, lower, and digit maps. (Plus the underscore character, of course.)
257     5. The above bug also affected the handling of POSIX character classes such as
258     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
259     permanent tables. Instead, the bit maps for such a class were previously
260     created as the appropriate unions of the upper, lower, and digit bitmaps.
261     Now they are created by subtraction from the [[:word:]] class, which has
262     its own bitmap.
264     6. The [[:blank:]] character class matches horizontal, but not vertical space.
265     It is created by subtracting the vertical space characters (\x09, \x0a,
266     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
267     subtraction was done in the overall bitmap for a character class, meaning
268     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
269     be recognized. This bug has been fixed.
271     7. Patches from the folks at Google:
273     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
274     real life, but is still worth protecting against".
276     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
277     regular expressions".
279     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
280     have it.
282     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
283     "configure" and the latter not, in order to fix a problem somebody had
284     with compiling the Arg class on HP-UX.
286     (e) Improve the error-handling of the C++ wrapper a little bit.
288     (f) New tests for checking recursion limiting.
290     8. The pcre_memmove() function, which is used only if the environment does not
291     have a standard memmove() function (and is therefore rarely compiled),
292     contained two bugs: (a) use of int instead of size_t, and (b) it was not
293     returning a result (though PCRE never actually uses the result).
295     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
296     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
297     returned instead of calling malloc() with an overflowing number that would
298     most likely cause subsequent chaos.
300     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
302     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
303     with this option is matched, the nmatch and pmatch options of regexec() are
304     ignored.
306     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
307     provided in case anyone wants to the the POSIX interface with UTF-8
308     strings.
310     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
311     C++ linking (needed for some HP-UX environments).
313     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
314     (unused parameter) and in the pcre_printint() function (omitted "default"
315     switch label when the default is to do nothing).
317     15. Added some code to make it possible, when PCRE is compiled as a C++
318     library, to replace subject pointers for pcre_exec() with a smart pointer
319     class, thus making it possible to process discontinuous strings.
321     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
322     much the same function. They were added by different people who were trying
323     to make PCRE easy to compile on non-Unix systems. It has been suggested
324     that PCRE_EXPORT be abolished now that there is more automatic apparatus
325     for compiling on Windows systems. I have therefore replaced it with
326     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
327     defaults to "extern" for C or "extern C" for C++, which works fine on
328     Unix-like systems. It is now possible to override the value of PCRE_DATA_
329     SCOPE with something explicit in config.h. In addition:
331     (a) pcreposix.h still had just "extern" instead of either of these macros;
332     I have replaced it with PCRE_DATA_SCOPE.
334     (b) Functions such as _pcre_xclass(), which are internal to the library,
335     but external in the C sense, all had PCRE_EXPORT in their definitions.
336     This is apparently wrong for the Windows case, so I have removed it.
337     (It makes no difference on Unix-like systems.)
339     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
340     of recursive calls to match(). This is different to MATCH_LIMIT because
341     that limits the total number of calls to match(), not all of which increase
342     the depth of recursion. Limiting the recursion depth limits the amount of
343     stack (or heap if NO_RECURSE is set) that is used. The default can be set
344     when PCRE is compiled, and changed at run time. A patch from Google adds
345     this functionality to the C++ interface.
347     18. Changes to the handling of Unicode character properties:
349     (a) Updated the table to Unicode 4.1.0.
351     (b) Recognize characters that are not in the table as "Cn" (undefined).
353     (c) I revised the way the table is implemented to a much improved format
354     which includes recognition of ranges. It now supports the ranges that
355     are defined in UnicodeData.txt, and it also amalgamates other
356     characters into ranges. This has reduced the number of entries in the
357     table from around 16,000 to around 3,000, thus reducing its size
358     considerably. I realized I did not need to use a tree structure after
359     all - a binary chop search is just as efficient. Having reduced the
360     number of entries, I extended their size from 6 bytes to 8 bytes to
361     allow for more data.
363     (d) Added support for Unicode script names via properties such as \p{Han}.
365     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
366     matching that character.
368     20. When matching a repeated Unicode property with a minimum greater than zero,
369     (for example \pL{2,}), PCRE could look past the end of the subject if it
370     reached it while seeking the minimum number of characters. This could
371     happen only if some of the characters were more than one byte long, because
372     there is a check for at least the minimum number of bytes.
374     21. Refactored the implementation of \p and \P so as to be more general, to
375     allow for more different types of property in future. This has changed the
376     compiled form incompatibly. Anybody with saved compiled patterns that use
377     \p or \P will have to recompile them.
379     22. Added "Any" and "L&" to the supported property types.
381     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
382     but give a compile time error if the value is greater than 0xff.
384     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
385     accidentally not being installed or uninstalled.
387     25. The pcre.h file was built from pcre.h.in, but the only changes that were
388     made were to insert the current release number. This seemed silly, because
389     it made things harder for people building PCRE on systems that don't run
390     "configure". I have turned pcre.h into a distributed file, no longer built
391     by "configure", with the version identification directly included. There is
392     no longer a pcre.h.in file.
394     However, this change necessitated a change to the pcre-config script as
395     well. It is built from pcre-config.in, and one of the substitutions was the
396     release number. I have updated configure.ac so that ./configure now finds
397     the release number by grepping pcre.h.
399     26. Added the ability to run the tests under valgrind.
402 nigel 85 Version 6.4 05-Sep-05
403     ---------------------
405     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
406     "--" to be printed when multiple files were scanned, even when none of the
407     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
408     consider it to be a bug, and have restored the previous behaviour.
410     2. A couple of code tidies to get rid of compiler warnings.
412     3. The pcretest program used to cheat by referring to symbols in the library
413     whose names begin with _pcre_. These are internal symbols that are not
414     really supposed to be visible externally, and in some environments it is
415     possible to suppress them. The cheating is now confined to including
416     certain files from the library's source, which is a bit cleaner.
418     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
419     file's purpose clearer.
421     5. Reorganized pcre_ucp_findchar().
424 nigel 83 Version 6.3 15-Aug-05
425     ---------------------
427     1. The file libpcre.pc.in did not have general read permission in the tarball.
429     2. There were some problems when building without C++ support:
431     (a) If C++ support was not built, "make install" and "make test" still
432     tried to test it.
434     (b) There were problems when the value of CXX was explicitly set. Some
435     changes have been made to try to fix these, and ...
437     (c) --disable-cpp can now be used to explicitly disable C++ support.
439     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
440     backslash in a target when C++ was disabled. This confuses some
441     versions of "make", apparently. Using an intermediate variable solves
442     this. (Same for CPP_LOBJ.)
444     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
445     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
446     necessary on certain architectures.
448     4. Added a setting of -export-symbols-regex to the link command to remove
449     those symbols that are exported in the C sense, but actually are local
450     within the library, and not documented. Their names all begin with
451     "_pcre_". This is not a perfect job, because (a) we have to except some
452     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
453     available (and never for static libraries). I have made a note to try to
454     find a way round (a) in the future.
457 nigel 81 Version 6.2 01-Aug-05
458     ---------------------
460     1. There was no test for integer overflow of quantifier values. A construction
461     such as {1111111111111111} would give undefined results. What is worse, if
462     a minimum quantifier for a parenthesized subpattern overflowed and became
463     negative, the calculation of the memory size went wrong. This could have
464     led to memory overwriting.
466     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
468     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
469     operating environments where this matters.
471     4. Applied Giuseppe Maxia's patch to add additional features for controlling
472     PCRE options from within the C++ wrapper.
474     5. Named capturing subpatterns were not being correctly counted when a pattern
475     was compiled. This caused two problems: (a) If there were more than 100
476     such subpatterns, the calculation of the memory needed for the whole
477     compiled pattern went wrong, leading to an overflow error. (b) Numerical
478     back references of the form \12, where the number was greater than 9, were
479     not recognized as back references, even though there were sufficient
480     previous subpatterns.
482     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
483     versions of gcc, e.g. 2.95.4.
486 nigel 79 Version 6.1 21-Jun-05
487     ---------------------
489     1. There was one reference to the variable "posix" in pcretest.c that was not
490     surrounded by "#if !defined NOPOSIX".
492     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
493     the cross-check on the old pcre_info() function, for the benefit of the
494     cut-down version of PCRE that is currently imported into Exim.
496     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
497     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
498     patterns that start (?i) but I don't think that matters. The use of (?i) is
499     just an example; this all applies to the other options as well.
