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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 6.6 06-Feb-06
5    ---------------------
7     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
8        in pcreposix.h. I have copied the definition from pcre.h.
10     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
11        because pcre.h is no longer a built file.
13     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
14        not normally included in the compiled code.
17    Version 6.5 01-Feb-06
18    ---------------------
20     1. When using the partial match feature with pcre_dfa_exec(), it was not
21        anchoring the second and subsequent partial matches at the new starting
22        point. This could lead to incorrect results. For example, with the pattern
23        /1234/, partially matching against "123" and then "a4" gave a match.
25     2. Changes to pcregrep:
27        (a) All non-match returns from pcre_exec() were being treated as failures
28            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
29            error message is output. Some extra information is given for the
31            probably the only errors that are likely to be caused by users (by
32            specifying a regex that has nested indefinite repeats, for instance).
33            If there are more than 20 of these errors, pcregrep is abandoned.
35        (b) A binary zero was treated as data while matching, but terminated the
36            output line if it was written out. This has been fixed: binary zeroes
37            are now no different to any other data bytes.
39        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
40            used to set a locale for matching. The --locale=xxxx long option has
41            been added (no short equivalent) to specify a locale explicitly on the
42            pcregrep command, overriding the environment variables.
44        (d) When -B was used with -n, some line numbers in the output were one less
45            than they should have been.
47        (e) Added the -o (--only-matching) option.
49        (f) If -A or -C was used with -c (count only), some lines of context were
50            accidentally printed for the final match.
52        (g) Added the -H (--with-filename) option.
54        (h) The combination of options -rh failed to suppress file names for files
55            that were found from directory arguments.
57        (i) Added the -D (--devices) and -d (--directories) options.
59        (j) Added the -F (--fixed-strings) option.
61        (k) Allow "-" to be used as a file name for -f as well as for a data file.
63        (l) Added the --colo(u)r option.
65        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
66            is not present by default.
68     3. A nasty bug was discovered in the handling of recursive patterns, that is,
69        items such as (?R) or (?1), when the recursion could match a number of
70        alternatives. If it matched one of the alternatives, but subsequently,
71        outside the recursion, there was a failure, the code tried to back up into
72        the recursion. However, because of the way PCRE is implemented, this is not
73        possible, and the result was an incorrect result from the match.
75        In order to prevent this happening, the specification of recursion has
76        been changed so that all such subpatterns are automatically treated as
77        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
79     4. I had overlooked the fact that, in some locales, there are characters for
80        which isalpha() is true but neither isupper() nor islower() are true. In
81        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
82        and ordfeminine) are like this. This affected the treatment of \w and \W
83        when they appeared in character classes, but not when they appeared outside
84        a character class. The bit map for "word" characters is now created
85        separately from the results of isalnum() instead of just taking it from the
86        upper, lower, and digit maps. (Plus the underscore character, of course.)
88     5. The above bug also affected the handling of POSIX character classes such as
89        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
90        permanent tables. Instead, the bit maps for such a class were previously
91        created as the appropriate unions of the upper, lower, and digit bitmaps.
92        Now they are created by subtraction from the [[:word:]] class, which has
93        its own bitmap.
95     6. The [[:blank:]] character class matches horizontal, but not vertical space.
96        It is created by subtracting the vertical space characters (\x09, \x0a,
97        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
98        subtraction was done in the overall bitmap for a character class, meaning
99        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
100        be recognized. This bug has been fixed.
102     7. Patches from the folks at Google:
104          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
105          real life, but is still worth protecting against".
107          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
108          regular expressions".
110          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
111          have it.
113          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
114          "configure" and the latter not, in order to fix a problem somebody had
115          with compiling the Arg class on HP-UX.
117          (e) Improve the error-handling of the C++ wrapper a little bit.
119          (f) New tests for checking recursion limiting.
121     8. The pcre_memmove() function, which is used only if the environment does not
122        have a standard memmove() function (and is therefore rarely compiled),
123        contained two bugs: (a) use of int instead of size_t, and (b) it was not
124        returning a result (though PCRE never actually uses the result).
126     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
127        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
128        returned instead of calling malloc() with an overflowing number that would
129        most likely cause subsequent chaos.
131    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
133    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
134        with this option is matched, the nmatch and pmatch options of regexec() are
135        ignored.
137    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
138        provided in case anyone wants to the the POSIX interface with UTF-8
139        strings.
141    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
142        C++ linking (needed for some HP-UX environments).
144    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
145        (unused parameter) and in the pcre_printint() function (omitted "default"
146        switch label when the default is to do nothing).
148    15. Added some code to make it possible, when PCRE is compiled as a C++
149        library, to replace subject pointers for pcre_exec() with a smart pointer
150        class, thus making it possible to process discontinuous strings.
152    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
153        much the same function. They were added by different people who were trying
154        to make PCRE easy to compile on non-Unix systems. It has been suggested
155        that PCRE_EXPORT be abolished now that there is more automatic apparatus
156        for compiling on Windows systems. I have therefore replaced it with
157        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
158        defaults to "extern" for C or "extern C" for C++, which works fine on
159        Unix-like systems. It is now possible to override the value of PCRE_DATA_
160        SCOPE with something explicit in config.h. In addition:
162        (a) pcreposix.h still had just "extern" instead of either of these macros;
163            I have replaced it with PCRE_DATA_SCOPE.
165        (b) Functions such as _pcre_xclass(), which are internal to the library,
166            but external in the C sense, all had PCRE_EXPORT in their definitions.
167            This is apparently wrong for the Windows case, so I have removed it.
168            (It makes no difference on Unix-like systems.)
170    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
171        of recursive calls to match(). This is different to MATCH_LIMIT because
172        that limits the total number of calls to match(), not all of which increase
173        the depth of recursion. Limiting the recursion depth limits the amount of
174        stack (or heap if NO_RECURSE is set) that is used. The default can be set
175        when PCRE is compiled, and changed at run time. A patch from Google adds
176        this functionality to the C++ interface.
178    18. Changes to the handling of Unicode character properties:
180        (a) Updated the table to Unicode 4.1.0.
182        (b) Recognize characters that are not in the table as "Cn" (undefined).
