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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.5 12-Nov-07
5    ---------------------
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
21    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing). Both these problems are fixed. "Subpattern name
25        expected" is now given for (?&) (a zero-length name), and this patch also
26        makes it give the same error for \k'' (previously it complained that that
27        was a reference to a non-existent subpattern).
29    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
30        this is right because (?- can be followed by option settings as well as by
31        digits. I have, however, made the messages clearer.
33    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34        than the number used in the conditional) now cause a compile-time error.
35        This is actually not compatible with Perl, which accepts such patterns, but
36        treats the conditional as always being FALSE (as PCRE used to), but it
37        seems to me that giving a diagnostic is better.
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
48    11. The program that makes PCRE's Unicode character property table had a bug
49        which caused it to generate incorrect table entries for sequences of
50        characters that have the same character type, but are in different scripts.
51        It amalgamated them into a single range, with the script of the first of
52        them. In other words, some characters were in the wrong script. There were
53        thirteen such cases, affecting characters in the following ranges:
55          U+002b0 - U+002c1
56          U+0060c - U+0060d
57          U+0061e - U+00612
58          U+0064b - U+0065e
59          U+0074d - U+0076d
60          U+01800 - U+01805
61          U+01d00 - U+01d77
62          U+01d9b - U+01dbf
63          U+0200b - U+0200f
64          U+030fc - U+030fe
65          U+03260 - U+0327f
66          U+0fb46 - U+0fbb1
67          U+10450 - U+1049d
69    12. The -o option (show only the matching part of a line) for pcregrep was not
70        compatible with GNU grep in that, if there was more than one match in a
71        line, it showed only the first of them. It now behaves in the same way as
72        GNU grep.
74    13. If the -o and -v options were combined for pcregrep, it printed a blank
75        line for every non-matching line. GNU grep prints nothing, and pcregrep now
76        does the same. The return code can be used to tell if there were any
77        non-matching lines.
79    14. The pattern (?=something)(?R) was not being diagnosed as a potentially
80        infinitely looping recursion. The bug was that positive lookaheads were not
81        being skipped when checking for a possible empty match (negative lookaheads
82        and both kinds of lookbehind were skipped).
84    15. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
85        inclusion of <windows.h> to before rather than after the definition of
86        INVALID_FILE_ATTRIBUTES (patch from David Byron).
88    16. Specifying a possessive quantifier with a specific limit for a Unicode
89        character property caused pcre_compile() to compile bad code, which led at
90        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
91        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
92        caused the error; without that there was no problem.
94    17. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
96    18. Added --enable-pcretest-libreadline.
98    19. In pcrecpp.cc, the variable 'count' was incremented twice in
99        RE::GlobalReplace(). As a result, the number of replacements returned was
100        double what it should be. I have removed one of the increments.
103    Version 7.4 21-Sep-07
104    ---------------------
106    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
107        means that a class such as [\s] counted as "explicit reference to CR or
108        LF". That isn't really right - the whole point of the change was to try to
109        help when there was an actual mention of one of the two characters. So now
110        the change happens only if \r or \n (or a literal CR or LF) character is
111        encountered.
113    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
114        of both had grown to the point where there were only 3 bits left.
115        Fortunately, there was spare space in the data structure, and so I have
116        moved the internal flags into a new 16-bit field to free up more option
117        bits.
119    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
120        but did not set the internal JCHANGED flag - either of these is enough to
121        control the way the "get" function works - but the PCRE_INFO_JCHANGED
122        facility is supposed to tell if (?J) was ever used, so now (?J) at the
123        start sets both bits.
125    4.  Added options (at build time, compile time, exec time) to change \R from
126        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
128    5.  doc/pcresyntax.html was missing from the distribution.
130    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
131        compatibility, even though it is no longer used.
133    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
134        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
135        windows.h file is present (where different names are used). [This was
136        reversed later after testing - see 16 below.]
138    8.  Changed all #include <config.h> to #include "config.h". There were also
139        some further <pcre.h> cases that I changed to "pcre.h".
141    9.  When pcregrep was used with the --colour option, it missed the line ending
142        sequence off the lines that it output.