501     4. Since libtool seems to echo the compile commands it is issuing, the output
502     from "make" can be reduced a bit by putting "@" in front of each libtool
503     compile command.
505     5. Patch from the folks at Google for configure.in to be a bit more thorough
506     in checking for a suitable C++ installation before trying to compile the
507     C++ stuff. This should fix a reported problem when a compiler was present,
508     but no suitable headers.
510     6. The man pages all had just "PCRE" as their title. I have changed them to
511     be the relevant file name. I have also arranged that these names are
512     retained in the file doc/pcre.txt, which is a concatenation in text format
513     of all the man pages except the little individual ones for each function.
515     7. The NON-UNIX-USE file had not been updated for the different set of source
516     files that come with release 6. I also added a few comments about the C++
517     wrapper.
520 nigel 77 Version 6.0 07-Jun-05
521     ---------------------
523     1. Some minor internal re-organization to help with my DFA experiments.
525     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
526     didn't matter for the library itself when fully configured, but did matter
527     when compiling without UCP support, or within Exim, where the ucp files are
528     not imported.
530     3. Refactoring of the library code to split up the various functions into
531     different source modules. The addition of the new DFA matching code (see
532     below) to a single monolithic source would have made it really too
533     unwieldy, quite apart from causing all the code to be include in a
534     statically linked application, when only some functions are used. This is
535     relevant even without the DFA addition now that patterns can be compiled in
536     one application and matched in another.
538     The downside of splitting up is that there have to be some external
539     functions and data tables that are used internally in different modules of
540     the library but which are not part of the API. These have all had their
541     names changed to start with "_pcre_" so that they are unlikely to clash
542     with other external names.
544     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
545     a different (DFA) algorithm. Although it is slower than the original
546     function, it does have some advantages for certain types of matching
547     problem.
549     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
550     including restarting after a partial match.
552     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
553     defined when compiling for Windows was sent to me. I have put it into the
554     code, though I have no means of testing or verifying it.
556     7. Added the pcre_refcount() auxiliary function.
558     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
559     match before or at the first newline in the subject string. In pcretest,
560     the /f option on a pattern can be used to set this.
562     9. A repeated \w when used in UTF-8 mode with characters greater than 256
563     would behave wrongly. This has been present in PCRE since release 4.0.
565     10. A number of changes to the pcregrep command:
567     (a) Refactored how -x works; insert ^(...)$ instead of setting
568     PCRE_ANCHORED and checking the length, in preparation for adding
569     something similar for -w.
571     (b) Added the -w (match as a word) option.
573     (c) Refactored the way lines are read and buffered so as to have more
574     than one at a time available.
576     (d) Implemented a pcregrep test script.
578     (e) Added the -M (multiline match) option. This allows patterns to match
579     over several lines of the subject. The buffering ensures that at least
580     8K, or the rest of the document (whichever is the shorter) is available
581     for matching (and similarly the previous 8K for lookbehind assertions).
583     (f) Changed the --help output so that it now says
585     -w, --word-regex(p)
587     instead of two lines, one with "regex" and the other with "regexp"
588     because that confused at least one person since the short forms are the
589     same. (This required a bit of code, as the output is generated
590     automatically from a table. It wasn't just a text change.)
592     (g) -- can be used to terminate pcregrep options if the next thing isn't an
593     option but starts with a hyphen. Could be a pattern or a path name
594     starting with a hyphen, for instance.
596     (h) "-" can be given as a file name to represent stdin.
598     (i) When file names are being printed, "(standard input)" is used for
599     the standard input, for compatibility with GNU grep. Previously
600     "<stdin>" was used.
602     (j) The option --label=xxx can be used to supply a name to be used for
603     stdin when file names are being printed. There is no short form.
605     (k) Re-factored the options decoding logic because we are going to add
606     two more options that take data. Such options can now be given in four
607     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
609     (l) Added the -A, -B, and -C options for requesting that lines of context
610     around matches be printed.
612     (m) Added the -L option to print the names of files that do not contain
613     any matching lines, that is, the complement of -l.
615     (n) The return code is 2 if any file cannot be opened, but pcregrep does
616     continue to scan other files.
618     (o) The -s option was incorrectly implemented. For compatibility with other
619     greps, it now suppresses the error message for a non-existent or non-
620     accessible file (but not the return code). There is a new option called
621     -q that suppresses the output of matching lines, which was what -s was
622     previously doing.
624     (p) Added --include and --exclude options to specify files for inclusion
625     and exclusion when recursing.
627     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
628     Hopefully, it now does.
630     12. Missing cast in pcre_study().
632     13. Added an "uninstall" target to the makefile.
634     14. Replaced "extern" in the function prototypes in Makefile.in with
635     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
636     world, but is set differently for Windows.
638     15. Added a second compiling function called pcre_compile2(). The only
639     difference is that it has an extra argument, which is a pointer to an
640     integer error code. When there is a compile-time failure, this is set
641     non-zero, in addition to the error test pointer being set to point to an
642     error message. The new argument may be NULL if no error number is required
643     (but then you may as well call pcre_compile(), which is now just a
644     wrapper). This facility is provided because some applications need a
645     numeric error indication, but it has also enabled me to tidy up the way
646     compile-time errors are handled in the POSIX wrapper.
648     16. Added VPATH=.libs to the makefile; this should help when building with one
649     prefix path and installing with another. (Or so I'm told by someone who
650     knows more about this stuff than I do.)
652     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
653     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
654     match everything, including newlines. This is not POSIX-compatible, but
655     somebody wanted the feature. From pcretest it can be activated by using
656     both the P and the s flags.
658     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
660     19. libpcre.pc was being incorrectly installed as executable.
662     20. A couple of places in pcretest check for end-of-line by looking for '\n';
663     it now also looks for '\r' so that it will work unmodified on Windows.
665     21. Added Google's contributed C++ wrapper to the distribution.
667     22. Added some untidy missing memory free() calls in pcretest, to keep
668     Electric Fence happy when testing.
672 nigel 75 Version 5.0 13-Sep-04
673     ---------------------
675     1. Internal change: literal characters are no longer packed up into items
676     containing multiple characters in a single byte-string. Each character
677     is now matched using a separate opcode. However, there may be more than one
678     byte in the character in UTF-8 mode.
680     2. The pcre_callout_block structure has two new fields: pattern_position and
681     next_item_length. These contain the offset in the pattern to the next match
682     item, and its length, respectively.
684     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
685     insertion of callouts before each pattern item. Added the /C option to
686     pcretest to make use of this.
688     4. On the advice of a Windows user, the lines
690     #if defined(_WIN32) || defined(WIN32)
691     _setmode( _fileno( stdout ), 0x8000 );
692     #endif /* defined(_WIN32) || defined(WIN32) */
694     have been added to the source of pcretest. This apparently does useful
695     magic in relation to line terminators.
697     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
698     for the benefit of those environments where the "b" makes a difference.
700     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
701     to know about it. I have put a hack into configure.in that adds in code
702     to set GCC=yes if CC=icc. This seems to end up at a point in the
703     generated configure script that is early enough to affect the setting of
704     compiler options, which is what is needed, but I have no means of testing
705     whether it really works. (The user who reported this had patched the
706     generated configure script, which of course I cannot do.)
708     LATER: After change 22 below (new libtool files), the configure script
709     seems to know about icc (and also ecc). Therefore, I have commented out
710     this hack in configure.in.
712     7. Added support for pkg-config (2 patches were sent in).
714     8. Negated POSIX character classes that used a combination of internal tables
715     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
716     [[:^ascii]]. Typically, they would match almost any characters. The other
717     POSIX classes were not broken in this way.
719     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
720     to find the match, as PCRE was deluded into thinking that the match had to
721     start at the start point or following a newline. The same bug applied to
722     patterns with negative forward assertions or any backward assertions
723     preceding ".*" at the start, unless the pattern required a fixed first
724     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
726     10. In UTF-8 mode, when moving forwards in the subject after a failed match
727     starting at the last subject character, bytes beyond the end of the subject
728     string were read.
730     11. Renamed the variable "class" as "classbits" to make life easier for C++
731     users. (Previously there was a macro definition, but it apparently wasn't
732     enough.)
734     12. Added the new field "tables" to the extra data so that tables can be passed
735     in at exec time, or the internal tables can be re-selected. This allows
736     a compiled regex to be saved and re-used at a later time by a different
737     program that might have everything at different addresses.