184        (c) I revised the way the table is implemented to a much improved format
185            which includes recognition of ranges. It now supports the ranges that
186            are defined in UnicodeData.txt, and it also amalgamates other
187            characters into ranges. This has reduced the number of entries in the
188            table from around 16,000 to around 3,000, thus reducing its size
189            considerably. I realized I did not need to use a tree structure after
190            all - a binary chop search is just as efficient. Having reduced the
191            number of entries, I extended their size from 6 bytes to 8 bytes to
192            allow for more data.
194        (d) Added support for Unicode script names via properties such as \p{Han}.
196    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
197        matching that character.
199    20. When matching a repeated Unicode property with a minimum greater than zero,
200        (for example \pL{2,}), PCRE could look past the end of the subject if it
201        reached it while seeking the minimum number of characters. This could
202        happen only if some of the characters were more than one byte long, because
203        there is a check for at least the minimum number of bytes.
205    21. Refactored the implementation of \p and \P so as to be more general, to
206        allow for more different types of property in future. This has changed the
207        compiled form incompatibly. Anybody with saved compiled patterns that use
208        \p or \P will have to recompile them.
210    22. Added "Any" and "L&" to the supported property types.
212    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
213        but give a compile time error if the value is greater than 0xff.
215    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
216        accidentally not being installed or uninstalled.
218    25. The pcre.h file was built from pcre.h.in, but the only changes that were
219        made were to insert the current release number. This seemed silly, because
220        it made things harder for people building PCRE on systems that don't run
221        "configure". I have turned pcre.h into a distributed file, no longer built
222        by "configure", with the version identification directly included. There is
223        no longer a pcre.h.in file.
225        However, this change necessitated a change to the pcre-config script as
226        well. It is built from pcre-config.in, and one of the substitutions was the
227        release number. I have updated configure.ac so that ./configure now finds
228        the release number by grepping pcre.h.
230    26. Added the ability to run the tests under valgrind.
233    Version 6.4 05-Sep-05
234    ---------------------
236     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
237        "--" to be printed when multiple files were scanned, even when none of the
238        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
239        consider it to be a bug, and have restored the previous behaviour.
241     2. A couple of code tidies to get rid of compiler warnings.
243     3. The pcretest program used to cheat by referring to symbols in the library
244        whose names begin with _pcre_. These are internal symbols that are not
245        really supposed to be visible externally, and in some environments it is
246        possible to suppress them. The cheating is now confined to including
247        certain files from the library's source, which is a bit cleaner.
249     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
250        file's purpose clearer.
252     5. Reorganized pcre_ucp_findchar().
255    Version 6.3 15-Aug-05
256    ---------------------
258     1. The file libpcre.pc.in did not have general read permission in the tarball.
260     2. There were some problems when building without C++ support:
262        (a) If C++ support was not built, "make install" and "make test" still
263            tried to test it.
265        (b) There were problems when the value of CXX was explicitly set. Some
266            changes have been made to try to fix these, and ...
268        (c) --disable-cpp can now be used to explicitly disable C++ support.
270        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
271            backslash in a target when C++ was disabled. This confuses some
272            versions of "make", apparently. Using an intermediate variable solves
273            this. (Same for CPP_LOBJ.)
275     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
276        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
277        necessary on certain architectures.
279     4. Added a setting of -export-symbols-regex to the link command to remove
280        those symbols that are exported in the C sense, but actually are local
281        within the library, and not documented. Their names all begin with
282        "_pcre_". This is not a perfect job, because (a) we have to except some
283        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
284        available (and never for static libraries). I have made a note to try to
285        find a way round (a) in the future.
288    Version 6.2 01-Aug-05
289    ---------------------
291     1. There was no test for integer overflow of quantifier values. A construction
292        such as {1111111111111111} would give undefined results. What is worse, if
293        a minimum quantifier for a parenthesized subpattern overflowed and became
294        negative, the calculation of the memory size went wrong. This could have
295        led to memory overwriting.
297     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
299     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
300        operating environments where this matters.
302     4. Applied Giuseppe Maxia's patch to add additional features for controlling
303        PCRE options from within the C++ wrapper.
305     5. Named capturing subpatterns were not being correctly counted when a pattern
306        was compiled. This caused two problems: (a) If there were more than 100
307        such subpatterns, the calculation of the memory needed for the whole
308        compiled pattern went wrong, leading to an overflow error. (b) Numerical
309        back references of the form \12, where the number was greater than 9, were
310        not recognized as back references, even though there were sufficient
311        previous subpatterns.
313     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
314        versions of gcc, e.g. 2.95.4.
317    Version 6.1 21-Jun-05
318    ---------------------
320     1. There was one reference to the variable "posix" in pcretest.c that was not
321        surrounded by "#if !defined NOPOSIX".
323     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
324        the cross-check on the old pcre_info() function, for the benefit of the
325        cut-down version of PCRE that is currently imported into Exim.
327     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
328        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
329        patterns that start (?i) but I don't think that matters. The use of (?i) is
330        just an example; this all applies to the other options as well.
332     4. Since libtool seems to echo the compile commands it is issuing, the output
333        from "make" can be reduced a bit by putting "@" in front of each libtool
334        compile command.
336     5. Patch from the folks at Google for configure.in to be a bit more thorough
337        in checking for a suitable C++ installation before trying to compile the
338        C++ stuff. This should fix a reported problem when a compiler was present,
339        but no suitable headers.
341     6. The man pages all had just "PCRE" as their title. I have changed them to
342        be the relevant file name. I have also arranged that these names are
343        retained in the file doc/pcre.txt, which is a concatenation in text format
344        of all the man pages except the little individual ones for each function.
346     7. The NON-UNIX-USE file had not been updated for the different set of source
347        files that come with release 6. I also added a few comments about the C++
348        wrapper.
351    Version 6.0 07-Jun-05
352    ---------------------
354     1. Some minor internal re-organization to help with my DFA experiments.
356     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
357        didn't matter for the library itself when fully configured, but did matter
358        when compiling without UCP support, or within Exim, where the ucp files are
359        not imported.
361     3. Refactoring of the library code to split up the various functions into
362        different source modules. The addition of the new DFA matching code (see
363        below) to a single monolithic source would have made it really too
364        unwieldy, quite apart from causing all the code to be include in a
365        statically linked application, when only some functions are used. This is
366        relevant even without the DFA addition now that patterns can be compiled in
367        one application and matched in another.
