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revision 17 by nigel, Sat Feb 24 21:38:29 2007 UTC revision 330 by ph10, Sat Apr 5 15:31:38 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.7 05-Mar-08
5    ---------------------
6    
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.
10    
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.
14    
15    3.  Remove a line of dead code, identified by coverity and reported by Nuno
16        Lopes.
17    
18    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
19    
20        (1) The include/exclude patterns were being applied to the whole pathnames
21            of files, instead of just to the final components.
22    
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.
29    
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.
32    
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.
36    
37    7.  Added some missing "const"s to declarations of static tables in
38        pcre_compile.c and pcre_dfa_exec.c.
39    
40    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
41        caused by fix #2  above. (Subsequently also a second patch to fix the
42        first patch. And a third patch - this was a messy problem.)
43    
44    
45    Version 7.6 28-Jan-08
46    ---------------------
47    
48    1.  A character class containing a very large number of characters with
49        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
50        overflow.
51    
52    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
53        HAVE_LONG_LONG is not defined.
54    
55    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
56        bring them up to date and include new features. This patch includes:
57    
58        - Fixed PH's badly added libz and libbz2 support.
59        - Fixed a problem with static linking.
60        - Added pcredemo. [But later removed - see 7 below.]
61        - Fixed dftables problem and added an option.
62        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
63            HAVE_LONG_LONG.
64        - Added readline support for pcretest.
65        - Added an listing of the option settings after cmake has run.
66    
67    4.  A user submitted a patch to Makefile that makes it easy to create
68        "pcre.dll" under mingw when using Configure/Make. I added stuff to
69        Makefile.am that cause it to include this special target, without
70        affecting anything else. Note that the same mingw target plus all
71        the other distribution libraries and programs are now supported
72        when configuring with CMake (see 6 below) instead of with
73        Configure/Make.
74    
75    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
76        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
77        exported in the Windows port". It has not yet been confirmed that the patch
78        solves the problem, but it does no harm.
79    
80    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
81        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
82        with CMake, and also correct the comment about stack recursion.
83    
84    7.  Remove the automatic building of pcredemo from the ./configure system and
85        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
86        of a program that users should build themselves after PCRE is installed, so
87        building it automatically is not really right. What is more, it gave
88        trouble in some build environments.
89    
90    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
91    
92    
93    Version 7.5 10-Jan-08
94    ---------------------
95    
96    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
97        values in parens when parsing an RE using the C++ wrapper."
98    
99    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
100        Characters greater than 255 were excluded from the class instead of being
101        included.
102    
103    3.  The same bug as (2) above applied to negated POSIX classes such as
104        [:^space:].
105    
106    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
107        defined or documented. It seems to have been a typo for PCRE_STATIC, so
108        I have changed it.
109    
110    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
111        first named subpattern) and a construct such as (?&a) would reference the
112        first named subpattern whose name started with "a" (in other words, the
113        length check was missing). Both these problems are fixed. "Subpattern name
114        expected" is now given for (?&) (a zero-length name), and this patch also
115        makes it give the same error for \k'' (previously it complained that that
116        was a reference to a non-existent subpattern).
117    
118    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
119        this is right because (?- can be followed by option settings as well as by
120        digits. I have, however, made the messages clearer.
121    
122    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
123        than the number used in the conditional) now cause a compile-time error.
124        This is actually not compatible with Perl, which accepts such patterns, but
125        treats the conditional as always being FALSE (as PCRE used to), but it
126        seems to me that giving a diagnostic is better.
127    
128    8.  Change "alphameric" to the more common word "alphanumeric" in comments
129        and messages.
130    
131    9.  Fix two occurrences of "backslash" in comments that should have been
132        "backspace".
133    
134    10. Remove two redundant lines of code that can never be obeyed (their function
135        was moved elsewhere).
136    
137    11. The program that makes PCRE's Unicode character property table had a bug
138        which caused it to generate incorrect table entries for sequences of
139        characters that have the same character type, but are in different scripts.
140        It amalgamated them into a single range, with the script of the first of
141        them. In other words, some characters were in the wrong script. There were
142        thirteen such cases, affecting characters in the following ranges:
143    
144          U+002b0 - U+002c1
145          U+0060c - U+0060d
146          U+0061e - U+00612
147          U+0064b - U+0065e
148          U+0074d - U+0076d
149          U+01800 - U+01805
150          U+01d00 - U+01d77
151          U+01d9b - U+01dbf
152          U+0200b - U+0200f
153          U+030fc - U+030fe
154          U+03260 - U+0327f
155          U+0fb46 - U+0fbb1
156          U+10450 - U+1049d
157    
158    12. The -o option (show only the matching part of a line) for pcregrep was not
159        compatible with GNU grep in that, if there was more than one match in a
160        line, it showed only the first of them. It now behaves in the same way as
161        GNU grep.
162    
163    13. If the -o and -v options were combined for pcregrep, it printed a blank
164        line for every non-matching line. GNU grep prints nothing, and pcregrep now
165        does the same. The return code can be used to tell if there were any
166        non-matching lines.
167    
168    14. Added --file-offsets and --line-offsets to pcregrep.
169    
170    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
171        infinitely looping recursion. The bug was that positive lookaheads were not
172        being skipped when checking for a possible empty match (negative lookaheads
173        and both kinds of lookbehind were skipped).
174    
175    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
176        inclusion of <windows.h> to before rather than after the definition of
177        INVALID_FILE_ATTRIBUTES (patch from David Byron).
178    
179    17. Specifying a possessive quantifier with a specific limit for a Unicode
180        character property caused pcre_compile() to compile bad code, which led at
181        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
182        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
183        caused the error; without that there was no problem.
184    
185    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
186    
187    19. Added --enable-pcretest-libreadline.
188    
189    20. In pcrecpp.cc, the variable 'count' was incremented twice in
190        RE::GlobalReplace(). As a result, the number of replacements returned was
191        double what it should be. I removed one of the increments, but Craig sent a
192        later patch that removed the other one (the right fix) and added unit tests
193        that check the return values (which was not done before).
194    
195    21. Several CMake things:
196    
197        (1) Arranged that, when cmake is used on Unix, the libraries end up with
198            the names libpcre and libpcreposix, not just pcre and pcreposix.
199    
200        (2) The above change means that pcretest and pcregrep are now correctly
201            linked with the newly-built libraries, not previously installed ones.
202    
203        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
204    
205    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
206        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
207        UTF-8 newline character). The key issue is that the pattern starts .*;
208        this means that the match must be either at the beginning, or after a
209        newline. The bug was in the code for advancing after a failed match and
210        checking that the new position followed a newline. It was not taking
211        account of UTF-8 characters correctly.