739     13. Modified the pcre-config script so that, when run on Solaris, it shows a
740     -R library as well as a -L library.
742     14. The debugging options of pcretest (-d on the command line or D on a
743     pattern) showed incorrect output for anything following an extended class
744     that contained multibyte characters and which was followed by a quantifier.
746     15. Added optional support for general category Unicode character properties
747     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
748     support. It adds about 90K to the size of the library. The meanings of the
749     inbuilt class escapes such as \d and \s have NOT been changed.
751     16. Updated pcredemo.c to include calls to free() to release the memory for the
752     compiled pattern.
754     17. The generated file chartables.c was being created in the source directory
755     instead of in the building directory. This caused the build to fail if the
756     source directory was different from the building directory, and was
757     read-only.
759     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
760     file. No doubt somebody will tell me if they don't make sense... Also added
761     Dan Mooney's comments about building on OpenVMS.
763     19. Added support for partial matching via the PCRE_PARTIAL option for
764     pcre_exec() and the \P data escape in pcretest.
766     20. Extended pcretest with 3 new pattern features:
768     (i) A pattern option of the form ">rest-of-line" causes pcretest to
769     write the compiled pattern to the file whose name is "rest-of-line".
770     This is a straight binary dump of the data, with the saved pointer to
771     the character tables forced to be NULL. The study data, if any, is
772     written too. After writing, pcretest reads a new pattern.
774     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
775     compiled pattern from the given file. There must not be any
776     occurrences of "<" in the file name (pretty unlikely); if there are,
777     pcretest will instead treat the initial "<" as a pattern delimiter.
778     After reading in the pattern, pcretest goes on to read data lines as
779     usual.
781     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
782     and 16-bit fields in a compiled pattern, to simulate a pattern that
783     was compiled on a host of opposite endianness.
785     21. The pcre-exec() function can now cope with patterns that were compiled on
786     hosts of opposite endianness, with this restriction:
788     As for any compiled expression that is saved and used later, the tables
789     pointer field cannot be preserved; the extra_data field in the arguments
790     to pcre_exec() should be used to pass in a tables address if a value
791     other than the default internal tables were used at compile time.
793     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
794     now diagnosed as an error. Previously, most of the time, a negative number
795     would have been treated as zero, but if in addition "ovector" was passed as
796     NULL, a crash could occur.
798     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
799     new versions from the libtool 1.5 distribution (the last one is a copy of
800     a file called libtool.m4). This seems to have fixed the need to patch
801     "configure" to support Darwin 1.3 (which I used to do). However, I still
802     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
803     workstation).
805     24. Changed the PCRE licence to be the more standard "BSD" licence.
808 nigel 73 Version 4.5 01-Dec-03
809     ---------------------
811     1. There has been some re-arrangement of the code for the match() function so
812     that it can be compiled in a version that does not call itself recursively.
813     Instead, it keeps those local variables that need separate instances for
814     each "recursion" in a frame on the heap, and gets/frees frames whenever it
815     needs to "recurse". Keeping track of where control must go is done by means
816     of setjmp/longjmp. The whole thing is implemented by a set of macros that
817     hide most of the details from the main code, and operates only if
818     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
819     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
820     operating.
822     To make it easier for callers to provide specially tailored get/free
823     functions for this usage, two new functions, pcre_stack_malloc, and
824     pcre_stack_free, are used. They are always called in strict stacking order,
825     and the size of block requested is always the same.
827     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
828     PCRE has been compiled to use the stack or the heap for recursion. The
829     -C option of pcretest uses this to show which version is compiled.
831     A new data escape \S, is added to pcretest; it causes the amounts of store
832     obtained and freed by both kinds of malloc/free at match time to be added
833     to the output.
835     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
836     what's available on my current Linux desktop machine.
838     3. When matching a UTF-8 string, the test for a valid string at the start has
839     been extended. If start_offset is not zero, PCRE now checks that it points
840     to a byte that is the start of a UTF-8 character. If not, it returns
841     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
842     this is necessary because there may be backward assertions in the pattern.
843     When matching the same subject several times, it may save resources to use
844     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
846     4. The code for checking the validity of UTF-8 strings has been tightened so
847     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
848     containing "overlong sequences".
850     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
851     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
852     should have been "&", but it just so happened that all the cases this let
853     through by mistake were picked up later in the function.
855     6. I had used a variable called "isblank" - this is a C99 function, causing
856     some compilers to warn. To avoid this, I renamed it (as "blankclass").
858     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
859     prompting; (b) run "./pcretest /dev/null" at the start of the test script
860     so the version is shown; (c) stop "make test" echoing "./RunTest".
862     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
864     9. The prototype for memmove() for systems that don't have it was using
865     size_t, but the inclusion of the header that defines size_t was later. I've
866     moved the #includes for the C headers earlier to avoid this.
868     10. Added some adjustments to the code to make it easier to compiler on certain
869     special systems:
871     (a) Some "const" qualifiers were missing.
872     (b) Added the macro EXPORT before all exported functions; by default this
873     is defined to be empty.
874     (c) Changed the dftables auxiliary program (that builds chartables.c) so
875     that it reads its output file name as an argument instead of writing
876     to the standard output and assuming this can be redirected.
878     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
879     class containing characters with values greater than 255, PCRE compilation
880     went into a loop.
882     12. A recursive reference to a subpattern that was within another subpattern
883     that had a minimum quantifier of zero caused PCRE to crash. For example,
884     (x(y(?2))z)? provoked this bug with a subject that got as far as the
885     recursion. If the recursively-called subpattern itself had a zero repeat,
886     that was OK.
888     13. In pcretest, the buffer for reading a data line was set at 30K, but the
889     buffer into which it was copied (for escape processing) was still set at
890     1024, so long lines caused crashes.
892     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
893     "internal error: code overflow...". This applied to any character class
894     that was followed by a possessive quantifier.
896     15. Modified the Makefile to add libpcre.la as a prerequisite for
897     libpcreposix.la because I was told this is needed for a parallel build to
898     work.
900     16. If a pattern that contained .* following optional items at the start was
901     studied, the wrong optimizing data was generated, leading to matching
902     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
903     matching string must start with a or b or c. The correct conclusion for
904     this pattern is that a match can start with any character.
907 nigel 71 Version 4.4 13-Aug-03
908     ---------------------
910     1. In UTF-8 mode, a character class containing characters with values between
911     127 and 255 was not handled correctly if the compiled pattern was studied.
912     In fixing this, I have also improved the studying algorithm for such
913     classes (slightly).
915     2. Three internal functions had redundant arguments passed to them. Removal
916     might give a very teeny performance improvement.
918     3. Documentation bug: the value of the capture_top field in a callout is *one
919     more than* the number of the hightest numbered captured substring.
921     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
922     in incorrectly linking with a previously installed version. They now link
923     explicitly with libpcre.la.
925     5. configure.in no longer needs to recognize Cygwin specially.
927     6. A problem in pcre.in for Windows platforms is fixed.
929     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
930     pcretest, it used to include the size of the study block as part of its
931     output. Unfortunately, the structure contains a field that has a different
932     size on different hardware architectures. This meant that the tests that
933     showed this size failed. As the block is currently always of a fixed size,
934     this information isn't actually particularly useful in pcretest output, so
935     I have just removed it.
937     8. Three pre-processor statements accidentally did not start in column 1.
938     Sadly, there are *still* compilers around that complain, even though
939     standard C has not required this for well over a decade. Sigh.
941     9. In pcretest, the code for checking callouts passed small integers in the
942     callout_data field, which is a void * field. However, some picky compilers
943     complained about the casts involved for this on 64-bit systems. Now
944     pcretest passes the address of the small integer instead, which should get
945     rid of the warnings.
947     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
948     both compile and run time, and gives an error if an invalid UTF-8 sequence
949     is found. There is a option for disabling this check in cases where the
950     string is known to be correct and/or the maximum performance is wanted.
952     11. In response to a bug report, I changed one line in Makefile.in from
954     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
955     to
956     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
958     to look similar to other lines, but I have no way of telling whether this
959     is the right thing to do, as I do not use Windows. No doubt I'll get told
960     if it's wrong...
963 nigel 69 Version 4.3 21-May-03
964     ---------------------
966     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
967     Makefile.
969     2. Some refactoring to improve the quality of the code:
971     (i) The utf8_table... variables are now declared "const".