369        The downside of splitting up is that there have to be some external
370        functions and data tables that are used internally in different modules of
371        the library but which are not part of the API. These have all had their
372        names changed to start with "_pcre_" so that they are unlikely to clash
373        with other external names.
375     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
376        a different (DFA) algorithm. Although it is slower than the original
377        function, it does have some advantages for certain types of matching
378        problem.
380     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
381        including restarting after a partial match.
383     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
384        defined when compiling for Windows was sent to me. I have put it into the
385        code, though I have no means of testing or verifying it.
387     7. Added the pcre_refcount() auxiliary function.
389     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
390        match before or at the first newline in the subject string. In pcretest,
391        the /f option on a pattern can be used to set this.
393     9. A repeated \w when used in UTF-8 mode with characters greater than 256
394        would behave wrongly. This has been present in PCRE since release 4.0.
396    10. A number of changes to the pcregrep command:
398        (a) Refactored how -x works; insert ^(...)$ instead of setting
399            PCRE_ANCHORED and checking the length, in preparation for adding
400            something similar for -w.
402        (b) Added the -w (match as a word) option.
404        (c) Refactored the way lines are read and buffered so as to have more
405            than one at a time available.
407        (d) Implemented a pcregrep test script.
409        (e) Added the -M (multiline match) option. This allows patterns to match
410            over several lines of the subject. The buffering ensures that at least
411            8K, or the rest of the document (whichever is the shorter) is available
412            for matching (and similarly the previous 8K for lookbehind assertions).
414        (f) Changed the --help output so that it now says
416              -w, --word-regex(p)
418            instead of two lines, one with "regex" and the other with "regexp"
419            because that confused at least one person since the short forms are the
420            same. (This required a bit of code, as the output is generated
421            automatically from a table. It wasn't just a text change.)
423        (g) -- can be used to terminate pcregrep options if the next thing isn't an
424            option but starts with a hyphen. Could be a pattern or a path name
425            starting with a hyphen, for instance.
427        (h) "-" can be given as a file name to represent stdin.
429        (i) When file names are being printed, "(standard input)" is used for
430            the standard input, for compatibility with GNU grep. Previously
431            "<stdin>" was used.
433        (j) The option --label=xxx can be used to supply a name to be used for
434            stdin when file names are being printed. There is no short form.
436        (k) Re-factored the options decoding logic because we are going to add
437            two more options that take data. Such options can now be given in four
438            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
440        (l) Added the -A, -B, and -C options for requesting that lines of context
441            around matches be printed.
443        (m) Added the -L option to print the names of files that do not contain
444            any matching lines, that is, the complement of -l.
446        (n) The return code is 2 if any file cannot be opened, but pcregrep does
447            continue to scan other files.
449        (o) The -s option was incorrectly implemented. For compatibility with other
450            greps, it now suppresses the error message for a non-existent or non-
451            accessible file (but not the return code). There is a new option called
452            -q that suppresses the output of matching lines, which was what -s was
453            previously doing.
455        (p) Added --include and --exclude options to specify files for inclusion
456            and exclusion when recursing.
458    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
459        Hopefully, it now does.
461    12. Missing cast in pcre_study().
463    13. Added an "uninstall" target to the makefile.
465    14. Replaced "extern" in the function prototypes in Makefile.in with
466        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
467        world, but is set differently for Windows.
469    15. Added a second compiling function called pcre_compile2(). The only
470        difference is that it has an extra argument, which is a pointer to an
471        integer error code. When there is a compile-time failure, this is set
472        non-zero, in addition to the error test pointer being set to point to an
473        error message. The new argument may be NULL if no error number is required
474        (but then you may as well call pcre_compile(), which is now just a
475        wrapper). This facility is provided because some applications need a
476        numeric error indication, but it has also enabled me to tidy up the way
477        compile-time errors are handled in the POSIX wrapper.
479    16. Added VPATH=.libs to the makefile; this should help when building with one
480        prefix path and installing with another. (Or so I'm told by someone who
481        knows more about this stuff than I do.)
483    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
484        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
485        match everything, including newlines. This is not POSIX-compatible, but
486        somebody wanted the feature. From pcretest it can be activated by using
487        both the P and the s flags.
489    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
491    19. libpcre.pc was being incorrectly installed as executable.
493    20. A couple of places in pcretest check for end-of-line by looking for '\n';
494        it now also looks for '\r' so that it will work unmodified on Windows.
496    21. Added Google's contributed C++ wrapper to the distribution.
498    22. Added some untidy missing memory free() calls in pcretest, to keep
499        Electric Fence happy when testing.
503    Version 5.0 13-Sep-04
504    ---------------------
506     1. Internal change: literal characters are no longer packed up into items
507        containing multiple characters in a single byte-string. Each character
508        is now matched using a separate opcode. However, there may be more than one
509        byte in the character in UTF-8 mode.
511     2. The pcre_callout_block structure has two new fields: pattern_position and
512        next_item_length. These contain the offset in the pattern to the next match
513        item, and its length, respectively.
515     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
516        insertion of callouts before each pattern item. Added the /C option to
517        pcretest to make use of this.
519     4. On the advice of a Windows user, the lines
521          #if defined(_WIN32) || defined(WIN32)
522          _setmode( _fileno( stdout ), 0x8000 );
523          #endif  /* defined(_WIN32) || defined(WIN32) */
525        have been added to the source of pcretest. This apparently does useful
526        magic in relation to line terminators.
528     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
529        for the benefit of those environments where the "b" makes a difference.
531     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
532        to know about it. I have put a hack into configure.in that adds in code
533        to set GCC=yes if CC=icc. This seems to end up at a point in the
534        generated configure script that is early enough to affect the setting of
535        compiler options, which is what is needed, but I have no means of testing
536        whether it really works. (The user who reported this had patched the
537        generated configure script, which of course I cannot do.)
539        LATER: After change 22 below (new libtool files), the configure script
540        seems to know about icc (and also ecc). Therefore, I have commented out
541        this hack in configure.in.
543     7. Added support for pkg-config (2 patches were sent in).