212    
213    23. PCRE was behaving differently from Perl in the way it recognized POSIX
214        character classes. PCRE was not treating the sequence [:...:] as a
215        character class unless the ... were all letters. Perl, however, seems to
216        allow any characters between [: and :], though of course it rejects as
217        unknown any "names" that contain non-letters, because all the known class
218        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
219        for example, whereas PCRE did not - it did not recognize a POSIX character
220        class. This seemed a bit dangerous, so the code has been changed to be
221        closer to Perl. The behaviour is not identical to Perl, because PCRE will
222        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
223        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
224        Perl does, and where it didn't before.
225    
226    24. Rewrite so as to remove the single use of %n from pcregrep because in some
227        Windows environments %n is disabled by default.
228    
229    
230    Version 7.4 21-Sep-07
231    ---------------------
232    
233    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
234        means that a class such as [\s] counted as "explicit reference to CR or
235        LF". That isn't really right - the whole point of the change was to try to
236        help when there was an actual mention of one of the two characters. So now
237        the change happens only if \r or \n (or a literal CR or LF) character is
238        encountered.
239    
240    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
241        of both had grown to the point where there were only 3 bits left.
242        Fortunately, there was spare space in the data structure, and so I have
243        moved the internal flags into a new 16-bit field to free up more option
244        bits.
245    
246    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
247        but did not set the internal JCHANGED flag - either of these is enough to
248        control the way the "get" function works - but the PCRE_INFO_JCHANGED
249        facility is supposed to tell if (?J) was ever used, so now (?J) at the
250        start sets both bits.
251    
252    4.  Added options (at build time, compile time, exec time) to change \R from
253        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
254    
255    5.  doc/pcresyntax.html was missing from the distribution.
256    
257    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
258        compatibility, even though it is no longer used.
259    
260    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
261        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
262        windows.h file is present (where different names are used). [This was
263        reversed later after testing - see 16 below.]
264    
265    8.  Changed all #include <config.h> to #include "config.h". There were also
266        some further <pcre.h> cases that I changed to "pcre.h".
267    
268    9.  When pcregrep was used with the --colour option, it missed the line ending
269        sequence off the lines that it output.
270    
271    10. It was pointed out to me that arrays of string pointers cause lots of
272        relocations when a shared library is dynamically loaded. A technique of
273        using a single long string with a table of offsets can drastically reduce
274        these. I have refactored PCRE in four places to do this. The result is
275        dramatic:
276    
277          Originally:                          290
278          After changing UCP table:            187
279          After changing error message table:   43
280          After changing table of "verbs"       36
281          After changing table of Posix names   22
282    
283        Thanks to the folks working on Gregex for glib for this insight.
284    
285    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
286        unicode-properties was also set.
287    
288    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
289    
290    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
291        checked only for CRLF.
292    
293    14. Added casts to pcretest.c to avoid compiler warnings.
294    
295    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
296    
297    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
298        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
299        entirely. This removes changes made in 7 above.
300    
301    17. The CMake files have been updated, and there is now more information about
302        building with CMake in the NON-UNIX-USE document.
303    
304    
305    Version 7.3 28-Aug-07
306    ---------------------
307    
308     1. In the rejigging of the build system that eventually resulted in 7.1, the
309        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
310        brackets there is not right, since it causes compilers to look for an
311        installed pcre.h, not the version that is in the source that is being
312        compiled (which of course may be different). I have changed it back to:
313    
314          #include "pcre.h"
315    
316        I have a vague recollection that the change was concerned with compiling in
317        different directories, but in the new build system, that is taken care of
318        by the VPATH setting the Makefile.
319    
320     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
321        when the subject happened to end in the byte 0x85 (e.g. if the last
322        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
323        characters but of course it shouldn't be taken as a newline when it is part
324        of another character. The bug was that, for an unlimited repeat of . in
325        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
326        characters when looking for a newline.
327    
328     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
329    
330     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
331        in debug output.
332    
333     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
334        long printing in the pcrecpp unittest when running under MinGW.
335    
336     6. ESC_K was left out of the EBCDIC table.
337    
338     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
339        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
340        limit also applies to "virtual nesting" when a pattern is recursive, and in
341        this case 1000 isn't so big. I have been able to remove this limit at the
342        expense of backing off one optimization in certain circumstances. Normally,
343        when pcre_exec() would call its internal match() function recursively and
344        immediately return the result unconditionally, it uses a "tail recursion"
345        feature to save stack. However, when a subpattern that can match an empty
346        string has an unlimited repetition quantifier, it no longer makes this
347        optimization. That gives it a stack frame in which to save the data for
348        checking that an empty string has been matched. Previously this was taken
349        from the 1000-entry workspace that had been reserved. So now there is no
350        explicit limit, but more stack is used.
351    
352     8. Applied Daniel's patches to solve problems with the import/export magic
353        syntax that is required for Windows, and which was going wrong for the
354        pcreposix and pcrecpp parts of the library. These were overlooked when this
355        problem was solved for the main library.
356    
357     9. There were some crude static tests to avoid integer overflow when computing
358        the size of patterns that contain repeated groups with explicit upper
359        limits. As the maximum quantifier is 65535, the maximum group length was
360        set at 30,000 so that the product of these two numbers did not overflow a
361        32-bit integer. However, it turns out that people want to use groups that
362        are longer than 30,000 bytes (though not repeat them that many times).
363        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
364        made it possible to implement the integer overflow checks in a much more
365        dynamic way, which I have now done. The artificial limitation on group
366        length has been removed - we now have only the limit on the total length of
367        the compiled pattern, which depends on the LINK_SIZE setting.
368    
369    10. Fixed a bug in the documentation for get/copy named substring when
370        duplicate names are permitted. If none of the named substrings are set, the
371        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
372        empty string.
373    
374    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
375        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
376        because the ] is interpreted as the first data character and the
377        terminating ] is not found. PCRE has been made compatible with Perl in this
378        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
379        cause memory overwriting.
380    
381    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
382        string has been matched (to stop an infinite loop). It was not recognizing
383        a conditional subpattern that could match an empty string if that
384        subpattern was within another subpattern. For example, it looped when
385        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
386        condition was not nested. This bug has been fixed.
387    
388    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
389        past the start of the subject in the presence of bytes with the top bit
390        set, for example "\x8aBCD".
391    
392    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
393        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
394    
395    14. Optimized (?!) to (*FAIL).
396    
397    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
398        This restricts code points to be within the range 0 to 0x10FFFF, excluding
399        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
400        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
401        does: it's just the validity check that is more restrictive.
402    
403    16. Inserted checks for integer overflows during escape sequence (backslash)
404        processing, and also fixed erroneous offset values for syntax errors during
405        backslash processing.
406    
407    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
408        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
409    
410    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
411        caused an overrun.
412    
413    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
414        something other than just ASCII characters) inside a group that had an
415        unlimited repeat caused a loop at compile time (while checking to see
416        whether the group could match an empty string).