973     (ii) The code for \cx, which used the "case flipping" table to upper case
974     lower case letters, now just substracts 32. This is ASCII-specific,
975     but the whole concept of \cx is ASCII-specific, so it seems
976     reasonable.
978     (iii) PCRE was using its character types table to recognize decimal and
979     hexadecimal digits in the pattern. This is silly, because it handles
980     only 0-9, a-f, and A-F, but the character types table is locale-
981     specific, which means strange things might happen. A private
982     table is now used for this - though it costs 256 bytes, a table is
983     much faster than multiple explicit tests. Of course, the standard
984     character types table is still used for matching digits in subject
985     strings against \d.
987     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
988     ending in _t are). So I've renamed it as ESC_tee.
990     3. The first argument for regexec() in the POSIX wrapper should have been
991     defined as "const".
993     4. Changed pcretest to use malloc() for its buffers so that they can be
994     Electric Fenced for debugging.
996     5. There were several places in the code where, in UTF-8 mode, PCRE would try
997     to read one or more bytes before the start of the subject string. Often this
998     had no effect on PCRE's behaviour, but in some circumstances it could
999     provoke a segmentation fault.
1001     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1002     to try to read one or more bytes before the start of the subject string.
1004     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1005     UTF-8 support could misbehave in various ways if the subject string
1006     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1007     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1008     back over UTF-8 characters.)
1011 nigel 67 Version 4.2 14-Apr-03
1012     ---------------------
1014     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1016     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1017     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1018     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1019     [WIN_PREFIX]: new variable, "cyg" for Cygwin
1020     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1021     and BUILD_EXEEXT
1022     Note: automatic setting of the BUILD variables is not yet working
1023     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1024     compile-time but not at link-time
1025     [LINK]: use for linking executables only
1026     make different versions for Windows and non-Windows
1027     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1028     libraries
1029     [LINK_FOR_BUILD]: new variable
1030     [OBJEXT]: use throughout
1031     [EXEEXT]: use throughout
1032     <winshared>: new target
1033     <wininstall>: new target
1034     <dftables.o>: use native compiler
1035     <dftables>: use native linker
1036     <install>: handle Windows platform correctly
1037     <clean>: ditto
1038     <check>: ditto
1039     copy DLL to top builddir before testing
1041     As part of these changes, -no-undefined was removed again. This was reported
1042     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1043     in any case.
1045     3. Some tidies to get rid of compiler warnings:
1047     . In the match_data structure, match_limit was an unsigned long int, whereas
1048     match_call_count was an int. I've made them both unsigned long ints.
1050     . In pcretest the fact that a const uschar * doesn't automatically cast to
1051     a void * provoked a warning.
1053     . Turning on some more compiler warnings threw up some "shadow" variables
1054     and a few more missing casts.
1056     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1057     option, a class that contained a single character with a value between 128
1058     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1060     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1061     option, a class that contained several characters, but with at least one
1062     whose value was between 128 and 255 caused PCRE to crash.
1065 nigel 65 Version 4.1 12-Mar-03
1066     ---------------------
1067 nigel 63
1068 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
1069     needed, and a string in dftables.c that was longer than standard compilers are
1070     required to support.
1072     2. Compiling with Sun's compiler found a few more places where the code could
1073     be tidied up in order to avoid warnings.
1075     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1076     first of these names is deprecated in the latest Autoconf in favour of the name
1077     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1078     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1079     analogy I have changed it to CFLAGS_FOR_BUILD.
1081     4. Added -no-undefined to the linking command in the Makefile, because this is
1082     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1083     linking step for the pcreposix library.
1085     5. PCRE was failing to diagnose the case of two named groups with the same
1086     name.
1088     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1089     literal character that is needed in the subject for a match, and scans along to
1090     ensure that it is present before embarking on the full matching process. This
1091     saves time in cases of nested unlimited repeats that are never going to match.
1092     Problem: the scan can take a lot of time if the subject is very long (e.g.
1093     megabytes), thus penalizing straightforward matches. It is now done only if the
1094     amount of subject to be scanned is less than 1000 bytes.
1096     7. A lesser problem with the same optimization is that it was recording the
1097     first character of an anchored pattern as "needed", thus provoking a search
1098     right along the subject, even when the first match of the pattern was going to
1099     fail. The "needed" character is now not set for anchored patterns, unless it
1100     follows something in the pattern that is of non-fixed length. Thus, it still
1101     fulfils its original purpose of finding quick non-matches in cases of nested
1102     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1105     Version 4.0 17-Feb-03
1106     ---------------------
1108 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
1109     extended to the end of string, PCRE compiled incorrect data. This could lead to
1110     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1112     2. Moved to autoconf 2.53 and libtool 1.4.2.
1114     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1115     the special perltest8 script is no longer needed - all the tests can be run
1116     from a single perltest script.
1118     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1119     by \s. It has now been removed in PCRE. This means it isn't recognized as
1120     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1121     class [:space:] *does* include VT, thereby creating a mess.
1123     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1124     space and tab.
1126     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1127     its new features into the main test script, reducing the number of scripts.
1129     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1130     were backward compatible, and made the (?i) apply to the whole pattern, as if
1131     /i were given. Now it behaves more logically, and applies the option setting
1132     only to what follows. PCRE has been changed to follow suit. However, if it
1133     finds options settings right at the start of the pattern, it extracts them into
1134     the global options, as before. Thus, they show up in the info data.
1136     8. Added support for the \Q...\E escape sequence. Characters in between are
1137     treated as literals. This is slightly different from Perl in that $ and @ are
1138     also handled as literals inside the quotes. In Perl, they will cause variable
1139     interpolation. Note the following examples:
1141     Pattern PCRE matches Perl matches
1143     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
1144     \Qabc\$xyz\E abc\$xyz abc\$xyz
1145     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
1147     For compatibility with Perl, \Q...\E sequences are recognized inside character
1148     classes as well as outside them.
1150     9. Re-organized 3 code statements in pcretest to avoid "overflow in
1151     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1152     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1153     signed/unsigned warnings.
1155     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1156     option for pcretest, so I've replaced it by a simple function that does just
1157     that job.
1159     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1160     "pcregrep -".
1162     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1163     Java package. This provides some syntactic sugar for simple cases of what my
1164     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1165     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1166     item, you can use this simplified notation. Note that only makes sense with
1167     greedy quantifiers. Consequently, the use of the possessive quantifier forces
1168     greediness, whatever the setting of the PCRE_UNGREEDY option.
1170     13. A change of greediness default within a pattern was not taking effect at
1171     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1172     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1173     was abstracted outside.
1175     14. PCRE now supports the \G assertion. It is true when the current matching
1176     position is at the start point of the match. This differs from \A when the
1177     starting offset is non-zero. Used with the /g option of pcretest (or similar
1178     code), it works in the same way as it does for Perl's /g option. If all
1179     alternatives of a regex begin with \G, the expression is anchored to the start
1180     match position, and the "anchored" flag is set in the compiled expression.
1182     15. Some bugs concerning the handling of certain option changes within patterns
1183     have been fixed. These applied to options other than (?ims). For example,
1184     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1185     been the other way round. Some of this was related to change 7 above.
1187     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1188     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1189     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1190     POSIX classes only within a class (e.g. /[[:alpha:]]/).
1192     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1193     mode. Unlike ".", it always matches newline, whatever the setting of
1194     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1195     assertions. Perl allows it, but it doesn't (in general) work because it can't
1196     calculate the length of the lookbehind. At least, that's the case for Perl
1197     5.8.0 - I've been told they are going to document that it doesn't work in
1198     future.
1200     18. Added an error diagnosis for escapes that PCRE does not support: these are
1201     \L, \l, \N, \P, \p, \U, \u, and \X.
1203     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1204     reading past the end of the pattern in cases such as /[abcd/.
1206     20. PCRE was getting more memory than necessary for patterns with classes that
1207     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1209     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1210     compiling PCRE for use with Virtual Pascal.
1212     22. Small fix to the Makefile to make it work properly if the build is done
1213     outside the source tree.
1215     23. Added a new extension: a condition to go with recursion. If a conditional
1216     subpattern starts with (?(R) the "true" branch is used if recursion has
1217     happened, whereas the "false" branch is used only at the top level.
1219     24. When there was a very long string of literal characters (over 255 bytes
1220     without UTF support, over 250 bytes with UTF support), the computation of how
1221     much memory was required could be incorrect, leading to segfaults or other
1222     strange effects.
