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revision 51 by nigel, Sat Feb 24 21:39:37 2007 UTC revision 324 by ph10, Fri Mar 7 19:48:32 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.7 05-Mar-08
5    ---------------------
7    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
8        a string to a long long, pretend we don't even have a long long." This is
9        done by checking for the strtoq, strtoll, and _strtoi64 functions.
11    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
12        pre-7.6 versions, which defined a global no_arg variable instead of putting
13        it in the RE class.
15    3.  Remove a line of dead code, identified by coverity and reported by Nuno
16        Lopes.
18    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
20        (1) The include/exclude patterns were being applied to the whole pathnames
21            of files, instead of just to the final components.
23        (2) If there was more than one level of directory, the subdirectories were
24            skipped unless they satisfied the include/exclude conditions. This is
25            inconsistent with GNU grep (and could even be seen as contrary to the
26            pcregrep specification - which I improved to make it absolutely clear).
27            The action now is always to scan all levels of directory, and just
28            apply the include/exclude patterns to regular files.
31    Version 7.6 28-Jan-08
32    ---------------------
34    1.  A character class containing a very large number of characters with
35        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
36        overflow.
38    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
39        HAVE_LONG_LONG is not defined.
41    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
42        bring them up to date and include new features. This patch includes:
44        - Fixed PH's badly added libz and libbz2 support.
45        - Fixed a problem with static linking.
46        - Added pcredemo. [But later removed - see 7 below.]
47        - Fixed dftables problem and added an option.
48        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
49            HAVE_LONG_LONG.
50        - Added readline support for pcretest.
51        - Added an listing of the option settings after cmake has run.
53    4.  A user submitted a patch to Makefile that makes it easy to create
54        "pcre.dll" under mingw when using Configure/Make. I added stuff to
55        Makefile.am that cause it to include this special target, without
56        affecting anything else. Note that the same mingw target plus all
57        the other distribution libraries and programs are now supported
58        when configuring with CMake (see 6 below) instead of with
59        Configure/Make.
61    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
62        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
63        exported in the Windows port". It has not yet been confirmed that the patch
64        solves the problem, but it does no harm.
66    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
67        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
68        with CMake, and also correct the comment about stack recursion.
70    7.  Remove the automatic building of pcredemo from the ./configure system and
71        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
72        of a program that users should build themselves after PCRE is installed, so
73        building it automatically is not really right. What is more, it gave
74        trouble in some build environments.
76    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
79    Version 7.5 10-Jan-08
80    ---------------------
82    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
83        values in parens when parsing an RE using the C++ wrapper."
85    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
86        Characters greater than 255 were excluded from the class instead of being
87        included.
89    3.  The same bug as (2) above applied to negated POSIX classes such as
90        [:^space:].
92    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
93        defined or documented. It seems to have been a typo for PCRE_STATIC, so
94        I have changed it.
96    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
97        first named subpattern) and a construct such as (?&a) would reference the
98        first named subpattern whose name started with "a" (in other words, the
99        length check was missing). Both these problems are fixed. "Subpattern name
100        expected" is now given for (?&) (a zero-length name), and this patch also
101        makes it give the same error for \k'' (previously it complained that that
102        was a reference to a non-existent subpattern).
104    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
105        this is right because (?- can be followed by option settings as well as by
106        digits. I have, however, made the messages clearer.
108    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
109        than the number used in the conditional) now cause a compile-time error.
110        This is actually not compatible with Perl, which accepts such patterns, but
111        treats the conditional as always being FALSE (as PCRE used to), but it
112        seems to me that giving a diagnostic is better.
114    8.  Change "alphameric" to the more common word "alphanumeric" in comments
115        and messages.
117    9.  Fix two occurrences of "backslash" in comments that should have been
118        "backspace".
120    10. Remove two redundant lines of code that can never be obeyed (their function
121        was moved elsewhere).
123    11. The program that makes PCRE's Unicode character property table had a bug
124        which caused it to generate incorrect table entries for sequences of
125        characters that have the same character type, but are in different scripts.
126        It amalgamated them into a single range, with the script of the first of
127        them. In other words, some characters were in the wrong script. There were
128        thirteen such cases, affecting characters in the following ranges:
130          U+002b0 - U+002c1
131          U+0060c - U+0060d
132          U+0061e - U+00612
133          U+0064b - U+0065e
134          U+0074d - U+0076d
135          U+01800 - U+01805
136          U+01d00 - U+01d77
137          U+01d9b - U+01dbf
138          U+0200b - U+0200f
139          U+030fc - U+030fe
140          U+03260 - U+0327f
141          U+0fb46 - U+0fbb1
142          U+10450 - U+1049d
144    12. The -o option (show only the matching part of a line) for pcregrep was not
145        compatible with GNU grep in that, if there was more than one match in a
146        line, it showed only the first of them. It now behaves in the same way as
147        GNU grep.
149    13. If the -o and -v options were combined for pcregrep, it printed a blank
150        line for every non-matching line. GNU grep prints nothing, and pcregrep now
151        does the same. The return code can be used to tell if there were any
152        non-matching lines.
154    14. Added --file-offsets and --line-offsets to pcregrep.
156    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
157        infinitely looping recursion. The bug was that positive lookaheads were not
158        being skipped when checking for a possible empty match (negative lookaheads
159        and both kinds of lookbehind were skipped).
161    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
162        inclusion of <windows.h> to before rather than after the definition of
163        INVALID_FILE_ATTRIBUTES (patch from David Byron).
165    17. Specifying a possessive quantifier with a specific limit for a Unicode
166        character property caused pcre_compile() to compile bad code, which led at
167        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
168        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
169        caused the error; without that there was no problem.
171    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
173    19. Added --enable-pcretest-libreadline.
175    20. In pcrecpp.cc, the variable 'count' was incremented twice in
176        RE::GlobalReplace(). As a result, the number of replacements returned was
177        double what it should be. I removed one of the increments, but Craig sent a
178        later patch that removed the other one (the right fix) and added unit tests
179        that check the return values (which was not done before).
181    21. Several CMake things:
183        (1) Arranged that, when cmake is used on Unix, the libraries end up with
184            the names libpcre and libpcreposix, not just pcre and pcreposix.
186        (2) The above change means that pcretest and pcregrep are now correctly
187            linked with the newly-built libraries, not previously installed ones.
191    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
192        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
193        UTF-8 newline character). The key issue is that the pattern starts .*;
194        this means that the match must be either at the beginning, or after a
195        newline. The bug was in the code for advancing after a failed match and
196        checking that the new position followed a newline. It was not taking
197        account of UTF-8 characters correctly.
199    23. PCRE was behaving differently from Perl in the way it recognized POSIX
200        character classes. PCRE was not treating the sequence [:...:] as a
201        character class unless the ... were all letters. Perl, however, seems to
202        allow any characters between [: and :], though of course it rejects as
203        unknown any "names" that contain non-letters, because all the known class
204        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
205        for example, whereas PCRE did not - it did not recognize a POSIX character
206        class. This seemed a bit dangerous, so the code has been changed to be
207        closer to Perl. The behaviour is not identical to Perl, because PCRE will
208        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
209        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
210        Perl does, and where it didn't before.
212    24. Rewrite so as to remove the single use of %n from pcregrep because in some
213        Windows environments %n is disabled by default.
216    Version 7.4 21-Sep-07
217    ---------------------
219    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
220        means that a class such as [\s] counted as "explicit reference to CR or
221        LF". That isn't really right - the whole point of the change was to try to
222        help when there was an actual mention of one of the two characters. So now
223        the change happens only if \r or \n (or a literal CR or LF) character is
224        encountered.
226    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
227        of both had grown to the point where there were only 3 bits left.
228        Fortunately, there was spare space in the data structure, and so I have
229        moved the internal flags into a new 16-bit field to free up more option
230        bits.
232    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
233        but did not set the internal JCHANGED flag - either of these is enough to
234        control the way the "get" function works - but the PCRE_INFO_JCHANGED
235        facility is supposed to tell if (?J) was ever used, so now (?J) at the
236        start sets both bits.
238    4.  Added options (at build time, compile time, exec time) to change \R from
239        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
241    5.  doc/pcresyntax.html was missing from the distribution.
243    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
244        compatibility, even though it is no longer used.
246    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
247        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
248        windows.h file is present (where different names are used). [This was
249        reversed later after testing - see 16 below.]
251    8.  Changed all #include <config.h> to #include "config.h". There were also
252        some further <pcre.h> cases that I changed to "pcre.h".
254    9.  When pcregrep was used with the --colour option, it missed the line ending
255        sequence off the lines that it output.
257    10. It was pointed out to me that arrays of string pointers cause lots of
258        relocations when a shared library is dynamically loaded. A technique of
259        using a single long string with a table of offsets can drastically reduce
260        these. I have refactored PCRE in four places to do this. The result is
261        dramatic:
263          Originally:                          290
264          After changing UCP table:            187
265          After changing error message table:   43
266          After changing table of "verbs"       36
267          After changing table of Posix names   22
269        Thanks to the folks working on Gregex for glib for this insight.
271    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
272        unicode-properties was also set.
274    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
276    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
277        checked only for CRLF.
279    14. Added casts to pcretest.c to avoid compiler warnings.
281    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
283    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
284        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
285        entirely. This removes changes made in 7 above.
287    17. The CMake files have been updated, and there is now more information about
288        building with CMake in the NON-UNIX-USE document.
291    Version 7.3 28-Aug-07
292    ---------------------
294     1. In the rejigging of the build system that eventually resulted in 7.1, the
295        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
296        brackets there is not right, since it causes compilers to look for an
297        installed pcre.h, not the version that is in the source that is being
298        compiled (which of course may be different). I have changed it back to:
300          #include "pcre.h"
302        I have a vague recollection that the change was concerned with compiling in
303        different directories, but in the new build system, that is taken care of
304        by the VPATH setting the Makefile.
306     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
307        when the subject happened to end in the byte 0x85 (e.g. if the last
308        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
309        characters but of course it shouldn't be taken as a newline when it is part
310        of another character. The bug was that, for an unlimited repeat of . in
311        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
312        characters when looking for a newline.
314     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
316     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
317        in debug output.
319     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
320        long printing in the pcrecpp unittest when running under MinGW.
322     6. ESC_K was left out of the EBCDIC table.
324     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
325        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
326        limit also applies to "virtual nesting" when a pattern is recursive, and in
327        this case 1000 isn't so big. I have been able to remove this limit at the
328        expense of backing off one optimization in certain circumstances. Normally,
329        when pcre_exec() would call its internal match() function recursively and
330        immediately return the result unconditionally, it uses a "tail recursion"
331        feature to save stack. However, when a subpattern that can match an empty
332        string has an unlimited repetition quantifier, it no longer makes this
333        optimization. That gives it a stack frame in which to save the data for
334        checking that an empty string has been matched. Previously this was taken
335        from the 1000-entry workspace that had been reserved. So now there is no
336        explicit limit, but more stack is used.