144    10. It was pointed out to me that arrays of string pointers cause lots of
145        relocations when a shared library is dynamically loaded. A technique of
146        using a single long string with a table of offsets can drastically reduce
147        these. I have refactored PCRE in four places to do this. The result is
148        dramatic:
150          Originally:                          290
151          After changing UCP table:            187
152          After changing error message table:   43
153          After changing table of "verbs"       36
154          After changing table of Posix names   22
156        Thanks to the folks working on Gregex for glib for this insight.
158    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
159        unicode-properties was also set.
161    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
163    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
164        checked only for CRLF.
166    14. Added casts to pcretest.c to avoid compiler warnings.
168    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
170    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
171        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
172        entirely. This removes changes made in 7 above.
174    17. The CMake files have been updated, and there is now more information about
175        building with CMake in the NON-UNIX-USE document.
178    Version 7.3 28-Aug-07
179    ---------------------
181     1. In the rejigging of the build system that eventually resulted in 7.1, the
182        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
183        brackets there is not right, since it causes compilers to look for an
184        installed pcre.h, not the version that is in the source that is being
185        compiled (which of course may be different). I have changed it back to:
187          #include "pcre.h"
189        I have a vague recollection that the change was concerned with compiling in
190        different directories, but in the new build system, that is taken care of
191        by the VPATH setting the Makefile.
193     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
194        when the subject happened to end in the byte 0x85 (e.g. if the last
195        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
196        characters but of course it shouldn't be taken as a newline when it is part
197        of another character. The bug was that, for an unlimited repeat of . in
198        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
199        characters when looking for a newline.
201     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
203     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
204        in debug output.
206     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
207        long printing in the pcrecpp unittest when running under MinGW.
209     6. ESC_K was left out of the EBCDIC table.
211     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
212        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
213        limit also applies to "virtual nesting" when a pattern is recursive, and in
214        this case 1000 isn't so big. I have been able to remove this limit at the
215        expense of backing off one optimization in certain circumstances. Normally,
216        when pcre_exec() would call its internal match() function recursively and
217        immediately return the result unconditionally, it uses a "tail recursion"
218        feature to save stack. However, when a subpattern that can match an empty
219        string has an unlimited repetition quantifier, it no longer makes this
220        optimization. That gives it a stack frame in which to save the data for
221        checking that an empty string has been matched. Previously this was taken
222        from the 1000-entry workspace that had been reserved. So now there is no
223        explicit limit, but more stack is used.
225     8. Applied Daniel's patches to solve problems with the import/export magic
226        syntax that is required for Windows, and which was going wrong for the
227        pcreposix and pcrecpp parts of the library. These were overlooked when this
228        problem was solved for the main library.
230     9. There were some crude static tests to avoid integer overflow when computing
231        the size of patterns that contain repeated groups with explicit upper
232        limits. As the maximum quantifier is 65535, the maximum group length was
233        set at 30,000 so that the product of these two numbers did not overflow a
234        32-bit integer. However, it turns out that people want to use groups that
235        are longer than 30,000 bytes (though not repeat them that many times).
236        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
237        made it possible to implement the integer overflow checks in a much more
238        dynamic way, which I have now done. The artificial limitation on group
239        length has been removed - we now have only the limit on the total length of
240        the compiled pattern, which depends on the LINK_SIZE setting.
242    10. Fixed a bug in the documentation for get/copy named substring when
243        duplicate names are permitted. If none of the named substrings are set, the
244        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
245        empty string.
247    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
248        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
249        because the ] is interpreted as the first data character and the
250        terminating ] is not found. PCRE has been made compatible with Perl in this
251        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
252        cause memory overwriting.
254    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
255        string has been matched (to stop an infinite loop). It was not recognizing
256        a conditional subpattern that could match an empty string if that
257        subpattern was within another subpattern. For example, it looped when
258        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
259        condition was not nested. This bug has been fixed.
261    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
262        past the start of the subject in the presence of bytes with the top bit
263        set, for example "\x8aBCD".
265    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
266        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
268    14. Optimized (?!) to (*FAIL).
270    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
271        This restricts code points to be within the range 0 to 0x10FFFF, excluding
272        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
273        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
274        does: it's just the validity check that is more restrictive.
276    16. Inserted checks for integer overflows during escape sequence (backslash)
277        processing, and also fixed erroneous offset values for syntax errors during
278        backslash processing.
280    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
281        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
283    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
284        caused an overrun.
286    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
287        something other than just ASCII characters) inside a group that had an
288        unlimited repeat caused a loop at compile time (while checking to see
289        whether the group could match an empty string).