1224     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1225     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1226     there was a subsequent back reference to those brackets. This meant that, for
1227     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1228     possible to check for precisely this case. All we can do is abandon the
1229     optimization if .* occurs inside capturing brackets when there are any back
1230     references whatsoever. (See below for a better fix that came later.)
1232     26. The handling of the optimization for finding the first character of a
1233     non-anchored pattern, and for finding a character that is required later in the
1234     match were failing in some cases. This didn't break the matching; it just
1235     failed to optimize when it could. The way this is done has been re-implemented.
1237     27. Fixed typo in error message for invalid (?R item (it said "(?p").
1239     28. Added a new feature that provides some of the functionality that Perl
1240     provides with (?{...}). The facility is termed a "callout". The way it is done
1241     in PCRE is for the caller to provide an optional function, by setting
1242     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1243     global variable. By default it is unset, which disables all calling out. To get
1244     the function called, the regex must include (?C) at appropriate points. This
1245     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1246     This provides a means of identifying different callout points. When PCRE
1247     reaches such a point in the regex, if pcre_callout has been set, the external
1248     function is called. It is provided with data in a structure called
1249     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1250     matching continues; if it returns a non-zero value, the match at the current
1251     point fails. However, backtracking will occur if possible. [This was changed
1252     later and other features added - see item 49 below.]
1254     29. pcretest is upgraded to test the callout functionality. It provides a
1255     callout function that displays information. By default, it shows the start of
1256     the match and the current position in the text. There are some new data escapes
1257     to vary what happens:
1259     \C+ in addition, show current contents of captured substrings
1260     \C- do not supply a callout function
1261     \C!n return 1 when callout number n is reached
1262     \C!n!m return 1 when callout number n is reached for the mth time
1264     30. If pcregrep was called with the -l option and just a single file name, it
1265     output "<stdin>" if a match was found, instead of the file name.
1267     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1268     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1269     pcre_exec(). This saves a malloc/free per call. The default value of
1270     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1271     when configuring.
1273     32. The default maximum size of a compiled pattern is 64K. There have been a
1274     few cases of people hitting this limit. The code now uses macros to handle the
1275     storing of links as offsets within the compiled pattern. It defaults to 2-byte
1276     links, but this can be changed to 3 or 4 bytes by --with-link-size when
1277     configuring. Tests 2 and 5 work only with 2-byte links because they output
1278     debugging information about compiled patterns.
1280     33. Internal code re-arrangements:
1282     (a) Moved the debugging function for printing out a compiled regex into
1283     its own source file (printint.c) and used #include to pull it into
1284     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1285     separate copies.
1287     (b) Defined the list of op-code names for debugging as a macro in
1288     internal.h so that it is next to the definition of the opcodes.
1290     (c) Defined a table of op-code lengths for simpler skipping along compiled
1291     code. This is again a macro in internal.h so that it is next to the
1292     definition of the opcodes.
1294     34. Added support for recursive calls to individual subpatterns, along the
1295     lines of Robin Houston's patch (but implemented somewhat differently).
1297     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1298     allow it to read and process whole directories in Win32. This code was
1299     contributed by Lionel Fourquaux; it has not been tested by me.
1301     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1302     used to name a group. Names consist of alphanumerics and underscores, and must
1303     be unique. Back references use the syntax (?P=name) and recursive calls use
1304     (?P>name) which is a PCRE extension to the Python extension. Groups still have
1305     numbers. The function pcre_fullinfo() can be used after compilation to extract
1306     a name/number map. There are three relevant calls:
1308     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
1309     PCRE_INFO_NAMECOUNT yields the number of entries
1310     PCRE_INFO_NAMETABLE yields a pointer to the map.
1312     The map is a vector of fixed-size entries. The size of each entry depends on
1313     the length of the longest name used. The first two bytes of each entry are the
1314     group number, most significant byte first. There follows the corresponding
1315     name, zero terminated. The names are in alphabetical order.
1317     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1318     case instead of 255. Making it the same both with and without UTF-8 support
1319     means that the same test output works with both.
1321     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1322     calling malloc() with a zero argument.
1324     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1325     optimization. I've improved things by keeping a bitmap of backreferences with
1326     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1327     fact referenced, the optimization can be applied. It is unlikely that a
1328     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1329     the match to follow \n) will appear inside brackets with a number greater than
1330     31, but if it does, any back reference > 31 suppresses the optimization.
1332     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1333     of disabling numbered capturing parentheses. Any opening parenthesis that is
1334     not followed by ? behaves as if it were followed by ?: but named parentheses
1335     can still be used for capturing (and they will acquire numbers in the usual
1336     way).
1338     41. Redesigned the return codes from the match() function into yes/no/error so
1339     that errors can be passed back from deep inside the nested calls. A malloc
1340     failure while inside a recursive subpattern call now causes the
1341     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1343     42. It is now possible to set a limit on the number of times the match()
1344     function is called in a call to pcre_exec(). This facility makes it possible to
1345     limit the amount of recursion and backtracking, though not in a directly
1346     obvious way, because the match() function is used in a number of different
1347     circumstances. The count starts from zero for each position in the subject
1348     string (for non-anchored patterns). The default limit is, for compatibility, a
1349     large number, namely 10 000 000. You can change this in two ways:
1351     (a) When configuring PCRE before making, you can use --with-match-limit=n
1352     to set a default value for the compiled library.
1354     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1355     a different value is set. See 45 below.
1357     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1359     43. Added a new function pcre_config(int, void *) to enable run-time extraction
1360     of things that can be changed at compile time. The first argument specifies
1361     what is wanted and the second points to where the information is to be placed.
1362     The current list of available information is:
1366     The output is an integer that is set to one if UTF-8 support is available;
1367     otherwise it is set to zero.
1371     The output is an integer that it set to the value of the code that is used for
1372     newline. It is either LF (10) or CR (13).
1376     The output is an integer that contains the number of bytes used for internal
1377     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1381     The output is an integer that contains the threshold above which the POSIX
1382     interface uses malloc() for output vectors. See item 31 above.
1386     The output is an unsigned integer that contains the default limit of the number
1387     of match() calls in a pcre_exec() execution. See 42 above.
1389     44. pcretest has been upgraded by the addition of the -C option. This causes it
1390     to extract all the available output from the new pcre_config() function, and to
1391     output it. The program then exits immediately.
1393     45. A need has arisen to pass over additional data with calls to pcre_exec() in
1394     order to support additional features. One way would have been to define
1395     pcre_exec2() (for example) with extra arguments, but this would not have been
1396     extensible, and would also have required all calls to the original function to
1397     be mapped to the new one. Instead, I have chosen to extend the mechanism that
1398     is used for passing in "extra" data from pcre_study().
1400     The pcre_extra structure is now exposed and defined in pcre.h. It currently
1401     contains the following fields:
1403     flags a bitmap indicating which of the following fields are set
1404     study_data opaque data from pcre_study()
1405     match_limit a way of specifying a limit on match() calls for a specific
1406     call to pcre_exec()
1407     callout_data data for callouts (see 49 below)
1409     The flag bits are also defined in pcre.h, and are
1415     The pcre_study() function now returns one of these new pcre_extra blocks, with
1416     the actual study data pointed to by the study_data field, and the
1417     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1418     before. That is, this change is entirely upwards-compatible and requires no
1419     change to existing code.
1421     If you want to pass in additional data to pcre_exec(), you can either place it
1422     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1423     block.
1425     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1426     data string contains the escape sequence \M, pcretest calls pcre_exec() several
1427     times with different match limits, until it finds the minimum value needed for
1428     pcre_exec() to complete. The value is then output. This can be instructive; for
1429     most simple matches the number is quite small, but for pathological cases it
1430     gets very large very quickly.
1432     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1433     returns the size of the data block pointed to by the study_data field in a
1434     pcre_extra block, that is, the value that was passed as the argument to
1435     pcre_malloc() when PCRE was getting memory in which to place the information
1436     created by pcre_study(). The fourth argument should point to a size_t variable.
1437     pcretest has been extended so that this information is shown after a successful
1438     pcre_study() call when information about the compiled regex is being displayed.
1440     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1441     because what follows is always an absolute path. (Later: it turns out that this
1442     is more than cosmetic for MinGW, because it doesn't like empty path
1443     components.)