338     8. Applied Daniel's patches to solve problems with the import/export magic
339        syntax that is required for Windows, and which was going wrong for the
340        pcreposix and pcrecpp parts of the library. These were overlooked when this
341        problem was solved for the main library.
343     9. There were some crude static tests to avoid integer overflow when computing
344        the size of patterns that contain repeated groups with explicit upper
345        limits. As the maximum quantifier is 65535, the maximum group length was
346        set at 30,000 so that the product of these two numbers did not overflow a
347        32-bit integer. However, it turns out that people want to use groups that
348        are longer than 30,000 bytes (though not repeat them that many times).
349        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
350        made it possible to implement the integer overflow checks in a much more
351        dynamic way, which I have now done. The artificial limitation on group
352        length has been removed - we now have only the limit on the total length of
353        the compiled pattern, which depends on the LINK_SIZE setting.
355    10. Fixed a bug in the documentation for get/copy named substring when
356        duplicate names are permitted. If none of the named substrings are set, the
357        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
358        empty string.
360    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
361        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
362        because the ] is interpreted as the first data character and the
363        terminating ] is not found. PCRE has been made compatible with Perl in this
364        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
365        cause memory overwriting.
367    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
368        string has been matched (to stop an infinite loop). It was not recognizing
369        a conditional subpattern that could match an empty string if that
370        subpattern was within another subpattern. For example, it looped when
371        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
372        condition was not nested. This bug has been fixed.
374    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
375        past the start of the subject in the presence of bytes with the top bit
376        set, for example "\x8aBCD".
378    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
379        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
381    14. Optimized (?!) to (*FAIL).
383    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
384        This restricts code points to be within the range 0 to 0x10FFFF, excluding
385        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
386        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
387        does: it's just the validity check that is more restrictive.
389    16. Inserted checks for integer overflows during escape sequence (backslash)
390        processing, and also fixed erroneous offset values for syntax errors during
391        backslash processing.
393    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
394        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
396    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
397        caused an overrun.
399    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
400        something other than just ASCII characters) inside a group that had an
401        unlimited repeat caused a loop at compile time (while checking to see
402        whether the group could match an empty string).
404    20. Debugging a pattern containing \p or \P could cause a crash. For example,
405        [\P{Any}] did so. (Error in the code for printing property names.)
407    21. An orphan \E inside a character class could cause a crash.
409    22. A repeated capturing bracket such as (A)? could cause a wild memory
410        reference during compilation.
412    23. There are several functions in pcre_compile() that scan along a compiled
413        expression for various reasons (e.g. to see if it's fixed length for look
414        behind). There were bugs in these functions when a repeated \p or \P was
415        present in the pattern. These operators have additional parameters compared
416        with \d, etc, and these were not being taken into account when moving along
417        the compiled data. Specifically:
419        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
420            length.
422        (b) An item such as \pL+ within a repeated group could cause crashes or
423            loops.
425        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
426            "reference to non-existent subpattern" error.
428        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
430    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
431        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
433    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
435    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
436        character were causing crashes (broken optimization).
438    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
439        \p or \P) caused a compile-time loop.
441    28. More problems have arisen in unanchored patterns when CRLF is a valid line
442        break. For example, the unstudied pattern [\r\n]A does not match the string
443        "\r\nA" because change 7.0/46 below moves the current point on by two
444        characters after failing to match at the start. However, the pattern \nA
445        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
446        the same is true. There doesn't seem any very clean way out of this, but
447        what I have chosen to do makes the common cases work: PCRE now takes note
448        of whether there can be an explicit match for \r or \n anywhere in the
449        pattern, and if so, 7.0/46 no longer applies. As part of this change,
450        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
451        pattern has explicit CR or LF references.
453    29. Added (*CR) etc for changing newline setting at start of pattern.
456    Version 7.2 19-Jun-07
457    ---------------------
459     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
460        which is apparently normally available under Windows.
462     2. Re-jig the pcregrep tests with different newline settings in an attempt
463        to make them independent of the local environment's newline setting.
465     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
467     4. Some of the "internals" tests were previously cut out when the link size
468        was not 2, because the output contained actual offsets. The recent new
469        "Z" feature of pcretest means that these can be cut out, making the tests
470        usable with all link sizes.
472     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
473        stack recursion. This gives a massive performance boost under BSD, but just
474        a small improvement under Linux. However, it saves one field in the frame
475        in all cases.
477     6. Added more features from the forthcoming Perl 5.10:
479        (a) (?-n) (where n is a string of digits) is a relative subroutine or
480            recursion call. It refers to the nth most recently opened parentheses.
482        (b) (?+n) is also a relative subroutine call; it refers to the nth next
483            to be opened parentheses.
485        (c) Conditions that refer to capturing parentheses can be specified
486            relatively, for example, (?(-2)... or (?(+3)...
488        (d) \K resets the start of the current match so that everything before
489            is not part of it.
491        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
493        (f) \g{name} is another synonym - part of Perl 5.10's unification of
494            reference syntax.
496        (g) (?| introduces a group in which the numbering of parentheses in each
497            alternative starts with the same number.
499        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
501     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
504     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
505        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
506        for detecting groups that can match an empty string.
508     9. A pattern with a very large number of alternatives (more than several
509        hundred) was running out of internal workspace during the pre-compile
510        phase, where pcre_compile() figures out how much memory will be needed. A
511        bit of new cunning has reduced the workspace needed for groups with
512        alternatives. The 1000-alternative test pattern now uses 12 bytes of
513        workspace instead of running out of the 4096 that are available.
515    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
517    11. Applied patch from Google to remove an optimization that didn't quite work.
518        The report of the bug said:
520          pcrecpp::RE("a*").FullMatch("aaa") matches, while
521          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
522          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
524    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
525        it matched the wrong number of bytes.
528    Version 7.1 24-Apr-07
529    ---------------------
531     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
532        that is more "standard", making use of automake and other Autotools. There
533        is some re-arrangement of the files and adjustment of comments consequent
534        on this.
536     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
537        for recursive directory scanning broke on some systems because the files
538        are not scanned in any specific order and on different systems the order
539        was different. A call to "sort" has been inserted into RunGrepTest for the
540        approprate test as a short-term fix. In the longer term there may be an
541        alternative.
543     3. I had an email from Eric Raymond about problems translating some of PCRE's
544        man pages to HTML (despite the fact that I distribute HTML pages, some
545        people do their own conversions for various reasons). The problems
546        concerned the use of low-level troff macros .br and .in. I have therefore
547        removed all such uses from the man pages (some were redundant, some could
548        be replaced by .nf/.fi pairs). The 132html script that I use to generate
549        HTML has been updated to handle .nf/.fi and to complain if it encounters
550        .br or .in.
552     4. Updated comments in configure.ac that get placed in config.h.in and also
553        arranged for config.h to be included in the distribution, with the name
554        config.h.generic, for the benefit of those who have to compile without
555        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
557     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
558        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
559        makevp.bat for the current PCRE, using the additional files
560        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
562     6. A Windows user reported a minor discrepancy with test 2, which turned out
563        to be caused by a trailing space on an input line that had got lost in his
564        copy. The trailing space was an accident, so I've just removed it.
566     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
567        that is needed.
569     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
570        as "const" (a) because they are and (b) because it helps the PHP
571        maintainers who have recently made a script to detect big data structures
572        in the php code that should be moved to the .rodata section. I remembered
573        to update Builducptable as well, so it won't revert if ucptable.h is ever
574        re-created.
576     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
577        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
578        order to be able to cut out the UTF-8 tables in the latter when UTF-8
579        support is not required. This saves 1.5-2K of code, which is important in
580        some applications.
582        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
583        so as not to refer to the tables, even though these functions will never be
584        called when UTF-8 support is disabled. Otherwise there are problems with a
585        shared library.
587    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
589        (a) It was defining its arguments as char * instead of void *.
591        (b) It was assuming that all moves were upwards in memory; this was true
592            a long time ago when I wrote it, but is no longer the case.
594        The emulated memove() is provided for those environments that have neither
595        memmove() nor bcopy(). I didn't think anyone used it these days, but that
596        is clearly not the case, as these two bugs were recently reported.
598    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
599        and Detrail to create the HTML documentation, the .txt form of the man
600        pages, and it removes trailing spaces from listed files. It also creates
601        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
602        case, it wraps all the #defines with #ifndefs. This script should be run
603        before "make dist".
605    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
606        with Unicode property support.
608        (a) For a maximizing quantifier, if the two different cases of the
609            character were of different lengths in their UTF-8 codings (there are
610            some cases like this - I found 11), and the matching function had to
611            back up over a mixture of the two cases, it incorrectly assumed they
612            were both the same length.
614        (b) When PCRE was configured to use the heap rather than the stack for
615            recursion during matching, it was not correctly preserving the data for
616            the other case of a UTF-8 character when checking ahead for a match
617            while processing a minimizing repeat. If the check also involved
618            matching a wide character, but failed, corruption could cause an
619            erroneous result when trying to check for a repeat of the original
620            character.
622    13. Some tidying changes to the testing mechanism:
624        (a) The RunTest script now detects the internal link size and whether there
625            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
626            values substituted by "configure". (The RunGrepTest script already did
627            this for UTF-8.) The configure.ac script no longer substitutes the
628            relevant variables.
630        (b) The debugging options /B and /D in pcretest show the compiled bytecode
631            with length and offset values. This means that the output is different
632            for different internal link sizes. Test 2 is skipped for link sizes
633            other than 2 because of this, bypassing the problem. Unfortunately,
634            there was also a test in test 3 (the locale tests) that used /B and
635            failed for link sizes other than 2. Rather than cut the whole test out,
636            I have added a new /Z option to pcretest that replaces the length and
637            offset values with spaces. This is now used to make test 3 independent
638            of link size. (Test 2 will be tidied up later.)
640    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
641        segmentation fault instead of returning the appropriate error message.
643    15. In multiline mode when the newline sequence was set to "any", the pattern
644        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
645        This doesn't seem right; it now treats the CRLF combination as the line
646        ending, and so does not match in that case. It's only a pattern such as ^$
647        that would hit this one: something like ^ABC$ would have failed after \r
648        and then tried again after \r\n.
650    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
651        in an attempt to make files that differ only in their line terminators
652        compare equal. This works on Linux.
654    17. Under certain error circumstances pcregrep might try to free random memory
655        as it exited. This is now fixed, thanks to valgrind.
657    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
658        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
659        was because its rules for how to advance for /g after matching an empty
660        string at the end of a line did not allow for this case. They now check for
661        it specially.
663    20. pcretest is supposed to handle patterns and data of any length, by
664        extending its buffers when necessary. It was getting this wrong when the
665        buffer for a data line had to be extended.
667    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
668        CRLF as a newline sequence.
670    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
671        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
672        I have nevertheless tidied it up.
674    23. Added some casts to kill warnings from HP-UX ia64 compiler.