291    20. Debugging a pattern containing \p or \P could cause a crash. For example,
292        [\P{Any}] did so. (Error in the code for printing property names.)
294    21. An orphan \E inside a character class could cause a crash.
296    22. A repeated capturing bracket such as (A)? could cause a wild memory
297        reference during compilation.
299    23. There are several functions in pcre_compile() that scan along a compiled
300        expression for various reasons (e.g. to see if it's fixed length for look
301        behind). There were bugs in these functions when a repeated \p or \P was
302        present in the pattern. These operators have additional parameters compared
303        with \d, etc, and these were not being taken into account when moving along
304        the compiled data. Specifically:
306        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
307            length.
309        (b) An item such as \pL+ within a repeated group could cause crashes or
310            loops.
312        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
313            "reference to non-existent subpattern" error.
315        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
317    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
318        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
320    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
322    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
323        character were causing crashes (broken optimization).
325    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
326        \p or \P) caused a compile-time loop.
328    28. More problems have arisen in unanchored patterns when CRLF is a valid line
329        break. For example, the unstudied pattern [\r\n]A does not match the string
330        "\r\nA" because change 7.0/46 below moves the current point on by two
331        characters after failing to match at the start. However, the pattern \nA
332        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
333        the same is true. There doesn't seem any very clean way out of this, but
334        what I have chosen to do makes the common cases work: PCRE now takes note
335        of whether there can be an explicit match for \r or \n anywhere in the
336        pattern, and if so, 7.0/46 no longer applies. As part of this change,
337        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
338        pattern has explicit CR or LF references.
340    29. Added (*CR) etc for changing newline setting at start of pattern.
343    Version 7.2 19-Jun-07
344    ---------------------
346     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
347        which is apparently normally available under Windows.
349     2. Re-jig the pcregrep tests with different newline settings in an attempt
350        to make them independent of the local environment's newline setting.
352     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
354     4. Some of the "internals" tests were previously cut out when the link size
355        was not 2, because the output contained actual offsets. The recent new
356        "Z" feature of pcretest means that these can be cut out, making the tests
357        usable with all link sizes.
359     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
360        stack recursion. This gives a massive performance boost under BSD, but just
361        a small improvement under Linux. However, it saves one field in the frame
362        in all cases.
364     6. Added more features from the forthcoming Perl 5.10:
366        (a) (?-n) (where n is a string of digits) is a relative subroutine or
367            recursion call. It refers to the nth most recently opened parentheses.
369        (b) (?+n) is also a relative subroutine call; it refers to the nth next
370            to be opened parentheses.
372        (c) Conditions that refer to capturing parentheses can be specified
373            relatively, for example, (?(-2)... or (?(+3)...
375        (d) \K resets the start of the current match so that everything before
376            is not part of it.
378        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
380        (f) \g{name} is another synonym - part of Perl 5.10's unification of
381            reference syntax.
383        (g) (?| introduces a group in which the numbering of parentheses in each
384            alternative starts with the same number.
386        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
388     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
391     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
392        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
393        for detecting groups that can match an empty string.
395     9. A pattern with a very large number of alternatives (more than several
396        hundred) was running out of internal workspace during the pre-compile
397        phase, where pcre_compile() figures out how much memory will be needed. A
398        bit of new cunning has reduced the workspace needed for groups with
399        alternatives. The 1000-alternative test pattern now uses 12 bytes of
400        workspace instead of running out of the 4096 that are available.
402    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
404    11. Applied patch from Google to remove an optimization that didn't quite work.
405        The report of the bug said:
407          pcrecpp::RE("a*").FullMatch("aaa") matches, while
408          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
409          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
411    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
412        it matched the wrong number of bytes.
415    Version 7.1 24-Apr-07
416    ---------------------
418     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
419        that is more "standard", making use of automake and other Autotools. There
420        is some re-arrangement of the files and adjustment of comments consequent
421        on this.
423     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
424        for recursive directory scanning broke on some systems because the files
425        are not scanned in any specific order and on different systems the order
426        was different. A call to "sort" has been inserted into RunGrepTest for the
427        approprate test as a short-term fix. In the longer term there may be an
428        alternative.