417    
418    20. Debugging a pattern containing \p or \P could cause a crash. For example,
419        [\P{Any}] did so. (Error in the code for printing property names.)
420    
421    21. An orphan \E inside a character class could cause a crash.
422    
423    22. A repeated capturing bracket such as (A)? could cause a wild memory
424        reference during compilation.
425    
426    23. There are several functions in pcre_compile() that scan along a compiled
427        expression for various reasons (e.g. to see if it's fixed length for look
428        behind). There were bugs in these functions when a repeated \p or \P was
429        present in the pattern. These operators have additional parameters compared
430        with \d, etc, and these were not being taken into account when moving along
431        the compiled data. Specifically:
432    
433        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
434            length.
435    
436        (b) An item such as \pL+ within a repeated group could cause crashes or
437            loops.
438    
439        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
440            "reference to non-existent subpattern" error.
441    
442        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
443    
444    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
445        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
446    
447    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
448    
449    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
450        character were causing crashes (broken optimization).
451    
452    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
453        \p or \P) caused a compile-time loop.
454    
455    28. More problems have arisen in unanchored patterns when CRLF is a valid line
456        break. For example, the unstudied pattern [\r\n]A does not match the string
457        "\r\nA" because change 7.0/46 below moves the current point on by two
458        characters after failing to match at the start. However, the pattern \nA
459        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
460        the same is true. There doesn't seem any very clean way out of this, but
461        what I have chosen to do makes the common cases work: PCRE now takes note
462        of whether there can be an explicit match for \r or \n anywhere in the
463        pattern, and if so, 7.0/46 no longer applies. As part of this change,
464        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
465        pattern has explicit CR or LF references.
466    
467    29. Added (*CR) etc for changing newline setting at start of pattern.
468    
469    
470    Version 7.2 19-Jun-07
471    ---------------------
472    
473     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
474        which is apparently normally available under Windows.
475    
476     2. Re-jig the pcregrep tests with different newline settings in an attempt
477        to make them independent of the local environment's newline setting.
478    
479     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
480    
481     4. Some of the "internals" tests were previously cut out when the link size
482        was not 2, because the output contained actual offsets. The recent new
483        "Z" feature of pcretest means that these can be cut out, making the tests
484        usable with all link sizes.
485    
486     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
487        stack recursion. This gives a massive performance boost under BSD, but just
488        a small improvement under Linux. However, it saves one field in the frame
489        in all cases.
490    
491     6. Added more features from the forthcoming Perl 5.10:
492    
493        (a) (?-n) (where n is a string of digits) is a relative subroutine or
494            recursion call. It refers to the nth most recently opened parentheses.
495    
496        (b) (?+n) is also a relative subroutine call; it refers to the nth next
497            to be opened parentheses.
498    
499        (c) Conditions that refer to capturing parentheses can be specified
500            relatively, for example, (?(-2)... or (?(+3)...
501    
502        (d) \K resets the start of the current match so that everything before
503            is not part of it.
504    
505        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
506    
507        (f) \g{name} is another synonym - part of Perl 5.10's unification of
508            reference syntax.
509    
510        (g) (?| introduces a group in which the numbering of parentheses in each
511            alternative starts with the same number.
512    
513        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
514    
515     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
516        PCRE_INFO_JCHANGED.
517    
518     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
519        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
520        for detecting groups that can match an empty string.
521    
522     9. A pattern with a very large number of alternatives (more than several
523        hundred) was running out of internal workspace during the pre-compile
524        phase, where pcre_compile() figures out how much memory will be needed. A
525        bit of new cunning has reduced the workspace needed for groups with
526        alternatives. The 1000-alternative test pattern now uses 12 bytes of
527        workspace instead of running out of the 4096 that are available.
528    
529    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
530    
531    11. Applied patch from Google to remove an optimization that didn't quite work.
532        The report of the bug said:
533    
534          pcrecpp::RE("a*").FullMatch("aaa") matches, while
535          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
536          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
537    
538    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
539        it matched the wrong number of bytes.
540    
541    
542    Version 7.1 24-Apr-07
543    ---------------------
544    
545     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
546        that is more "standard", making use of automake and other Autotools. There
547        is some re-arrangement of the files and adjustment of comments consequent
548        on this.
549    
550     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
551        for recursive directory scanning broke on some systems because the files
552        are not scanned in any specific order and on different systems the order
553        was different. A call to "sort" has been inserted into RunGrepTest for the
554        approprate test as a short-term fix. In the longer term there may be an
555        alternative.
556    
557     3. I had an email from Eric Raymond about problems translating some of PCRE's
558        man pages to HTML (despite the fact that I distribute HTML pages, some
559        people do their own conversions for various reasons). The problems
560        concerned the use of low-level troff macros .br and .in. I have therefore
561        removed all such uses from the man pages (some were redundant, some could
562        be replaced by .nf/.fi pairs). The 132html script that I use to generate
563        HTML has been updated to handle .nf/.fi and to complain if it encounters
564        .br or .in.
565    
566     4. Updated comments in configure.ac that get placed in config.h.in and also
567        arranged for config.h to be included in the distribution, with the name
568        config.h.generic, for the benefit of those who have to compile without
569        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
570    
571     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
572        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
573        makevp.bat for the current PCRE, using the additional files
574        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
575    
576     6. A Windows user reported a minor discrepancy with test 2, which turned out
577        to be caused by a trailing space on an input line that had got lost in his
578        copy. The trailing space was an accident, so I've just removed it.
579    
580     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
581        that is needed.
582    
583     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
584        as "const" (a) because they are and (b) because it helps the PHP
585        maintainers who have recently made a script to detect big data structures
586        in the php code that should be moved to the .rodata section. I remembered
587        to update Builducptable as well, so it won't revert if ucptable.h is ever
588        re-created.
589    
590     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
591        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
592        order to be able to cut out the UTF-8 tables in the latter when UTF-8
593        support is not required. This saves 1.5-2K of code, which is important in
594        some applications.
595    
596        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
597        so as not to refer to the tables, even though these functions will never be
598        called when UTF-8 support is disabled. Otherwise there are problems with a
599        shared library.
600    
601    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
602    
603        (a) It was defining its arguments as char * instead of void *.
604    
605        (b) It was assuming that all moves were upwards in memory; this was true
606            a long time ago when I wrote it, but is no longer the case.
607    
608        The emulated memove() is provided for those environments that have neither
609        memmove() nor bcopy(). I didn't think anyone used it these days, but that
610        is clearly not the case, as these two bugs were recently reported.
611    
612    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
613        and Detrail to create the HTML documentation, the .txt form of the man
614        pages, and it removes trailing spaces from listed files. It also creates
615        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
616        case, it wraps all the #defines with #ifndefs. This script should be run
617        before "make dist".
618    
619    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
620        with Unicode property support.
