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revision 47 by nigel, Sat Feb 24 21:39:29 2007 UTC revision 328 by ph10, Wed Mar 26 17:39:06 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.
30    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
31        --exclude_dir in the tests to avoid scanning .svn directories.
33    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
34        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
35        doesn't support NULs in patterns.
37    7.  Added some missing "const"s to declarations of static tables in
38        pcre_compile.c and pcre_dfa_exec.c.
40    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
41        caused by fix #2  above.
44    Version 7.6 28-Jan-08
45    ---------------------
47    1.  A character class containing a very large number of characters with
48        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
49        overflow.
51    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
52        HAVE_LONG_LONG is not defined.
54    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
55        bring them up to date and include new features. This patch includes:
57        - Fixed PH's badly added libz and libbz2 support.
58        - Fixed a problem with static linking.
59        - Added pcredemo. [But later removed - see 7 below.]
60        - Fixed dftables problem and added an option.
61        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
62            HAVE_LONG_LONG.
63        - Added readline support for pcretest.
64        - Added an listing of the option settings after cmake has run.
66    4.  A user submitted a patch to Makefile that makes it easy to create
67        "pcre.dll" under mingw when using Configure/Make. I added stuff to
68        Makefile.am that cause it to include this special target, without
69        affecting anything else. Note that the same mingw target plus all
70        the other distribution libraries and programs are now supported
71        when configuring with CMake (see 6 below) instead of with
72        Configure/Make.
74    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
75        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
76        exported in the Windows port". It has not yet been confirmed that the patch
77        solves the problem, but it does no harm.
79    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
80        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
81        with CMake, and also correct the comment about stack recursion.
83    7.  Remove the automatic building of pcredemo from the ./configure system and
84        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
85        of a program that users should build themselves after PCRE is installed, so
86        building it automatically is not really right. What is more, it gave
87        trouble in some build environments.
89    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
92    Version 7.5 10-Jan-08
93    ---------------------
95    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
96        values in parens when parsing an RE using the C++ wrapper."
98    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
99        Characters greater than 255 were excluded from the class instead of being
100        included.
102    3.  The same bug as (2) above applied to negated POSIX classes such as
103        [:^space:].
105    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
106        defined or documented. It seems to have been a typo for PCRE_STATIC, so
107        I have changed it.
109    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
110        first named subpattern) and a construct such as (?&a) would reference the
111        first named subpattern whose name started with "a" (in other words, the
112        length check was missing). Both these problems are fixed. "Subpattern name
113        expected" is now given for (?&) (a zero-length name), and this patch also
114        makes it give the same error for \k'' (previously it complained that that
115        was a reference to a non-existent subpattern).
117    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
118        this is right because (?- can be followed by option settings as well as by
119        digits. I have, however, made the messages clearer.
121    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
122        than the number used in the conditional) now cause a compile-time error.
123        This is actually not compatible with Perl, which accepts such patterns, but
124        treats the conditional as always being FALSE (as PCRE used to), but it
125        seems to me that giving a diagnostic is better.
127    8.  Change "alphameric" to the more common word "alphanumeric" in comments
128        and messages.
130    9.  Fix two occurrences of "backslash" in comments that should have been
131        "backspace".
133    10. Remove two redundant lines of code that can never be obeyed (their function
134        was moved elsewhere).
136    11. The program that makes PCRE's Unicode character property table had a bug
137        which caused it to generate incorrect table entries for sequences of
138        characters that have the same character type, but are in different scripts.
139        It amalgamated them into a single range, with the script of the first of
140        them. In other words, some characters were in the wrong script. There were
141        thirteen such cases, affecting characters in the following ranges:
143          U+002b0 - U+002c1
144          U+0060c - U+0060d
145          U+0061e - U+00612
146          U+0064b - U+0065e
147          U+0074d - U+0076d
148          U+01800 - U+01805
149          U+01d00 - U+01d77
150          U+01d9b - U+01dbf
151          U+0200b - U+0200f
152          U+030fc - U+030fe
153          U+03260 - U+0327f
154          U+0fb46 - U+0fbb1
155          U+10450 - U+1049d
157    12. The -o option (show only the matching part of a line) for pcregrep was not
158        compatible with GNU grep in that, if there was more than one match in a
159        line, it showed only the first of them. It now behaves in the same way as
160        GNU grep.
162    13. If the -o and -v options were combined for pcregrep, it printed a blank
163        line for every non-matching line. GNU grep prints nothing, and pcregrep now
164        does the same. The return code can be used to tell if there were any
165        non-matching lines.
167    14. Added --file-offsets and --line-offsets to pcregrep.
169    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
170        infinitely looping recursion. The bug was that positive lookaheads were not
171        being skipped when checking for a possible empty match (negative lookaheads
172        and both kinds of lookbehind were skipped).
174    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
175        inclusion of <windows.h> to before rather than after the definition of
176        INVALID_FILE_ATTRIBUTES (patch from David Byron).
178    17. Specifying a possessive quantifier with a specific limit for a Unicode
179        character property caused pcre_compile() to compile bad code, which led at
180        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
181        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
182        caused the error; without that there was no problem.
184    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
186    19. Added --enable-pcretest-libreadline.
188    20. In pcrecpp.cc, the variable 'count' was incremented twice in
189        RE::GlobalReplace(). As a result, the number of replacements returned was
190        double what it should be. I removed one of the increments, but Craig sent a
191        later patch that removed the other one (the right fix) and added unit tests
192        that check the return values (which was not done before).
194    21. Several CMake things:
196        (1) Arranged that, when cmake is used on Unix, the libraries end up with
197            the names libpcre and libpcreposix, not just pcre and pcreposix.
199        (2) The above change means that pcretest and pcregrep are now correctly
200            linked with the newly-built libraries, not previously installed ones.
204    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
205        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
206        UTF-8 newline character). The key issue is that the pattern starts .*;
207        this means that the match must be either at the beginning, or after a
208        newline. The bug was in the code for advancing after a failed match and
209        checking that the new position followed a newline. It was not taking
210        account of UTF-8 characters correctly.
212    23. PCRE was behaving differently from Perl in the way it recognized POSIX
213        character classes. PCRE was not treating the sequence [:...:] as a
214        character class unless the ... were all letters. Perl, however, seems to
215        allow any characters between [: and :], though of course it rejects as
216        unknown any "names" that contain non-letters, because all the known class
217        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
218        for example, whereas PCRE did not - it did not recognize a POSIX character
219        class. This seemed a bit dangerous, so the code has been changed to be
220        closer to Perl. The behaviour is not identical to Perl, because PCRE will
221        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
222        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
223        Perl does, and where it didn't before.
225    24. Rewrite so as to remove the single use of %n from pcregrep because in some
226        Windows environments %n is disabled by default.
229    Version 7.4 21-Sep-07
230    ---------------------
232    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
233        means that a class such as [\s] counted as "explicit reference to CR or
234        LF". That isn't really right - the whole point of the change was to try to
235        help when there was an actual mention of one of the two characters. So now
236        the change happens only if \r or \n (or a literal CR or LF) character is
237        encountered.
239    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
240        of both had grown to the point where there were only 3 bits left.
241        Fortunately, there was spare space in the data structure, and so I have
242        moved the internal flags into a new 16-bit field to free up more option
243        bits.
245    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
246        but did not set the internal JCHANGED flag - either of these is enough to
247        control the way the "get" function works - but the PCRE_INFO_JCHANGED
248        facility is supposed to tell if (?J) was ever used, so now (?J) at the
249        start sets both bits.
251    4.  Added options (at build time, compile time, exec time) to change \R from
252        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
254    5.  doc/pcresyntax.html was missing from the distribution.
256    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
257        compatibility, even though it is no longer used.
259    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
260        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
261        windows.h file is present (where different names are used). [This was
262        reversed later after testing - see 16 below.]
264    8.  Changed all #include <config.h> to #include "config.h". There were also
265        some further <pcre.h> cases that I changed to "pcre.h".
267    9.  When pcregrep was used with the --colour option, it missed the line ending
268        sequence off the lines that it output.
270    10. It was pointed out to me that arrays of string pointers cause lots of
271        relocations when a shared library is dynamically loaded. A technique of
272        using a single long string with a table of offsets can drastically reduce
273        these. I have refactored PCRE in four places to do this. The result is
274        dramatic:
276          Originally:                          290
277          After changing UCP table:            187
278          After changing error message table:   43
279          After changing table of "verbs"       36
280          After changing table of Posix names   22
282        Thanks to the folks working on Gregex for glib for this insight.
284    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
285        unicode-properties was also set.
287    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
289    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
290        checked only for CRLF.
292    14. Added casts to pcretest.c to avoid compiler warnings.
294    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
296    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
297        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
298        entirely. This removes changes made in 7 above.
300    17. The CMake files have been updated, and there is now more information about
301        building with CMake in the NON-UNIX-USE document.
304    Version 7.3 28-Aug-07
305    ---------------------
307     1. In the rejigging of the build system that eventually resulted in 7.1, the
308        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
309        brackets there is not right, since it causes compilers to look for an
310        installed pcre.h, not the version that is in the source that is being
311        compiled (which of course may be different). I have changed it back to:
313          #include "pcre.h"
315        I have a vague recollection that the change was concerned with compiling in
316        different directories, but in the new build system, that is taken care of
317        by the VPATH setting the Makefile.
319     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
320        when the subject happened to end in the byte 0x85 (e.g. if the last
321        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
322        characters but of course it shouldn't be taken as a newline when it is part
323        of another character. The bug was that, for an unlimited repeat of . in
324        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
325        characters when looking for a newline.
327     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
329     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
330        in debug output.
332     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
333        long printing in the pcrecpp unittest when running under MinGW.
335     6. ESC_K was left out of the EBCDIC table.
337     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
338        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
339        limit also applies to "virtual nesting" when a pattern is recursive, and in
340        this case 1000 isn't so big. I have been able to remove this limit at the
341        expense of backing off one optimization in certain circumstances. Normally,
342        when pcre_exec() would call its internal match() function recursively and
343        immediately return the result unconditionally, it uses a "tail recursion"
344        feature to save stack. However, when a subpattern that can match an empty
345        string has an unlimited repetition quantifier, it no longer makes this
346        optimization. That gives it a stack frame in which to save the data for
347        checking that an empty string has been matched. Previously this was taken
348        from the 1000-entry workspace that had been reserved. So now there is no
349        explicit limit, but more stack is used.
351     8. Applied Daniel's patches to solve problems with the import/export magic
352        syntax that is required for Windows, and which was going wrong for the
353        pcreposix and pcrecpp parts of the library. These were overlooked when this
354        problem was solved for the main library.
356     9. There were some crude static tests to avoid integer overflow when computing
357        the size of patterns that contain repeated groups with explicit upper
358        limits. As the maximum quantifier is 65535, the maximum group length was
359        set at 30,000 so that the product of these two numbers did not overflow a
360        32-bit integer. However, it turns out that people want to use groups that
361        are longer than 30,000 bytes (though not repeat them that many times).