430     3. I had an email from Eric Raymond about problems translating some of PCRE's
431        man pages to HTML (despite the fact that I distribute HTML pages, some
432        people do their own conversions for various reasons). The problems
433        concerned the use of low-level troff macros .br and .in. I have therefore
434        removed all such uses from the man pages (some were redundant, some could
435        be replaced by .nf/.fi pairs). The 132html script that I use to generate
436        HTML has been updated to handle .nf/.fi and to complain if it encounters
437        .br or .in.
439     4. Updated comments in configure.ac that get placed in config.h.in and also
440        arranged for config.h to be included in the distribution, with the name
441        config.h.generic, for the benefit of those who have to compile without
442        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
444     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
445        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
446        makevp.bat for the current PCRE, using the additional files
447        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
449     6. A Windows user reported a minor discrepancy with test 2, which turned out
450        to be caused by a trailing space on an input line that had got lost in his
451        copy. The trailing space was an accident, so I've just removed it.
453     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
454        that is needed.
456     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
457        as "const" (a) because they are and (b) because it helps the PHP
458        maintainers who have recently made a script to detect big data structures
459        in the php code that should be moved to the .rodata section. I remembered
460        to update Builducptable as well, so it won't revert if ucptable.h is ever
461        re-created.
463     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
464        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
465        order to be able to cut out the UTF-8 tables in the latter when UTF-8
466        support is not required. This saves 1.5-2K of code, which is important in
467        some applications.
469        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
470        so as not to refer to the tables, even though these functions will never be
471        called when UTF-8 support is disabled. Otherwise there are problems with a
472        shared library.
474    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
476        (a) It was defining its arguments as char * instead of void *.
478        (b) It was assuming that all moves were upwards in memory; this was true
479            a long time ago when I wrote it, but is no longer the case.
481        The emulated memove() is provided for those environments that have neither
482        memmove() nor bcopy(). I didn't think anyone used it these days, but that
483        is clearly not the case, as these two bugs were recently reported.
485    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
486        and Detrail to create the HTML documentation, the .txt form of the man
487        pages, and it removes trailing spaces from listed files. It also creates
488        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
489        case, it wraps all the #defines with #ifndefs. This script should be run
490        before "make dist".
492    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
493        with Unicode property support.
495        (a) For a maximizing quantifier, if the two different cases of the
496            character were of different lengths in their UTF-8 codings (there are
497            some cases like this - I found 11), and the matching function had to
498            back up over a mixture of the two cases, it incorrectly assumed they
499            were both the same length.
501        (b) When PCRE was configured to use the heap rather than the stack for
502            recursion during matching, it was not correctly preserving the data for
503            the other case of a UTF-8 character when checking ahead for a match
504            while processing a minimizing repeat. If the check also involved
505            matching a wide character, but failed, corruption could cause an
506            erroneous result when trying to check for a repeat of the original
507            character.
509    13. Some tidying changes to the testing mechanism:
511        (a) The RunTest script now detects the internal link size and whether there
512            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
513            values substituted by "configure". (The RunGrepTest script already did
514            this for UTF-8.) The configure.ac script no longer substitutes the
515            relevant variables.
517        (b) The debugging options /B and /D in pcretest show the compiled bytecode
518            with length and offset values. This means that the output is different
519            for different internal link sizes. Test 2 is skipped for link sizes
520            other than 2 because of this, bypassing the problem. Unfortunately,
521            there was also a test in test 3 (the locale tests) that used /B and
522            failed for link sizes other than 2. Rather than cut the whole test out,
523            I have added a new /Z option to pcretest that replaces the length and
524            offset values with spaces. This is now used to make test 3 independent
525            of link size. (Test 2 will be tidied up later.)
527    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
528        segmentation fault instead of returning the appropriate error message.
530    15. In multiline mode when the newline sequence was set to "any", the pattern
531        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
532        This doesn't seem right; it now treats the CRLF combination as the line
533        ending, and so does not match in that case. It's only a pattern such as ^$
534        that would hit this one: something like ^ABC$ would have failed after \r
535        and then tried again after \r\n.
537    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
538        in an attempt to make files that differ only in their line terminators
539        compare equal. This works on Linux.
541    17. Under certain error circumstances pcregrep might try to free random memory
542        as it exited. This is now fixed, thanks to valgrind.
544    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
545        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
546        was because its rules for how to advance for /g after matching an empty
547        string at the end of a line did not allow for this case. They now check for
548        it specially.