621    
622        (a) For a maximizing quantifier, if the two different cases of the
623            character were of different lengths in their UTF-8 codings (there are
624            some cases like this - I found 11), and the matching function had to
625            back up over a mixture of the two cases, it incorrectly assumed they
626            were both the same length.
627    
628        (b) When PCRE was configured to use the heap rather than the stack for
629            recursion during matching, it was not correctly preserving the data for
630            the other case of a UTF-8 character when checking ahead for a match
631            while processing a minimizing repeat. If the check also involved
632            matching a wide character, but failed, corruption could cause an
633            erroneous result when trying to check for a repeat of the original
634            character.
635    
636    13. Some tidying changes to the testing mechanism:
637    
638        (a) The RunTest script now detects the internal link size and whether there
639            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
640            values substituted by "configure". (The RunGrepTest script already did
641            this for UTF-8.) The configure.ac script no longer substitutes the
642            relevant variables.
643    
644        (b) The debugging options /B and /D in pcretest show the compiled bytecode
645            with length and offset values. This means that the output is different
646            for different internal link sizes. Test 2 is skipped for link sizes
647            other than 2 because of this, bypassing the problem. Unfortunately,
648            there was also a test in test 3 (the locale tests) that used /B and
649            failed for link sizes other than 2. Rather than cut the whole test out,
650            I have added a new /Z option to pcretest that replaces the length and
651            offset values with spaces. This is now used to make test 3 independent
652            of link size. (Test 2 will be tidied up later.)
653    
654    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
655        segmentation fault instead of returning the appropriate error message.
656    
657    15. In multiline mode when the newline sequence was set to "any", the pattern
658        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
659        This doesn't seem right; it now treats the CRLF combination as the line
660        ending, and so does not match in that case. It's only a pattern such as ^$
661        that would hit this one: something like ^ABC$ would have failed after \r
662        and then tried again after \r\n.
663    
664    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
665        in an attempt to make files that differ only in their line terminators
666        compare equal. This works on Linux.
667    
668    17. Under certain error circumstances pcregrep might try to free random memory
669        as it exited. This is now fixed, thanks to valgrind.
670    
671    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
672        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
673        was because its rules for how to advance for /g after matching an empty
674        string at the end of a line did not allow for this case. They now check for
675        it specially.
676    
677    20. pcretest is supposed to handle patterns and data of any length, by
678        extending its buffers when necessary. It was getting this wrong when the
679        buffer for a data line had to be extended.
680    
681    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
682        CRLF as a newline sequence.
683    
684    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
685        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
686        I have nevertheless tidied it up.
687    
688    23. Added some casts to kill warnings from HP-UX ia64 compiler.
689    
690    24. Added a man page for pcre-config.
691    
692    
693    Version 7.0 19-Dec-06
694    ---------------------
695    
696     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
697        moving to gcc 4.1.1.
698    
699     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
700        sys/time.h, which is documented as needed for this function. It doesn't
701        seem to matter on Linux, but it showed up on some releases of OS X.
702    
703     3. It seems that there are systems where bytes whose values are greater than
704        127 match isprint() in the "C" locale. The "C" locale should be the
705        default when a C program starts up. In most systems, only ASCII printing
706        characters match isprint(). This difference caused the output from pcretest
707        to vary, making some of the tests fail. I have changed pcretest so that:
708    
709        (a) When it is outputting text in the compiled version of a pattern, bytes
710            other than 32-126 are always shown as hex escapes.
711    
712        (b) When it is outputting text that is a matched part of a subject string,
713            it does the same, unless a different locale has been set for the match
714            (using the /L modifier). In this case, it uses isprint() to decide.
715    
716     4. Fixed a major bug that caused incorrect computation of the amount of memory
717        required for a compiled pattern when options that changed within the
718        pattern affected the logic of the preliminary scan that determines the
719        length. The relevant options are -x, and -i in UTF-8 mode. The result was
720        that the computed length was too small. The symptoms of this bug were
721        either the PCRE error "internal error: code overflow" from pcre_compile(),
722        or a glibc crash with a message such as "pcretest: free(): invalid next
723        size (fast)". Examples of patterns that provoked this bug (shown in
724        pcretest format) are:
725    
726          /(?-x: )/x
727          /(?x)(?-x: \s*#\s*)/
728          /((?i)[\x{c0}])/8
729          /(?i:[\x{c0}])/8
730    
731        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
732        is now done differently.
733    
734     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
735        wrapper classes; (b) implement a new function in the C++ scanner that is
736        more efficient than the old way of doing things because it avoids levels of
737        recursion in the regex matching; (c) add a paragraph to the documentation
738        for the FullMatch() function.
739    
740     6. The escape sequence \n was being treated as whatever was defined as
741        "newline". Not only was this contrary to the documentation, which states
742        that \n is character 10 (hex 0A), but it also went horribly wrong when
743        "newline" was defined as CRLF. This has been fixed.
744    
745     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
746        was being set to -1 for the "end of line" case (supposedly a value that no
747        character can have). Though this value is never used (the check for end of
748        line is "zero bytes in current character"), it caused compiler complaints.
749        I've changed it to 0xffffffff.
750    
751     8. In pcre_version.c, the version string was being built by a sequence of
752        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
753        string (as it is for production releases) called a macro with an empty
754        argument. The C standard says the result of this is undefined. The gcc
755        compiler treats it as an empty string (which was what was wanted) but it is
756        reported that Visual C gives an error. The source has been hacked around to
757        avoid this problem.
758    
759     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
760        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
761        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
762        of them did).
763    
764    10. Originally, pcretest opened its input and output without "b"; then I was
765        told that "b" was needed in some environments, so it was added for release
766        5.0 to both the input and output. (It makes no difference on Unix-like
767        systems.) Later I was told that it is wrong for the input on Windows. I've
768        now abstracted the modes into two macros, to make it easier to fiddle with
769        them, and removed "b" from the input mode under Windows.
770    
771    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
772    
773    12. Added -help and --help to pcretest as an official way of being reminded
774        of the options.
775    
776    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
777        and pcrecpp.cc because they annoy compilers at high warning levels.
778    
779    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
780    
781    15. Fixed an occurrence of == in configure.ac that should have been = (shell
782        scripts are not C programs :-) and which was not noticed because it works
783        on Linux.
784    
785    16. pcretest is supposed to handle any length of pattern and data line (as one
786        line or as a continued sequence of lines) by extending its input buffer if
787        necessary. This feature was broken for very long pattern lines, leading to
788        a string of junk being passed to pcre_compile() if the pattern was longer
789        than about 50K.