545     8. Negated POSIX character classes that used a combination of internal tables
546        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
547        [[:^ascii]]. Typically, they would match almost any characters. The other
548        POSIX classes were not broken in this way.
550     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
551        to find the match, as PCRE was deluded into thinking that the match had to
552        start at the start point or following a newline. The same bug applied to
553        patterns with negative forward assertions or any backward assertions
554        preceding ".*" at the start, unless the pattern required a fixed first
555        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
557    10. In UTF-8 mode, when moving forwards in the subject after a failed match
558        starting at the last subject character, bytes beyond the end of the subject
559        string were read.
561    11. Renamed the variable "class" as "classbits" to make life easier for C++
562        users. (Previously there was a macro definition, but it apparently wasn't
563        enough.)
565    12. Added the new field "tables" to the extra data so that tables can be passed
566        in at exec time, or the internal tables can be re-selected. This allows
567        a compiled regex to be saved and re-used at a later time by a different
568        program that might have everything at different addresses.
570    13. Modified the pcre-config script so that, when run on Solaris, it shows a
571        -R library as well as a -L library.
573    14. The debugging options of pcretest (-d on the command line or D on a
574        pattern) showed incorrect output for anything following an extended class
575        that contained multibyte characters and which was followed by a quantifier.
577    15. Added optional support for general category Unicode character properties
578        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
579        support. It adds about 90K to the size of the library. The meanings of the
580        inbuilt class escapes such as \d and \s have NOT been changed.
582    16. Updated pcredemo.c to include calls to free() to release the memory for the
583        compiled pattern.
585    17. The generated file chartables.c was being created in the source directory
586        instead of in the building directory. This caused the build to fail if the
587        source directory was different from the building directory, and was
588        read-only.
590    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
591        file. No doubt somebody will tell me if they don't make sense... Also added
592        Dan Mooney's comments about building on OpenVMS.
594    19. Added support for partial matching via the PCRE_PARTIAL option for
595        pcre_exec() and the \P data escape in pcretest.
597    20. Extended pcretest with 3 new pattern features:
599        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
600              write the compiled pattern to the file whose name is "rest-of-line".
601              This is a straight binary dump of the data, with the saved pointer to
602              the character tables forced to be NULL. The study data, if any, is
603              written too. After writing, pcretest reads a new pattern.
605        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
606              compiled pattern from the given file. There must not be any
607              occurrences of "<" in the file name (pretty unlikely); if there are,
608              pcretest will instead treat the initial "<" as a pattern delimiter.
609              After reading in the pattern, pcretest goes on to read data lines as
610              usual.
612        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
613              and 16-bit fields in a compiled pattern, to simulate a pattern that
614              was compiled on a host of opposite endianness.
616    21. The pcre-exec() function can now cope with patterns that were compiled on
617        hosts of opposite endianness, with this restriction:
619          As for any compiled expression that is saved and used later, the tables
620          pointer field cannot be preserved; the extra_data field in the arguments
621          to pcre_exec() should be used to pass in a tables address if a value
622          other than the default internal tables were used at compile time.
624    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
625        now diagnosed as an error. Previously, most of the time, a negative number
626        would have been treated as zero, but if in addition "ovector" was passed as
627        NULL, a crash could occur.
629    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
630        new versions from the libtool 1.5 distribution (the last one is a copy of
631        a file called libtool.m4). This seems to have fixed the need to patch
632        "configure" to support Darwin 1.3 (which I used to do). However, I still
633        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
634        workstation).
636    24. Changed the PCRE licence to be the more standard "BSD" licence.
639    Version 4.5 01-Dec-03
640    ---------------------
642     1. There has been some re-arrangement of the code for the match() function so
643        that it can be compiled in a version that does not call itself recursively.
644        Instead, it keeps those local variables that need separate instances for
645        each "recursion" in a frame on the heap, and gets/frees frames whenever it
646        needs to "recurse". Keeping track of where control must go is done by means
647        of setjmp/longjmp. The whole thing is implemented by a set of macros that
648        hide most of the details from the main code, and operates only if
649        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
650        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
651        operating.
653        To make it easier for callers to provide specially tailored get/free
654        functions for this usage, two new functions, pcre_stack_malloc, and
655        pcre_stack_free, are used. They are always called in strict stacking order,
656        and the size of block requested is always the same.
658        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
659        PCRE has been compiled to use the stack or the heap for recursion. The
660        -C option of pcretest uses this to show which version is compiled.
662        A new data escape \S, is added to pcretest; it causes the amounts of store
663        obtained and freed by both kinds of malloc/free at match time to be added
664        to the output.
666     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
667        what's available on my current Linux desktop machine.
669     3. When matching a UTF-8 string, the test for a valid string at the start has
670        been extended. If start_offset is not zero, PCRE now checks that it points
671        to a byte that is the start of a UTF-8 character. If not, it returns
672        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
673        this is necessary because there may be backward assertions in the pattern.
674        When matching the same subject several times, it may save resources to use
675        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
677     4. The code for checking the validity of UTF-8 strings has been tightened so
678        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
679        containing "overlong sequences".
681     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
682        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
683        should have been "&", but it just so happened that all the cases this let
684        through by mistake were picked up later in the function.
686     6. I had used a variable called "isblank" - this is a C99 function, causing
687        some compilers to warn. To avoid this, I renamed it (as "blankclass").
689     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
690        prompting; (b) run "./pcretest /dev/null" at the start of the test script
691        so the version is shown; (c) stop "make test" echoing "./RunTest".
693     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
695     9. The prototype for memmove() for systems that don't have it was using
696        size_t, but the inclusion of the header that defines size_t was later. I've
697        moved the #includes for the C headers earlier to avoid this.
699    10. Added some adjustments to the code to make it easier to compiler on certain
700        special systems:
702          (a) Some "const" qualifiers were missing.
703          (b) Added the macro EXPORT before all exported functions; by default this
704              is defined to be empty.
705          (c) Changed the dftables auxiliary program (that builds chartables.c) so
706              that it reads its output file name as an argument instead of writing
707              to the standard output and assuming this can be redirected.
709    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
710        class containing characters with values greater than 255, PCRE compilation
711        went into a loop.
713    12. A recursive reference to a subpattern that was within another subpattern
714        that had a minimum quantifier of zero caused PCRE to crash. For example,
715        (x(y(?2))z)? provoked this bug with a subject that got as far as the
716        recursion. If the recursively-called subpattern itself had a zero repeat,
717        that was OK.