550    20. pcretest is supposed to handle patterns and data of any length, by
551        extending its buffers when necessary. It was getting this wrong when the
552        buffer for a data line had to be extended.
554    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
555        CRLF as a newline sequence.
557    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
558        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
559        I have nevertheless tidied it up.
561    23. Added some casts to kill warnings from HP-UX ia64 compiler.
563    24. Added a man page for pcre-config.
566    Version 7.0 19-Dec-06
567    ---------------------
569     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
570        moving to gcc 4.1.1.
572     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
573        sys/time.h, which is documented as needed for this function. It doesn't
574        seem to matter on Linux, but it showed up on some releases of OS X.
576     3. It seems that there are systems where bytes whose values are greater than
577        127 match isprint() in the "C" locale. The "C" locale should be the
578        default when a C program starts up. In most systems, only ASCII printing
579        characters match isprint(). This difference caused the output from pcretest
580        to vary, making some of the tests fail. I have changed pcretest so that:
582        (a) When it is outputting text in the compiled version of a pattern, bytes
583            other than 32-126 are always shown as hex escapes.
585        (b) When it is outputting text that is a matched part of a subject string,
586            it does the same, unless a different locale has been set for the match
587            (using the /L modifier). In this case, it uses isprint() to decide.
589     4. Fixed a major bug that caused incorrect computation of the amount of memory
590        required for a compiled pattern when options that changed within the
591        pattern affected the logic of the preliminary scan that determines the
592        length. The relevant options are -x, and -i in UTF-8 mode. The result was
593        that the computed length was too small. The symptoms of this bug were
594        either the PCRE error "internal error: code overflow" from pcre_compile(),
595        or a glibc crash with a message such as "pcretest: free(): invalid next
596        size (fast)". Examples of patterns that provoked this bug (shown in
597        pcretest format) are:
599          /(?-x: )/x
600          /(?x)(?-x: \s*#\s*)/
601          /((?i)[\x{c0}])/8
602          /(?i:[\x{c0}])/8
604        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
605        is now done differently.
607     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
608        wrapper classes; (b) implement a new function in the C++ scanner that is
609        more efficient than the old way of doing things because it avoids levels of
610        recursion in the regex matching; (c) add a paragraph to the documentation
611        for the FullMatch() function.
613     6. The escape sequence \n was being treated as whatever was defined as
614        "newline". Not only was this contrary to the documentation, which states
615        that \n is character 10 (hex 0A), but it also went horribly wrong when
616        "newline" was defined as CRLF. This has been fixed.
618     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
619        was being set to -1 for the "end of line" case (supposedly a value that no
620        character can have). Though this value is never used (the check for end of
621        line is "zero bytes in current character"), it caused compiler complaints.
622        I've changed it to 0xffffffff.
624     8. In pcre_version.c, the version string was being built by a sequence of
625        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
626        string (as it is for production releases) called a macro with an empty
627        argument. The C standard says the result of this is undefined. The gcc
628        compiler treats it as an empty string (which was what was wanted) but it is
629        reported that Visual C gives an error. The source has been hacked around to
630        avoid this problem.
632     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
633        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
634        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
635        of them did).
637    10. Originally, pcretest opened its input and output without "b"; then I was
638        told that "b" was needed in some environments, so it was added for release
639        5.0 to both the input and output. (It makes no difference on Unix-like
640        systems.) Later I was told that it is wrong for the input on Windows. I've
641        now abstracted the modes into two macros, to make it easier to fiddle with
642        them, and removed "b" from the input mode under Windows.
644    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
646    12. Added -help and --help to pcretest as an official way of being reminded
647        of the options.
649    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
650        and pcrecpp.cc because they annoy compilers at high warning levels.
652    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
654    15. Fixed an occurrence of == in configure.ac that should have been = (shell
655        scripts are not C programs :-) and which was not noticed because it works
656        on Linux.
658    16. pcretest is supposed to handle any length of pattern and data line (as one
659        line or as a continued sequence of lines) by extending its input buffer if
660        necessary. This feature was broken for very long pattern lines, leading to
661        a string of junk being passed to pcre_compile() if the pattern was longer
662        than about 50K.