790    
791    17. I have done a major re-factoring of the way pcre_compile() computes the
792        amount of memory needed for a compiled pattern. Previously, there was code
793        that made a preliminary scan of the pattern in order to do this. That was
794        OK when PCRE was new, but as the facilities have expanded, it has become
795        harder and harder to keep it in step with the real compile phase, and there
796        have been a number of bugs (see for example, 4 above). I have now found a
797        cunning way of running the real compile function in a "fake" mode that
798        enables it to compute how much memory it would need, while actually only
799        ever using a few hundred bytes of working memory and without too many
800        tests of the mode. This should make future maintenance and development
801        easier. A side effect of this work is that the limit of 200 on the nesting
802        depth of parentheses has been removed (though this was never a serious
803        limitation, I suspect). However, there is a downside: pcre_compile() now
804        runs more slowly than before (30% or more, depending on the pattern). I
805        hope this isn't a big issue. There is no effect on runtime performance.
806    
807    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
808        newline (only possible for the last line of a file) and it was a
809        pattern that set a locale (followed by /Lsomething), pcretest crashed.
810    
811    19. Added additional timing features to pcretest. (1) The -tm option now times
812        matching only, not compiling. (2) Both -t and -tm can be followed, as a
813        separate command line item, by a number that specifies the number of
814        repeats to use when timing. The default is 50000; this gives better
815        precision, but takes uncomfortably long for very large patterns.
816    
817    20. Extended pcre_study() to be more clever in cases where a branch of a
818        subpattern has no definite first character. For example, (a*|b*)[cd] would
819        previously give no result from pcre_study(). Now it recognizes that the
820        first character must be a, b, c, or d.
821    
822    21. There was an incorrect error "recursive call could loop indefinitely" if
823        a subpattern (or the entire pattern) that was being tested for matching an
824        empty string contained only one non-empty item after a nested subpattern.
825        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
826        incorrectly, because the \d was being skipped in the check.
827    
828    22. The pcretest program now has a new pattern option /B and a command line
829        option -b, which is equivalent to adding /B to every pattern. This causes
830        it to show the compiled bytecode, without the additional information that
831        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
832        is the same as /B/I).
833    
834    23. A new optimization is now able automatically to treat some sequences such
835        as a*b as a*+b. More specifically, if something simple (such as a character
836        or a simple class like \d) has an unlimited quantifier, and is followed by
837        something that cannot possibly match the quantified thing, the quantifier
838        is automatically "possessified".
839    
840    24. A recursive reference to a subpattern whose number was greater than 39
841        went wrong under certain circumstances in UTF-8 mode. This bug could also
842        have affected the operation of pcre_study().
843    
844    25. Realized that a little bit of performance could be had by replacing
845        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
846    
847    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
848    
849    27. Possessive quantifiers such as a++ were previously implemented by turning
850        them into atomic groups such as ($>a+). Now they have their own opcodes,
851        which improves performance. This includes the automatically created ones
852        from 23 above.
853    
854    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
855        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
856        the first matched character to be a colon. This applied both to named and
857        numbered groups.
858    
859    29. The ucpinternal.h header file was missing its idempotency #ifdef.
860    
861    30. I was sent a "project" file called libpcre.a.dev which I understand makes
862        building PCRE on Windows easier, so I have included it in the distribution.
863    
864    31. There is now a check in pcretest against a ridiculously large number being
865        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
866        loop, the loop is abandoned.
867    
868    32. Forward references to subpatterns in conditions such as (?(2)...) where
869        subpattern 2 is defined later cause pcre_compile() to search forwards in
870        the pattern for the relevant set of parentheses. This search went wrong
871        when there were unescaped parentheses in a character class, parentheses
872        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
873    
874    33. "Subroutine" calls and backreferences were previously restricted to
875        referencing subpatterns earlier in the regex. This restriction has now
876        been removed.
877    
878    34. Added a number of extra features that are going to be in Perl 5.10. On the
879        whole, these are just syntactic alternatives for features that PCRE had
880        previously implemented using the Python syntax or my own invention. The
881        other formats are all retained for compatibility.
882    
883        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
884            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
885            also .NET compatible.
886    
887        (b) A recursion or subroutine call to a named group can now be defined as
888            (?&name) as well as (?P>name).
889    
890        (c) A backreference to a named group can now be defined as \k<name> or
891            \k'name' as well as (?P=name). The new forms, as well as being in Perl
892            5.10, are also .NET compatible.
893    
894        (d) A conditional reference to a named group can now use the syntax
895            (?(<name>) or (?('name') as well as (?(name).
896    
897        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
898            groups (named and numbered) that are never evaluated inline, but can be
899            called as "subroutines" from elsewhere. In effect, the DEFINE condition
900            is always false. There may be only one alternative in such a group.
901    
902        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
903            as the simple (?(R). The condition is true only if the most recent
904            recursion is that of the given number or name. It does not search out
905            through the entire recursion stack.
906    
907        (g) The escape \gN or \g{N} has been added, where N is a positive or
908            negative number, specifying an absolute or relative reference.
909    
910    35. Tidied to get rid of some further signed/unsigned compiler warnings and
911        some "unreachable code" warnings.
912    
913    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
914        things, this adds five new scripts.
915    
916    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
917        There were also incompatibilities regarding the handling of \Q..\E inside
918        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
919        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
920    
921    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
922        matches an empty string, and forcibly breaks the loop. There were bugs in
923        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
924        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
925        separate and independent bugs (that affected different cases) have been
926        fixed.
927    
928    39. Refactored the code to abolish the use of different opcodes for small
929        capturing bracket numbers. This is a tidy that I avoided doing when I
930        removed the limit on the number of capturing brackets for 3.5 back in 2001.
931        The new approach is not only tidier, it makes it possible to reduce the
932        memory needed to fix the previous bug (38).
933    
934    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
935        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
936        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
937        mode.
938    
939    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
940        report.
941    
942    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
943        copy construction and assignment in the C++ wrapper.
944    
945    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
946        couple of bugs that could have given wrong results in the "--newline=crlf"
947        case.
948    
949    44. Added a number of casts and did some reorganization of signed/unsigned int
950        variables following suggestions from Dair Grant. Also renamed the variable
951        "this" as "item" because it is a C++ keyword.
952    
953    45. Arranged for dftables to add
954    
955          #include "pcre_internal.h"
956    
957        to pcre_chartables.c because without it, gcc 4.x may remove the array
958        definition from the final binary if PCRE is built into a static library and
959        dead code stripping is activated.
960    
961    46. For an unanchored pattern, if a match attempt fails at the start of a
962        newline sequence, and the newline setting is CRLF or ANY, and the next two
963        characters are CRLF, advance by two characters instead of one.
964    
965    
966    Version 6.7 04-Jul-06
967    ---------------------
968    
969     1. In order to handle tests when input lines are enormously long, pcretest has
970        been re-factored so that it automatically extends its buffers when
971        necessary. The code is crude, but this _is_ just a test program. The
972        default size has been increased from 32K to 50K.