719    13. In pcretest, the buffer for reading a data line was set at 30K, but the
720        buffer into which it was copied (for escape processing) was still set at
721        1024, so long lines caused crashes.
723    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
724        "internal error: code overflow...". This applied to any character class
725        that was followed by a possessive quantifier.
727    15. Modified the Makefile to add libpcre.la as a prerequisite for
728        libpcreposix.la because I was told this is needed for a parallel build to
729        work.
731    16. If a pattern that contained .* following optional items at the start was
732        studied, the wrong optimizing data was generated, leading to matching
733        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
734        matching string must start with a or b or c. The correct conclusion for
735        this pattern is that a match can start with any character.
738    Version 4.4 13-Aug-03
739    ---------------------
741     1. In UTF-8 mode, a character class containing characters with values between
742        127 and 255 was not handled correctly if the compiled pattern was studied.
743        In fixing this, I have also improved the studying algorithm for such
744        classes (slightly).
746     2. Three internal functions had redundant arguments passed to them. Removal
747        might give a very teeny performance improvement.
749     3. Documentation bug: the value of the capture_top field in a callout is *one
750        more than* the number of the hightest numbered captured substring.
752     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
753        in incorrectly linking with a previously installed version. They now link
754        explicitly with libpcre.la.
756     5. configure.in no longer needs to recognize Cygwin specially.
758     6. A problem in pcre.in for Windows platforms is fixed.
760     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
761        pcretest, it used to include the size of the study block as part of its
762        output. Unfortunately, the structure contains a field that has a different
763        size on different hardware architectures. This meant that the tests that
764        showed this size failed. As the block is currently always of a fixed size,
765        this information isn't actually particularly useful in pcretest output, so
766        I have just removed it.
768     8. Three pre-processor statements accidentally did not start in column 1.
769        Sadly, there are *still* compilers around that complain, even though
770        standard C has not required this for well over a decade. Sigh.
772     9. In pcretest, the code for checking callouts passed small integers in the
773        callout_data field, which is a void * field. However, some picky compilers
774        complained about the casts involved for this on 64-bit systems. Now
775        pcretest passes the address of the small integer instead, which should get
776        rid of the warnings.
778    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
779        both compile and run time, and gives an error if an invalid UTF-8 sequence
780        is found. There is a option for disabling this check in cases where the
781        string is known to be correct and/or the maximum performance is wanted.
783    11. In response to a bug report, I changed one line in Makefile.in from
785            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
786        to
787            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
789        to look similar to other lines, but I have no way of telling whether this
790        is the right thing to do, as I do not use Windows. No doubt I'll get told
791        if it's wrong...
794    Version 4.3 21-May-03
795    ---------------------
797    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
798       Makefile.
800    2. Some refactoring to improve the quality of the code:
802       (i)   The utf8_table... variables are now declared "const".
804       (ii)  The code for \cx, which used the "case flipping" table to upper case
805             lower case letters, now just substracts 32. This is ASCII-specific,
806             but the whole concept of \cx is ASCII-specific, so it seems
807             reasonable.
809       (iii) PCRE was using its character types table to recognize decimal and
810             hexadecimal digits in the pattern. This is silly, because it handles
811             only 0-9, a-f, and A-F, but the character types table is locale-
812             specific, which means strange things might happen. A private
813             table is now used for this - though it costs 256 bytes, a table is
814             much faster than multiple explicit tests. Of course, the standard
815             character types table is still used for matching digits in subject
816             strings against \d.
818       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
819             ending in _t are). So I've renamed it as ESC_tee.
821    3. The first argument for regexec() in the POSIX wrapper should have been
822       defined as "const".
824    4. Changed pcretest to use malloc() for its buffers so that they can be
825       Electric Fenced for debugging.
827    5. There were several places in the code where, in UTF-8 mode, PCRE would try
828       to read one or more bytes before the start of the subject string. Often this
829       had no effect on PCRE's behaviour, but in some circumstances it could
830       provoke a segmentation fault.
832    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
833       to try to read one or more bytes before the start of the subject string.
835    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
836       UTF-8 support could misbehave in various ways if the subject string
837       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
838       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
839       back over UTF-8 characters.)
842    Version 4.2 14-Apr-03
843    ---------------------
845    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
847    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
848         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
849         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
850         [WIN_PREFIX]: new variable, "cyg" for Cygwin
851         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
852           and BUILD_EXEEXT
853         Note: automatic setting of the BUILD variables is not yet working
854         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
855           compile-time but not at link-time
856         [LINK]: use for linking executables only
857         make different versions for Windows and non-Windows
858         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
859           libraries
860         [LINK_FOR_BUILD]: new variable
861         [OBJEXT]: use throughout
862         [EXEEXT]: use throughout
863         <winshared>: new target
864         <wininstall>: new target
865         <dftables.o>: use native compiler
866         <dftables>: use native linker
867         <install>: handle Windows platform correctly
868         <clean>: ditto
869         <check>: ditto
870         copy DLL to top builddir before testing
872       As part of these changes, -no-undefined was removed again. This was reported
873       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
874       in any case.
876    3. Some tidies to get rid of compiler warnings:
878       . In the match_data structure, match_limit was an unsigned long int, whereas
879         match_call_count was an int. I've made them both unsigned long ints.
881       . In pcretest the fact that a const uschar * doesn't automatically cast to
882         a void * provoked a warning.
884       . Turning on some more compiler warnings threw up some "shadow" variables
885         and a few more missing casts.
887    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
888       option, a class that contained a single character with a value between 128
889       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
891    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
892       option, a class that contained several characters, but with at least one
893       whose value was between 128 and 255 caused PCRE to crash.
896    Version 4.1 12-Mar-03
897    ---------------------
899    1. Compiling with gcc -pedantic found a couple of places where casts were
900    needed, and a string in dftables.c that was longer than standard compilers are
901    required to support.
903    2. Compiling with Sun's compiler found a few more places where the code could
904    be tidied up in order to avoid warnings.
906    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
907    first of these names is deprecated in the latest Autoconf in favour of the name
908    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
909    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
910    analogy I have changed it to CFLAGS_FOR_BUILD.
912    4. Added -no-undefined to the linking command in the Makefile, because this is
913    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
914    linking step for the pcreposix library.
916    5. PCRE was failing to diagnose the case of two named groups with the same
917    name.