1445     49. Some changes have been made to the callout feature (see 28 above):
1447     (i) A callout function now has three choices for what it returns:
1449     0 => success, carry on matching
1450     > 0 => failure at this point, but backtrack if possible
1451     < 0 => serious error, return this value from pcre_exec()
1453     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1454     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1455     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1456     use by callout functions. It will never be used by PCRE itself.
1458     (ii) The pcre_extra structure (see 45 above) has a void * field called
1459     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1460     pcre_callout_block structure has a field of the same name. The contents of
1461     the field passed in the pcre_extra structure are passed to the callout
1462     function in the corresponding field in the callout block. This makes it
1463     easier to use the same callout-containing regex from multiple threads. For
1464     testing, the pcretest program has a new data escape
1466     \C*n pass the number n (may be negative) as callout_data
1468     If the callout function in pcretest receives a non-zero value as
1469     callout_data, it returns that value.
1471     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1472     there were some redundant $(CFLAGS) in commands that are now specified as
1473     $(LINK), which already includes $(CFLAGS).
1475     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1476     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1477     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1478     one-byte characters throughout. Note that case-insensitive matching applies
1479     only to characters whose values are less than 256. PCRE doesn't support the
1480     notion of cases for higher-valued characters.
1482     (i) A character class whose characters are all within 0-255 is handled as
1483     a bit map, and the map is inverted for negative classes. Previously, a
1484     character > 255 always failed to match such a class; however it should
1485     match if the class was a negative one (e.g. [^ab]). This has been fixed.
1487     (ii) A negated character class with a single character < 255 is coded as
1488     "not this character" (OP_NOT). This wasn't working properly when the test
1489     character was multibyte, either singly or repeated.
1491     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1492     mode, for example: \x{100}{2,3}.
1494     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1495     singly or repeated) now correctly test multibyte characters. However,
1496     PCRE doesn't recognize any characters with values greater than 255 as
1497     digits, spaces, or word characters. Such characters always match \D, \S,
1498     and \W, and never match \d, \s, or \w.
1500     (v) Classes may now contain characters and character ranges with values
1501     greater than 255. For example: [ab\x{100}-\x{400}].
1503     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
1504     PCRE in UTF-8 mode.
1506     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1507     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1508     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1509     value.)
1511     53. The single man page has become too large. I have therefore split it up into
1512     a number of separate man pages. These also give rise to individual HTML pages;
1513     these are now put in a separate directory, and there is an index.html page that
1514     lists them all. Some hyperlinking between the pages has been installed.
1516     54. Added convenience functions for handling named capturing parentheses.
1518     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1519     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1520     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1521     are faulted.
1523     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1524     calling configure. These values are used when compiling the dftables.c program
1525     which is run to generate the source of the default character tables. They
1526     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1527     you will need to set these values.
1529     57. Updated the building process for Windows DLL, as provided by Fred Cox.
1532     Version 3.9 02-Jan-02
1533 nigel 61 ---------------------
1535     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1537     2. If --disable-static was given, the building process failed when trying to
1538     build pcretest and pcregrep. (For some reason it was using libtool to compile
1539     them, which is not right, as they aren't part of the library.)
1542 nigel 59 Version 3.8 18-Dec-01
1543     ---------------------
1545     1. The experimental UTF-8 code was completely screwed up. It was packing the
1546     bytes in the wrong order. How dumb can you get?
1549 nigel 57 Version 3.7 29-Oct-01
1550     ---------------------
1552     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1553     This caused pcretest, when used on the test data, to segfault. Unfortunately,
1554     this didn't happen under Solaris 8, where I normally test things.
1556 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1557     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1558     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
1559     this fix an hour or so after the initial 3.7 release.)
1560 nigel 57
1561 nigel 59
1562 nigel 55 Version 3.6 23-Oct-01
1563     ---------------------
1565     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1566     offsets passed as NULL with zero offset count.
1568     2. The config.guess and config.sub files had not been updated when I moved to
1569     the latest autoconf.
1572 nigel 53 Version 3.5 15-Aug-01
1573     ---------------------
1574 nigel 5
1575 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
1576     had been forgotten.
1578     2. By using declared but undefined structures, we can avoid using "void"
1579     definitions in pcre.h while keeping the internal definitions of the structures
1580     private.
1582     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
1583     user point of view, this means that both static and shared libraries are built
1584     by default, but this can be individually controlled. More of the work of
1585     handling this static/shared cases is now inside libtool instead of PCRE's make
1586     file.
1588     4. The pcretest utility is now installed along with pcregrep because it is
1589     useful for users (to test regexs) and by doing this, it automatically gets
1590     relinked by libtool. The documentation has been turned into a man page, so
1591     there are now .1, .txt, and .html versions in /doc.
1593     5. Upgrades to pcregrep:
1594     (i) Added long-form option names like gnu grep.
1595     (ii) Added --help to list all options with an explanatory phrase.
1596     (iii) Added -r, --recursive to recurse into sub-directories.
1597     (iv) Added -f, --file to read patterns from a file.
1599     6. pcre_exec() was referring to its "code" argument before testing that
1600     argument for NULL (and giving an error if it was NULL).
1602     7. Upgraded Makefile.in to allow for compiling in a different directory from
1603     the source directory.
1605     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
1606     options bits, the pointer it was passed was to an int instead of to an unsigned
1607     long int. This mattered only on 64-bit systems.
1609     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
1610     generated) instead of pcre.in, which it its source. Also made the same change
1611     in several of the .c files.
1613     10. A new release of gcc defines printf() as a macro, which broke pcretest
1614     because it had an ifdef in the middle of a string argument for printf(). Fixed
1615     by using separate calls to printf().
1617     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
1618     script, to force use of CR or LF instead of \n in the source. On non-Unix
1619     systems, the value can be set in config.h.
1621     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
1622     absolute limit. Changed the text of the error message to make this clear, and
1623     likewise updated the man page.
1625     13. The limit of 99 on the number of capturing subpatterns has been removed.
1626     The new limit is 65535, which I hope will not be a "real" limit.
1629 nigel 51 Version 3.4 22-Aug-00
1630     ---------------------
1632     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
1634     2. Diagnose condition (?(0) as an error instead of crashing on matching.
1637 nigel 49 Version 3.3 01-Aug-00
1638     ---------------------
1640     1. If an octal character was given, but the value was greater than \377, it
1641     was not getting masked to the least significant bits, as documented. This could
1642     lead to crashes in some systems.
1644     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
1645     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
1647     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
1648     These just pass their arguments on to (pcre_free)(), but they are provided
1649     because some uses of PCRE bind it to non-C systems that can call its functions,
1650     but cannot call free() or pcre_free() directly.
1652     4. Add "make test" as a synonym for "make check". Corrected some comments in
1653     the Makefile.
1655     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
1656     Makefile.
1658     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
1659     command called pgrep for grepping around the active processes.
1661     7. Added the beginnings of support for UTF-8 character strings.
1663     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
1664     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
1665     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
1666     out for the ar command.)
1669 nigel 47 Version 3.2 12-May-00
1670     ---------------------
1672     This is purely a bug fixing release.
1674     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
1675     of ZA. This was just one example of several cases that could provoke this bug,
1676     which was introduced by change 9 of version 2.00. The code for breaking
1677     infinite loops after an iteration that matches an empty string was't working
1678     correctly.
1680     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
1681     when matched against abbab (for example). After matching an empty string, it
1682     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
1683     caused it to match further down the string than it should.
1685     3. The code contained an inclusion of sys/types.h. It isn't clear why this
1686     was there because it doesn't seem to be needed, and it causes trouble on some
1687     systems, as it is not a Standard C header. It has been removed.
1689     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
1690     were reported on the Macintosh. The changes were from
1692     while ((c = *(++ptr)) != 0 && c != '\n');
1693     to
1694     while ((c = *(++ptr)) != 0 && c != '\n') ;
1696     Totally extraordinary, but if that's what it takes...
1698     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
1699     available. Added HAVE_BCOPY and an autoconf test for it; if neither
1700     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
1701     assumes the way PCRE uses memmove() (always moving upwards).
1703     6. PCRE is being used in one environment where strchr() is not available. There
1704     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
1705     faster code anyway.
1708 nigel 45 Version 3.1 09-Feb-00
1709     ---------------------
1711     The only change in this release is the fixing of some bugs in Makefile.in for
1712     the "install" target:
1714     (1) It was failing to install pcreposix.h.