973    
974     2. The code in pcre_study() was using the value of the re argument before
975        testing it for NULL. (Of course, in any sensible call of the function, it
976        won't be NULL.)
977    
978     3. The memmove() emulation function in pcre_internal.h, which is used on
979        systems that lack both memmove() and bcopy() - that is, hardly ever -
980        was missing a "static" storage class specifier.
981    
982     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
983        containing an extended class (one that cannot be represented by a bitmap
984        because it contains high-valued characters or Unicode property items, e.g.
985        [\pZ]). Almost always one would set UTF-8 mode when processing such a
986        pattern, but PCRE should not loop if you do not (it no longer does).
987        [Detail: two cases were found: (a) a repeated subpattern containing an
988        extended class; (b) a recursive reference to a subpattern that followed a
989        previous extended class. It wasn't skipping over the extended class
990        correctly when UTF-8 mode was not set.]
991    
992     5. A negated single-character class was not being recognized as fixed-length
993        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
994        compile error "lookbehind assertion is not fixed length".
995    
996     6. The RunPerlTest auxiliary script was showing an unexpected difference
997        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
998        write a Perl script that can interpret lines of an input file either as
999        byte characters or as UTF-8, which is what "perltest" was being required to
1000        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1001        can't do is switch easily at run time between having the "use utf8;" pragma
1002        or not. In the end, I fudged it by using the RunPerlTest script to insert
1003        "use utf8;" explicitly for the UTF-8 tests.
1004    
1005     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1006        the end of the subject string, contrary to the documentation and to what
1007        Perl does. This was true of both matching functions. Now it matches only at
1008        the start of the subject and immediately after *internal* newlines.
1009    
1010     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1011        a pointer to an int instead of a pointer to an unsigned long int. This
1012        caused problems on 64-bit systems.
1013    
1014     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1015        instance of the 'standard' template library not being so standard".
1016    
1017    10. There was no check on the number of named subpatterns nor the maximum
1018        length of a subpattern name. The product of these values is used to compute
1019        the size of the memory block for a compiled pattern. By supplying a very
1020        long subpattern name and a large number of named subpatterns, the size
1021        computation could be caused to overflow. This is now prevented by limiting
1022        the length of names to 32 characters, and the number of named subpatterns
1023        to 10,000.
1024    
1025    11. Subpatterns that are repeated with specific counts have to be replicated in
1026        the compiled pattern. The size of memory for this was computed from the
1027        length of the subpattern and the repeat count. The latter is limited to
1028        65535, but there was no limit on the former, meaning that integer overflow
1029        could in principle occur. The compiled length of a repeated subpattern is
1030        now limited to 30,000 bytes in order to prevent this.
1031    
1032    12. Added the optional facility to have named substrings with the same name.
1033    
1034    13. Added the ability to use a named substring as a condition, using the
1035        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1036        are numbers (not recommended). Forward references are permitted.
1037    
1038    14. Added forward references in named backreferences (if you see what I mean).
1039    
1040    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1041        pattern could run off the end of the subject. For example, the pattern
1042        "(?s)(.{1,5})"8 did this with the subject "ab".
1043    
1044    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1045        PCRE_CASELESS was set when matching characters that were quantified with ?
1046        or *.
1047    
1048    17. A character class other than a single negated character that had a minimum
1049        but no maximum quantifier - for example [ab]{6,} - was not handled
1050        correctly by pce_dfa_exec(). It would match only one character.
1051    
1052    18. A valid (though odd) pattern that looked like a POSIX character
1053        class but used an invalid character after [ (for example [[,abc,]]) caused
1054        pcre_compile() to give the error "Failed: internal error: code overflow" or
1055        in some cases to crash with a glibc free() error. This could even happen if
1056        the pattern terminated after [[ but there just happened to be a sequence of
1057        letters, a binary zero, and a closing ] in the memory that followed.
1058    
1059    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1060        over the years. Originally (before any Unicode support), just the bottom 8
1061        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1062        output from "man perlunicode" includes this:
1063    
1064          The regular expression compiler produces polymorphic opcodes.  That
1065          is, the pattern adapts to the data and automatically switches to
1066          the Unicode character scheme when presented with Unicode data--or
1067          instead uses a traditional byte scheme when presented with byte
1068          data.
1069    
1070        Sadly, a wide octal escape does not cause a switch, and in a string with
1071        no other multibyte characters, these octal escapes are treated as before.
1072        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1073        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1074        Unicode string.
1075    
1076        I have not perpetrated such confusion in PCRE. Up till now, it took just
1077        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1078        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1079        translate to the appropriate multibyte character.
1080    
1081    29. Applied some refactoring to reduce the number of warnings from Microsoft
1082        and Borland compilers. This has included removing the fudge introduced
1083        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1084        a warning about an unused variable.
1085    
1086    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1087        characters since release 4.0, because Perl (from release 5.004) does not.
1088        [Or at least, is documented not to: some releases seem to be in conflict
1089        with the documentation.] However, when a pattern was studied with
1090        pcre_study() and all its branches started with \s, PCRE still included VT
1091        as a possible starting character. Of course, this did no harm; it just
1092        caused an unnecessary match attempt.
1093    
1094    22. Removed a now-redundant internal flag bit that recorded the fact that case
1095        dependency changed within the pattern. This was once needed for "required
1096        byte" processing, but is no longer used. This recovers a now-scarce options
1097        bit. Also moved the least significant internal flag bit to the most-
1098        significant bit of the word, which was not previously used (hangover from
1099        the days when it was an int rather than a uint) to free up another bit for
1100        the future.
1101    
1102    23. Added support for CRLF line endings as well as CR and LF. As well as the
1103        default being selectable at build time, it can now be changed at runtime
1104        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1105        specify that it is scanning data with non-default line endings.
1106    
1107    24. Changed the definition of CXXLINK to make it agree with the definition of
1108        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1109    
1110    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1111        recursions. This makes a big different to stack usage for some patterns.
1112    
1113    26. If a subpattern containing a named recursion or subroutine reference such
1114        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1115        the space required for the compiled pattern went wrong and gave too small a
1116        value. Depending on the environment, this could lead to "Failed: internal
1117        error: code overflow at offset 49" or "glibc detected double free or
1118        corruption" errors.
1119    
1120    27. Applied patches from Google (a) to support the new newline modes and (b) to
1121        advance over multibyte UTF-8 characters in GlobalReplace.
1122    
1123    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1124        difference for some implementation of PCRE in some Windows version.
1125    
1126    29. Added some extra testing facilities to pcretest:
1127    
1128        \q<number>   in a data line sets the "match limit" value
1129        \Q<number>   in a data line sets the "match recursion limt" value
1130        -S <number>  sets the stack size, where <number> is in megabytes
1131    
1132        The -S option isn't available for Windows.
1133    
1134    
1135    Version 6.6 06-Feb-06
1136    ---------------------
1137    
1138     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1139        in pcreposix.h. I have copied the definition from pcre.h.