919    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
920    literal character that is needed in the subject for a match, and scans along to
921    ensure that it is present before embarking on the full matching process. This
922    saves time in cases of nested unlimited repeats that are never going to match.
923    Problem: the scan can take a lot of time if the subject is very long (e.g.
924    megabytes), thus penalizing straightforward matches. It is now done only if the
925    amount of subject to be scanned is less than 1000 bytes.
927    7. A lesser problem with the same optimization is that it was recording the
928    first character of an anchored pattern as "needed", thus provoking a search
929    right along the subject, even when the first match of the pattern was going to
930    fail. The "needed" character is now not set for anchored patterns, unless it
931    follows something in the pattern that is of non-fixed length. Thus, it still
932    fulfils its original purpose of finding quick non-matches in cases of nested
933    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
936    Version 4.0 17-Feb-03
937    ---------------------
939    1. If a comment in an extended regex that started immediately after a meta-item
940    extended to the end of string, PCRE compiled incorrect data. This could lead to
941    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
943    2. Moved to autoconf 2.53 and libtool 1.4.2.
945    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
946    the special perltest8 script is no longer needed - all the tests can be run
947    from a single perltest script.
949    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
950    by \s. It has now been removed in PCRE. This means it isn't recognized as
951    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
952    class [:space:] *does* include VT, thereby creating a mess.
954    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
955    space and tab.
957    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
958    its new features into the main test script, reducing the number of scripts.
960    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
961    were backward compatible, and made the (?i) apply to the whole pattern, as if
962    /i were given. Now it behaves more logically, and applies the option setting
963    only to what follows. PCRE has been changed to follow suit. However, if it
964    finds options settings right at the start of the pattern, it extracts them into
965    the global options, as before. Thus, they show up in the info data.
967    8. Added support for the \Q...\E escape sequence. Characters in between are
968    treated as literals. This is slightly different from Perl in that $ and @ are
969    also handled as literals inside the quotes. In Perl, they will cause variable
970    interpolation. Note the following examples:
972        Pattern            PCRE matches      Perl matches
974        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
975        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
976        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
978    For compatibility with Perl, \Q...\E sequences are recognized inside character
979    classes as well as outside them.
981    9. Re-organized 3 code statements in pcretest to avoid "overflow in
982    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
983    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
984    signed/unsigned warnings.
986    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
987    option for pcretest, so I've replaced it by a simple function that does just
988    that job.
990    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
991    "pcregrep -".
993    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
994    Java package. This provides some syntactic sugar for simple cases of what my
995    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
996    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
997    item, you can use this simplified notation. Note that only makes sense with
998    greedy quantifiers. Consequently, the use of the possessive quantifier forces
999    greediness, whatever the setting of the PCRE_UNGREEDY option.
1001    13. A change of greediness default within a pattern was not taking effect at
1002    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1003    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1004    was abstracted outside.
1006    14. PCRE now supports the \G assertion. It is true when the current matching
1007    position is at the start point of the match. This differs from \A when the
1008    starting offset is non-zero. Used with the /g option of pcretest (or similar
1009    code), it works in the same way as it does for Perl's /g option. If all
1010    alternatives of a regex begin with \G, the expression is anchored to the start
1011    match position, and the "anchored" flag is set in the compiled expression.
1013    15. Some bugs concerning the handling of certain option changes within patterns
1014    have been fixed. These applied to options other than (?ims). For example,
1015    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1016    been the other way round. Some of this was related to change 7 above.
1018    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1019    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1020    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1021    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1023    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1024    mode. Unlike ".", it always matches newline, whatever the setting of
1025    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1026    assertions. Perl allows it, but it doesn't (in general) work because it can't
1027    calculate the length of the lookbehind. At least, that's the case for Perl
1028    5.8.0 - I've been told they are going to document that it doesn't work in
1029    future.
1031    18. Added an error diagnosis for escapes that PCRE does not support: these are
1032    \L, \l, \N, \P, \p, \U, \u, and \X.
1034    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1035    reading past the end of the pattern in cases such as /[abcd/.
1037    20. PCRE was getting more memory than necessary for patterns with classes that
1038    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1040    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1041    compiling PCRE for use with Virtual Pascal.
1043    22. Small fix to the Makefile to make it work properly if the build is done
1044    outside the source tree.
1046    23. Added a new extension: a condition to go with recursion. If a conditional
1047    subpattern starts with (?(R) the "true" branch is used if recursion has
1048    happened, whereas the "false" branch is used only at the top level.
1050    24. When there was a very long string of literal characters (over 255 bytes
1051    without UTF support, over 250 bytes with UTF support), the computation of how
1052    much memory was required could be incorrect, leading to segfaults or other
1053    strange effects.
1055    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1056    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1057    there was a subsequent back reference to those brackets. This meant that, for
1058    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1059    possible to check for precisely this case. All we can do is abandon the
1060    optimization if .* occurs inside capturing brackets when there are any back
1061    references whatsoever. (See below for a better fix that came later.)
1063    26. The handling of the optimization for finding the first character of a
1064    non-anchored pattern, and for finding a character that is required later in the
1065    match were failing in some cases. This didn't break the matching; it just
1066    failed to optimize when it could. The way this is done has been re-implemented.
1068    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1070    28. Added a new feature that provides some of the functionality that Perl
1071    provides with (?{...}). The facility is termed a "callout". The way it is done
1072    in PCRE is for the caller to provide an optional function, by setting
1073    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1074    global variable. By default it is unset, which disables all calling out. To get
1075    the function called, the regex must include (?C) at appropriate points. This
1076    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1077    This provides a means of identifying different callout points. When PCRE
1078    reaches such a point in the regex, if pcre_callout has been set, the external
1079    function is called. It is provided with data in a structure called
1080    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1081    matching continues; if it returns a non-zero value, the match at the current
1082    point fails. However, backtracking will occur if possible. [This was changed
1083    later and other features added - see item 49 below.]
1085    29. pcretest is upgraded to test the callout functionality. It provides a
1086    callout function that displays information. By default, it shows the start of
1087    the match and the current position in the text. There are some new data escapes
1088    to vary what happens:
1090        \C+         in addition, show current contents of captured substrings
1091        \C-         do not supply a callout function
1092        \C!n        return 1 when callout number n is reached
1093        \C!n!m      return 1 when callout number n is reached for the mth time
1095    30. If pcregrep was called with the -l option and just a single file name, it
1096    output "<stdin>" if a match was found, instead of the file name.