362        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
363        made it possible to implement the integer overflow checks in a much more
364        dynamic way, which I have now done. The artificial limitation on group
365        length has been removed - we now have only the limit on the total length of
366        the compiled pattern, which depends on the LINK_SIZE setting.
368    10. Fixed a bug in the documentation for get/copy named substring when
369        duplicate names are permitted. If none of the named substrings are set, the
370        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
371        empty string.
373    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
374        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
375        because the ] is interpreted as the first data character and the
376        terminating ] is not found. PCRE has been made compatible with Perl in this
377        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
378        cause memory overwriting.
380    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
381        string has been matched (to stop an infinite loop). It was not recognizing
382        a conditional subpattern that could match an empty string if that
383        subpattern was within another subpattern. For example, it looped when
384        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
385        condition was not nested. This bug has been fixed.
387    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
388        past the start of the subject in the presence of bytes with the top bit
389        set, for example "\x8aBCD".
391    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
392        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
394    14. Optimized (?!) to (*FAIL).
396    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
397        This restricts code points to be within the range 0 to 0x10FFFF, excluding
398        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
399        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
400        does: it's just the validity check that is more restrictive.
402    16. Inserted checks for integer overflows during escape sequence (backslash)
403        processing, and also fixed erroneous offset values for syntax errors during
404        backslash processing.
406    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
407        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
409    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
410        caused an overrun.
412    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
413        something other than just ASCII characters) inside a group that had an
414        unlimited repeat caused a loop at compile time (while checking to see
415        whether the group could match an empty string).
417    20. Debugging a pattern containing \p or \P could cause a crash. For example,
418        [\P{Any}] did so. (Error in the code for printing property names.)
420    21. An orphan \E inside a character class could cause a crash.
422    22. A repeated capturing bracket such as (A)? could cause a wild memory
423        reference during compilation.
425    23. There are several functions in pcre_compile() that scan along a compiled
426        expression for various reasons (e.g. to see if it's fixed length for look
427        behind). There were bugs in these functions when a repeated \p or \P was
428        present in the pattern. These operators have additional parameters compared
429        with \d, etc, and these were not being taken into account when moving along
430        the compiled data. Specifically:
432        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
433            length.
435        (b) An item such as \pL+ within a repeated group could cause crashes or
436            loops.
438        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
439            "reference to non-existent subpattern" error.
441        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
443    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
444        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
446    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
448    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
449        character were causing crashes (broken optimization).
451    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
452        \p or \P) caused a compile-time loop.
454    28. More problems have arisen in unanchored patterns when CRLF is a valid line
455        break. For example, the unstudied pattern [\r\n]A does not match the string
456        "\r\nA" because change 7.0/46 below moves the current point on by two
457        characters after failing to match at the start. However, the pattern \nA
458        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
459        the same is true. There doesn't seem any very clean way out of this, but
460        what I have chosen to do makes the common cases work: PCRE now takes note
461        of whether there can be an explicit match for \r or \n anywhere in the
462        pattern, and if so, 7.0/46 no longer applies. As part of this change,
463        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
464        pattern has explicit CR or LF references.
466    29. Added (*CR) etc for changing newline setting at start of pattern.
469    Version 7.2 19-Jun-07
470    ---------------------
472     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
473        which is apparently normally available under Windows.
475     2. Re-jig the pcregrep tests with different newline settings in an attempt
476        to make them independent of the local environment's newline setting.
478     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
480     4. Some of the "internals" tests were previously cut out when the link size
481        was not 2, because the output contained actual offsets. The recent new
482        "Z" feature of pcretest means that these can be cut out, making the tests
483        usable with all link sizes.
485     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
486        stack recursion. This gives a massive performance boost under BSD, but just
487        a small improvement under Linux. However, it saves one field in the frame
488        in all cases.
490     6. Added more features from the forthcoming Perl 5.10:
492        (a) (?-n) (where n is a string of digits) is a relative subroutine or
493            recursion call. It refers to the nth most recently opened parentheses.
495        (b) (?+n) is also a relative subroutine call; it refers to the nth next
496            to be opened parentheses.
498        (c) Conditions that refer to capturing parentheses can be specified
499            relatively, for example, (?(-2)... or (?(+3)...
501        (d) \K resets the start of the current match so that everything before
502            is not part of it.
504        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
506        (f) \g{name} is another synonym - part of Perl 5.10's unification of
507            reference syntax.
509        (g) (?| introduces a group in which the numbering of parentheses in each
510            alternative starts with the same number.
512        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
514     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
517     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
518        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
519        for detecting groups that can match an empty string.
521     9. A pattern with a very large number of alternatives (more than several
522        hundred) was running out of internal workspace during the pre-compile
523        phase, where pcre_compile() figures out how much memory will be needed. A
524        bit of new cunning has reduced the workspace needed for groups with
525        alternatives. The 1000-alternative test pattern now uses 12 bytes of
526        workspace instead of running out of the 4096 that are available.
528    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
530    11. Applied patch from Google to remove an optimization that didn't quite work.
531        The report of the bug said:
533          pcrecpp::RE("a*").FullMatch("aaa") matches, while
534          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
535          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
537    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
538        it matched the wrong number of bytes.
541    Version 7.1 24-Apr-07
542    ---------------------
544     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
545        that is more "standard", making use of automake and other Autotools. There
546        is some re-arrangement of the files and adjustment of comments consequent
547        on this.
549     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
550        for recursive directory scanning broke on some systems because the files
551        are not scanned in any specific order and on different systems the order
552        was different. A call to "sort" has been inserted into RunGrepTest for the
553        approprate test as a short-term fix. In the longer term there may be an
554        alternative.
556     3. I had an email from Eric Raymond about problems translating some of PCRE's
557        man pages to HTML (despite the fact that I distribute HTML pages, some
558        people do their own conversions for various reasons). The problems
559        concerned the use of low-level troff macros .br and .in. I have therefore
560        removed all such uses from the man pages (some were redundant, some could
561        be replaced by .nf/.fi pairs). The 132html script that I use to generate
562        HTML has been updated to handle .nf/.fi and to complain if it encounters
563        .br or .in.
565     4. Updated comments in configure.ac that get placed in config.h.in and also
566        arranged for config.h to be included in the distribution, with the name
567        config.h.generic, for the benefit of those who have to compile without
568        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
570     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
571        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
572        makevp.bat for the current PCRE, using the additional files
573        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
575     6. A Windows user reported a minor discrepancy with test 2, which turned out
576        to be caused by a trailing space on an input line that had got lost in his
577        copy. The trailing space was an accident, so I've just removed it.
579     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
580        that is needed.
582     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
583        as "const" (a) because they are and (b) because it helps the PHP
584        maintainers who have recently made a script to detect big data structures
585        in the php code that should be moved to the .rodata section. I remembered
586        to update Builducptable as well, so it won't revert if ucptable.h is ever
587        re-created.
589     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
590        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
591        order to be able to cut out the UTF-8 tables in the latter when UTF-8
592        support is not required. This saves 1.5-2K of code, which is important in
593        some applications.
595        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
596        so as not to refer to the tables, even though these functions will never be
597        called when UTF-8 support is disabled. Otherwise there are problems with a
598        shared library.
600    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
602        (a) It was defining its arguments as char * instead of void *.
604        (b) It was assuming that all moves were upwards in memory; this was true
605            a long time ago when I wrote it, but is no longer the case.
607        The emulated memove() is provided for those environments that have neither
608        memmove() nor bcopy(). I didn't think anyone used it these days, but that
609        is clearly not the case, as these two bugs were recently reported.
611    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
612        and Detrail to create the HTML documentation, the .txt form of the man
613        pages, and it removes trailing spaces from listed files. It also creates
614        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
615        case, it wraps all the #defines with #ifndefs. This script should be run
616        before "make dist".
618    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
619        with Unicode property support.
621        (a) For a maximizing quantifier, if the two different cases of the
622            character were of different lengths in their UTF-8 codings (there are
623            some cases like this - I found 11), and the matching function had to
624            back up over a mixture of the two cases, it incorrectly assumed they
625            were both the same length.
627        (b) When PCRE was configured to use the heap rather than the stack for
628            recursion during matching, it was not correctly preserving the data for
629            the other case of a UTF-8 character when checking ahead for a match
630            while processing a minimizing repeat. If the check also involved
631            matching a wide character, but failed, corruption could cause an
632            erroneous result when trying to check for a repeat of the original
633            character.
635    13. Some tidying changes to the testing mechanism:
637        (a) The RunTest script now detects the internal link size and whether there
638            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
639            values substituted by "configure". (The RunGrepTest script already did
640            this for UTF-8.) The configure.ac script no longer substitutes the
641            relevant variables.
643        (b) The debugging options /B and /D in pcretest show the compiled bytecode
644            with length and offset values. This means that the output is different
645            for different internal link sizes. Test 2 is skipped for link sizes
646            other than 2 because of this, bypassing the problem. Unfortunately,
647            there was also a test in test 3 (the locale tests) that used /B and
648            failed for link sizes other than 2. Rather than cut the whole test out,
649            I have added a new /Z option to pcretest that replaces the length and
650            offset values with spaces. This is now used to make test 3 independent
651            of link size. (Test 2 will be tidied up later.)
653    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
654        segmentation fault instead of returning the appropriate error message.
656    15. In multiline mode when the newline sequence was set to "any", the pattern
657        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
658        This doesn't seem right; it now treats the CRLF combination as the line
659        ending, and so does not match in that case. It's only a pattern such as ^$
660        that would hit this one: something like ^ABC$ would have failed after \r
661        and then tried again after \r\n.
663    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
664        in an attempt to make files that differ only in their line terminators
665        compare equal. This works on Linux.
667    17. Under certain error circumstances pcregrep might try to free random memory
668        as it exited. This is now fixed, thanks to valgrind.
670    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
671        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
672        was because its rules for how to advance for /g after matching an empty
673        string at the end of a line did not allow for this case. They now check for
674        it specially.
676    20. pcretest is supposed to handle patterns and data of any length, by
677        extending its buffers when necessary. It was getting this wrong when the
678        buffer for a data line had to be extended.
680    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
681        CRLF as a newline sequence.
683    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
684        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
685        I have nevertheless tidied it up.
687    23. Added some casts to kill warnings from HP-UX ia64 compiler.
689    24. Added a man page for pcre-config.
692    Version 7.0 19-Dec-06
693    ---------------------
695     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
696        moving to gcc 4.1.1.
698     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
699        sys/time.h, which is documented as needed for this function. It doesn't
700        seem to matter on Linux, but it showed up on some releases of OS X.
702     3. It seems that there are systems where bytes whose values are greater than
703        127 match isprint() in the "C" locale. The "C" locale should be the
704        default when a C program starts up. In most systems, only ASCII printing
705        characters match isprint(). This difference caused the output from pcretest
706        to vary, making some of the tests fail. I have changed pcretest so that:
708        (a) When it is outputting text in the compiled version of a pattern, bytes
709            other than 32-126 are always shown as hex escapes.