1140    
1141     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1142        because pcre.h is no longer a built file.
1143    
1144     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1145        not normally included in the compiled code.
1146    
1147    
1148    Version 6.5 01-Feb-06
1149    ---------------------
1150    
1151     1. When using the partial match feature with pcre_dfa_exec(), it was not
1152        anchoring the second and subsequent partial matches at the new starting
1153        point. This could lead to incorrect results. For example, with the pattern
1154        /1234/, partially matching against "123" and then "a4" gave a match.
1155    
1156     2. Changes to pcregrep:
1157    
1158        (a) All non-match returns from pcre_exec() were being treated as failures
1159            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1160            error message is output. Some extra information is given for the
1161            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1162            probably the only errors that are likely to be caused by users (by
1163            specifying a regex that has nested indefinite repeats, for instance).
1164            If there are more than 20 of these errors, pcregrep is abandoned.
1165    
1166        (b) A binary zero was treated as data while matching, but terminated the
1167            output line if it was written out. This has been fixed: binary zeroes
1168            are now no different to any other data bytes.
1169    
1170        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1171            used to set a locale for matching. The --locale=xxxx long option has
1172            been added (no short equivalent) to specify a locale explicitly on the
1173            pcregrep command, overriding the environment variables.
1174    
1175        (d) When -B was used with -n, some line numbers in the output were one less
1176            than they should have been.
1177    
1178        (e) Added the -o (--only-matching) option.
1179    
1180        (f) If -A or -C was used with -c (count only), some lines of context were
1181            accidentally printed for the final match.
1182    
1183        (g) Added the -H (--with-filename) option.
1184    
1185        (h) The combination of options -rh failed to suppress file names for files
1186            that were found from directory arguments.
1187    
1188        (i) Added the -D (--devices) and -d (--directories) options.
1189    
1190        (j) Added the -F (--fixed-strings) option.
1191    
1192        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1193    
1194        (l) Added the --colo(u)r option.
1195    
1196        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1197            is not present by default.
1198    
1199     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1200        items such as (?R) or (?1), when the recursion could match a number of
1201        alternatives. If it matched one of the alternatives, but subsequently,
1202        outside the recursion, there was a failure, the code tried to back up into
1203        the recursion. However, because of the way PCRE is implemented, this is not
1204        possible, and the result was an incorrect result from the match.
1205    
1206        In order to prevent this happening, the specification of recursion has
1207        been changed so that all such subpatterns are automatically treated as
1208        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1209    
1210     4. I had overlooked the fact that, in some locales, there are characters for
1211        which isalpha() is true but neither isupper() nor islower() are true. In
1212        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1213        and ordfeminine) are like this. This affected the treatment of \w and \W
1214        when they appeared in character classes, but not when they appeared outside
1215        a character class. The bit map for "word" characters is now created
1216        separately from the results of isalnum() instead of just taking it from the
1217        upper, lower, and digit maps. (Plus the underscore character, of course.)
1218    
1219     5. The above bug also affected the handling of POSIX character classes such as
1220        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1221        permanent tables. Instead, the bit maps for such a class were previously
1222        created as the appropriate unions of the upper, lower, and digit bitmaps.
1223        Now they are created by subtraction from the [[:word:]] class, which has
1224        its own bitmap.
1225    
1226     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1227        It is created by subtracting the vertical space characters (\x09, \x0a,
1228        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1229        subtraction was done in the overall bitmap for a character class, meaning
1230        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1231        be recognized. This bug has been fixed.
1232    
1233     7. Patches from the folks at Google:
1234    
1235          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1236          real life, but is still worth protecting against".
1237    
1238          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1239          regular expressions".
1240    
1241          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1242          have it.
1243    
1244          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1245          "configure" and the latter not, in order to fix a problem somebody had
1246          with compiling the Arg class on HP-UX.
1247    
1248          (e) Improve the error-handling of the C++ wrapper a little bit.
1249    
1250          (f) New tests for checking recursion limiting.
1251    
1252     8. The pcre_memmove() function, which is used only if the environment does not
1253        have a standard memmove() function (and is therefore rarely compiled),
1254        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1255        returning a result (though PCRE never actually uses the result).
1256    
1257     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1258        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1259        returned instead of calling malloc() with an overflowing number that would
1260        most likely cause subsequent chaos.
1261    
1262    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1263    
1264    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1265        with this option is matched, the nmatch and pmatch options of regexec() are
1266        ignored.
1267    
1268    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1269        provided in case anyone wants to the the POSIX interface with UTF-8
1270        strings.
1271    
1272    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1273        C++ linking (needed for some HP-UX environments).
1274    
1275    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1276        (unused parameter) and in the pcre_printint() function (omitted "default"
1277        switch label when the default is to do nothing).
1278    
1279    15. Added some code to make it possible, when PCRE is compiled as a C++
1280        library, to replace subject pointers for pcre_exec() with a smart pointer
1281        class, thus making it possible to process discontinuous strings.
1282    
1283    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1284        much the same function. They were added by different people who were trying
1285        to make PCRE easy to compile on non-Unix systems. It has been suggested
1286        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1287        for compiling on Windows systems. I have therefore replaced it with
1288        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1289        defaults to "extern" for C or "extern C" for C++, which works fine on
1290        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1291        SCOPE with something explicit in config.h. In addition:
1292    
1293        (a) pcreposix.h still had just "extern" instead of either of these macros;
1294            I have replaced it with PCRE_DATA_SCOPE.
1295    
1296        (b) Functions such as _pcre_xclass(), which are internal to the library,
1297            but external in the C sense, all had PCRE_EXPORT in their definitions.
1298            This is apparently wrong for the Windows case, so I have removed it.
1299            (It makes no difference on Unix-like systems.)
1300    
1301    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1302        of recursive calls to match(). This is different to MATCH_LIMIT because
1303        that limits the total number of calls to match(), not all of which increase
1304        the depth of recursion. Limiting the recursion depth limits the amount of
1305        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1306        when PCRE is compiled, and changed at run time. A patch from Google adds
1307        this functionality to the C++ interface.
1308    
1309    18. Changes to the handling of Unicode character properties:
1310    
1311        (a) Updated the table to Unicode 4.1.0.
1312    
1313        (b) Recognize characters that are not in the table as "Cn" (undefined).
1314    
1315        (c) I revised the way the table is implemented to a much improved format
1316            which includes recognition of ranges. It now supports the ranges that
1317            are defined in UnicodeData.txt, and it also amalgamates other
1318            characters into ranges. This has reduced the number of entries in the
1319            table from around 16,000 to around 3,000, thus reducing its size
1320            considerably. I realized I did not need to use a tree structure after
1321            all - a binary chop search is just as efficient. Having reduced the
1322            number of entries, I extended their size from 6 bytes to 8 bytes to
1323            allow for more data.