676    24. Added a man page for pcre-config.
679    Version 7.0 19-Dec-06
680    ---------------------
682     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
683        moving to gcc 4.1.1.
685     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
686        sys/time.h, which is documented as needed for this function. It doesn't
687        seem to matter on Linux, but it showed up on some releases of OS X.
689     3. It seems that there are systems where bytes whose values are greater than
690        127 match isprint() in the "C" locale. The "C" locale should be the
691        default when a C program starts up. In most systems, only ASCII printing
692        characters match isprint(). This difference caused the output from pcretest
693        to vary, making some of the tests fail. I have changed pcretest so that:
695        (a) When it is outputting text in the compiled version of a pattern, bytes
696            other than 32-126 are always shown as hex escapes.
698        (b) When it is outputting text that is a matched part of a subject string,
699            it does the same, unless a different locale has been set for the match
700            (using the /L modifier). In this case, it uses isprint() to decide.
702     4. Fixed a major bug that caused incorrect computation of the amount of memory
703        required for a compiled pattern when options that changed within the
704        pattern affected the logic of the preliminary scan that determines the
705        length. The relevant options are -x, and -i in UTF-8 mode. The result was
706        that the computed length was too small. The symptoms of this bug were
707        either the PCRE error "internal error: code overflow" from pcre_compile(),
708        or a glibc crash with a message such as "pcretest: free(): invalid next
709        size (fast)". Examples of patterns that provoked this bug (shown in
710        pcretest format) are:
712          /(?-x: )/x
713          /(?x)(?-x: \s*#\s*)/
714          /((?i)[\x{c0}])/8
715          /(?i:[\x{c0}])/8
717        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
718        is now done differently.
720     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
721        wrapper classes; (b) implement a new function in the C++ scanner that is
722        more efficient than the old way of doing things because it avoids levels of
723        recursion in the regex matching; (c) add a paragraph to the documentation
724        for the FullMatch() function.
726     6. The escape sequence \n was being treated as whatever was defined as
727        "newline". Not only was this contrary to the documentation, which states
728        that \n is character 10 (hex 0A), but it also went horribly wrong when
729        "newline" was defined as CRLF. This has been fixed.
731     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
732        was being set to -1 for the "end of line" case (supposedly a value that no
733        character can have). Though this value is never used (the check for end of
734        line is "zero bytes in current character"), it caused compiler complaints.
735        I've changed it to 0xffffffff.
737     8. In pcre_version.c, the version string was being built by a sequence of
738        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
739        string (as it is for production releases) called a macro with an empty
740        argument. The C standard says the result of this is undefined. The gcc
741        compiler treats it as an empty string (which was what was wanted) but it is
742        reported that Visual C gives an error. The source has been hacked around to
743        avoid this problem.
745     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
746        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
747        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
748        of them did).
750    10. Originally, pcretest opened its input and output without "b"; then I was
751        told that "b" was needed in some environments, so it was added for release
752        5.0 to both the input and output. (It makes no difference on Unix-like
753        systems.) Later I was told that it is wrong for the input on Windows. I've
754        now abstracted the modes into two macros, to make it easier to fiddle with
755        them, and removed "b" from the input mode under Windows.
757    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
759    12. Added -help and --help to pcretest as an official way of being reminded
760        of the options.
762    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
763        and pcrecpp.cc because they annoy compilers at high warning levels.
765    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
767    15. Fixed an occurrence of == in configure.ac that should have been = (shell
768        scripts are not C programs :-) and which was not noticed because it works
769        on Linux.
771    16. pcretest is supposed to handle any length of pattern and data line (as one
772        line or as a continued sequence of lines) by extending its input buffer if
773        necessary. This feature was broken for very long pattern lines, leading to
774        a string of junk being passed to pcre_compile() if the pattern was longer
775        than about 50K.
777    17. I have done a major re-factoring of the way pcre_compile() computes the
778        amount of memory needed for a compiled pattern. Previously, there was code
779        that made a preliminary scan of the pattern in order to do this. That was
780        OK when PCRE was new, but as the facilities have expanded, it has become
781        harder and harder to keep it in step with the real compile phase, and there
782        have been a number of bugs (see for example, 4 above). I have now found a
783        cunning way of running the real compile function in a "fake" mode that
784        enables it to compute how much memory it would need, while actually only
785        ever using a few hundred bytes of working memory and without too many
786        tests of the mode. This should make future maintenance and development
787        easier. A side effect of this work is that the limit of 200 on the nesting
788        depth of parentheses has been removed (though this was never a serious
789        limitation, I suspect). However, there is a downside: pcre_compile() now
790        runs more slowly than before (30% or more, depending on the pattern). I
791        hope this isn't a big issue. There is no effect on runtime performance.
793    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
794        newline (only possible for the last line of a file) and it was a
795        pattern that set a locale (followed by /Lsomething), pcretest crashed.
797    19. Added additional timing features to pcretest. (1) The -tm option now times
798        matching only, not compiling. (2) Both -t and -tm can be followed, as a
799        separate command line item, by a number that specifies the number of
800        repeats to use when timing. The default is 50000; this gives better
801        precision, but takes uncomfortably long for very large patterns.
803    20. Extended pcre_study() to be more clever in cases where a branch of a
804        subpattern has no definite first character. For example, (a*|b*)[cd] would
805        previously give no result from pcre_study(). Now it recognizes that the
806        first character must be a, b, c, or d.
808    21. There was an incorrect error "recursive call could loop indefinitely" if
809        a subpattern (or the entire pattern) that was being tested for matching an
810        empty string contained only one non-empty item after a nested subpattern.
811        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
812        incorrectly, because the \d was being skipped in the check.
814    22. The pcretest program now has a new pattern option /B and a command line
815        option -b, which is equivalent to adding /B to every pattern. This causes
816        it to show the compiled bytecode, without the additional information that
817        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
818        is the same as /B/I).
820    23. A new optimization is now able automatically to treat some sequences such
821        as a*b as a*+b. More specifically, if something simple (such as a character
822        or a simple class like \d) has an unlimited quantifier, and is followed by
823        something that cannot possibly match the quantified thing, the quantifier
824        is automatically "possessified".
826    24. A recursive reference to a subpattern whose number was greater than 39
827        went wrong under certain circumstances in UTF-8 mode. This bug could also
828        have affected the operation of pcre_study().
830    25. Realized that a little bit of performance could be had by replacing
831        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
833    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
835    27. Possessive quantifiers such as a++ were previously implemented by turning
836        them into atomic groups such as ($>a+). Now they have their own opcodes,
837        which improves performance. This includes the automatically created ones
838        from 23 above.
840    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
841        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
842        the first matched character to be a colon. This applied both to named and
843        numbered groups.
845    29. The ucpinternal.h header file was missing its idempotency #ifdef.
847    30. I was sent a "project" file called libpcre.a.dev which I understand makes
848        building PCRE on Windows easier, so I have included it in the distribution.
850    31. There is now a check in pcretest against a ridiculously large number being
851        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
852        loop, the loop is abandoned.
854    32. Forward references to subpatterns in conditions such as (?(2)...) where
855        subpattern 2 is defined later cause pcre_compile() to search forwards in
856        the pattern for the relevant set of parentheses. This search went wrong
857        when there were unescaped parentheses in a character class, parentheses
858        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
860    33. "Subroutine" calls and backreferences were previously restricted to
861        referencing subpatterns earlier in the regex. This restriction has now
862        been removed.
864    34. Added a number of extra features that are going to be in Perl 5.10. On the
865        whole, these are just syntactic alternatives for features that PCRE had
866        previously implemented using the Python syntax or my own invention. The
867        other formats are all retained for compatibility.
869        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
870            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
871            also .NET compatible.
873        (b) A recursion or subroutine call to a named group can now be defined as
874            (?&name) as well as (?P>name).
876        (c) A backreference to a named group can now be defined as \k<name> or
877            \k'name' as well as (?P=name). The new forms, as well as being in Perl
878            5.10, are also .NET compatible.
880        (d) A conditional reference to a named group can now use the syntax
881            (?(<name>) or (?('name') as well as (?(name).
883        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
884            groups (named and numbered) that are never evaluated inline, but can be
885            called as "subroutines" from elsewhere. In effect, the DEFINE condition
886            is always false. There may be only one alternative in such a group.
888        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
889            as the simple (?(R). The condition is true only if the most recent
890            recursion is that of the given number or name. It does not search out
891            through the entire recursion stack.
893        (g) The escape \gN or \g{N} has been added, where N is a positive or
894            negative number, specifying an absolute or relative reference.
896    35. Tidied to get rid of some further signed/unsigned compiler warnings and
897        some "unreachable code" warnings.
899    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
900        things, this adds five new scripts.
902    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
903        There were also incompatibilities regarding the handling of \Q..\E inside
904        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
905        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
907    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
908        matches an empty string, and forcibly breaks the loop. There were bugs in
909        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
910        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
911        separate and independent bugs (that affected different cases) have been
912        fixed.
914    39. Refactored the code to abolish the use of different opcodes for small
915        capturing bracket numbers. This is a tidy that I avoided doing when I
916        removed the limit on the number of capturing brackets for 3.5 back in 2001.
917        The new approach is not only tidier, it makes it possible to reduce the
918        memory needed to fix the previous bug (38).
920    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
921        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
922        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
923        mode.
925    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
926        report.
928    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
929        copy construction and assignment in the C++ wrapper.
931    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
932        couple of bugs that could have given wrong results in the "--newline=crlf"
933        case.
935    44. Added a number of casts and did some reorganization of signed/unsigned int
936        variables following suggestions from Dair Grant. Also renamed the variable
937        "this" as "item" because it is a C++ keyword.
939    45. Arranged for dftables to add
941          #include "pcre_internal.h"
943        to pcre_chartables.c because without it, gcc 4.x may remove the array
944        definition from the final binary if PCRE is built into a static library and
945        dead code stripping is activated.
947    46. For an unanchored pattern, if a match attempt fails at the start of a
948        newline sequence, and the newline setting is CRLF or ANY, and the next two
949        characters are CRLF, advance by two characters instead of one.
952    Version 6.7 04-Jul-06
953    ---------------------
955     1. In order to handle tests when input lines are enormously long, pcretest has
956        been re-factored so that it automatically extends its buffers when
957        necessary. The code is crude, but this _is_ just a test program. The
958        default size has been increased from 32K to 50K.
960     2. The code in pcre_study() was using the value of the re argument before
961        testing it for NULL. (Of course, in any sensible call of the function, it
962        won't be NULL.)
964     3. The memmove() emulation function in pcre_internal.h, which is used on
965        systems that lack both memmove() and bcopy() - that is, hardly ever -
966        was missing a "static" storage class specifier.
968     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
969        containing an extended class (one that cannot be represented by a bitmap
970        because it contains high-valued characters or Unicode property items, e.g.
971        [\pZ]). Almost always one would set UTF-8 mode when processing such a
972        pattern, but PCRE should not loop if you do not (it no longer does).