664    17. I have done a major re-factoring of the way pcre_compile() computes the
665        amount of memory needed for a compiled pattern. Previously, there was code
666        that made a preliminary scan of the pattern in order to do this. That was
667        OK when PCRE was new, but as the facilities have expanded, it has become
668        harder and harder to keep it in step with the real compile phase, and there
669        have been a number of bugs (see for example, 4 above). I have now found a
670        cunning way of running the real compile function in a "fake" mode that
671        enables it to compute how much memory it would need, while actually only
672        ever using a few hundred bytes of working memory and without too many
673        tests of the mode. This should make future maintenance and development
674        easier. A side effect of this work is that the limit of 200 on the nesting
675        depth of parentheses has been removed (though this was never a serious
676        limitation, I suspect). However, there is a downside: pcre_compile() now
677        runs more slowly than before (30% or more, depending on the pattern). I
678        hope this isn't a big issue. There is no effect on runtime performance.
680    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
681        newline (only possible for the last line of a file) and it was a
682        pattern that set a locale (followed by /Lsomething), pcretest crashed.
684    19. Added additional timing features to pcretest. (1) The -tm option now times
685        matching only, not compiling. (2) Both -t and -tm can be followed, as a
686        separate command line item, by a number that specifies the number of
687        repeats to use when timing. The default is 50000; this gives better
688        precision, but takes uncomfortably long for very large patterns.
690    20. Extended pcre_study() to be more clever in cases where a branch of a
691        subpattern has no definite first character. For example, (a*|b*)[cd] would
692        previously give no result from pcre_study(). Now it recognizes that the
693        first character must be a, b, c, or d.
695    21. There was an incorrect error "recursive call could loop indefinitely" if
696        a subpattern (or the entire pattern) that was being tested for matching an
697        empty string contained only one non-empty item after a nested subpattern.
698        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
699        incorrectly, because the \d was being skipped in the check.
701    22. The pcretest program now has a new pattern option /B and a command line
702        option -b, which is equivalent to adding /B to every pattern. This causes
703        it to show the compiled bytecode, without the additional information that
704        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
705        is the same as /B/I).
707    23. A new optimization is now able automatically to treat some sequences such
708        as a*b as a*+b. More specifically, if something simple (such as a character
709        or a simple class like \d) has an unlimited quantifier, and is followed by
710        something that cannot possibly match the quantified thing, the quantifier
711        is automatically "possessified".
713    24. A recursive reference to a subpattern whose number was greater than 39
714        went wrong under certain circumstances in UTF-8 mode. This bug could also
715        have affected the operation of pcre_study().
717    25. Realized that a little bit of performance could be had by replacing
718        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
720    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
722    27. Possessive quantifiers such as a++ were previously implemented by turning
723        them into atomic groups such as ($>a+). Now they have their own opcodes,
724        which improves performance. This includes the automatically created ones
725        from 23 above.
727    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
728        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
729        the first matched character to be a colon. This applied both to named and
730        numbered groups.
732    29. The ucpinternal.h header file was missing its idempotency #ifdef.
734    30. I was sent a "project" file called libpcre.a.dev which I understand makes
735        building PCRE on Windows easier, so I have included it in the distribution.
737    31. There is now a check in pcretest against a ridiculously large number being
738        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
739        loop, the loop is abandoned.
741    32. Forward references to subpatterns in conditions such as (?(2)...) where
742        subpattern 2 is defined later cause pcre_compile() to search forwards in
743        the pattern for the relevant set of parentheses. This search went wrong
744        when there were unescaped parentheses in a character class, parentheses
745        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
747    33. "Subroutine" calls and backreferences were previously restricted to
748        referencing subpatterns earlier in the regex. This restriction has now
749        been removed.
751    34. Added a number of extra features that are going to be in Perl 5.10. On the
752        whole, these are just syntactic alternatives for features that PCRE had
753        previously implemented using the Python syntax or my own invention. The
754        other formats are all retained for compatibility.
756        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
757            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
758            also .NET compatible.
760        (b) A recursion or subroutine call to a named group can now be defined as
761            (?&name) as well as (?P>name).
763        (c) A backreference to a named group can now be defined as \k<name> or
764            \k'name' as well as (?P=name). The new forms, as well as being in Perl
765            5.10, are also .NET compatible.
767        (d) A conditional reference to a named group can now use the syntax
768            (?(<name>) or (?('name') as well as (?(name).
770        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
771            groups (named and numbered) that are never evaluated inline, but can be
772            called as "subroutines" from elsewhere. In effect, the DEFINE condition
773            is always false. There may be only one alternative in such a group.