711        (b) When it is outputting text that is a matched part of a subject string,
712            it does the same, unless a different locale has been set for the match
713            (using the /L modifier). In this case, it uses isprint() to decide.
715     4. Fixed a major bug that caused incorrect computation of the amount of memory
716        required for a compiled pattern when options that changed within the
717        pattern affected the logic of the preliminary scan that determines the
718        length. The relevant options are -x, and -i in UTF-8 mode. The result was
719        that the computed length was too small. The symptoms of this bug were
720        either the PCRE error "internal error: code overflow" from pcre_compile(),
721        or a glibc crash with a message such as "pcretest: free(): invalid next
722        size (fast)". Examples of patterns that provoked this bug (shown in
723        pcretest format) are:
725          /(?-x: )/x
726          /(?x)(?-x: \s*#\s*)/
727          /((?i)[\x{c0}])/8
728          /(?i:[\x{c0}])/8
730        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
731        is now done differently.
733     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
734        wrapper classes; (b) implement a new function in the C++ scanner that is
735        more efficient than the old way of doing things because it avoids levels of
736        recursion in the regex matching; (c) add a paragraph to the documentation
737        for the FullMatch() function.
739     6. The escape sequence \n was being treated as whatever was defined as
740        "newline". Not only was this contrary to the documentation, which states
741        that \n is character 10 (hex 0A), but it also went horribly wrong when
742        "newline" was defined as CRLF. This has been fixed.
744     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
745        was being set to -1 for the "end of line" case (supposedly a value that no
746        character can have). Though this value is never used (the check for end of
747        line is "zero bytes in current character"), it caused compiler complaints.
748        I've changed it to 0xffffffff.
750     8. In pcre_version.c, the version string was being built by a sequence of
751        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
752        string (as it is for production releases) called a macro with an empty
753        argument. The C standard says the result of this is undefined. The gcc
754        compiler treats it as an empty string (which was what was wanted) but it is
755        reported that Visual C gives an error. The source has been hacked around to
756        avoid this problem.
758     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
759        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
760        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
761        of them did).
763    10. Originally, pcretest opened its input and output without "b"; then I was
764        told that "b" was needed in some environments, so it was added for release
765        5.0 to both the input and output. (It makes no difference on Unix-like
766        systems.) Later I was told that it is wrong for the input on Windows. I've
767        now abstracted the modes into two macros, to make it easier to fiddle with
768        them, and removed "b" from the input mode under Windows.
770    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
772    12. Added -help and --help to pcretest as an official way of being reminded
773        of the options.
775    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
776        and pcrecpp.cc because they annoy compilers at high warning levels.
778    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
780    15. Fixed an occurrence of == in configure.ac that should have been = (shell
781        scripts are not C programs :-) and which was not noticed because it works
782        on Linux.
784    16. pcretest is supposed to handle any length of pattern and data line (as one
785        line or as a continued sequence of lines) by extending its input buffer if
786        necessary. This feature was broken for very long pattern lines, leading to
787        a string of junk being passed to pcre_compile() if the pattern was longer
788        than about 50K.
790    17. I have done a major re-factoring of the way pcre_compile() computes the
791        amount of memory needed for a compiled pattern. Previously, there was code
792        that made a preliminary scan of the pattern in order to do this. That was
793        OK when PCRE was new, but as the facilities have expanded, it has become
794        harder and harder to keep it in step with the real compile phase, and there
795        have been a number of bugs (see for example, 4 above). I have now found a
796        cunning way of running the real compile function in a "fake" mode that
797        enables it to compute how much memory it would need, while actually only
798        ever using a few hundred bytes of working memory and without too many
799        tests of the mode. This should make future maintenance and development
800        easier. A side effect of this work is that the limit of 200 on the nesting
801        depth of parentheses has been removed (though this was never a serious
802        limitation, I suspect). However, there is a downside: pcre_compile() now
803        runs more slowly than before (30% or more, depending on the pattern). I
804        hope this isn't a big issue. There is no effect on runtime performance.
806    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
807        newline (only possible for the last line of a file) and it was a
808        pattern that set a locale (followed by /Lsomething), pcretest crashed.
810    19. Added additional timing features to pcretest. (1) The -tm option now times
811        matching only, not compiling. (2) Both -t and -tm can be followed, as a
812        separate command line item, by a number that specifies the number of
813        repeats to use when timing. The default is 50000; this gives better
814        precision, but takes uncomfortably long for very large patterns.
816    20. Extended pcre_study() to be more clever in cases where a branch of a
817        subpattern has no definite first character. For example, (a*|b*)[cd] would
818        previously give no result from pcre_study(). Now it recognizes that the
819        first character must be a, b, c, or d.
821    21. There was an incorrect error "recursive call could loop indefinitely" if
822        a subpattern (or the entire pattern) that was being tested for matching an
823        empty string contained only one non-empty item after a nested subpattern.
824        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
825        incorrectly, because the \d was being skipped in the check.
827    22. The pcretest program now has a new pattern option /B and a command line
828        option -b, which is equivalent to adding /B to every pattern. This causes
829        it to show the compiled bytecode, without the additional information that
830        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
831        is the same as /B/I).
833    23. A new optimization is now able automatically to treat some sequences such
834        as a*b as a*+b. More specifically, if something simple (such as a character
835        or a simple class like \d) has an unlimited quantifier, and is followed by
836        something that cannot possibly match the quantified thing, the quantifier
837        is automatically "possessified".
839    24. A recursive reference to a subpattern whose number was greater than 39
840        went wrong under certain circumstances in UTF-8 mode. This bug could also
841        have affected the operation of pcre_study().
843    25. Realized that a little bit of performance could be had by replacing
844        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
846    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
848    27. Possessive quantifiers such as a++ were previously implemented by turning
849        them into atomic groups such as ($>a+). Now they have their own opcodes,
850        which improves performance. This includes the automatically created ones
851        from 23 above.
853    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
854        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
855        the first matched character to be a colon. This applied both to named and
856        numbered groups.
858    29. The ucpinternal.h header file was missing its idempotency #ifdef.
860    30. I was sent a "project" file called libpcre.a.dev which I understand makes
861        building PCRE on Windows easier, so I have included it in the distribution.
863    31. There is now a check in pcretest against a ridiculously large number being
864        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
865        loop, the loop is abandoned.
867    32. Forward references to subpatterns in conditions such as (?(2)...) where
868        subpattern 2 is defined later cause pcre_compile() to search forwards in
869        the pattern for the relevant set of parentheses. This search went wrong
870        when there were unescaped parentheses in a character class, parentheses
871        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
873    33. "Subroutine" calls and backreferences were previously restricted to
874        referencing subpatterns earlier in the regex. This restriction has now
875        been removed.
877    34. Added a number of extra features that are going to be in Perl 5.10. On the
878        whole, these are just syntactic alternatives for features that PCRE had
879        previously implemented using the Python syntax or my own invention. The
880        other formats are all retained for compatibility.
882        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
883            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
884            also .NET compatible.
886        (b) A recursion or subroutine call to a named group can now be defined as
887            (?&name) as well as (?P>name).
889        (c) A backreference to a named group can now be defined as \k<name> or
890            \k'name' as well as (?P=name). The new forms, as well as being in Perl
891            5.10, are also .NET compatible.
893        (d) A conditional reference to a named group can now use the syntax
894            (?(<name>) or (?('name') as well as (?(name).
896        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
897            groups (named and numbered) that are never evaluated inline, but can be
898            called as "subroutines" from elsewhere. In effect, the DEFINE condition
899            is always false. There may be only one alternative in such a group.
901        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
902            as the simple (?(R). The condition is true only if the most recent
903            recursion is that of the given number or name. It does not search out
904            through the entire recursion stack.
906        (g) The escape \gN or \g{N} has been added, where N is a positive or
907            negative number, specifying an absolute or relative reference.
909    35. Tidied to get rid of some further signed/unsigned compiler warnings and
910        some "unreachable code" warnings.
912    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
913        things, this adds five new scripts.
915    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
916        There were also incompatibilities regarding the handling of \Q..\E inside
917        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
918        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
920    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
921        matches an empty string, and forcibly breaks the loop. There were bugs in
922        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
923        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
924        separate and independent bugs (that affected different cases) have been
925        fixed.
927    39. Refactored the code to abolish the use of different opcodes for small
928        capturing bracket numbers. This is a tidy that I avoided doing when I
929        removed the limit on the number of capturing brackets for 3.5 back in 2001.
930        The new approach is not only tidier, it makes it possible to reduce the
931        memory needed to fix the previous bug (38).
933    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
934        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
935        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
936        mode.
938    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
939        report.
941    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
942        copy construction and assignment in the C++ wrapper.
944    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
945        couple of bugs that could have given wrong results in the "--newline=crlf"
946        case.
948    44. Added a number of casts and did some reorganization of signed/unsigned int
949        variables following suggestions from Dair Grant. Also renamed the variable
950        "this" as "item" because it is a C++ keyword.
952    45. Arranged for dftables to add
954          #include "pcre_internal.h"
956        to pcre_chartables.c because without it, gcc 4.x may remove the array
957        definition from the final binary if PCRE is built into a static library and
958        dead code stripping is activated.
960    46. For an unanchored pattern, if a match attempt fails at the start of a
961        newline sequence, and the newline setting is CRLF or ANY, and the next two
962        characters are CRLF, advance by two characters instead of one.
965    Version 6.7 04-Jul-06
966    ---------------------
968     1. In order to handle tests when input lines are enormously long, pcretest has
969        been re-factored so that it automatically extends its buffers when
970        necessary. The code is crude, but this _is_ just a test program. The
971        default size has been increased from 32K to 50K.
973     2. The code in pcre_study() was using the value of the re argument before
974        testing it for NULL. (Of course, in any sensible call of the function, it
975        won't be NULL.)
977     3. The memmove() emulation function in pcre_internal.h, which is used on
978        systems that lack both memmove() and bcopy() - that is, hardly ever -
979        was missing a "static" storage class specifier.
981     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
982        containing an extended class (one that cannot be represented by a bitmap
983        because it contains high-valued characters or Unicode property items, e.g.
984        [\pZ]). Almost always one would set UTF-8 mode when processing such a
985        pattern, but PCRE should not loop if you do not (it no longer does).
986        [Detail: two cases were found: (a) a repeated subpattern containing an
987        extended class; (b) a recursive reference to a subpattern that followed a
988        previous extended class. It wasn't skipping over the extended class
989        correctly when UTF-8 mode was not set.]
991     5. A negated single-character class was not being recognized as fixed-length
992        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
993        compile error "lookbehind assertion is not fixed length".
995     6. The RunPerlTest auxiliary script was showing an unexpected difference
996        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
997        write a Perl script that can interpret lines of an input file either as
998        byte characters or as UTF-8, which is what "perltest" was being required to
999        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1000        can't do is switch easily at run time between having the "use utf8;" pragma
1001        or not. In the end, I fudged it by using the RunPerlTest script to insert
1002        "use utf8;" explicitly for the UTF-8 tests.