973        [Detail: two cases were found: (a) a repeated subpattern containing an
974        extended class; (b) a recursive reference to a subpattern that followed a
975        previous extended class. It wasn't skipping over the extended class
976        correctly when UTF-8 mode was not set.]
978     5. A negated single-character class was not being recognized as fixed-length
979        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
980        compile error "lookbehind assertion is not fixed length".
982     6. The RunPerlTest auxiliary script was showing an unexpected difference
983        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
984        write a Perl script that can interpret lines of an input file either as
985        byte characters or as UTF-8, which is what "perltest" was being required to
986        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
987        can't do is switch easily at run time between having the "use utf8;" pragma
988        or not. In the end, I fudged it by using the RunPerlTest script to insert
989        "use utf8;" explicitly for the UTF-8 tests.
991     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
992        the end of the subject string, contrary to the documentation and to what
993        Perl does. This was true of both matching functions. Now it matches only at
994        the start of the subject and immediately after *internal* newlines.
996     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
997        a pointer to an int instead of a pointer to an unsigned long int. This
998        caused problems on 64-bit systems.
1000     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1001        instance of the 'standard' template library not being so standard".
1003    10. There was no check on the number of named subpatterns nor the maximum
1004        length of a subpattern name. The product of these values is used to compute
1005        the size of the memory block for a compiled pattern. By supplying a very
1006        long subpattern name and a large number of named subpatterns, the size
1007        computation could be caused to overflow. This is now prevented by limiting
1008        the length of names to 32 characters, and the number of named subpatterns
1009        to 10,000.
1011    11. Subpatterns that are repeated with specific counts have to be replicated in
1012        the compiled pattern. The size of memory for this was computed from the
1013        length of the subpattern and the repeat count. The latter is limited to
1014        65535, but there was no limit on the former, meaning that integer overflow
1015        could in principle occur. The compiled length of a repeated subpattern is
1016        now limited to 30,000 bytes in order to prevent this.
1018    12. Added the optional facility to have named substrings with the same name.
1020    13. Added the ability to use a named substring as a condition, using the
1021        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1022        are numbers (not recommended). Forward references are permitted.
1024    14. Added forward references in named backreferences (if you see what I mean).
1026    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1027        pattern could run off the end of the subject. For example, the pattern
1028        "(?s)(.{1,5})"8 did this with the subject "ab".
1030    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1031        PCRE_CASELESS was set when matching characters that were quantified with ?
1032        or *.
1034    17. A character class other than a single negated character that had a minimum
1035        but no maximum quantifier - for example [ab]{6,} - was not handled
1036        correctly by pce_dfa_exec(). It would match only one character.
1038    18. A valid (though odd) pattern that looked like a POSIX character
1039        class but used an invalid character after [ (for example [[,abc,]]) caused
1040        pcre_compile() to give the error "Failed: internal error: code overflow" or
1041        in some cases to crash with a glibc free() error. This could even happen if
1042        the pattern terminated after [[ but there just happened to be a sequence of
1043        letters, a binary zero, and a closing ] in the memory that followed.
1045    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1046        over the years. Originally (before any Unicode support), just the bottom 8
1047        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1048        output from "man perlunicode" includes this:
1050          The regular expression compiler produces polymorphic opcodes.  That
1051          is, the pattern adapts to the data and automatically switches to
1052          the Unicode character scheme when presented with Unicode data--or
1053          instead uses a traditional byte scheme when presented with byte
1054          data.
1056        Sadly, a wide octal escape does not cause a switch, and in a string with
1057        no other multibyte characters, these octal escapes are treated as before.
1058        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1059        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1060        Unicode string.
1062        I have not perpetrated such confusion in PCRE. Up till now, it took just
1063        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1064        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1065        translate to the appropriate multibyte character.
1067    29. Applied some refactoring to reduce the number of warnings from Microsoft
1068        and Borland compilers. This has included removing the fudge introduced
1069        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1070        a warning about an unused variable.
1072    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1073        characters since release 4.0, because Perl (from release 5.004) does not.
1074        [Or at least, is documented not to: some releases seem to be in conflict
1075        with the documentation.] However, when a pattern was studied with
1076        pcre_study() and all its branches started with \s, PCRE still included VT
1077        as a possible starting character. Of course, this did no harm; it just
1078        caused an unnecessary match attempt.
1080    22. Removed a now-redundant internal flag bit that recorded the fact that case
1081        dependency changed within the pattern. This was once needed for "required
1082        byte" processing, but is no longer used. This recovers a now-scarce options
1083        bit. Also moved the least significant internal flag bit to the most-
1084        significant bit of the word, which was not previously used (hangover from
1085        the days when it was an int rather than a uint) to free up another bit for
1086        the future.
1088    23. Added support for CRLF line endings as well as CR and LF. As well as the
1089        default being selectable at build time, it can now be changed at runtime
1090        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1091        specify that it is scanning data with non-default line endings.
1093    24. Changed the definition of CXXLINK to make it agree with the definition of
1094        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1096    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1097        recursions. This makes a big different to stack usage for some patterns.
1099    26. If a subpattern containing a named recursion or subroutine reference such
1100        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1101        the space required for the compiled pattern went wrong and gave too small a
1102        value. Depending on the environment, this could lead to "Failed: internal
1103        error: code overflow at offset 49" or "glibc detected double free or
1104        corruption" errors.
1106    27. Applied patches from Google (a) to support the new newline modes and (b) to
1107        advance over multibyte UTF-8 characters in GlobalReplace.
1109    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1110        difference for some implementation of PCRE in some Windows version.
1112    29. Added some extra testing facilities to pcretest:
1114        \q<number>   in a data line sets the "match limit" value
1115        \Q<number>   in a data line sets the "match recursion limt" value
1116        -S <number>  sets the stack size, where <number> is in megabytes
1118        The -S option isn't available for Windows.
1121    Version 6.6 06-Feb-06
1122    ---------------------
1124     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1125        in pcreposix.h. I have copied the definition from pcre.h.
1127     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1128        because pcre.h is no longer a built file.
1130     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1131        not normally included in the compiled code.
1134    Version 6.5 01-Feb-06
1135    ---------------------
1137     1. When using the partial match feature with pcre_dfa_exec(), it was not
1138        anchoring the second and subsequent partial matches at the new starting
1139        point. This could lead to incorrect results. For example, with the pattern
1140        /1234/, partially matching against "123" and then "a4" gave a match.
1142     2. Changes to pcregrep:
1144        (a) All non-match returns from pcre_exec() were being treated as failures
1145            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1146            error message is output. Some extra information is given for the
1147            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1148            probably the only errors that are likely to be caused by users (by
1149            specifying a regex that has nested indefinite repeats, for instance).
1150            If there are more than 20 of these errors, pcregrep is abandoned.
1152        (b) A binary zero was treated as data while matching, but terminated the
1153            output line if it was written out. This has been fixed: binary zeroes
1154            are now no different to any other data bytes.
1156        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1157            used to set a locale for matching. The --locale=xxxx long option has
1158            been added (no short equivalent) to specify a locale explicitly on the
1159            pcregrep command, overriding the environment variables.
1161        (d) When -B was used with -n, some line numbers in the output were one less
1162            than they should have been.
1164        (e) Added the -o (--only-matching) option.
1166        (f) If -A or -C was used with -c (count only), some lines of context were
1167            accidentally printed for the final match.
1169        (g) Added the -H (--with-filename) option.
1171        (h) The combination of options -rh failed to suppress file names for files
1172            that were found from directory arguments.
1174        (i) Added the -D (--devices) and -d (--directories) options.
1176        (j) Added the -F (--fixed-strings) option.
1178        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1180        (l) Added the --colo(u)r option.
1182        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1183            is not present by default.
1185     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1186        items such as (?R) or (?1), when the recursion could match a number of
1187        alternatives. If it matched one of the alternatives, but subsequently,
1188        outside the recursion, there was a failure, the code tried to back up into
1189        the recursion. However, because of the way PCRE is implemented, this is not
1190        possible, and the result was an incorrect result from the match.
1192        In order to prevent this happening, the specification of recursion has
1193        been changed so that all such subpatterns are automatically treated as
1194        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1196     4. I had overlooked the fact that, in some locales, there are characters for
1197        which isalpha() is true but neither isupper() nor islower() are true. In
1198        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1199        and ordfeminine) are like this. This affected the treatment of \w and \W
1200        when they appeared in character classes, but not when they appeared outside
1201        a character class. The bit map for "word" characters is now created
1202        separately from the results of isalnum() instead of just taking it from the
1203        upper, lower, and digit maps. (Plus the underscore character, of course.)
1205     5. The above bug also affected the handling of POSIX character classes such as
1206        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1207        permanent tables. Instead, the bit maps for such a class were previously
1208        created as the appropriate unions of the upper, lower, and digit bitmaps.
1209        Now they are created by subtraction from the [[:word:]] class, which has
1210        its own bitmap.
1212     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1213        It is created by subtracting the vertical space characters (\x09, \x0a,
1214        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1215        subtraction was done in the overall bitmap for a character class, meaning
1216        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1217        be recognized. This bug has been fixed.
1219     7. Patches from the folks at Google:
1221          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1222          real life, but is still worth protecting against".
1224          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1225          regular expressions".
1227          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1228          have it.
1230          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1231          "configure" and the latter not, in order to fix a problem somebody had
1232          with compiling the Arg class on HP-UX.
1234          (e) Improve the error-handling of the C++ wrapper a little bit.
1236          (f) New tests for checking recursion limiting.
1238     8. The pcre_memmove() function, which is used only if the environment does not
1239        have a standard memmove() function (and is therefore rarely compiled),
1240        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1241        returning a result (though PCRE never actually uses the result).
1243     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1244        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1245        returned instead of calling malloc() with an overflowing number that would
1246        most likely cause subsequent chaos.
1248    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1250    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1251        with this option is matched, the nmatch and pmatch options of regexec() are
1252        ignored.
1254    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1255        provided in case anyone wants to the the POSIX interface with UTF-8
1256        strings.
1258    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1259        C++ linking (needed for some HP-UX environments).
1261    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1262        (unused parameter) and in the pcre_printint() function (omitted "default"
1263        switch label when the default is to do nothing).
1265    15. Added some code to make it possible, when PCRE is compiled as a C++
1266        library, to replace subject pointers for pcre_exec() with a smart pointer
1267        class, thus making it possible to process discontinuous strings.
1269    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1270        much the same function. They were added by different people who were trying
1271        to make PCRE easy to compile on non-Unix systems. It has been suggested
1272        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1273        for compiling on Windows systems. I have therefore replaced it with
1274        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1275        defaults to "extern" for C or "extern C" for C++, which works fine on
1276        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1277        SCOPE with something explicit in config.h. In addition:
1279        (a) pcreposix.h still had just "extern" instead of either of these macros;
1280            I have replaced it with PCRE_DATA_SCOPE.
1282        (b) Functions such as _pcre_xclass(), which are internal to the library,
1283            but external in the C sense, all had PCRE_EXPORT in their definitions.