1098    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1099    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1100    pcre_exec(). This saves a malloc/free per call. The default value of
1101    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1102    when configuring.
1104    32. The default maximum size of a compiled pattern is 64K. There have been a
1105    few cases of people hitting this limit. The code now uses macros to handle the
1106    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1107    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1108    configuring. Tests 2 and 5 work only with 2-byte links because they output
1109    debugging information about compiled patterns.
1111    33. Internal code re-arrangements:
1113    (a) Moved the debugging function for printing out a compiled regex into
1114        its own source file (printint.c) and used #include to pull it into
1115        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1116        separate copies.
1118    (b) Defined the list of op-code names for debugging as a macro in
1119        internal.h so that it is next to the definition of the opcodes.
1121    (c) Defined a table of op-code lengths for simpler skipping along compiled
1122        code. This is again a macro in internal.h so that it is next to the
1123        definition of the opcodes.
1125    34. Added support for recursive calls to individual subpatterns, along the
1126    lines of Robin Houston's patch (but implemented somewhat differently).
1128    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1129    allow it to read and process whole directories in Win32. This code was
1130    contributed by Lionel Fourquaux; it has not been tested by me.
1132    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1133    used to name a group. Names consist of alphanumerics and underscores, and must
1134    be unique. Back references use the syntax (?P=name) and recursive calls use
1135    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1136    numbers. The function pcre_fullinfo() can be used after compilation to extract
1137    a name/number map. There are three relevant calls:
1139      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1140      PCRE_INFO_NAMECOUNT            yields the number of entries
1141      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1143    The map is a vector of fixed-size entries. The size of each entry depends on
1144    the length of the longest name used. The first two bytes of each entry are the
1145    group number, most significant byte first. There follows the corresponding
1146    name, zero terminated. The names are in alphabetical order.
1148    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1149    case instead of 255. Making it the same both with and without UTF-8 support
1150    means that the same test output works with both.
1152    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1153    calling malloc() with a zero argument.
1155    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1156    optimization. I've improved things by keeping a bitmap of backreferences with
1157    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1158    fact referenced, the optimization can be applied. It is unlikely that a
1159    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1160    the match to follow \n) will appear inside brackets with a number greater than
1161    31, but if it does, any back reference > 31 suppresses the optimization.
1163    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1164    of disabling numbered capturing parentheses. Any opening parenthesis that is
1165    not followed by ? behaves as if it were followed by ?: but named parentheses
1166    can still be used for capturing (and they will acquire numbers in the usual
1167    way).
1169    41. Redesigned the return codes from the match() function into yes/no/error so
1170    that errors can be passed back from deep inside the nested calls. A malloc
1171    failure while inside a recursive subpattern call now causes the
1172    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1174    42. It is now possible to set a limit on the number of times the match()
1175    function is called in a call to pcre_exec(). This facility makes it possible to
1176    limit the amount of recursion and backtracking, though not in a directly
1177    obvious way, because the match() function is used in a number of different
1178    circumstances. The count starts from zero for each position in the subject
1179    string (for non-anchored patterns). The default limit is, for compatibility, a
1180    large number, namely 10 000 000. You can change this in two ways:
1182    (a) When configuring PCRE before making, you can use --with-match-limit=n
1183        to set a default value for the compiled library.
1185    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1186        a different value is set. See 45 below.
1188    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1190    43. Added a new function pcre_config(int, void *) to enable run-time extraction
1191    of things that can be changed at compile time. The first argument specifies
1192    what is wanted and the second points to where the information is to be placed.
1193    The current list of available information is:
1195      PCRE_CONFIG_UTF8
1197    The output is an integer that is set to one if UTF-8 support is available;
1198    otherwise it is set to zero.
1202    The output is an integer that it set to the value of the code that is used for
1203    newline. It is either LF (10) or CR (13).
1207    The output is an integer that contains the number of bytes used for internal
1208    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1212    The output is an integer that contains the threshold above which the POSIX
1213    interface uses malloc() for output vectors. See item 31 above.
1217    The output is an unsigned integer that contains the default limit of the number
1218    of match() calls in a pcre_exec() execution. See 42 above.
1220    44. pcretest has been upgraded by the addition of the -C option. This causes it
1221    to extract all the available output from the new pcre_config() function, and to
1222    output it. The program then exits immediately.
1224    45. A need has arisen to pass over additional data with calls to pcre_exec() in
1225    order to support additional features. One way would have been to define
1226    pcre_exec2() (for example) with extra arguments, but this would not have been
1227    extensible, and would also have required all calls to the original function to
1228    be mapped to the new one. Instead, I have chosen to extend the mechanism that
1229    is used for passing in "extra" data from pcre_study().
1231    The pcre_extra structure is now exposed and defined in pcre.h. It currently
1232    contains the following fields:
1234      flags         a bitmap indicating which of the following fields are set
1235      study_data    opaque data from pcre_study()
1236      match_limit   a way of specifying a limit on match() calls for a specific
1237                      call to pcre_exec()
1238      callout_data  data for callouts (see 49 below)
1240    The flag bits are also defined in pcre.h, and are
1246    The pcre_study() function now returns one of these new pcre_extra blocks, with
1247    the actual study data pointed to by the study_data field, and the
1248    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1249    before. That is, this change is entirely upwards-compatible and requires no
1250    change to existing code.
1252    If you want to pass in additional data to pcre_exec(), you can either place it
1253    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1254    block.
1256    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1257    data string contains the escape sequence \M, pcretest calls pcre_exec() several
1258    times with different match limits, until it finds the minimum value needed for
1259    pcre_exec() to complete. The value is then output. This can be instructive; for
1260    most simple matches the number is quite small, but for pathological cases it
1261    gets very large very quickly.
1263    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1264    returns the size of the data block pointed to by the study_data field in a
1265    pcre_extra block, that is, the value that was passed as the argument to
1266    pcre_malloc() when PCRE was getting memory in which to place the information
1267    created by pcre_study(). The fourth argument should point to a size_t variable.
1268    pcretest has been extended so that this information is shown after a successful
1269    pcre_study() call when information about the compiled regex is being displayed.