1004     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1005        the end of the subject string, contrary to the documentation and to what
1006        Perl does. This was true of both matching functions. Now it matches only at
1007        the start of the subject and immediately after *internal* newlines.
1009     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1010        a pointer to an int instead of a pointer to an unsigned long int. This
1011        caused problems on 64-bit systems.
1013     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1014        instance of the 'standard' template library not being so standard".
1016    10. There was no check on the number of named subpatterns nor the maximum
1017        length of a subpattern name. The product of these values is used to compute
1018        the size of the memory block for a compiled pattern. By supplying a very
1019        long subpattern name and a large number of named subpatterns, the size
1020        computation could be caused to overflow. This is now prevented by limiting
1021        the length of names to 32 characters, and the number of named subpatterns
1022        to 10,000.
1024    11. Subpatterns that are repeated with specific counts have to be replicated in
1025        the compiled pattern. The size of memory for this was computed from the
1026        length of the subpattern and the repeat count. The latter is limited to
1027        65535, but there was no limit on the former, meaning that integer overflow
1028        could in principle occur. The compiled length of a repeated subpattern is
1029        now limited to 30,000 bytes in order to prevent this.
1031    12. Added the optional facility to have named substrings with the same name.
1033    13. Added the ability to use a named substring as a condition, using the
1034        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1035        are numbers (not recommended). Forward references are permitted.
1037    14. Added forward references in named backreferences (if you see what I mean).
1039    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1040        pattern could run off the end of the subject. For example, the pattern
1041        "(?s)(.{1,5})"8 did this with the subject "ab".
1043    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1044        PCRE_CASELESS was set when matching characters that were quantified with ?
1045        or *.
1047    17. A character class other than a single negated character that had a minimum
1048        but no maximum quantifier - for example [ab]{6,} - was not handled
1049        correctly by pce_dfa_exec(). It would match only one character.
1051    18. A valid (though odd) pattern that looked like a POSIX character
1052        class but used an invalid character after [ (for example [[,abc,]]) caused
1053        pcre_compile() to give the error "Failed: internal error: code overflow" or
1054        in some cases to crash with a glibc free() error. This could even happen if
1055        the pattern terminated after [[ but there just happened to be a sequence of
1056        letters, a binary zero, and a closing ] in the memory that followed.
1058    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1059        over the years. Originally (before any Unicode support), just the bottom 8
1060        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1061        output from "man perlunicode" includes this:
1063          The regular expression compiler produces polymorphic opcodes.  That
1064          is, the pattern adapts to the data and automatically switches to
1065          the Unicode character scheme when presented with Unicode data--or
1066          instead uses a traditional byte scheme when presented with byte
1067          data.
1069        Sadly, a wide octal escape does not cause a switch, and in a string with
1070        no other multibyte characters, these octal escapes are treated as before.
1071        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1072        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1073        Unicode string.
1075        I have not perpetrated such confusion in PCRE. Up till now, it took just
1076        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1077        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1078        translate to the appropriate multibyte character.
1080    29. Applied some refactoring to reduce the number of warnings from Microsoft
1081        and Borland compilers. This has included removing the fudge introduced
1082        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1083        a warning about an unused variable.
1085    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1086        characters since release 4.0, because Perl (from release 5.004) does not.
1087        [Or at least, is documented not to: some releases seem to be in conflict
1088        with the documentation.] However, when a pattern was studied with
1089        pcre_study() and all its branches started with \s, PCRE still included VT
1090        as a possible starting character. Of course, this did no harm; it just
1091        caused an unnecessary match attempt.
1093    22. Removed a now-redundant internal flag bit that recorded the fact that case
1094        dependency changed within the pattern. This was once needed for "required
1095        byte" processing, but is no longer used. This recovers a now-scarce options
1096        bit. Also moved the least significant internal flag bit to the most-
1097        significant bit of the word, which was not previously used (hangover from
1098        the days when it was an int rather than a uint) to free up another bit for
1099        the future.
1101    23. Added support for CRLF line endings as well as CR and LF. As well as the
1102        default being selectable at build time, it can now be changed at runtime
1103        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1104        specify that it is scanning data with non-default line endings.
1106    24. Changed the definition of CXXLINK to make it agree with the definition of
1107        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1109    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1110        recursions. This makes a big different to stack usage for some patterns.
1112    26. If a subpattern containing a named recursion or subroutine reference such
1113        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1114        the space required for the compiled pattern went wrong and gave too small a
1115        value. Depending on the environment, this could lead to "Failed: internal
1116        error: code overflow at offset 49" or "glibc detected double free or
1117        corruption" errors.
1119    27. Applied patches from Google (a) to support the new newline modes and (b) to
1120        advance over multibyte UTF-8 characters in GlobalReplace.
1122    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1123        difference for some implementation of PCRE in some Windows version.
1125    29. Added some extra testing facilities to pcretest:
1127        \q<number>   in a data line sets the "match limit" value
1128        \Q<number>   in a data line sets the "match recursion limt" value
1129        -S <number>  sets the stack size, where <number> is in megabytes
1131        The -S option isn't available for Windows.
1134    Version 6.6 06-Feb-06
1135    ---------------------
1137     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1138        in pcreposix.h. I have copied the definition from pcre.h.
1140     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1141        because pcre.h is no longer a built file.
1143     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1144        not normally included in the compiled code.
1147    Version 6.5 01-Feb-06
1148    ---------------------
1150     1. When using the partial match feature with pcre_dfa_exec(), it was not
1151        anchoring the second and subsequent partial matches at the new starting
1152        point. This could lead to incorrect results. For example, with the pattern
1153        /1234/, partially matching against "123" and then "a4" gave a match.
1155     2. Changes to pcregrep:
1157        (a) All non-match returns from pcre_exec() were being treated as failures
1158            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1159            error message is output. Some extra information is given for the
1160            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1161            probably the only errors that are likely to be caused by users (by
1162            specifying a regex that has nested indefinite repeats, for instance).
1163            If there are more than 20 of these errors, pcregrep is abandoned.
1165        (b) A binary zero was treated as data while matching, but terminated the
1166            output line if it was written out. This has been fixed: binary zeroes
1167            are now no different to any other data bytes.
1169        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1170            used to set a locale for matching. The --locale=xxxx long option has
1171            been added (no short equivalent) to specify a locale explicitly on the
1172            pcregrep command, overriding the environment variables.
1174        (d) When -B was used with -n, some line numbers in the output were one less
1175            than they should have been.
1177        (e) Added the -o (--only-matching) option.
1179        (f) If -A or -C was used with -c (count only), some lines of context were
1180            accidentally printed for the final match.
1182        (g) Added the -H (--with-filename) option.
1184        (h) The combination of options -rh failed to suppress file names for files
1185            that were found from directory arguments.
1187        (i) Added the -D (--devices) and -d (--directories) options.
1189        (j) Added the -F (--fixed-strings) option.
1191        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1193        (l) Added the --colo(u)r option.
1195        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1196            is not present by default.
1198     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1199        items such as (?R) or (?1), when the recursion could match a number of
1200        alternatives. If it matched one of the alternatives, but subsequently,
1201        outside the recursion, there was a failure, the code tried to back up into
1202        the recursion. However, because of the way PCRE is implemented, this is not
1203        possible, and the result was an incorrect result from the match.
1205        In order to prevent this happening, the specification of recursion has
1206        been changed so that all such subpatterns are automatically treated as
1207        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1209     4. I had overlooked the fact that, in some locales, there are characters for
1210        which isalpha() is true but neither isupper() nor islower() are true. In
1211        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1212        and ordfeminine) are like this. This affected the treatment of \w and \W
1213        when they appeared in character classes, but not when they appeared outside
1214        a character class. The bit map for "word" characters is now created
1215        separately from the results of isalnum() instead of just taking it from the
1216        upper, lower, and digit maps. (Plus the underscore character, of course.)
1218     5. The above bug also affected the handling of POSIX character classes such as
1219        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1220        permanent tables. Instead, the bit maps for such a class were previously
1221        created as the appropriate unions of the upper, lower, and digit bitmaps.
1222        Now they are created by subtraction from the [[:word:]] class, which has
1223        its own bitmap.
1225     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1226        It is created by subtracting the vertical space characters (\x09, \x0a,
1227        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1228        subtraction was done in the overall bitmap for a character class, meaning
1229        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1230        be recognized. This bug has been fixed.
1232     7. Patches from the folks at Google:
1234          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1235          real life, but is still worth protecting against".
1237          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1238          regular expressions".
1240          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1241          have it.
1243          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1244          "configure" and the latter not, in order to fix a problem somebody had
1245          with compiling the Arg class on HP-UX.
1247          (e) Improve the error-handling of the C++ wrapper a little bit.
1249          (f) New tests for checking recursion limiting.
1251     8. The pcre_memmove() function, which is used only if the environment does not
1252        have a standard memmove() function (and is therefore rarely compiled),
1253        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1254        returning a result (though PCRE never actually uses the result).
1256     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1257        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1258        returned instead of calling malloc() with an overflowing number that would
1259        most likely cause subsequent chaos.
1261    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1263    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1264        with this option is matched, the nmatch and pmatch options of regexec() are
1265        ignored.
1267    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1268        provided in case anyone wants to the the POSIX interface with UTF-8
1269        strings.
1271    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1272        C++ linking (needed for some HP-UX environments).
1274    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1275        (unused parameter) and in the pcre_printint() function (omitted "default"
1276        switch label when the default is to do nothing).
1278    15. Added some code to make it possible, when PCRE is compiled as a C++
1279        library, to replace subject pointers for pcre_exec() with a smart pointer
1280        class, thus making it possible to process discontinuous strings.
1282    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1283        much the same function. They were added by different people who were trying
1284        to make PCRE easy to compile on non-Unix systems. It has been suggested
1285        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1286        for compiling on Windows systems. I have therefore replaced it with
1287        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1288        defaults to "extern" for C or "extern C" for C++, which works fine on
1289        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1290        SCOPE with something explicit in config.h. In addition:
1292        (a) pcreposix.h still had just "extern" instead of either of these macros;
1293            I have replaced it with PCRE_DATA_SCOPE.
1295        (b) Functions such as _pcre_xclass(), which are internal to the library,
1296            but external in the C sense, all had PCRE_EXPORT in their definitions.
1297            This is apparently wrong for the Windows case, so I have removed it.
1298            (It makes no difference on Unix-like systems.)
1300    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1301        of recursive calls to match(). This is different to MATCH_LIMIT because
1302        that limits the total number of calls to match(), not all of which increase
1303        the depth of recursion. Limiting the recursion depth limits the amount of
1304        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1305        when PCRE is compiled, and changed at run time. A patch from Google adds
1306        this functionality to the C++ interface.
1308    18. Changes to the handling of Unicode character properties:
1310        (a) Updated the table to Unicode 4.1.0.