1716     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
1719 nigel 43 Version 3.0 01-Feb-00
1720     ---------------------
1721 nigel 41
1722     1. Add support for the /+ modifier to perltest (to output $` like it does in
1723     pcretest).
1725     2. Add support for the /g modifier to perltest.
1727     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
1728     matches null strings.
1730     4. Fix perltest so that it doesn't do unwanted things when fed an empty
1731     pattern. Perl treats empty patterns specially - it reuses the most recent
1732     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
1733     effect.
1735     5. The POSIX interface was broken in that it was just handing over the POSIX
1736     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
1737     required a bigger vector, with some working space on the end. This means that
1738     the POSIX wrapper now has to get and free some memory, and copy the results.
1740 nigel 43 6. Added some simple autoconf support, placing the test data and the
1741     documentation in separate directories, re-organizing some of the
1742     information files, and making it build pcre-config (a GNU standard). Also added
1743     libtool support for building PCRE as a shared library, which is now the
1744     default.
1745 nigel 41
1746 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
1747     09 are not valid octal constants. Single digits will be used for minor values
1748     less than 10.
1750     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
1751     existing programs that set these in the POSIX interface can use PCRE without
1752     modification.
1754     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
1755     return all that pcre_info() returns, plus additional data. The pcre_info()
1756     function is retained for compatibility, but is considered to be obsolete.
1758     10. Added experimental recursion feature (?R) to handle one common case that
1759     Perl 5.6 will be able to do with (?p{...}).
1761     11. Added support for POSIX character classes like [:alpha:], which Perl is
1762     adopting.
1765 nigel 39 Version 2.08 31-Aug-99
1766     ----------------------
1768     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
1769     trying to match at the startoffset position, but instead was moving forward to
1770     the next newline as if a previous match had failed.
1772     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
1773     and could get into a loop if a null string was matched other than at the start
1774     of the subject.
1776     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
1777     be distinguished at compile time, and for completeness also added PCRE_DATE.
1779     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
1780     in GnuWin32 environments.
1783 nigel 37 Version 2.07 29-Jul-99
1784     ----------------------
1786     1. The documentation is now supplied in plain text form and HTML as well as in
1787     the form of man page sources.
1789     2. C++ compilers don't like assigning (void *) values to other pointer types.
1790     In particular this affects malloc(). Although there is no problem in Standard
1791     C, I've put in casts to keep C++ compilers happy.
1793     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
1794     should be (const char *).
1796     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
1797     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
1798     However, I haven't made this a standard facility. The documentation doesn't
1799     mention it, and the Makefile doesn't support it.
1801     5. The Makefile now contains an "install" target, with editable destinations at
1802     the top of the file. The pcretest program is not installed.
1804     6. pgrep -V now gives the PCRE version number and date.
1806     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
1807     causing the entire string to be ignored, instead of just the last character.
1809     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
1810     non-matching string, it can take a very, very long time, even for strings of
1811     quite modest length, because of the nested recursion. PCRE now does better in
1812     some of these cases. It does this by remembering the last required literal
1813     character in the pattern, and pre-searching the subject to ensure it is present
1814     before running the real match. In other words, it applies a heuristic to detect
1815     some types of certain failure quickly, and in the above example, if presented
1816     with a string that has no trailing " it gives "no match" very quickly.
1818     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
1819     other alternatives are tried instead.
1822 nigel 35 Version 2.06 09-Jun-99
1823     ----------------------
1825     1. Change pcretest's output for amount of store used to show just the code
1826     space, because the remainder (the data block) varies in size between 32-bit and
1827     64-bit systems.
1829     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
1830     start matching at. This allows lookbehinds to work when searching for multiple
1831     occurrences in a string.
1833     3. Added additional options to pcretest for testing multiple occurrences:
1835     /+ outputs the rest of the string that follows a match
1836     /g loops for multiple occurrences, using the new startoffset argument
1837     /G loops for multiple occurrences by passing an incremented pointer
1839     4. PCRE wasn't doing the "first character" optimization for patterns starting
1840     with \b or \B, though it was doing it for other lookbehind assertions. That is,
1841     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
1842     the letter 'x'. On long subject strings, this gives a significant speed-up.
1845 nigel 33 Version 2.05 21-Apr-99
1846     ----------------------
1848     1. Changed the type of magic_number from int to long int so that it works
1849     properly on 16-bit systems.
1851     2. Fixed a bug which caused patterns starting with .* not to work correctly
1852     when the subject string contained newline characters. PCRE was assuming
1853     anchoring for such patterns in all cases, which is not correct because .* will
1854     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
1855     DOTALL is set at top level; otherwise it knows that patterns starting with .*
1856     must be retried after every newline in the subject.
1859 nigel 31 Version 2.04 18-Feb-99
1860     ----------------------
1862     1. For parenthesized subpatterns with repeats whose minimum was zero, the
1863     computation of the store needed to hold the pattern was incorrect (too large).
1864     If such patterns were nested a few deep, this could multiply and become a real
1865     problem.
1867     2. Added /M option to pcretest to show the memory requirement of a specific
1868     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
1870     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
1871     compiled in such a way that the backtracking after subsequent failure was
1872     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
1873     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
1876 nigel 29 Version 2.03 02-Feb-99
1877     ----------------------
1879     1. Fixed typo and small mistake in man page.
1881 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
1882     LICENCE file containing the conditions.
1883 nigel 29
1884     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
1885     Perl, that is the internal \ allows the delimiter to be included in the
1886     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
1887     the final delimiter, add \ to the end of the pattern (to test the error).
1889     4. Added the convenience functions for extracting substrings after a successful
1890     match. Updated pcretest to make it able to test these functions.
1893 nigel 27 Version 2.02 14-Jan-99
1894     ----------------------
1896     1. Initialized the working variables associated with each extraction so that
1897     their saving and restoring doesn't refer to uninitialized store.
1899     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
1900     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
1901     fix the problem.
1903     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
1904     calls, and wasn't printing the correct value for compiling calls. Increased the
1905     default value of LOOPREPEAT, and the number of significant figures in the
1906     times.
1908     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
1910     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
1911     a building problem on Windows NT with a FAT file system.
1914 nigel 25 Version 2.01 21-Oct-98
1915     ----------------------
1917     1. Changed the API for pcre_compile() to allow for the provision of a pointer
1918     to character tables built by pcre_maketables() in the current locale. If NULL
1919     is passed, the default tables are used.
1922 nigel 23 Version 2.00 24-Sep-98
1923 nigel 21 ----------------------
1925 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
1926     it any more.
1928     2. Allow quantification of (?>) groups, and make it work correctly.
1930     3. The first character computation wasn't working for (?>) groups.
1932     4. Correct the implementation of \Z (it is permitted to match on the \n at the
1933     end of the subject) and add 5.005's \z, which really does match only at the
1934     very end of the subject.
1936     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
1938     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
1939     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
1940     localized options. All options to pcre_study() were also removed.
1942     7. Add other new features from 5.005:
1944     $(?<= positive lookbehind
1945     $(?<! negative lookbehind
1946     (?imsx-imsx) added the unsetting capability
1947     such a setting is global if at outer level; local otherwise
1948     (?imsx-imsx:) non-capturing groups with option setting
1949     (?(cond)re|re) conditional pattern matching
1951     A backreference to itself in a repeated group matches the previous
1952     captured string.
1954     8. General tidying up of studying (both automatic and via "study")
1955     consequential on the addition of new assertions.
1957     9. As in 5.005, unlimited repeated groups that could match an empty substring
1958     are no longer faulted at compile time. Instead, the loop is forcibly broken at
1959     runtime if any iteration does actually match an empty substring.
1961     10. Include the RunTest script in the distribution.
1963     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
1964     discrepancies, some of which were old and were also with respect to 5.004. They
1965     have now been fixed.
1968     Version 1.09 28-Apr-98
1969     ----------------------
1971 nigel 21 1. A negated single character class followed by a quantifier with a minimum
1972     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
1973     program crashes, or just wrong answers. This did not apply to negated classes
1974     containing more than one character, or to minima other than one.
1977 nigel 19 Version 1.08 27-Mar-98
1978     ----------------------
1980     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
1982     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
1983     latter must appear before anything that relies on it in the pattern.
1986 nigel 17 Version 1.07 16-Feb-98
1987     ----------------------
1989     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
1990     repeat of a potentially empty string).