1284            This is apparently wrong for the Windows case, so I have removed it.
1285            (It makes no difference on Unix-like systems.)
1287    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1288        of recursive calls to match(). This is different to MATCH_LIMIT because
1289        that limits the total number of calls to match(), not all of which increase
1290        the depth of recursion. Limiting the recursion depth limits the amount of
1291        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1292        when PCRE is compiled, and changed at run time. A patch from Google adds
1293        this functionality to the C++ interface.
1295    18. Changes to the handling of Unicode character properties:
1297        (a) Updated the table to Unicode 4.1.0.
1299        (b) Recognize characters that are not in the table as "Cn" (undefined).
1301        (c) I revised the way the table is implemented to a much improved format
1302            which includes recognition of ranges. It now supports the ranges that
1303            are defined in UnicodeData.txt, and it also amalgamates other
1304            characters into ranges. This has reduced the number of entries in the
1305            table from around 16,000 to around 3,000, thus reducing its size
1306            considerably. I realized I did not need to use a tree structure after
1307            all - a binary chop search is just as efficient. Having reduced the
1308            number of entries, I extended their size from 6 bytes to 8 bytes to
1309            allow for more data.
1311        (d) Added support for Unicode script names via properties such as \p{Han}.
1313    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1314        matching that character.
1316    20. When matching a repeated Unicode property with a minimum greater than zero,
1317        (for example \pL{2,}), PCRE could look past the end of the subject if it
1318        reached it while seeking the minimum number of characters. This could
1319        happen only if some of the characters were more than one byte long, because
1320        there is a check for at least the minimum number of bytes.
1322    21. Refactored the implementation of \p and \P so as to be more general, to
1323        allow for more different types of property in future. This has changed the
1324        compiled form incompatibly. Anybody with saved compiled patterns that use
1325        \p or \P will have to recompile them.
1327    22. Added "Any" and "L&" to the supported property types.
1329    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1330        but give a compile time error if the value is greater than 0xff.
1332    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1333        accidentally not being installed or uninstalled.
1335    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1336        made were to insert the current release number. This seemed silly, because
1337        it made things harder for people building PCRE on systems that don't run
1338        "configure". I have turned pcre.h into a distributed file, no longer built
1339        by "configure", with the version identification directly included. There is
1340        no longer a pcre.h.in file.
1342        However, this change necessitated a change to the pcre-config script as
1343        well. It is built from pcre-config.in, and one of the substitutions was the
1344        release number. I have updated configure.ac so that ./configure now finds
1345        the release number by grepping pcre.h.
1347    26. Added the ability to run the tests under valgrind.
1350    Version 6.4 05-Sep-05
1351    ---------------------
1353     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1354        "--" to be printed when multiple files were scanned, even when none of the
1355        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1356        consider it to be a bug, and have restored the previous behaviour.
1358     2. A couple of code tidies to get rid of compiler warnings.
1360     3. The pcretest program used to cheat by referring to symbols in the library
1361        whose names begin with _pcre_. These are internal symbols that are not
1362        really supposed to be visible externally, and in some environments it is
1363        possible to suppress them. The cheating is now confined to including
1364        certain files from the library's source, which is a bit cleaner.
1366     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1367        file's purpose clearer.
1369     5. Reorganized pcre_ucp_findchar().
1372    Version 6.3 15-Aug-05
1373    ---------------------
1375     1. The file libpcre.pc.in did not have general read permission in the tarball.
1377     2. There were some problems when building without C++ support:
1379        (a) If C++ support was not built, "make install" and "make test" still
1380            tried to test it.
1382        (b) There were problems when the value of CXX was explicitly set. Some
1383            changes have been made to try to fix these, and ...
1385        (c) --disable-cpp can now be used to explicitly disable C++ support.
1387        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1388            backslash in a target when C++ was disabled. This confuses some
1389            versions of "make", apparently. Using an intermediate variable solves
1390            this. (Same for CPP_LOBJ.)
1392     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1393        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1394        necessary on certain architectures.
1396     4. Added a setting of -export-symbols-regex to the link command to remove
1397        those symbols that are exported in the C sense, but actually are local
1398        within the library, and not documented. Their names all begin with
1399        "_pcre_". This is not a perfect job, because (a) we have to except some
1400        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1401        available (and never for static libraries). I have made a note to try to
1402        find a way round (a) in the future.
1405    Version 6.2 01-Aug-05
1406    ---------------------
1408     1. There was no test for integer overflow of quantifier values. A construction
1409        such as {1111111111111111} would give undefined results. What is worse, if
1410        a minimum quantifier for a parenthesized subpattern overflowed and became
1411        negative, the calculation of the memory size went wrong. This could have
1412        led to memory overwriting.
1414     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1416     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1417        operating environments where this matters.
1419     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1420        PCRE options from within the C++ wrapper.
1422     5. Named capturing subpatterns were not being correctly counted when a pattern
1423        was compiled. This caused two problems: (a) If there were more than 100
1424        such subpatterns, the calculation of the memory needed for the whole
1425        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1426        back references of the form \12, where the number was greater than 9, were
1427        not recognized as back references, even though there were sufficient
1428        previous subpatterns.
1430     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1431        versions of gcc, e.g. 2.95.4.
1434    Version 6.1 21-Jun-05
1435    ---------------------
1437     1. There was one reference to the variable "posix" in pcretest.c that was not
1438        surrounded by "#if !defined NOPOSIX".
1440     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1441        the cross-check on the old pcre_info() function, for the benefit of the
1442        cut-down version of PCRE that is currently imported into Exim.
1444     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1445        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1446        patterns that start (?i) but I don't think that matters. The use of (?i) is
1447        just an example; this all applies to the other options as well.
1449     4. Since libtool seems to echo the compile commands it is issuing, the output
1450        from "make" can be reduced a bit by putting "@" in front of each libtool
1451        compile command.
1453     5. Patch from the folks at Google for configure.in to be a bit more thorough
1454        in checking for a suitable C++ installation before trying to compile the
1455        C++ stuff. This should fix a reported problem when a compiler was present,
1456        but no suitable headers.
1458     6. The man pages all had just "PCRE" as their title. I have changed them to
1459        be the relevant file name. I have also arranged that these names are
1460        retained in the file doc/pcre.txt, which is a concatenation in text format
1461        of all the man pages except the little individual ones for each function.
1463     7. The NON-UNIX-USE file had not been updated for the different set of source
1464        files that come with release 6. I also added a few comments about the C++
1465        wrapper.
1468    Version 6.0 07-Jun-05
1469    ---------------------
1471     1. Some minor internal re-organization to help with my DFA experiments.
1473     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1474        didn't matter for the library itself when fully configured, but did matter
1475        when compiling without UCP support, or within Exim, where the ucp files are
1476        not imported.
1478     3. Refactoring of the library code to split up the various functions into
1479        different source modules. The addition of the new DFA matching code (see
1480        below) to a single monolithic source would have made it really too
1481        unwieldy, quite apart from causing all the code to be include in a
1482        statically linked application, when only some functions are used. This is
1483        relevant even without the DFA addition now that patterns can be compiled in
1484        one application and matched in another.
1486        The downside of splitting up is that there have to be some external
1487        functions and data tables that are used internally in different modules of
1488        the library but which are not part of the API. These have all had their
1489        names changed to start with "_pcre_" so that they are unlikely to clash
1490        with other external names.
1492     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1493        a different (DFA) algorithm. Although it is slower than the original
1494        function, it does have some advantages for certain types of matching
1495        problem.
1497     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1498        including restarting after a partial match.
1500     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1501        defined when compiling for Windows was sent to me. I have put it into the
1502        code, though I have no means of testing or verifying it.
1504     7. Added the pcre_refcount() auxiliary function.
1506     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1507        match before or at the first newline in the subject string. In pcretest,
1508        the /f option on a pattern can be used to set this.
1510     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1511        would behave wrongly. This has been present in PCRE since release 4.0.
1513    10. A number of changes to the pcregrep command:
1515        (a) Refactored how -x works; insert ^(...)$ instead of setting
1516            PCRE_ANCHORED and checking the length, in preparation for adding
1517            something similar for -w.
1519        (b) Added the -w (match as a word) option.
1521        (c) Refactored the way lines are read and buffered so as to have more
1522            than one at a time available.
1524        (d) Implemented a pcregrep test script.
1526        (e) Added the -M (multiline match) option. This allows patterns to match
1527            over several lines of the subject. The buffering ensures that at least
1528            8K, or the rest of the document (whichever is the shorter) is available
1529            for matching (and similarly the previous 8K for lookbehind assertions).
1531        (f) Changed the --help output so that it now says
1533              -w, --word-regex(p)
1535            instead of two lines, one with "regex" and the other with "regexp"
1536            because that confused at least one person since the short forms are the
1537            same. (This required a bit of code, as the output is generated
1538            automatically from a table. It wasn't just a text change.)
1540        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1541            option but starts with a hyphen. Could be a pattern or a path name
1542            starting with a hyphen, for instance.
1544        (h) "-" can be given as a file name to represent stdin.
1546        (i) When file names are being printed, "(standard input)" is used for
1547            the standard input, for compatibility with GNU grep. Previously
1548            "<stdin>" was used.
1550        (j) The option --label=xxx can be used to supply a name to be used for
1551            stdin when file names are being printed. There is no short form.
1553        (k) Re-factored the options decoding logic because we are going to add
1554            two more options that take data. Such options can now be given in four
1555            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1557        (l) Added the -A, -B, and -C options for requesting that lines of context
1558            around matches be printed.
1560        (m) Added the -L option to print the names of files that do not contain
1561            any matching lines, that is, the complement of -l.
1563        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1564            continue to scan other files.
1566        (o) The -s option was incorrectly implemented. For compatibility with other
1567            greps, it now suppresses the error message for a non-existent or non-
1568            accessible file (but not the return code). There is a new option called
1569            -q that suppresses the output of matching lines, which was what -s was
1570            previously doing.
1572        (p) Added --include and --exclude options to specify files for inclusion
1573            and exclusion when recursing.
1575    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1576        Hopefully, it now does.
1578    12. Missing cast in pcre_study().
1580    13. Added an "uninstall" target to the makefile.
1582    14. Replaced "extern" in the function prototypes in Makefile.in with
1583        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1584        world, but is set differently for Windows.
1586    15. Added a second compiling function called pcre_compile2(). The only
1587        difference is that it has an extra argument, which is a pointer to an
1588        integer error code. When there is a compile-time failure, this is set
1589        non-zero, in addition to the error test pointer being set to point to an
1590        error message. The new argument may be NULL if no error number is required
1591        (but then you may as well call pcre_compile(), which is now just a
1592        wrapper). This facility is provided because some applications need a
1593        numeric error indication, but it has also enabled me to tidy up the way
1594        compile-time errors are handled in the POSIX wrapper.