1312        (b) Recognize characters that are not in the table as "Cn" (undefined).
1314        (c) I revised the way the table is implemented to a much improved format
1315            which includes recognition of ranges. It now supports the ranges that
1316            are defined in UnicodeData.txt, and it also amalgamates other
1317            characters into ranges. This has reduced the number of entries in the
1318            table from around 16,000 to around 3,000, thus reducing its size
1319            considerably. I realized I did not need to use a tree structure after
1320            all - a binary chop search is just as efficient. Having reduced the
1321            number of entries, I extended their size from 6 bytes to 8 bytes to
1322            allow for more data.
1324        (d) Added support for Unicode script names via properties such as \p{Han}.
1326    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1327        matching that character.
1329    20. When matching a repeated Unicode property with a minimum greater than zero,
1330        (for example \pL{2,}), PCRE could look past the end of the subject if it
1331        reached it while seeking the minimum number of characters. This could
1332        happen only if some of the characters were more than one byte long, because
1333        there is a check for at least the minimum number of bytes.
1335    21. Refactored the implementation of \p and \P so as to be more general, to
1336        allow for more different types of property in future. This has changed the
1337        compiled form incompatibly. Anybody with saved compiled patterns that use
1338        \p or \P will have to recompile them.
1340    22. Added "Any" and "L&" to the supported property types.
1342    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1343        but give a compile time error if the value is greater than 0xff.
1345    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1346        accidentally not being installed or uninstalled.
1348    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1349        made were to insert the current release number. This seemed silly, because
1350        it made things harder for people building PCRE on systems that don't run
1351        "configure". I have turned pcre.h into a distributed file, no longer built
1352        by "configure", with the version identification directly included. There is
1353        no longer a pcre.h.in file.
1355        However, this change necessitated a change to the pcre-config script as
1356        well. It is built from pcre-config.in, and one of the substitutions was the
1357        release number. I have updated configure.ac so that ./configure now finds
1358        the release number by grepping pcre.h.
1360    26. Added the ability to run the tests under valgrind.
1363    Version 6.4 05-Sep-05
1364    ---------------------
1366     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1367        "--" to be printed when multiple files were scanned, even when none of the
1368        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1369        consider it to be a bug, and have restored the previous behaviour.
1371     2. A couple of code tidies to get rid of compiler warnings.
1373     3. The pcretest program used to cheat by referring to symbols in the library
1374        whose names begin with _pcre_. These are internal symbols that are not
1375        really supposed to be visible externally, and in some environments it is
1376        possible to suppress them. The cheating is now confined to including
1377        certain files from the library's source, which is a bit cleaner.
1379     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1380        file's purpose clearer.
1382     5. Reorganized pcre_ucp_findchar().
1385    Version 6.3 15-Aug-05
1386    ---------------------
1388     1. The file libpcre.pc.in did not have general read permission in the tarball.
1390     2. There were some problems when building without C++ support:
1392        (a) If C++ support was not built, "make install" and "make test" still
1393            tried to test it.
1395        (b) There were problems when the value of CXX was explicitly set. Some
1396            changes have been made to try to fix these, and ...
1398        (c) --disable-cpp can now be used to explicitly disable C++ support.
1400        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1401            backslash in a target when C++ was disabled. This confuses some
1402            versions of "make", apparently. Using an intermediate variable solves
1403            this. (Same for CPP_LOBJ.)
1405     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1406        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1407        necessary on certain architectures.
1409     4. Added a setting of -export-symbols-regex to the link command to remove
1410        those symbols that are exported in the C sense, but actually are local
1411        within the library, and not documented. Their names all begin with
1412        "_pcre_". This is not a perfect job, because (a) we have to except some
1413        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1414        available (and never for static libraries). I have made a note to try to
1415        find a way round (a) in the future.
1418    Version 6.2 01-Aug-05
1419    ---------------------
1421     1. There was no test for integer overflow of quantifier values. A construction
1422        such as {1111111111111111} would give undefined results. What is worse, if
1423        a minimum quantifier for a parenthesized subpattern overflowed and became
1424        negative, the calculation of the memory size went wrong. This could have
1425        led to memory overwriting.
1427     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1429     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1430        operating environments where this matters.
1432     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1433        PCRE options from within the C++ wrapper.
1435     5. Named capturing subpatterns were not being correctly counted when a pattern
1436        was compiled. This caused two problems: (a) If there were more than 100
1437        such subpatterns, the calculation of the memory needed for the whole
1438        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1439        back references of the form \12, where the number was greater than 9, were
1440        not recognized as back references, even though there were sufficient
1441        previous subpatterns.
1443     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1444        versions of gcc, e.g. 2.95.4.
1447    Version 6.1 21-Jun-05
1448    ---------------------
1450     1. There was one reference to the variable "posix" in pcretest.c that was not
1451        surrounded by "#if !defined NOPOSIX".
1453     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1454        the cross-check on the old pcre_info() function, for the benefit of the
1455        cut-down version of PCRE that is currently imported into Exim.
1457     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1458        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1459        patterns that start (?i) but I don't think that matters. The use of (?i) is
1460        just an example; this all applies to the other options as well.
1462     4. Since libtool seems to echo the compile commands it is issuing, the output
1463        from "make" can be reduced a bit by putting "@" in front of each libtool
1464        compile command.
1466     5. Patch from the folks at Google for configure.in to be a bit more thorough
1467        in checking for a suitable C++ installation before trying to compile the
1468        C++ stuff. This should fix a reported problem when a compiler was present,
1469        but no suitable headers.
1471     6. The man pages all had just "PCRE" as their title. I have changed them to
1472        be the relevant file name. I have also arranged that these names are
1473        retained in the file doc/pcre.txt, which is a concatenation in text format
1474        of all the man pages except the little individual ones for each function.
1476     7. The NON-UNIX-USE file had not been updated for the different set of source
1477        files that come with release 6. I also added a few comments about the C++
1478        wrapper.
1481    Version 6.0 07-Jun-05
1482    ---------------------
1484     1. Some minor internal re-organization to help with my DFA experiments.
1486     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1487        didn't matter for the library itself when fully configured, but did matter
1488        when compiling without UCP support, or within Exim, where the ucp files are
1489        not imported.
1491     3. Refactoring of the library code to split up the various functions into
1492        different source modules. The addition of the new DFA matching code (see
1493        below) to a single monolithic source would have made it really too
1494        unwieldy, quite apart from causing all the code to be include in a
1495        statically linked application, when only some functions are used. This is
1496        relevant even without the DFA addition now that patterns can be compiled in
1497        one application and matched in another.
1499        The downside of splitting up is that there have to be some external
1500        functions and data tables that are used internally in different modules of
1501        the library but which are not part of the API. These have all had their
1502        names changed to start with "_pcre_" so that they are unlikely to clash
1503        with other external names.
1505     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1506        a different (DFA) algorithm. Although it is slower than the original
1507        function, it does have some advantages for certain types of matching
1508        problem.
1510     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1511        including restarting after a partial match.
1513     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1514        defined when compiling for Windows was sent to me. I have put it into the
1515        code, though I have no means of testing or verifying it.
1517     7. Added the pcre_refcount() auxiliary function.
1519     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1520        match before or at the first newline in the subject string. In pcretest,
1521        the /f option on a pattern can be used to set this.
1523     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1524        would behave wrongly. This has been present in PCRE since release 4.0.
1526    10. A number of changes to the pcregrep command:
1528        (a) Refactored how -x works; insert ^(...)$ instead of setting
1529            PCRE_ANCHORED and checking the length, in preparation for adding
1530            something similar for -w.
1532        (b) Added the -w (match as a word) option.
1534        (c) Refactored the way lines are read and buffered so as to have more
1535            than one at a time available.
1537        (d) Implemented a pcregrep test script.
1539        (e) Added the -M (multiline match) option. This allows patterns to match
1540            over several lines of the subject. The buffering ensures that at least
1541            8K, or the rest of the document (whichever is the shorter) is available
1542            for matching (and similarly the previous 8K for lookbehind assertions).
1544        (f) Changed the --help output so that it now says
1546              -w, --word-regex(p)
1548            instead of two lines, one with "regex" and the other with "regexp"
1549            because that confused at least one person since the short forms are the
1550            same. (This required a bit of code, as the output is generated
1551            automatically from a table. It wasn't just a text change.)
1553        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1554            option but starts with a hyphen. Could be a pattern or a path name
1555            starting with a hyphen, for instance.
1557        (h) "-" can be given as a file name to represent stdin.
1559        (i) When file names are being printed, "(standard input)" is used for
1560            the standard input, for compatibility with GNU grep. Previously
1561            "<stdin>" was used.
1563        (j) The option --label=xxx can be used to supply a name to be used for
1564            stdin when file names are being printed. There is no short form.
1566        (k) Re-factored the options decoding logic because we are going to add
1567            two more options that take data. Such options can now be given in four
1568            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1570        (l) Added the -A, -B, and -C options for requesting that lines of context
1571            around matches be printed.
1573        (m) Added the -L option to print the names of files that do not contain
1574            any matching lines, that is, the complement of -l.
1576        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1577            continue to scan other files.
1579        (o) The -s option was incorrectly implemented. For compatibility with other
1580            greps, it now suppresses the error message for a non-existent or non-
1581            accessible file (but not the return code). There is a new option called
1582            -q that suppresses the output of matching lines, which was what -s was
1583            previously doing.
1585        (p) Added --include and --exclude options to specify files for inclusion
1586            and exclusion when recursing.
1588    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1589        Hopefully, it now does.
1591    12. Missing cast in pcre_study().
1593    13. Added an "uninstall" target to the makefile.
1595    14. Replaced "extern" in the function prototypes in Makefile.in with
1596        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1597        world, but is set differently for Windows.
1599    15. Added a second compiling function called pcre_compile2(). The only
1600        difference is that it has an extra argument, which is a pointer to an
1601        integer error code. When there is a compile-time failure, this is set
1602        non-zero, in addition to the error test pointer being set to point to an
1603        error message. The new argument may be NULL if no error number is required
1604        (but then you may as well call pcre_compile(), which is now just a
1605        wrapper). This facility is provided because some applications need a
1606        numeric error indication, but it has also enabled me to tidy up the way
1607        compile-time errors are handled in the POSIX wrapper.
1609    16. Added VPATH=.libs to the makefile; this should help when building with one
1610        prefix path and installing with another. (Or so I'm told by someone who
1611        knows more about this stuff than I do.)
1613    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1614        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1615        match everything, including newlines. This is not POSIX-compatible, but
1616        somebody wanted the feature. From pcretest it can be activated by using
1617        both the P and the s flags.
1619    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1621    19. libpcre.pc was being incorrectly installed as executable.
1623    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1624        it now also looks for '\r' so that it will work unmodified on Windows.
1626    21. Added Google's contributed C++ wrapper to the distribution.