1993 nigel 15 Version 1.06 23-Jan-98
1994     ----------------------
1996     1. Added Markus Oberhumer's little patches for C++.
1998     2. Literal strings longer than 255 characters were broken.
2001 nigel 13 Version 1.05 23-Dec-97
2002     ----------------------
2004     1. Negated character classes containing more than one character were failing if
2005     PCRE_CASELESS was set at run time.
2008 nigel 11 Version 1.04 19-Dec-97
2009     ----------------------
2011     1. Corrected the man page, where some "const" qualifiers had been omitted.
2013     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2014     input syntax.
2016     3. Fixed memory leak which occurred when a regex with back references was
2017     matched with an offsets vector that wasn't big enough. The temporary memory
2018     that is used in this case wasn't being freed if the match failed.
2020     4. Tidied pcretest to ensure it frees memory that it gets.
2022     5. Temporary memory was being obtained in the case where the passed offsets
2023     vector was exactly big enough.
2025     6. Corrected definition of offsetof() from change 5 below.
2027     7. I had screwed up change 6 below and broken the rules for the use of
2028     setjmp(). Now fixed.
2031 nigel 9 Version 1.03 18-Dec-97
2032     ----------------------
2034     1. A erroneous regex with a missing opening parenthesis was correctly
2035     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2036     on some systems.
2038     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2039     it was reported that one broken compiler failed on the former because "code" is
2040     also an independent variable.
2042     3. The erroneous regex a[]b caused an array overrun reference.
2044     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2045     fail on data ending with that character. (It was going on too far, and checking
2046     the next character, typically a binary zero.) This was specific to the
2047     optimized code for single-character negative classes.
2049     5. Added a contributed patch from the TIN world which does the following:
2051     + Add an undef for memmove, in case the the system defines a macro for it.
2053     + Add a definition of offsetof(), in case there isn't one. (I don't know
2054     the reason behind this - offsetof() is part of the ANSI standard - but
2055     it does no harm).
2057     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2058     most of the places where whitespace preceded '#'. I have given up and
2059     allowed the remaining 2 cases to be at the margin.
2061     + Rename some variables in pcre to eliminate shadowing. This seems very
2062     pedantic, but does no harm, of course.
2064     6. Moved the call to setjmp() into its own function, to get rid of warnings
2065     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2067     7. Constructs such as \d{8,} were compiling into the equivalent of
2068 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2069 nigel 9 outcome, but in this particular case used more store than had been allocated,
2070     which caused the bug to be discovered because it threw up an internal error.
2072     8. The debugging code in both pcre and pcretest for outputting the compiled
2073     form of a regex was going wrong in the case of back references followed by
2074     curly-bracketed repeats.
2077 nigel 7 Version 1.02 12-Dec-97
2078     ----------------------
2080     1. Typos in pcre.3 and comments in the source fixed.
2082     2. Applied a contributed patch to get rid of places where it used to remove
2083     'const' from variables, and fixed some signed/unsigned and uninitialized
2084     variable warnings.
2086     3. Added the "runtest" target to Makefile.
2088     4. Set default compiler flag to -O2 rather than just -O.
2091 nigel 5 Version 1.01 19-Nov-97
2092     ----------------------
2094     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2095     like /([ab]*)*/, that is, for classes with more than one character in them.
2097     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2098     as /((?>a*))*/ (a PCRE_EXTRA facility).
2101     Version 1.00 18-Nov-97
2102     ----------------------
2104     1. Added compile-time macros to support systems such as SunOS4 which don't have
2105     memmove() or strerror() but have other things that can be used instead.
2107     2. Arranged that "make clean" removes the executables.
2110 nigel 3 Version 0.99 27-Oct-97
2111     ----------------------
2113     1. Fixed bug in code for optimizing classes with only one character. It was
2114     initializing a 32-byte map regardless, which could cause it to run off the end
2115     of the memory it had got.
2117     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
2120     Version 0.98 22-Oct-97
2121     ----------------------
2123     1. Fixed bug in code for handling temporary memory usage when there are more
2124     back references than supplied space in the ovector. This could cause segfaults.
2127     Version 0.97 21-Oct-97
2128     ----------------------
2130     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
2132     2. Optimized negated single characters not to use a bit map.
2134     3. Brought error texts together as macro definitions; clarified some of them;
2135     fixed one that was wrong - it said "range out of order" when it meant "invalid
2136     escape sequence".
2138     4. Changed some char * arguments to const char *.
2140     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
2142     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
2143     pcretest.
2146     Version 0.96 16-Oct-97
2147     ----------------------
2149     1. Added a simple "pgrep" utility to the distribution.
2151     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
2152     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
2153     where "ddd" means "one or more decimal digits".
2155     3. Fixed serious bug. If a pattern had a back reference, but the call to
2156     pcre_exec() didn't supply a large enough ovector to record the related
2157     identifying subpattern, the match always failed. PCRE now remembers the number
2158     of the largest back reference, and gets some temporary memory in which to save
2159     the offsets during matching if necessary, in order to ensure that
2160     backreferences always work.
2162     4. Increased the compatibility with Perl in a number of ways:
2164     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
2165     to request this handling. The option can be set at compile or exec time.
2167     (b) $ matches before a terminating newline by default; an option
2168     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
2169     mode). The option can be set at compile or exec time.
2171     (c) The handling of \ followed by a digit other than 0 is now supposed to be
2172     the same as Perl's. If the decimal number it represents is less than 10
2173     or there aren't that many previous left capturing parentheses, an octal
2174     escape is read. Inside a character class, it's always an octal escape,
2175     even if it is a single digit.
2177     (d) An escaped but undefined alphabetic character is taken as a literal,
2178     unless PCRE_EXTRA is set. Currently this just reserves the remaining
2179     escapes.
2181     (e) {0} is now permitted. (The previous item is removed from the compiled
2182     pattern).
2184     5. Changed all the names of code files so that the basic parts are no longer
2185     than 10 characters, and abolished the teeny "globals.c" file.
2187     6. Changed the handling of character classes; they are now done with a 32-byte
2188     bit map always.
2190     7. Added the -d and /D options to pcretest to make it possible to look at the
2191     internals of compilation without having to recompile pcre.
2194     Version 0.95 23-Sep-97
2195     ----------------------
2197     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
2198     \x20 at the start of a run of normal characters. These were being treated as
2199     real characters, instead of the source characters being re-checked.
2202     Version 0.94 18-Sep-97
2203     ----------------------
2205     1. The functions are now thread-safe, with the caveat that the global variables
2206     containing pointers to malloc() and free() or alternative functions are the
2207     same for all threads.
2209     2. Get pcre_study() to generate a bitmap of initial characters for non-
2210     anchored patterns when this is possible, and use it if passed to pcre_exec().
2213     Version 0.93 15-Sep-97
2214     ----------------------
2216     1. /(b)|(:+)/ was computing an incorrect first character.
2218     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
2219     but not actually doing anything yet.
2221     3. Treat "-" characters in classes that cannot be part of ranges as literals,
2222     as Perl does (e.g. [-az] or [az-]).
2224     4. Set the anchored flag if a branch starts with .* or .*? because that tests
2225     all possible positions.
2227     5. Split up into different modules to avoid including unneeded functions in a
2228     compiled binary. However, compile and exec are still in one module. The "study"
2229     function is split off.
2231     6. The character tables are now in a separate module whose source is generated
2232     by an auxiliary program - but can then be edited by hand if required. There are
2233     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
2234     toupper() in the code.
2236     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
2237     make them global. Abolish the function for setting them, as the caller can now
2238     set them directly.
2241     Version 0.92 11-Sep-97
2242     ----------------------
2244     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
2245     (e.g. /a{1,3}/) was broken (I mis-optimized it).
2247     2. Caseless matching was not working in character classes if the characters in
2248     the pattern were in upper case.
2250     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
2252     4. Make PCRE_ANCHORED public and accept as a compile option.
2254     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
2255     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
2256     pass them.
2258     6. Give an error if bad option bits passed at compile or run time.
2260     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
2261     pcretest to cause it to pass that flag.
2263     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
2264     options, and the first character, if set.
2266     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
2269     Version 0.91 10-Sep-97
2270     ----------------------
2272     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
2273     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
2275     2. PCRE was looping on encountering an indefinitely repeated back reference to
2276     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
2277     Perl does - treats the match as successful.
2279     ****

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