1596    16. Added VPATH=.libs to the makefile; this should help when building with one
1597        prefix path and installing with another. (Or so I'm told by someone who
1598        knows more about this stuff than I do.)
1600    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1601        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1602        match everything, including newlines. This is not POSIX-compatible, but
1603        somebody wanted the feature. From pcretest it can be activated by using
1604        both the P and the s flags.
1606    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1608    19. libpcre.pc was being incorrectly installed as executable.
1610    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1611        it now also looks for '\r' so that it will work unmodified on Windows.
1613    21. Added Google's contributed C++ wrapper to the distribution.
1615    22. Added some untidy missing memory free() calls in pcretest, to keep
1616        Electric Fence happy when testing.
1620    Version 5.0 13-Sep-04
1621    ---------------------
1623     1. Internal change: literal characters are no longer packed up into items
1624        containing multiple characters in a single byte-string. Each character
1625        is now matched using a separate opcode. However, there may be more than one
1626        byte in the character in UTF-8 mode.
1628     2. The pcre_callout_block structure has two new fields: pattern_position and
1629        next_item_length. These contain the offset in the pattern to the next match
1630        item, and its length, respectively.
1632     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1633        insertion of callouts before each pattern item. Added the /C option to
1634        pcretest to make use of this.
1636     4. On the advice of a Windows user, the lines
1638          #if defined(_WIN32) || defined(WIN32)
1639          _setmode( _fileno( stdout ), 0x8000 );
1640          #endif  /* defined(_WIN32) || defined(WIN32) */
1642        have been added to the source of pcretest. This apparently does useful
1643        magic in relation to line terminators.
1645     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1646        for the benefit of those environments where the "b" makes a difference.
1648     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1649        to know about it. I have put a hack into configure.in that adds in code
1650        to set GCC=yes if CC=icc. This seems to end up at a point in the
1651        generated configure script that is early enough to affect the setting of
1652        compiler options, which is what is needed, but I have no means of testing
1653        whether it really works. (The user who reported this had patched the
1654        generated configure script, which of course I cannot do.)
1656        LATER: After change 22 below (new libtool files), the configure script
1657        seems to know about icc (and also ecc). Therefore, I have commented out
1658        this hack in configure.in.
1660     7. Added support for pkg-config (2 patches were sent in).
1662     8. Negated POSIX character classes that used a combination of internal tables
1663        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1664        [[:^ascii]]. Typically, they would match almost any characters. The other
1665        POSIX classes were not broken in this way.
1667     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1668        to find the match, as PCRE was deluded into thinking that the match had to
1669        start at the start point or following a newline. The same bug applied to
1670        patterns with negative forward assertions or any backward assertions
1671        preceding ".*" at the start, unless the pattern required a fixed first
1672        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1674    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1675        starting at the last subject character, bytes beyond the end of the subject
1676        string were read.
1678    11. Renamed the variable "class" as "classbits" to make life easier for C++
1679        users. (Previously there was a macro definition, but it apparently wasn't
1680        enough.)
1682    12. Added the new field "tables" to the extra data so that tables can be passed
1683        in at exec time, or the internal tables can be re-selected. This allows
1684        a compiled regex to be saved and re-used at a later time by a different
1685        program that might have everything at different addresses.
1687    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1688        -R library as well as a -L library.
1690    14. The debugging options of pcretest (-d on the command line or D on a
1691        pattern) showed incorrect output for anything following an extended class
1692        that contained multibyte characters and which was followed by a quantifier.
1694    15. Added optional support for general category Unicode character properties
1695        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1696        support. It adds about 90K to the size of the library. The meanings of the
1697        inbuilt class escapes such as \d and \s have NOT been changed.
1699    16. Updated pcredemo.c to include calls to free() to release the memory for the
1700        compiled pattern.
1702    17. The generated file chartables.c was being created in the source directory
1703        instead of in the building directory. This caused the build to fail if the
1704        source directory was different from the building directory, and was
1705        read-only.
1707    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1708        file. No doubt somebody will tell me if they don't make sense... Also added
1709        Dan Mooney's comments about building on OpenVMS.
1711    19. Added support for partial matching via the PCRE_PARTIAL option for
1712        pcre_exec() and the \P data escape in pcretest.
1714    20. Extended pcretest with 3 new pattern features:
1716        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1717              write the compiled pattern to the file whose name is "rest-of-line".
1718              This is a straight binary dump of the data, with the saved pointer to
1719              the character tables forced to be NULL. The study data, if any, is
1720              written too. After writing, pcretest reads a new pattern.
1722        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1723              compiled pattern from the given file. There must not be any
1724              occurrences of "<" in the file name (pretty unlikely); if there are,
1725              pcretest will instead treat the initial "<" as a pattern delimiter.
1726              After reading in the pattern, pcretest goes on to read data lines as
1727              usual.
1729        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1730              and 16-bit fields in a compiled pattern, to simulate a pattern that
1731              was compiled on a host of opposite endianness.
1733    21. The pcre-exec() function can now cope with patterns that were compiled on
1734        hosts of opposite endianness, with this restriction:
1736          As for any compiled expression that is saved and used later, the tables
1737          pointer field cannot be preserved; the extra_data field in the arguments
1738          to pcre_exec() should be used to pass in a tables address if a value
1739          other than the default internal tables were used at compile time.
1741    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1742        now diagnosed as an error. Previously, most of the time, a negative number
1743        would have been treated as zero, but if in addition "ovector" was passed as
1744        NULL, a crash could occur.
1746    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1747        new versions from the libtool 1.5 distribution (the last one is a copy of
1748        a file called libtool.m4). This seems to have fixed the need to patch
1749        "configure" to support Darwin 1.3 (which I used to do). However, I still
1750        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1751        workstation).
1753    24. Changed the PCRE licence to be the more standard "BSD" licence.
1756    Version 4.5 01-Dec-03
1757    ---------------------
1759     1. There has been some re-arrangement of the code for the match() function so
1760        that it can be compiled in a version that does not call itself recursively.
1761        Instead, it keeps those local variables that need separate instances for
1762        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1763        needs to "recurse". Keeping track of where control must go is done by means
1764        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1765        hide most of the details from the main code, and operates only if
1766        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1767        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1768        operating.
1770        To make it easier for callers to provide specially tailored get/free
1771        functions for this usage, two new functions, pcre_stack_malloc, and
1772        pcre_stack_free, are used. They are always called in strict stacking order,
1773        and the size of block requested is always the same.
1775        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1776        PCRE has been compiled to use the stack or the heap for recursion. The
1777        -C option of pcretest uses this to show which version is compiled.
1779        A new data escape \S, is added to pcretest; it causes the amounts of store
1780        obtained and freed by both kinds of malloc/free at match time to be added
1781        to the output.
1783     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1784        what's available on my current Linux desktop machine.
1786     3. When matching a UTF-8 string, the test for a valid string at the start has
1787        been extended. If start_offset is not zero, PCRE now checks that it points
1788        to a byte that is the start of a UTF-8 character. If not, it returns
1789        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1790        this is necessary because there may be backward assertions in the pattern.
1791        When matching the same subject several times, it may save resources to use
1792        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1794     4. The code for checking the validity of UTF-8 strings has been tightened so
1795        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1796        containing "overlong sequences".
1798     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1799        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1800        should have been "&", but it just so happened that all the cases this let
1801        through by mistake were picked up later in the function.
1803     6. I had used a variable called "isblank" - this is a C99 function, causing
1804        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1806     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1807        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1808        so the version is shown; (c) stop "make test" echoing "./RunTest".
1810     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1812     9. The prototype for memmove() for systems that don't have it was using
1813        size_t, but the inclusion of the header that defines size_t was later. I've
1814        moved the #includes for the C headers earlier to avoid this.
1816    10. Added some adjustments to the code to make it easier to compiler on certain
1817        special systems:
1819          (a) Some "const" qualifiers were missing.
1820          (b) Added the macro EXPORT before all exported functions; by default this
1821              is defined to be empty.
1822          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1823              that it reads its output file name as an argument instead of writing
1824              to the standard output and assuming this can be redirected.
1826    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1827        class containing characters with values greater than 255, PCRE compilation
1828        went into a loop.
1830    12. A recursive reference to a subpattern that was within another subpattern
1831        that had a minimum quantifier of zero caused PCRE to crash. For example,
1832        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1833        recursion. If the recursively-called subpattern itself had a zero repeat,
1834        that was OK.
1836    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1837        buffer into which it was copied (for escape processing) was still set at
1838        1024, so long lines caused crashes.
1840    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1841        "internal error: code overflow...". This applied to any character class
1842        that was followed by a possessive quantifier.
1844    15. Modified the Makefile to add libpcre.la as a prerequisite for
1845        libpcreposix.la because I was told this is needed for a parallel build to
1846        work.
1848    16. If a pattern that contained .* following optional items at the start was
1849        studied, the wrong optimizing data was generated, leading to matching
1850        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1851        matching string must start with a or b or c. The correct conclusion for
1852        this pattern is that a match can start with any character.
1855    Version 4.4 13-Aug-03
1856    ---------------------
1858     1. In UTF-8 mode, a character class containing characters with values between
1859        127 and 255 was not handled correctly if the compiled pattern was studied.
1860        In fixing this, I have also improved the studying algorithm for such
1861        classes (slightly).
1863     2. Three internal functions had redundant arguments passed to them. Removal
1864        might give a very teeny performance improvement.
1866     3. Documentation bug: the value of the capture_top field in a callout is *one
1867        more than* the number of the hightest numbered captured substring.
1869     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1870        in incorrectly linking with a previously installed version. They now link
1871        explicitly with libpcre.la.
1873     5. configure.in no longer needs to recognize Cygwin specially.
1875     6. A problem in pcre.in for Windows platforms is fixed.
1877     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1878        pcretest, it used to include the size of the study block as part of its
1879        output. Unfortunately, the structure contains a field that has a different
1880        size on different hardware architectures. This meant that the tests that
1881        showed this size failed. As the block is currently always of a fixed size,
1882        this information isn't actually particularly useful in pcretest output, so
1883        I have just removed it.
1885     8. Three pre-processor statements accidentally did not start in column 1.
1886        Sadly, there are *still* compilers around that complain, even though
1887        standard C has not required this for well over a decade. Sigh.
1889     9. In pcretest, the code for checking callouts passed small integers in the
1890        callout_data field, which is a void * field. However, some picky compilers
1891        complained about the casts involved for this on 64-bit systems. Now
1892        pcretest passes the address of the small integer instead, which should get
1893        rid of the warnings.
1895    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1896        both compile and run time, and gives an error if an invalid UTF-8 sequence
1897        is found. There is a option for disabling this check in cases where the
1898        string is known to be correct and/or the maximum performance is wanted.
1900    11. In response to a bug report, I changed one line in Makefile.in from
1902            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1903        to
1904            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1906        to look similar to other lines, but I have no way of telling whether this
1907        is the right thing to do, as I do not use Windows. No doubt I'll get told
1908        if it's wrong...