775        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
776            as the simple (?(R). The condition is true only if the most recent
777            recursion is that of the given number or name. It does not search out
778            through the entire recursion stack.
780        (g) The escape \gN or \g{N} has been added, where N is a positive or
781            negative number, specifying an absolute or relative reference.
783    35. Tidied to get rid of some further signed/unsigned compiler warnings and
784        some "unreachable code" warnings.
786    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
787        things, this adds five new scripts.
789    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
790        There were also incompatibilities regarding the handling of \Q..\E inside
791        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
792        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
794    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
795        matches an empty string, and forcibly breaks the loop. There were bugs in
796        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
797        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
798        separate and independent bugs (that affected different cases) have been
799        fixed.
801    39. Refactored the code to abolish the use of different opcodes for small
802        capturing bracket numbers. This is a tidy that I avoided doing when I
803        removed the limit on the number of capturing brackets for 3.5 back in 2001.
804        The new approach is not only tidier, it makes it possible to reduce the
805        memory needed to fix the previous bug (38).
807    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
808        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
809        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
810        mode.
812    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
813        report.
815    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
816        copy construction and assignment in the C++ wrapper.
818    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
819        couple of bugs that could have given wrong results in the "--newline=crlf"
820        case.
822    44. Added a number of casts and did some reorganization of signed/unsigned int
823        variables following suggestions from Dair Grant. Also renamed the variable
824        "this" as "item" because it is a C++ keyword.
826    45. Arranged for dftables to add
828          #include "pcre_internal.h"
830        to pcre_chartables.c because without it, gcc 4.x may remove the array
831        definition from the final binary if PCRE is built into a static library and
832        dead code stripping is activated.
834    46. For an unanchored pattern, if a match attempt fails at the start of a
835        newline sequence, and the newline setting is CRLF or ANY, and the next two
836        characters are CRLF, advance by two characters instead of one.
839    Version 6.7 04-Jul-06
840    ---------------------
842     1. In order to handle tests when input lines are enormously long, pcretest has
843        been re-factored so that it automatically extends its buffers when
844        necessary. The code is crude, but this _is_ just a test program. The
845        default size has been increased from 32K to 50K.
847     2. The code in pcre_study() was using the value of the re argument before
848        testing it for NULL. (Of course, in any sensible call of the function, it
849        won't be NULL.)
851     3. The memmove() emulation function in pcre_internal.h, which is used on
852        systems that lack both memmove() and bcopy() - that is, hardly ever -
853        was missing a "static" storage class specifier.
855     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
856        containing an extended class (one that cannot be represented by a bitmap
857        because it contains high-valued characters or Unicode property items, e.g.
858        [\pZ]). Almost always one would set UTF-8 mode when processing such a
859        pattern, but PCRE should not loop if you do not (it no longer does).
860        [Detail: two cases were found: (a) a repeated subpattern containing an
861        extended class; (b) a recursive reference to a subpattern that followed a
862        previous extended class. It wasn't skipping over the extended class
863        correctly when UTF-8 mode was not set.]
865     5. A negated single-character class was not being recognized as fixed-length
866        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
867        compile error "lookbehind assertion is not fixed length".
869     6. The RunPerlTest auxiliary script was showing an unexpected difference
870        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
871        write a Perl script that can interpret lines of an input file either as
872        byte characters or as UTF-8, which is what "perltest" was being required to
873        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
874        can't do is switch easily at run time between having the "use utf8;" pragma
875        or not. In the end, I fudged it by using the RunPerlTest script to insert
876        "use utf8;" explicitly for the UTF-8 tests.
878     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
879        the end of the subject string, contrary to the documentation and to what
880        Perl does. This was true of both matching functions. Now it matches only at
881        the start of the subject and immediately after *internal* newlines.
883     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
884        a pointer to an int instead of a pointer to an unsigned long int. This
885        caused problems on 64-bit systems.
887     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
888        instance of the 'standard' template library not being so standard".
890    10. There was no check on the number of named subpatterns nor the maximum
891        length of a subpattern name. The product of these values is used to compute
892        the size of the memory block for a compiled pattern. By supplying a very
893        long subpattern name and a large number of named subpatterns, the size
894        computation could be caused to overflow. This is now prevented by limiting
895        the length of names to 32 characters, and the number of named subpatterns
896        to 10,000.