1271    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1272    because what follows is always an absolute path. (Later: it turns out that this
1273    is more than cosmetic for MinGW, because it doesn't like empty path
1274    components.)
1276    49. Some changes have been made to the callout feature (see 28 above):
1278    (i)  A callout function now has three choices for what it returns:
1280           0  =>  success, carry on matching
1281         > 0  =>  failure at this point, but backtrack if possible
1282         < 0  =>  serious error, return this value from pcre_exec()
1284         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1285         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1286         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1287         use by callout functions. It will never be used by PCRE itself.
1289    (ii) The pcre_extra structure (see 45 above) has a void * field called
1290         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1291         pcre_callout_block structure has a field of the same name. The contents of
1292         the field passed in the pcre_extra structure are passed to the callout
1293         function in the corresponding field in the callout block. This makes it
1294         easier to use the same callout-containing regex from multiple threads. For
1295         testing, the pcretest program has a new data escape
1297           \C*n        pass the number n (may be negative) as callout_data
1299         If the callout function in pcretest receives a non-zero value as
1300         callout_data, it returns that value.
1302    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1303    there were some redundant $(CFLAGS) in commands that are now specified as
1304    $(LINK), which already includes $(CFLAGS).
1306    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1307    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1308    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1309    one-byte characters throughout. Note that case-insensitive matching applies
1310    only to characters whose values are less than 256. PCRE doesn't support the
1311    notion of cases for higher-valued characters.
1313    (i)   A character class whose characters are all within 0-255 is handled as
1314          a bit map, and the map is inverted for negative classes. Previously, a
1315          character > 255 always failed to match such a class; however it should
1316          match if the class was a negative one (e.g. [^ab]). This has been fixed.
1318    (ii)  A negated character class with a single character < 255 is coded as
1319          "not this character" (OP_NOT). This wasn't working properly when the test
1320          character was multibyte, either singly or repeated.
1322    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1323          mode, for example: \x{100}{2,3}.
1325    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1326          singly or repeated) now correctly test multibyte characters. However,
1327          PCRE doesn't recognize any characters with values greater than 255 as
1328          digits, spaces, or word characters. Such characters always match \D, \S,
1329          and \W, and never match \d, \s, or \w.
1331    (v)   Classes may now contain characters and character ranges with values
1332          greater than 255. For example: [ab\x{100}-\x{400}].
1334    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
1335          PCRE in UTF-8 mode.
1337    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1338    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1339    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1340    value.)
1342    53. The single man page has become too large. I have therefore split it up into
1343    a number of separate man pages. These also give rise to individual HTML pages;
1344    these are now put in a separate directory, and there is an index.html page that
1345    lists them all. Some hyperlinking between the pages has been installed.
1347    54. Added convenience functions for handling named capturing parentheses.
1349    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1350    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1351    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1352    are faulted.
1354    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1355    calling configure. These values are used when compiling the dftables.c program
1356    which is run to generate the source of the default character tables. They
1357    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1358    you will need to set these values.
1360    57. Updated the building process for Windows DLL, as provided by Fred Cox.
1363    Version 3.9 02-Jan-02
1364    ---------------------
1366    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1368    2. If --disable-static was given, the building process failed when trying to
1369    build pcretest and pcregrep. (For some reason it was using libtool to compile
1370    them, which is not right, as they aren't part of the library.)
1373    Version 3.8 18-Dec-01
1374    ---------------------
1376    1. The experimental UTF-8 code was completely screwed up. It was packing the
1377    bytes in the wrong order. How dumb can you get?
1380    Version 3.7 29-Oct-01
1381    ---------------------
1383    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1384    This caused pcretest, when used on the test data, to segfault. Unfortunately,
1385    this didn't happen under Solaris 8, where I normally test things.
1387    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1388    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1389    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
1390    this fix an hour or so after the initial 3.7 release.)
1393    Version 3.6 23-Oct-01
1394    ---------------------
1396    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1397    offsets passed as NULL with zero offset count.
1399    2. The config.guess and config.sub files had not been updated when I moved to
1400    the latest autoconf.
1403    Version 3.5 15-Aug-01
1404    ---------------------
1406    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
1407    had been forgotten.
1409    2. By using declared but undefined structures, we can avoid using "void"
1410    definitions in pcre.h while keeping the internal definitions of the structures
1411    private.
1413    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
1414    user point of view, this means that both static and shared libraries are built
1415    by default, but this can be individually controlled. More of the work of
1416    handling this static/shared cases is now inside libtool instead of PCRE's make
1417    file.
1419    4. The pcretest utility is now installed along with pcregrep because it is
1420    useful for users (to test regexs) and by doing this, it automatically gets
1421    relinked by libtool. The documentation has been turned into a man page, so
1422    there are now .1, .txt, and .html versions in /doc.
1424    5. Upgrades to pcregrep:
1425       (i)   Added long-form option names like gnu grep.
1426       (ii)  Added --help to list all options with an explanatory phrase.
1427       (iii) Added -r, --recursive to recurse into sub-directories.
1428       (iv)  Added -f, --file to read patterns from a file.
1430    6. pcre_exec() was referring to its "code" argument before testing that
1431    argument for NULL (and giving an error if it was NULL).
1433    7. Upgraded Makefile.in to allow for compiling in a different directory from
1434    the source directory.
1436    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
1437    options bits, the pointer it was passed was to an int instead of to an unsigned
1438    long int. This mattered only on 64-bit systems.
1440    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
1441    generated) instead of pcre.in, which it its source. Also made the same change
1442    in several of the .c files.
1444    10. A new release of gcc defines printf() as a macro, which broke pcretest
1445    because it had an ifdef in the middle of a string argument for printf(). Fixed
1446    by using separate calls to printf().
1448    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
1449    script, to force use of CR or LF instead of \n in the source. On non-Unix
1450    systems, the value can be set in config.h.
1452    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
1453    absolute limit. Changed the text of the error message to make this clear, and
1454    likewise updated the man page.
1456    13. The limit of 99 on the number of capturing subpatterns has been removed.
1457    The new limit is 65535, which I hope will not be a "real" limit.
1460    Version 3.4 22-Aug-00
1461    ---------------------
1463    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
1465    2. Diagnose condition (?(0) as an error instead of crashing on matching.
1468  Version 3.3 01-Aug-00  Version 3.3 01-Aug-00
1469  ---------------------  ---------------------

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