1628    22. Added some untidy missing memory free() calls in pcretest, to keep
1629        Electric Fence happy when testing.
1633    Version 5.0 13-Sep-04
1634    ---------------------
1636     1. Internal change: literal characters are no longer packed up into items
1637        containing multiple characters in a single byte-string. Each character
1638        is now matched using a separate opcode. However, there may be more than one
1639        byte in the character in UTF-8 mode.
1641     2. The pcre_callout_block structure has two new fields: pattern_position and
1642        next_item_length. These contain the offset in the pattern to the next match
1643        item, and its length, respectively.
1645     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1646        insertion of callouts before each pattern item. Added the /C option to
1647        pcretest to make use of this.
1649     4. On the advice of a Windows user, the lines
1651          #if defined(_WIN32) || defined(WIN32)
1652          _setmode( _fileno( stdout ), 0x8000 );
1653          #endif  /* defined(_WIN32) || defined(WIN32) */
1655        have been added to the source of pcretest. This apparently does useful
1656        magic in relation to line terminators.
1658     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1659        for the benefit of those environments where the "b" makes a difference.
1661     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1662        to know about it. I have put a hack into configure.in that adds in code
1663        to set GCC=yes if CC=icc. This seems to end up at a point in the
1664        generated configure script that is early enough to affect the setting of
1665        compiler options, which is what is needed, but I have no means of testing
1666        whether it really works. (The user who reported this had patched the
1667        generated configure script, which of course I cannot do.)
1669        LATER: After change 22 below (new libtool files), the configure script
1670        seems to know about icc (and also ecc). Therefore, I have commented out
1671        this hack in configure.in.
1673     7. Added support for pkg-config (2 patches were sent in).
1675     8. Negated POSIX character classes that used a combination of internal tables
1676        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1677        [[:^ascii]]. Typically, they would match almost any characters. The other
1678        POSIX classes were not broken in this way.
1680     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1681        to find the match, as PCRE was deluded into thinking that the match had to
1682        start at the start point or following a newline. The same bug applied to
1683        patterns with negative forward assertions or any backward assertions
1684        preceding ".*" at the start, unless the pattern required a fixed first
1685        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1687    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1688        starting at the last subject character, bytes beyond the end of the subject
1689        string were read.
1691    11. Renamed the variable "class" as "classbits" to make life easier for C++
1692        users. (Previously there was a macro definition, but it apparently wasn't
1693        enough.)
1695    12. Added the new field "tables" to the extra data so that tables can be passed
1696        in at exec time, or the internal tables can be re-selected. This allows
1697        a compiled regex to be saved and re-used at a later time by a different
1698        program that might have everything at different addresses.
1700    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1701        -R library as well as a -L library.
1703    14. The debugging options of pcretest (-d on the command line or D on a
1704        pattern) showed incorrect output for anything following an extended class
1705        that contained multibyte characters and which was followed by a quantifier.
1707    15. Added optional support for general category Unicode character properties
1708        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1709        support. It adds about 90K to the size of the library. The meanings of the
1710        inbuilt class escapes such as \d and \s have NOT been changed.
1712    16. Updated pcredemo.c to include calls to free() to release the memory for the
1713        compiled pattern.
1715    17. The generated file chartables.c was being created in the source directory
1716        instead of in the building directory. This caused the build to fail if the
1717        source directory was different from the building directory, and was
1718        read-only.
1720    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1721        file. No doubt somebody will tell me if they don't make sense... Also added
1722        Dan Mooney's comments about building on OpenVMS.
1724    19. Added support for partial matching via the PCRE_PARTIAL option for
1725        pcre_exec() and the \P data escape in pcretest.
1727    20. Extended pcretest with 3 new pattern features:
1729        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1730              write the compiled pattern to the file whose name is "rest-of-line".
1731              This is a straight binary dump of the data, with the saved pointer to
1732              the character tables forced to be NULL. The study data, if any, is
1733              written too. After writing, pcretest reads a new pattern.
1735        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1736              compiled pattern from the given file. There must not be any
1737              occurrences of "<" in the file name (pretty unlikely); if there are,
1738              pcretest will instead treat the initial "<" as a pattern delimiter.
1739              After reading in the pattern, pcretest goes on to read data lines as
1740              usual.
1742        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1743              and 16-bit fields in a compiled pattern, to simulate a pattern that
1744              was compiled on a host of opposite endianness.
1746    21. The pcre-exec() function can now cope with patterns that were compiled on
1747        hosts of opposite endianness, with this restriction:
1749          As for any compiled expression that is saved and used later, the tables
1750          pointer field cannot be preserved; the extra_data field in the arguments
1751          to pcre_exec() should be used to pass in a tables address if a value
1752          other than the default internal tables were used at compile time.
1754    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1755        now diagnosed as an error. Previously, most of the time, a negative number
1756        would have been treated as zero, but if in addition "ovector" was passed as
1757        NULL, a crash could occur.
1759    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1760        new versions from the libtool 1.5 distribution (the last one is a copy of
1761        a file called libtool.m4). This seems to have fixed the need to patch
1762        "configure" to support Darwin 1.3 (which I used to do). However, I still
1763        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1764        workstation).
1766    24. Changed the PCRE licence to be the more standard "BSD" licence.
1769    Version 4.5 01-Dec-03
1770    ---------------------
1772     1. There has been some re-arrangement of the code for the match() function so
1773        that it can be compiled in a version that does not call itself recursively.
1774        Instead, it keeps those local variables that need separate instances for
1775        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1776        needs to "recurse". Keeping track of where control must go is done by means
1777        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1778        hide most of the details from the main code, and operates only if
1779        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1780        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1781        operating.
1783        To make it easier for callers to provide specially tailored get/free
1784        functions for this usage, two new functions, pcre_stack_malloc, and
1785        pcre_stack_free, are used. They are always called in strict stacking order,
1786        and the size of block requested is always the same.
1788        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1789        PCRE has been compiled to use the stack or the heap for recursion. The
1790        -C option of pcretest uses this to show which version is compiled.
1792        A new data escape \S, is added to pcretest; it causes the amounts of store
1793        obtained and freed by both kinds of malloc/free at match time to be added
1794        to the output.
1796     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1797        what's available on my current Linux desktop machine.
1799     3. When matching a UTF-8 string, the test for a valid string at the start has
1800        been extended. If start_offset is not zero, PCRE now checks that it points
1801        to a byte that is the start of a UTF-8 character. If not, it returns
1802        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1803        this is necessary because there may be backward assertions in the pattern.
1804        When matching the same subject several times, it may save resources to use
1805        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1807     4. The code for checking the validity of UTF-8 strings has been tightened so
1808        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1809        containing "overlong sequences".
1811     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1812        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1813        should have been "&", but it just so happened that all the cases this let
1814        through by mistake were picked up later in the function.
1816     6. I had used a variable called "isblank" - this is a C99 function, causing
1817        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1819     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1820        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1821        so the version is shown; (c) stop "make test" echoing "./RunTest".
1823     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1825     9. The prototype for memmove() for systems that don't have it was using
1826        size_t, but the inclusion of the header that defines size_t was later. I've
1827        moved the #includes for the C headers earlier to avoid this.
1829    10. Added some adjustments to the code to make it easier to compiler on certain
1830        special systems:
1832          (a) Some "const" qualifiers were missing.
1833          (b) Added the macro EXPORT before all exported functions; by default this
1834              is defined to be empty.
1835          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1836              that it reads its output file name as an argument instead of writing
1837              to the standard output and assuming this can be redirected.
1839    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1840        class containing characters with values greater than 255, PCRE compilation
1841        went into a loop.
1843    12. A recursive reference to a subpattern that was within another subpattern
1844        that had a minimum quantifier of zero caused PCRE to crash. For example,
1845        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1846        recursion. If the recursively-called subpattern itself had a zero repeat,
1847        that was OK.
1849    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1850        buffer into which it was copied (for escape processing) was still set at
1851        1024, so long lines caused crashes.
1853    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1854        "internal error: code overflow...". This applied to any character class
1855        that was followed by a possessive quantifier.
1857    15. Modified the Makefile to add libpcre.la as a prerequisite for
1858        libpcreposix.la because I was told this is needed for a parallel build to
1859        work.
1861    16. If a pattern that contained .* following optional items at the start was
1862        studied, the wrong optimizing data was generated, leading to matching
1863        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1864        matching string must start with a or b or c. The correct conclusion for
1865        this pattern is that a match can start with any character.
1868    Version 4.4 13-Aug-03
1869    ---------------------
1871     1. In UTF-8 mode, a character class containing characters with values between
1872        127 and 255 was not handled correctly if the compiled pattern was studied.
1873        In fixing this, I have also improved the studying algorithm for such
1874        classes (slightly).
1876     2. Three internal functions had redundant arguments passed to them. Removal
1877        might give a very teeny performance improvement.
1879     3. Documentation bug: the value of the capture_top field in a callout is *one
1880        more than* the number of the hightest numbered captured substring.
1882     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1883        in incorrectly linking with a previously installed version. They now link
1884        explicitly with libpcre.la.
1886     5. configure.in no longer needs to recognize Cygwin specially.
1888     6. A problem in pcre.in for Windows platforms is fixed.
1890     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1891        pcretest, it used to include the size of the study block as part of its
1892        output. Unfortunately, the structure contains a field that has a different
1893        size on different hardware architectures. This meant that the tests that
1894        showed this size failed. As the block is currently always of a fixed size,
1895        this information isn't actually particularly useful in pcretest output, so
1896        I have just removed it.
1898     8. Three pre-processor statements accidentally did not start in column 1.
1899        Sadly, there are *still* compilers around that complain, even though
1900        standard C has not required this for well over a decade. Sigh.
1902     9. In pcretest, the code for checking callouts passed small integers in the
1903        callout_data field, which is a void * field. However, some picky compilers
1904        complained about the casts involved for this on 64-bit systems. Now
1905        pcretest passes the address of the small integer instead, which should get
1906        rid of the warnings.
1908    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1909        both compile and run time, and gives an error if an invalid UTF-8 sequence
1910        is found. There is a option for disabling this check in cases where the
1911        string is known to be correct and/or the maximum performance is wanted.
1913    11. In response to a bug report, I changed one line in Makefile.in from
1915            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1916        to
1917            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1919        to look similar to other lines, but I have no way of telling whether this
1920        is the right thing to do, as I do not use Windows. No doubt I'll get told
1921        if it's wrong...
1924    Version 4.3 21-May-03
1925    ---------------------
1927    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1928       Makefile.
1930    2. Some refactoring to improve the quality of the code:
1932       (i)   The utf8_table... variables are now declared "const".
1934       (ii)  The code for \cx, which used the "case flipping" table to upper case
1935             lower case letters, now just substracts 32. This is ASCII-specific,
1936             but the whole concept of \cx is ASCII-specific, so it seems
1937             reasonable.