898    11. Subpatterns that are repeated with specific counts have to be replicated in
899        the compiled pattern. The size of memory for this was computed from the
900        length of the subpattern and the repeat count. The latter is limited to
901        65535, but there was no limit on the former, meaning that integer overflow
902        could in principle occur. The compiled length of a repeated subpattern is
903        now limited to 30,000 bytes in order to prevent this.
905    12. Added the optional facility to have named substrings with the same name.
907    13. Added the ability to use a named substring as a condition, using the
908        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
909        are numbers (not recommended). Forward references are permitted.
911    14. Added forward references in named backreferences (if you see what I mean).
913    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
914        pattern could run off the end of the subject. For example, the pattern
915        "(?s)(.{1,5})"8 did this with the subject "ab".
917    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
918        PCRE_CASELESS was set when matching characters that were quantified with ?
919        or *.
921    17. A character class other than a single negated character that had a minimum
922        but no maximum quantifier - for example [ab]{6,} - was not handled
923        correctly by pce_dfa_exec(). It would match only one character.
925    18. A valid (though odd) pattern that looked like a POSIX character
926        class but used an invalid character after [ (for example [[,abc,]]) caused
927        pcre_compile() to give the error "Failed: internal error: code overflow" or
928        in some cases to crash with a glibc free() error. This could even happen if
929        the pattern terminated after [[ but there just happened to be a sequence of
930        letters, a binary zero, and a closing ] in the memory that followed.
932    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
933        over the years. Originally (before any Unicode support), just the bottom 8
934        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
935        output from "man perlunicode" includes this:
937          The regular expression compiler produces polymorphic opcodes.  That
938          is, the pattern adapts to the data and automatically switches to
939          the Unicode character scheme when presented with Unicode data--or
940          instead uses a traditional byte scheme when presented with byte
941          data.
943        Sadly, a wide octal escape does not cause a switch, and in a string with
944        no other multibyte characters, these octal escapes are treated as before.
945        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
946        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
947        Unicode string.
949        I have not perpetrated such confusion in PCRE. Up till now, it took just
950        the bottom 8 bits, as in old Perl. I have now made octal escapes with
951        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
952        translate to the appropriate multibyte character.
954    29. Applied some refactoring to reduce the number of warnings from Microsoft
955        and Borland compilers. This has included removing the fudge introduced
956        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
957        a warning about an unused variable.
959    21. PCRE has not included VT (character 0x0b) in the set of whitespace
960        characters since release 4.0, because Perl (from release 5.004) does not.
961        [Or at least, is documented not to: some releases seem to be in conflict
962        with the documentation.] However, when a pattern was studied with
963        pcre_study() and all its branches started with \s, PCRE still included VT
964        as a possible starting character. Of course, this did no harm; it just
965        caused an unnecessary match attempt.
967    22. Removed a now-redundant internal flag bit that recorded the fact that case
968        dependency changed within the pattern. This was once needed for "required
969        byte" processing, but is no longer used. This recovers a now-scarce options
970        bit. Also moved the least significant internal flag bit to the most-
971        significant bit of the word, which was not previously used (hangover from
972        the days when it was an int rather than a uint) to free up another bit for
973        the future.
975    23. Added support for CRLF line endings as well as CR and LF. As well as the
976        default being selectable at build time, it can now be changed at runtime
977        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
978        specify that it is scanning data with non-default line endings.
980    24. Changed the definition of CXXLINK to make it agree with the definition of
981        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
983    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
984        recursions. This makes a big different to stack usage for some patterns.
986    26. If a subpattern containing a named recursion or subroutine reference such
987        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
988        the space required for the compiled pattern went wrong and gave too small a
989        value. Depending on the environment, this could lead to "Failed: internal
990        error: code overflow at offset 49" or "glibc detected double free or
991        corruption" errors.
993    27. Applied patches from Google (a) to support the new newline modes and (b) to
994        advance over multibyte UTF-8 characters in GlobalReplace.
996    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
997        difference for some implementation of PCRE in some Windows version.
999    29. Added some extra testing facilities to pcretest:
1001        \q<number>   in a data line sets the "match limit" value
1002        \Q<number>   in a data line sets the "match recursion limt" value
1003        -S <number>  sets the stack size, where <number> is in megabytes
1005        The -S option isn't available for Windows.
1008  Version 6.6 06-Feb-06  Version 6.6 06-Feb-06
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