1911    Version 4.3 21-May-03
1912    ---------------------
1914    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1915       Makefile.
1917    2. Some refactoring to improve the quality of the code:
1919       (i)   The utf8_table... variables are now declared "const".
1921       (ii)  The code for \cx, which used the "case flipping" table to upper case
1922             lower case letters, now just substracts 32. This is ASCII-specific,
1923             but the whole concept of \cx is ASCII-specific, so it seems
1924             reasonable.
1926       (iii) PCRE was using its character types table to recognize decimal and
1927             hexadecimal digits in the pattern. This is silly, because it handles
1928             only 0-9, a-f, and A-F, but the character types table is locale-
1929             specific, which means strange things might happen. A private
1930             table is now used for this - though it costs 256 bytes, a table is
1931             much faster than multiple explicit tests. Of course, the standard
1932             character types table is still used for matching digits in subject
1933             strings against \d.
1935       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1936             ending in _t are). So I've renamed it as ESC_tee.
1938    3. The first argument for regexec() in the POSIX wrapper should have been
1939       defined as "const".
1941    4. Changed pcretest to use malloc() for its buffers so that they can be
1942       Electric Fenced for debugging.
1944    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1945       to read one or more bytes before the start of the subject string. Often this
1946       had no effect on PCRE's behaviour, but in some circumstances it could
1947       provoke a segmentation fault.
1949    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1950       to try to read one or more bytes before the start of the subject string.
1952    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1953       UTF-8 support could misbehave in various ways if the subject string
1954       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1955       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1956       back over UTF-8 characters.)
1959    Version 4.2 14-Apr-03
1960    ---------------------
1962    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1964    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1965         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1966         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1967         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1968         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1969           and BUILD_EXEEXT
1970         Note: automatic setting of the BUILD variables is not yet working
1971         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1972           compile-time but not at link-time
1973         [LINK]: use for linking executables only
1974         make different versions for Windows and non-Windows
1975         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1976           libraries
1977         [LINK_FOR_BUILD]: new variable
1978         [OBJEXT]: use throughout
1979         [EXEEXT]: use throughout
1980         <winshared>: new target
1981         <wininstall>: new target
1982         <dftables.o>: use native compiler
1983         <dftables>: use native linker
1984         <install>: handle Windows platform correctly
1985         <clean>: ditto
1986         <check>: ditto
1987         copy DLL to top builddir before testing
1989       As part of these changes, -no-undefined was removed again. This was reported
1990       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1991       in any case.
1993    3. Some tidies to get rid of compiler warnings:
1995       . In the match_data structure, match_limit was an unsigned long int, whereas
1996         match_call_count was an int. I've made them both unsigned long ints.
1998       . In pcretest the fact that a const uschar * doesn't automatically cast to
1999         a void * provoked a warning.
2001       . Turning on some more compiler warnings threw up some "shadow" variables
2002         and a few more missing casts.
2004    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2005       option, a class that contained a single character with a value between 128
2006       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2008    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2009       option, a class that contained several characters, but with at least one
2010       whose value was between 128 and 255 caused PCRE to crash.
2013    Version 4.1 12-Mar-03
2014    ---------------------
2016    1. Compiling with gcc -pedantic found a couple of places where casts were
2017    needed, and a string in dftables.c that was longer than standard compilers are
2018    required to support.
2020    2. Compiling with Sun's compiler found a few more places where the code could
2021    be tidied up in order to avoid warnings.
2023    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2024    first of these names is deprecated in the latest Autoconf in favour of the name
2025    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2026    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2027    analogy I have changed it to CFLAGS_FOR_BUILD.
2029    4. Added -no-undefined to the linking command in the Makefile, because this is
2030    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2031    linking step for the pcreposix library.
2033    5. PCRE was failing to diagnose the case of two named groups with the same
2034    name.
2036    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2037    literal character that is needed in the subject for a match, and scans along to
2038    ensure that it is present before embarking on the full matching process. This
2039    saves time in cases of nested unlimited repeats that are never going to match.
2040    Problem: the scan can take a lot of time if the subject is very long (e.g.
2041    megabytes), thus penalizing straightforward matches. It is now done only if the
2042    amount of subject to be scanned is less than 1000 bytes.
2044    7. A lesser problem with the same optimization is that it was recording the
2045    first character of an anchored pattern as "needed", thus provoking a search
2046    right along the subject, even when the first match of the pattern was going to
2047    fail. The "needed" character is now not set for anchored patterns, unless it
2048    follows something in the pattern that is of non-fixed length. Thus, it still
2049    fulfils its original purpose of finding quick non-matches in cases of nested
2050    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2053    Version 4.0 17-Feb-03
2054    ---------------------
2056    1. If a comment in an extended regex that started immediately after a meta-item
2057    extended to the end of string, PCRE compiled incorrect data. This could lead to
2058    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2060    2. Moved to autoconf 2.53 and libtool 1.4.2.
2062    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2063    the special perltest8 script is no longer needed - all the tests can be run
2064    from a single perltest script.
2066    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2067    by \s. It has now been removed in PCRE. This means it isn't recognized as
2068    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2069    class [:space:] *does* include VT, thereby creating a mess.
2071    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2072    space and tab.
2074    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2075    its new features into the main test script, reducing the number of scripts.
2077    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2078    were backward compatible, and made the (?i) apply to the whole pattern, as if
2079    /i were given. Now it behaves more logically, and applies the option setting
2080    only to what follows. PCRE has been changed to follow suit. However, if it
2081    finds options settings right at the start of the pattern, it extracts them into
2082    the global options, as before. Thus, they show up in the info data.
2084    8. Added support for the \Q...\E escape sequence. Characters in between are
2085    treated as literals. This is slightly different from Perl in that $ and @ are
2086    also handled as literals inside the quotes. In Perl, they will cause variable
2087    interpolation. Note the following examples:
2089        Pattern            PCRE matches      Perl matches
2091        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2092        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2093        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2095    For compatibility with Perl, \Q...\E sequences are recognized inside character
2096    classes as well as outside them.
2098    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2099    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2100    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2101    signed/unsigned warnings.
2103    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2104    option for pcretest, so I've replaced it by a simple function that does just
2105    that job.
2107    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2108    "pcregrep -".
2110    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2111    Java package. This provides some syntactic sugar for simple cases of what my
2112    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2113    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2114    item, you can use this simplified notation. Note that only makes sense with
2115    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2116    greediness, whatever the setting of the PCRE_UNGREEDY option.
2118    13. A change of greediness default within a pattern was not taking effect at
2119    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2120    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2121    was abstracted outside.
2123    14. PCRE now supports the \G assertion. It is true when the current matching
2124    position is at the start point of the match. This differs from \A when the
2125    starting offset is non-zero. Used with the /g option of pcretest (or similar
2126    code), it works in the same way as it does for Perl's /g option. If all
2127    alternatives of a regex begin with \G, the expression is anchored to the start
2128    match position, and the "anchored" flag is set in the compiled expression.
2130    15. Some bugs concerning the handling of certain option changes within patterns
2131    have been fixed. These applied to options other than (?ims). For example,
2132    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2133    been the other way round. Some of this was related to change 7 above.
2135    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2136    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2137    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2138    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2140    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2141    mode. Unlike ".", it always matches newline, whatever the setting of
2142    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2143    assertions. Perl allows it, but it doesn't (in general) work because it can't
2144    calculate the length of the lookbehind. At least, that's the case for Perl
2145    5.8.0 - I've been told they are going to document that it doesn't work in
2146    future.
2148    18. Added an error diagnosis for escapes that PCRE does not support: these are
2149    \L, \l, \N, \P, \p, \U, \u, and \X.
2151    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2152    reading past the end of the pattern in cases such as /[abcd/.
2154    20. PCRE was getting more memory than necessary for patterns with classes that
2155    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2157    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2158    compiling PCRE for use with Virtual Pascal.
2160    22. Small fix to the Makefile to make it work properly if the build is done
2161    outside the source tree.
2163    23. Added a new extension: a condition to go with recursion. If a conditional
2164    subpattern starts with (?(R) the "true" branch is used if recursion has
2165    happened, whereas the "false" branch is used only at the top level.
2167    24. When there was a very long string of literal characters (over 255 bytes
2168    without UTF support, over 250 bytes with UTF support), the computation of how
2169    much memory was required could be incorrect, leading to segfaults or other
2170    strange effects.
2172    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2173    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2174    there was a subsequent back reference to those brackets. This meant that, for
2175    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2176    possible to check for precisely this case. All we can do is abandon the
2177    optimization if .* occurs inside capturing brackets when there are any back
2178    references whatsoever. (See below for a better fix that came later.)
2180    26. The handling of the optimization for finding the first character of a
2181    non-anchored pattern, and for finding a character that is required later in the
2182    match were failing in some cases. This didn't break the matching; it just
2183    failed to optimize when it could. The way this is done has been re-implemented.
2185    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2187    28. Added a new feature that provides some of the functionality that Perl
2188    provides with (?{...}). The facility is termed a "callout". The way it is done
2189    in PCRE is for the caller to provide an optional function, by setting
2190    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2191    global variable. By default it is unset, which disables all calling out. To get
2192    the function called, the regex must include (?C) at appropriate points. This
2193    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2194    This provides a means of identifying different callout points. When PCRE
2195    reaches such a point in the regex, if pcre_callout has been set, the external
2196    function is called. It is provided with data in a structure called
2197    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2198    matching continues; if it returns a non-zero value, the match at the current
2199    point fails. However, backtracking will occur if possible. [This was changed
2200    later and other features added - see item 49 below.]
2202    29. pcretest is upgraded to test the callout functionality. It provides a
2203    callout function that displays information. By default, it shows the start of
2204    the match and the current position in the text. There are some new data escapes
2205    to vary what happens:
2207        \C+         in addition, show current contents of captured substrings
2208        \C-         do not supply a callout function
2209        \C!n        return 1 when callout number n is reached
2210        \C!n!m      return 1 when callout number n is reached for the mth time
2212    30. If pcregrep was called with the -l option and just a single file name, it
2213    output "<stdin>" if a match was found, instead of the file name.
2215    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2216    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2217    pcre_exec(). This saves a malloc/free per call. The default value of
2218    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2219    when configuring.
2221    32. The default maximum size of a compiled pattern is 64K. There have been a
2222    few cases of people hitting this limit. The code now uses macros to handle the
2223    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2224    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2225    configuring. Tests 2 and 5 work only with 2-byte links because they output
2226    debugging information about compiled patterns.
2228    33. Internal code re-arrangements:
2230    (a) Moved the debugging function for printing out a compiled regex into
2231        its own source file (printint.c) and used #include to pull it into
2232        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2233        separate copies.
2235    (b) Defined the list of op-code names for debugging as a macro in
2236        internal.h so that it is next to the definition of the opcodes.