1939       (iii) PCRE was using its character types table to recognize decimal and
1940             hexadecimal digits in the pattern. This is silly, because it handles
1941             only 0-9, a-f, and A-F, but the character types table is locale-
1942             specific, which means strange things might happen. A private
1943             table is now used for this - though it costs 256 bytes, a table is
1944             much faster than multiple explicit tests. Of course, the standard
1945             character types table is still used for matching digits in subject
1946             strings against \d.
1948       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1949             ending in _t are). So I've renamed it as ESC_tee.
1951    3. The first argument for regexec() in the POSIX wrapper should have been
1952       defined as "const".
1954    4. Changed pcretest to use malloc() for its buffers so that they can be
1955       Electric Fenced for debugging.
1957    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1958       to read one or more bytes before the start of the subject string. Often this
1959       had no effect on PCRE's behaviour, but in some circumstances it could
1960       provoke a segmentation fault.
1962    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1963       to try to read one or more bytes before the start of the subject string.
1965    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1966       UTF-8 support could misbehave in various ways if the subject string
1967       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1968       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1969       back over UTF-8 characters.)
1972    Version 4.2 14-Apr-03
1973    ---------------------
1975    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1977    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1978         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1979         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1980         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1981         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1982           and BUILD_EXEEXT
1983         Note: automatic setting of the BUILD variables is not yet working
1984         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1985           compile-time but not at link-time
1986         [LINK]: use for linking executables only
1987         make different versions for Windows and non-Windows
1988         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1989           libraries
1990         [LINK_FOR_BUILD]: new variable
1991         [OBJEXT]: use throughout
1992         [EXEEXT]: use throughout
1993         <winshared>: new target
1994         <wininstall>: new target
1995         <dftables.o>: use native compiler
1996         <dftables>: use native linker
1997         <install>: handle Windows platform correctly
1998         <clean>: ditto
1999         <check>: ditto
2000         copy DLL to top builddir before testing
2002       As part of these changes, -no-undefined was removed again. This was reported
2003       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2004       in any case.
2006    3. Some tidies to get rid of compiler warnings:
2008       . In the match_data structure, match_limit was an unsigned long int, whereas
2009         match_call_count was an int. I've made them both unsigned long ints.
2011       . In pcretest the fact that a const uschar * doesn't automatically cast to
2012         a void * provoked a warning.
2014       . Turning on some more compiler warnings threw up some "shadow" variables
2015         and a few more missing casts.
2017    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2018       option, a class that contained a single character with a value between 128
2019       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2021    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2022       option, a class that contained several characters, but with at least one
2023       whose value was between 128 and 255 caused PCRE to crash.
2026    Version 4.1 12-Mar-03
2027    ---------------------
2029    1. Compiling with gcc -pedantic found a couple of places where casts were
2030    needed, and a string in dftables.c that was longer than standard compilers are
2031    required to support.
2033    2. Compiling with Sun's compiler found a few more places where the code could
2034    be tidied up in order to avoid warnings.
2036    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2037    first of these names is deprecated in the latest Autoconf in favour of the name
2038    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2039    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2040    analogy I have changed it to CFLAGS_FOR_BUILD.
2042    4. Added -no-undefined to the linking command in the Makefile, because this is
2043    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2044    linking step for the pcreposix library.
2046    5. PCRE was failing to diagnose the case of two named groups with the same
2047    name.
2049    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2050    literal character that is needed in the subject for a match, and scans along to
2051    ensure that it is present before embarking on the full matching process. This
2052    saves time in cases of nested unlimited repeats that are never going to match.
2053    Problem: the scan can take a lot of time if the subject is very long (e.g.
2054    megabytes), thus penalizing straightforward matches. It is now done only if the
2055    amount of subject to be scanned is less than 1000 bytes.
2057    7. A lesser problem with the same optimization is that it was recording the
2058    first character of an anchored pattern as "needed", thus provoking a search
2059    right along the subject, even when the first match of the pattern was going to
2060    fail. The "needed" character is now not set for anchored patterns, unless it
2061    follows something in the pattern that is of non-fixed length. Thus, it still
2062    fulfils its original purpose of finding quick non-matches in cases of nested
2063    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2066    Version 4.0 17-Feb-03
2067    ---------------------
2069    1. If a comment in an extended regex that started immediately after a meta-item
2070    extended to the end of string, PCRE compiled incorrect data. This could lead to
2071    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2073    2. Moved to autoconf 2.53 and libtool 1.4.2.
2075    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2076    the special perltest8 script is no longer needed - all the tests can be run
2077    from a single perltest script.
2079    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2080    by \s. It has now been removed in PCRE. This means it isn't recognized as
2081    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2082    class [:space:] *does* include VT, thereby creating a mess.
2084    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2085    space and tab.
2087    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2088    its new features into the main test script, reducing the number of scripts.
2090    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2091    were backward compatible, and made the (?i) apply to the whole pattern, as if
2092    /i were given. Now it behaves more logically, and applies the option setting
2093    only to what follows. PCRE has been changed to follow suit. However, if it
2094    finds options settings right at the start of the pattern, it extracts them into
2095    the global options, as before. Thus, they show up in the info data.
2097    8. Added support for the \Q...\E escape sequence. Characters in between are
2098    treated as literals. This is slightly different from Perl in that $ and @ are
2099    also handled as literals inside the quotes. In Perl, they will cause variable
2100    interpolation. Note the following examples:
2102        Pattern            PCRE matches      Perl matches
2104        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2105        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2106        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2108    For compatibility with Perl, \Q...\E sequences are recognized inside character
2109    classes as well as outside them.
2111    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2112    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2113    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2114    signed/unsigned warnings.
2116    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2117    option for pcretest, so I've replaced it by a simple function that does just
2118    that job.
2120    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2121    "pcregrep -".
2123    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2124    Java package. This provides some syntactic sugar for simple cases of what my
2125    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2126    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2127    item, you can use this simplified notation. Note that only makes sense with
2128    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2129    greediness, whatever the setting of the PCRE_UNGREEDY option.
2131    13. A change of greediness default within a pattern was not taking effect at
2132    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2133    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2134    was abstracted outside.
2136    14. PCRE now supports the \G assertion. It is true when the current matching
2137    position is at the start point of the match. This differs from \A when the
2138    starting offset is non-zero. Used with the /g option of pcretest (or similar
2139    code), it works in the same way as it does for Perl's /g option. If all
2140    alternatives of a regex begin with \G, the expression is anchored to the start
2141    match position, and the "anchored" flag is set in the compiled expression.
2143    15. Some bugs concerning the handling of certain option changes within patterns
2144    have been fixed. These applied to options other than (?ims). For example,
2145    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2146    been the other way round. Some of this was related to change 7 above.
2148    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2149    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2150    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2151    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2153    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2154    mode. Unlike ".", it always matches newline, whatever the setting of
2155    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2156    assertions. Perl allows it, but it doesn't (in general) work because it can't
2157    calculate the length of the lookbehind. At least, that's the case for Perl
2158    5.8.0 - I've been told they are going to document that it doesn't work in
2159    future.
2161    18. Added an error diagnosis for escapes that PCRE does not support: these are
2162    \L, \l, \N, \P, \p, \U, \u, and \X.
2164    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2165    reading past the end of the pattern in cases such as /[abcd/.
2167    20. PCRE was getting more memory than necessary for patterns with classes that
2168    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2170    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2171    compiling PCRE for use with Virtual Pascal.
2173    22. Small fix to the Makefile to make it work properly if the build is done
2174    outside the source tree.
2176    23. Added a new extension: a condition to go with recursion. If a conditional
2177    subpattern starts with (?(R) the "true" branch is used if recursion has
2178    happened, whereas the "false" branch is used only at the top level.
2180    24. When there was a very long string of literal characters (over 255 bytes
2181    without UTF support, over 250 bytes with UTF support), the computation of how
2182    much memory was required could be incorrect, leading to segfaults or other
2183    strange effects.
2185    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2186    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2187    there was a subsequent back reference to those brackets. This meant that, for
2188    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2189    possible to check for precisely this case. All we can do is abandon the
2190    optimization if .* occurs inside capturing brackets when there are any back
2191    references whatsoever. (See below for a better fix that came later.)
2193    26. The handling of the optimization for finding the first character of a
2194    non-anchored pattern, and for finding a character that is required later in the
2195    match were failing in some cases. This didn't break the matching; it just
2196    failed to optimize when it could. The way this is done has been re-implemented.
2198    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2200    28. Added a new feature that provides some of the functionality that Perl
2201    provides with (?{...}). The facility is termed a "callout". The way it is done
2202    in PCRE is for the caller to provide an optional function, by setting
2203    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2204    global variable. By default it is unset, which disables all calling out. To get
2205    the function called, the regex must include (?C) at appropriate points. This
2206    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2207    This provides a means of identifying different callout points. When PCRE
2208    reaches such a point in the regex, if pcre_callout has been set, the external
2209    function is called. It is provided with data in a structure called
2210    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2211    matching continues; if it returns a non-zero value, the match at the current
2212    point fails. However, backtracking will occur if possible. [This was changed
2213    later and other features added - see item 49 below.]
2215    29. pcretest is upgraded to test the callout functionality. It provides a
2216    callout function that displays information. By default, it shows the start of
2217    the match and the current position in the text. There are some new data escapes
2218    to vary what happens:
2220        \C+         in addition, show current contents of captured substrings
2221        \C-         do not supply a callout function
2222        \C!n        return 1 when callout number n is reached
2223        \C!n!m      return 1 when callout number n is reached for the mth time
2225    30. If pcregrep was called with the -l option and just a single file name, it
2226    output "<stdin>" if a match was found, instead of the file name.
2228    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2229    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2230    pcre_exec(). This saves a malloc/free per call. The default value of
2231    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2232    when configuring.
2234    32. The default maximum size of a compiled pattern is 64K. There have been a
2235    few cases of people hitting this limit. The code now uses macros to handle the
2236    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2237    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2238    configuring. Tests 2 and 5 work only with 2-byte links because they output
2239    debugging information about compiled patterns.
2241    33. Internal code re-arrangements:
2243    (a) Moved the debugging function for printing out a compiled regex into
2244        its own source file (printint.c) and used #include to pull it into
2245        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2246        separate copies.
2248    (b) Defined the list of op-code names for debugging as a macro in
2249        internal.h so that it is next to the definition of the opcodes.
2251    (c) Defined a table of op-code lengths for simpler skipping along compiled
2252        code. This is again a macro in internal.h so that it is next to the
2253        definition of the opcodes.
2255    34. Added support for recursive calls to individual subpatterns, along the
2256    lines of Robin Houston's patch (but implemented somewhat differently).
2258    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2259    allow it to read and process whole directories in Win32. This code was
2260    contributed by Lionel Fourquaux; it has not been tested by me.
2262    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2263    used to name a group. Names consist of alphanumerics and underscores, and must
2264    be unique. Back references use the syntax (?P=name) and recursive calls use
2265    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2266    numbers. The function pcre_fullinfo() can be used after compilation to extract
2267    a name/number map. There are three relevant calls:
2269      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2270      PCRE_INFO_NAMECOUNT            yields the number of entries
2271      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2273    The map is a vector of fixed-size entries. The size of each entry depends on
2274    the length of the longest name used. The first two bytes of each entry are the
2275    group number, most significant byte first. There follows the corresponding
2276    name, zero terminated. The names are in alphabetical order.
2278    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2279    case instead of 255. Making it the same both with and without UTF-8 support
2280    means that the same test output works with both.
2282    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2283    calling malloc() with a zero argument.
2285    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2286    optimization. I've improved things by keeping a bitmap of backreferences with
2287    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2288    fact referenced, the optimization can be applied. It is unlikely that a
2289    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2290    the match to follow \n) will appear inside brackets with a number greater than
2291    31, but if it does, any back reference > 31 suppresses the optimization.
2293    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2294    of disabling numbered capturing parentheses. Any opening parenthesis that is
2295    not followed by ? behaves as if it were followed by ?: but named parentheses
2296    can still be used for capturing (and they will acquire numbers in the usual
2297    way).
2299    41. Redesigned the return codes from the match() function into yes/no/error so
2300    that errors can be passed back from deep inside the nested calls. A malloc
2301    failure while inside a recursive subpattern call now causes the
2302    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2304    42. It is now possible to set a limit on the number of times the match()
2305    function is called in a call to pcre_exec(). This facility makes it possible to
2306    limit the amount of recursion and backtracking, though not in a directly
2307    obvious way, because the match() function is used in a number of different
2308    circumstances. The count starts from zero for each position in the subject
2309    string (for non-anchored patterns). The default limit is, for compatibility, a
2310    large number, namely 10 000 000. You can change this in two ways:
2312    (a) When configuring PCRE before making, you can use --with-match-limit=n
2313        to set a default value for the compiled library.
2315    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2316        a different value is set. See 45 below.
2318    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2320    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2321    of things that can be changed at compile time. The first argument specifies
2322    what is wanted and the second points to where the information is to be placed.
2323    The current list of available information is:
2325      PCRE_CONFIG_UTF8
2327    The output is an integer that is set to one if UTF-8 support is available;
2328    otherwise it is set to zero.
2332    The output is an integer that it set to the value of the code that is used for
2333    newline. It is either LF (10) or CR (13).
2337    The output is an integer that contains the number of bytes used for internal
2338    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2342    The output is an integer that contains the threshold above which the POSIX
2343    interface uses malloc() for output vectors. See item 31 above.
2347    The output is an unsigned integer that contains the default limit of the number
2348    of match() calls in a pcre_exec() execution. See 42 above.
2350    44. pcretest has been upgraded by the addition of the -C option. This causes it
2351    to extract all the available output from the new pcre_config() function, and to
2352    output it. The program then exits immediately.
2354    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2355    order to support additional features. One way would have been to define
2356    pcre_exec2() (for example) with extra arguments, but this would not have been
2357    extensible, and would also have required all calls to the original function to
2358    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2359    is used for passing in "extra" data from pcre_study().
2361    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2362    contains the following fields:
2364      flags         a bitmap indicating which of the following fields are set
2365      study_data    opaque data from pcre_study()
2366      match_limit   a way of specifying a limit on match() calls for a specific
2367                      call to pcre_exec()
2368      callout_data  data for callouts (see 49 below)
2370    The flag bits are also defined in pcre.h, and are
2376    The pcre_study() function now returns one of these new pcre_extra blocks, with
2377    the actual study data pointed to by the study_data field, and the
2378    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2379    before. That is, this change is entirely upwards-compatible and requires no
2380    change to existing code.
2382    If you want to pass in additional data to pcre_exec(), you can either place it
2383    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2384    block.
2386    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2387    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2388    times with different match limits, until it finds the minimum value needed for
2389    pcre_exec() to complete. The value is then output. This can be instructive; for
2390    most simple matches the number is quite small, but for pathological cases it
2391    gets very large very quickly.
2393    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2394    returns the size of the data block pointed to by the study_data field in a
2395    pcre_extra block, that is, the value that was passed as the argument to
2396    pcre_malloc() when PCRE was getting memory in which to place the information
2397    created by pcre_study(). The fourth argument should point to a size_t variable.
2398    pcretest has been extended so that this information is shown after a successful
2399    pcre_study() call when information about the compiled regex is being displayed.
2401    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2402    because what follows is always an absolute path. (Later: it turns out that this
2403    is more than cosmetic for MinGW, because it doesn't like empty path
2404    components.)
2406    49. Some changes have been made to the callout feature (see 28 above):
2408    (i)  A callout function now has three choices for what it returns:
2410           0  =>  success, carry on matching
2411         > 0  =>  failure at this point, but backtrack if possible
2412         < 0  =>  serious error, return this value from pcre_exec()
2414         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2415         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2416         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2417         use by callout functions. It will never be used by PCRE itself.
2419    (ii) The pcre_extra structure (see 45 above) has a void * field called
2420         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2421         pcre_callout_block structure has a field of the same name. The contents of
2422         the field passed in the pcre_extra structure are passed to the callout
2423         function in the corresponding field in the callout block. This makes it
2424         easier to use the same callout-containing regex from multiple threads. For
2425         testing, the pcretest program has a new data escape
2427           \C*n        pass the number n (may be negative) as callout_data
2429         If the callout function in pcretest receives a non-zero value as
2430         callout_data, it returns that value.
2432    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2433    there were some redundant $(CFLAGS) in commands that are now specified as
2434    $(LINK), which already includes $(CFLAGS).
2436    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2437    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2438    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2439    one-byte characters throughout. Note that case-insensitive matching applies
2440    only to characters whose values are less than 256. PCRE doesn't support the
2441    notion of cases for higher-valued characters.
2443    (i)   A character class whose characters are all within 0-255 is handled as
2444          a bit map, and the map is inverted for negative classes. Previously, a
2445          character > 255 always failed to match such a class; however it should
2446          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2448    (ii)  A negated character class with a single character < 255 is coded as
2449          "not this character" (OP_NOT). This wasn't working properly when the test
2450          character was multibyte, either singly or repeated.
2452    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2453          mode, for example: \x{100}{2,3}.
2455    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2456          singly or repeated) now correctly test multibyte characters. However,
2457          PCRE doesn't recognize any characters with values greater than 255 as
2458          digits, spaces, or word characters. Such characters always match \D, \S,
2459          and \W, and never match \d, \s, or \w.
2461    (v)   Classes may now contain characters and character ranges with values
2462          greater than 255. For example: [ab\x{100}-\x{400}].
2464    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2465          PCRE in UTF-8 mode.
2467    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2468    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2469    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2470    value.)
2472    53. The single man page has become too large. I have therefore split it up into
2473    a number of separate man pages. These also give rise to individual HTML pages;
2474    these are now put in a separate directory, and there is an index.html page that
2475    lists them all. Some hyperlinking between the pages has been installed.
2477    54. Added convenience functions for handling named capturing parentheses.
2479    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2480    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2481    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2482    are faulted.
2484    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2485    calling configure. These values are used when compiling the dftables.c program
2486    which is run to generate the source of the default character tables. They
2487    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2488    you will need to set these values.
2490    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2493    Version 3.9 02-Jan-02
2494    ---------------------
2496    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2498    2. If --disable-static was given, the building process failed when trying to
2499    build pcretest and pcregrep. (For some reason it was using libtool to compile
2500    them, which is not right, as they aren't part of the library.)
2503    Version 3.8 18-Dec-01
2504    ---------------------
2506    1. The experimental UTF-8 code was completely screwed up. It was packing the
2507    bytes in the wrong order. How dumb can you get?
2510    Version 3.7 29-Oct-01
2511    ---------------------
2513    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2514    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2515    this didn't happen under Solaris 8, where I normally test things.
2517    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2518    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2519    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2520    this fix an hour or so after the initial 3.7 release.)
2523    Version 3.6 23-Oct-01
2524    ---------------------
2526    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2527    offsets passed as NULL with zero offset count.
2529    2. The config.guess and config.sub files had not been updated when I moved to
2530    the latest autoconf.
2533    Version 3.5 15-Aug-01
2534    ---------------------
2536    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2537    had been forgotten.
2539    2. By using declared but undefined structures, we can avoid using "void"
2540    definitions in pcre.h while keeping the internal definitions of the structures
2541    private.
2543    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2544    user point of view, this means that both static and shared libraries are built
2545    by default, but this can be individually controlled. More of the work of
2546    handling this static/shared cases is now inside libtool instead of PCRE's make
2547    file.
2549    4. The pcretest utility is now installed along with pcregrep because it is
2550    useful for users (to test regexs) and by doing this, it automatically gets
2551    relinked by libtool. The documentation has been turned into a man page, so
2552    there are now .1, .txt, and .html versions in /doc.
2554    5. Upgrades to pcregrep:
2555       (i)   Added long-form option names like gnu grep.
2556       (ii)  Added --help to list all options with an explanatory phrase.
2557       (iii) Added -r, --recursive to recurse into sub-directories.
2558       (iv)  Added -f, --file to read patterns from a file.
2560    6. pcre_exec() was referring to its "code" argument before testing that
2561    argument for NULL (and giving an error if it was NULL).
2563    7. Upgraded Makefile.in to allow for compiling in a different directory from
2564    the source directory.
2566    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2567    options bits, the pointer it was passed was to an int instead of to an unsigned
2568    long int. This mattered only on 64-bit systems.
2570    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2571    generated) instead of pcre.in, which it its source. Also made the same change
2572    in several of the .c files.
2574    10. A new release of gcc defines printf() as a macro, which broke pcretest
2575    because it had an ifdef in the middle of a string argument for printf(). Fixed
2576    by using separate calls to printf().
2578    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2579    script, to force use of CR or LF instead of \n in the source. On non-Unix
2580    systems, the value can be set in config.h.
2582    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2583    absolute limit. Changed the text of the error message to make this clear, and
2584    likewise updated the man page.
2586    13. The limit of 99 on the number of capturing subpatterns has been removed.
2587    The new limit is 65535, which I hope will not be a "real" limit.
2590    Version 3.4 22-Aug-00
2591    ---------------------
2593    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2595    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2598    Version 3.3 01-Aug-00
2599    ---------------------
2601    1. If an octal character was given, but the value was greater than \377, it
2602    was not getting masked to the least significant bits, as documented. This could
2603    lead to crashes in some systems.
2605    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2606    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2608    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2609    These just pass their arguments on to (pcre_free)(), but they are provided
2610    because some uses of PCRE bind it to non-C systems that can call its functions,
2611    but cannot call free() or pcre_free() directly.
2613    4. Add "make test" as a synonym for "make check". Corrected some comments in
2614    the Makefile.
2616    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2617    Makefile.
2619    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2620    command called pgrep for grepping around the active processes.
2622    7. Added the beginnings of support for UTF-8 character strings.
2624    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2625    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2626    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2627    out for the ar command.)
2630  Version 3.2 12-May-00  Version 3.2 12-May-00
2631  ---------------------  ---------------------

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