2238    (c) Defined a table of op-code lengths for simpler skipping along compiled
2239        code. This is again a macro in internal.h so that it is next to the
2240        definition of the opcodes.
2242    34. Added support for recursive calls to individual subpatterns, along the
2243    lines of Robin Houston's patch (but implemented somewhat differently).
2245    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2246    allow it to read and process whole directories in Win32. This code was
2247    contributed by Lionel Fourquaux; it has not been tested by me.
2249    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2250    used to name a group. Names consist of alphanumerics and underscores, and must
2251    be unique. Back references use the syntax (?P=name) and recursive calls use
2252    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2253    numbers. The function pcre_fullinfo() can be used after compilation to extract
2254    a name/number map. There are three relevant calls:
2256      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2257      PCRE_INFO_NAMECOUNT            yields the number of entries
2258      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2260    The map is a vector of fixed-size entries. The size of each entry depends on
2261    the length of the longest name used. The first two bytes of each entry are the
2262    group number, most significant byte first. There follows the corresponding
2263    name, zero terminated. The names are in alphabetical order.
2265    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2266    case instead of 255. Making it the same both with and without UTF-8 support
2267    means that the same test output works with both.
2269    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2270    calling malloc() with a zero argument.
2272    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2273    optimization. I've improved things by keeping a bitmap of backreferences with
2274    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2275    fact referenced, the optimization can be applied. It is unlikely that a
2276    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2277    the match to follow \n) will appear inside brackets with a number greater than
2278    31, but if it does, any back reference > 31 suppresses the optimization.
2280    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2281    of disabling numbered capturing parentheses. Any opening parenthesis that is
2282    not followed by ? behaves as if it were followed by ?: but named parentheses
2283    can still be used for capturing (and they will acquire numbers in the usual
2284    way).
2286    41. Redesigned the return codes from the match() function into yes/no/error so
2287    that errors can be passed back from deep inside the nested calls. A malloc
2288    failure while inside a recursive subpattern call now causes the
2289    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2291    42. It is now possible to set a limit on the number of times the match()
2292    function is called in a call to pcre_exec(). This facility makes it possible to
2293    limit the amount of recursion and backtracking, though not in a directly
2294    obvious way, because the match() function is used in a number of different
2295    circumstances. The count starts from zero for each position in the subject
2296    string (for non-anchored patterns). The default limit is, for compatibility, a
2297    large number, namely 10 000 000. You can change this in two ways:
2299    (a) When configuring PCRE before making, you can use --with-match-limit=n
2300        to set a default value for the compiled library.
2302    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2303        a different value is set. See 45 below.
2305    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2307    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2308    of things that can be changed at compile time. The first argument specifies
2309    what is wanted and the second points to where the information is to be placed.
2310    The current list of available information is:
2312      PCRE_CONFIG_UTF8
2314    The output is an integer that is set to one if UTF-8 support is available;
2315    otherwise it is set to zero.
2319    The output is an integer that it set to the value of the code that is used for
2320    newline. It is either LF (10) or CR (13).
2324    The output is an integer that contains the number of bytes used for internal
2325    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2329    The output is an integer that contains the threshold above which the POSIX
2330    interface uses malloc() for output vectors. See item 31 above.
2334    The output is an unsigned integer that contains the default limit of the number
2335    of match() calls in a pcre_exec() execution. See 42 above.
2337    44. pcretest has been upgraded by the addition of the -C option. This causes it
2338    to extract all the available output from the new pcre_config() function, and to
2339    output it. The program then exits immediately.
2341    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2342    order to support additional features. One way would have been to define
2343    pcre_exec2() (for example) with extra arguments, but this would not have been
2344    extensible, and would also have required all calls to the original function to
2345    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2346    is used for passing in "extra" data from pcre_study().
2348    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2349    contains the following fields:
2351      flags         a bitmap indicating which of the following fields are set
2352      study_data    opaque data from pcre_study()
2353      match_limit   a way of specifying a limit on match() calls for a specific
2354                      call to pcre_exec()
2355      callout_data  data for callouts (see 49 below)
2357    The flag bits are also defined in pcre.h, and are
2363    The pcre_study() function now returns one of these new pcre_extra blocks, with
2364    the actual study data pointed to by the study_data field, and the
2365    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2366    before. That is, this change is entirely upwards-compatible and requires no
2367    change to existing code.
2369    If you want to pass in additional data to pcre_exec(), you can either place it
2370    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2371    block.
2373    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2374    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2375    times with different match limits, until it finds the minimum value needed for
2376    pcre_exec() to complete. The value is then output. This can be instructive; for
2377    most simple matches the number is quite small, but for pathological cases it
2378    gets very large very quickly.
2380    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2381    returns the size of the data block pointed to by the study_data field in a
2382    pcre_extra block, that is, the value that was passed as the argument to
2383    pcre_malloc() when PCRE was getting memory in which to place the information
2384    created by pcre_study(). The fourth argument should point to a size_t variable.
2385    pcretest has been extended so that this information is shown after a successful
2386    pcre_study() call when information about the compiled regex is being displayed.
2388    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2389    because what follows is always an absolute path. (Later: it turns out that this
2390    is more than cosmetic for MinGW, because it doesn't like empty path
2391    components.)
2393    49. Some changes have been made to the callout feature (see 28 above):
2395    (i)  A callout function now has three choices for what it returns:
2397           0  =>  success, carry on matching
2398         > 0  =>  failure at this point, but backtrack if possible
2399         < 0  =>  serious error, return this value from pcre_exec()
2401         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2402         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2403         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2404         use by callout functions. It will never be used by PCRE itself.
2406    (ii) The pcre_extra structure (see 45 above) has a void * field called
2407         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2408         pcre_callout_block structure has a field of the same name. The contents of
2409         the field passed in the pcre_extra structure are passed to the callout
2410         function in the corresponding field in the callout block. This makes it
2411         easier to use the same callout-containing regex from multiple threads. For
2412         testing, the pcretest program has a new data escape
2414           \C*n        pass the number n (may be negative) as callout_data
2416         If the callout function in pcretest receives a non-zero value as
2417         callout_data, it returns that value.
2419    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2420    there were some redundant $(CFLAGS) in commands that are now specified as
2421    $(LINK), which already includes $(CFLAGS).
2423    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2424    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2425    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2426    one-byte characters throughout. Note that case-insensitive matching applies
2427    only to characters whose values are less than 256. PCRE doesn't support the
2428    notion of cases for higher-valued characters.
2430    (i)   A character class whose characters are all within 0-255 is handled as
2431          a bit map, and the map is inverted for negative classes. Previously, a
2432          character > 255 always failed to match such a class; however it should
2433          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2435    (ii)  A negated character class with a single character < 255 is coded as
2436          "not this character" (OP_NOT). This wasn't working properly when the test
2437          character was multibyte, either singly or repeated.
2439    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2440          mode, for example: \x{100}{2,3}.
2442    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2443          singly or repeated) now correctly test multibyte characters. However,
2444          PCRE doesn't recognize any characters with values greater than 255 as
2445          digits, spaces, or word characters. Such characters always match \D, \S,
2446          and \W, and never match \d, \s, or \w.
2448    (v)   Classes may now contain characters and character ranges with values
2449          greater than 255. For example: [ab\x{100}-\x{400}].
2451    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2452          PCRE in UTF-8 mode.
2454    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2455    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2456    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2457    value.)
2459    53. The single man page has become too large. I have therefore split it up into
2460    a number of separate man pages. These also give rise to individual HTML pages;
2461    these are now put in a separate directory, and there is an index.html page that
2462    lists them all. Some hyperlinking between the pages has been installed.
2464    54. Added convenience functions for handling named capturing parentheses.
2466    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2467    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2468    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2469    are faulted.
2471    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2472    calling configure. These values are used when compiling the dftables.c program
2473    which is run to generate the source of the default character tables. They
2474    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2475    you will need to set these values.
2477    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2480    Version 3.9 02-Jan-02
2481    ---------------------
2483    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2485    2. If --disable-static was given, the building process failed when trying to
2486    build pcretest and pcregrep. (For some reason it was using libtool to compile
2487    them, which is not right, as they aren't part of the library.)
2490    Version 3.8 18-Dec-01
2491    ---------------------
2493    1. The experimental UTF-8 code was completely screwed up. It was packing the
2494    bytes in the wrong order. How dumb can you get?
2497    Version 3.7 29-Oct-01
2498    ---------------------
2500    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2501    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2502    this didn't happen under Solaris 8, where I normally test things.
2504    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2505    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2506    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2507    this fix an hour or so after the initial 3.7 release.)
2510    Version 3.6 23-Oct-01
2511    ---------------------
2513    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2514    offsets passed as NULL with zero offset count.
2516    2. The config.guess and config.sub files had not been updated when I moved to
2517    the latest autoconf.
2520    Version 3.5 15-Aug-01
2521    ---------------------
2523    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2524    had been forgotten.
2526    2. By using declared but undefined structures, we can avoid using "void"
2527    definitions in pcre.h while keeping the internal definitions of the structures
2528    private.
2530    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2531    user point of view, this means that both static and shared libraries are built
2532    by default, but this can be individually controlled. More of the work of
2533    handling this static/shared cases is now inside libtool instead of PCRE's make
2534    file.
2536    4. The pcretest utility is now installed along with pcregrep because it is
2537    useful for users (to test regexs) and by doing this, it automatically gets
2538    relinked by libtool. The documentation has been turned into a man page, so
2539    there are now .1, .txt, and .html versions in /doc.
2541    5. Upgrades to pcregrep:
2542       (i)   Added long-form option names like gnu grep.
2543       (ii)  Added --help to list all options with an explanatory phrase.
2544       (iii) Added -r, --recursive to recurse into sub-directories.
2545       (iv)  Added -f, --file to read patterns from a file.
2547    6. pcre_exec() was referring to its "code" argument before testing that
2548    argument for NULL (and giving an error if it was NULL).
2550    7. Upgraded Makefile.in to allow for compiling in a different directory from
2551    the source directory.
2553    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2554    options bits, the pointer it was passed was to an int instead of to an unsigned
2555    long int. This mattered only on 64-bit systems.
2557    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2558    generated) instead of pcre.in, which it its source. Also made the same change
2559    in several of the .c files.
2561    10. A new release of gcc defines printf() as a macro, which broke pcretest
2562    because it had an ifdef in the middle of a string argument for printf(). Fixed
2563    by using separate calls to printf().
2565    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2566    script, to force use of CR or LF instead of \n in the source. On non-Unix
2567    systems, the value can be set in config.h.
2569    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2570    absolute limit. Changed the text of the error message to make this clear, and
2571    likewise updated the man page.
2573    13. The limit of 99 on the number of capturing subpatterns has been removed.
2574    The new limit is 65535, which I hope will not be a "real" limit.
2577  Version 3.4 22-Aug-00  Version 3.4 22-Aug-00
2578  ---------------------  ---------------------

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