1324    
1325        (d) Added support for Unicode script names via properties such as \p{Han}.
1326    
1327    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1328        matching that character.
1329    
1330    20. When matching a repeated Unicode property with a minimum greater than zero,
1331        (for example \pL{2,}), PCRE could look past the end of the subject if it
1332        reached it while seeking the minimum number of characters. This could
1333        happen only if some of the characters were more than one byte long, because
1334        there is a check for at least the minimum number of bytes.
1335    
1336    21. Refactored the implementation of \p and \P so as to be more general, to
1337        allow for more different types of property in future. This has changed the
1338        compiled form incompatibly. Anybody with saved compiled patterns that use
1339        \p or \P will have to recompile them.
1340    
1341    22. Added "Any" and "L&" to the supported property types.
1342    
1343    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1344        but give a compile time error if the value is greater than 0xff.
1345    
1346    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1347        accidentally not being installed or uninstalled.
1348    
1349    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1350        made were to insert the current release number. This seemed silly, because
1351        it made things harder for people building PCRE on systems that don't run
1352        "configure". I have turned pcre.h into a distributed file, no longer built
1353        by "configure", with the version identification directly included. There is
1354        no longer a pcre.h.in file.
1355    
1356        However, this change necessitated a change to the pcre-config script as
1357        well. It is built from pcre-config.in, and one of the substitutions was the
1358        release number. I have updated configure.ac so that ./configure now finds
1359        the release number by grepping pcre.h.
1360    
1361    26. Added the ability to run the tests under valgrind.
1362    
1363    
1364    Version 6.4 05-Sep-05
1365    ---------------------
1366    
1367     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1368        "--" to be printed when multiple files were scanned, even when none of the
1369        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1370        consider it to be a bug, and have restored the previous behaviour.
1371    
1372     2. A couple of code tidies to get rid of compiler warnings.
1373    
1374     3. The pcretest program used to cheat by referring to symbols in the library
1375        whose names begin with _pcre_. These are internal symbols that are not
1376        really supposed to be visible externally, and in some environments it is
1377        possible to suppress them. The cheating is now confined to including
1378        certain files from the library's source, which is a bit cleaner.
1379    
1380     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1381        file's purpose clearer.
1382    
1383     5. Reorganized pcre_ucp_findchar().
1384    
1385    
1386    Version 6.3 15-Aug-05
1387    ---------------------
1388    
1389     1. The file libpcre.pc.in did not have general read permission in the tarball.
1390    
1391     2. There were some problems when building without C++ support:
1392    
1393        (a) If C++ support was not built, "make install" and "make test" still
1394            tried to test it.
1395    
1396        (b) There were problems when the value of CXX was explicitly set. Some
1397            changes have been made to try to fix these, and ...
1398    
1399        (c) --disable-cpp can now be used to explicitly disable C++ support.
1400    
1401        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1402            backslash in a target when C++ was disabled. This confuses some
1403            versions of "make", apparently. Using an intermediate variable solves
1404            this. (Same for CPP_LOBJ.)
1405    
1406     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1407        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1408        necessary on certain architectures.
1409    
1410     4. Added a setting of -export-symbols-regex to the link command to remove
1411        those symbols that are exported in the C sense, but actually are local
1412        within the library, and not documented. Their names all begin with
1413        "_pcre_". This is not a perfect job, because (a) we have to except some
1414        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1415        available (and never for static libraries). I have made a note to try to
1416        find a way round (a) in the future.
1417    
1418    
1419    Version 6.2 01-Aug-05
1420    ---------------------
1421    
1422     1. There was no test for integer overflow of quantifier values. A construction
1423        such as {1111111111111111} would give undefined results. What is worse, if
1424        a minimum quantifier for a parenthesized subpattern overflowed and became
1425        negative, the calculation of the memory size went wrong. This could have
1426        led to memory overwriting.
1427    
1428     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1429    
1430     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1431        operating environments where this matters.
1432    
1433     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1434        PCRE options from within the C++ wrapper.
1435    
1436     5. Named capturing subpatterns were not being correctly counted when a pattern
1437        was compiled. This caused two problems: (a) If there were more than 100
1438        such subpatterns, the calculation of the memory needed for the whole
1439        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1440        back references of the form \12, where the number was greater than 9, were
1441        not recognized as back references, even though there were sufficient
1442        previous subpatterns.
1443    
1444     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1445        versions of gcc, e.g. 2.95.4.
1446    
1447    
1448    Version 6.1 21-Jun-05
1449    ---------------------
1450    
1451     1. There was one reference to the variable "posix" in pcretest.c that was not
1452        surrounded by "#if !defined NOPOSIX".
1453    
1454     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1455        the cross-check on the old pcre_info() function, for the benefit of the
1456        cut-down version of PCRE that is currently imported into Exim.
1457    
1458     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1459        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1460        patterns that start (?i) but I don't think that matters. The use of (?i) is
1461        just an example; this all applies to the other options as well.
1462    
1463     4. Since libtool seems to echo the compile commands it is issuing, the output
1464        from "make" can be reduced a bit by putting "@" in front of each libtool
1465        compile command.
1466    
1467     5. Patch from the folks at Google for configure.in to be a bit more thorough
1468        in checking for a suitable C++ installation before trying to compile the
1469        C++ stuff. This should fix a reported problem when a compiler was present,
1470        but no suitable headers.
1471    
1472     6. The man pages all had just "PCRE" as their title. I have changed them to
1473        be the relevant file name. I have also arranged that these names are
1474        retained in the file doc/pcre.txt, which is a concatenation in text format
1475        of all the man pages except the little individual ones for each function.
1476    
1477     7. The NON-UNIX-USE file had not been updated for the different set of source
1478        files that come with release 6. I also added a few comments about the C++
1479        wrapper.
1480    
1481    
1482    Version 6.0 07-Jun-05
1483    ---------------------
1484    
1485     1. Some minor internal re-organization to help with my DFA experiments.
1486    
1487     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1488        didn't matter for the library itself when fully configured, but did matter
1489        when compiling without UCP support, or within Exim, where the ucp files are
1490        not imported.
1491    
1492     3. Refactoring of the library code to split up the various functions into
1493        different source modules. The addition of the new DFA matching code (see
1494        below) to a single monolithic source would have made it really too
1495        unwieldy, quite apart from causing all the code to be include in a
1496        statically linked application, when only some functions are used. This is
1497        relevant even without the DFA addition now that patterns can be compiled in
1498        one application and matched in another.
1499    
1500        The downside of splitting up is that there have to be some external
1501        functions and data tables that are used internally in different modules of
1502        the library but which are not part of the API. These have all had their
1503        names changed to start with "_pcre_" so that they are unlikely to clash
1504        with other external names.
1505    
1506     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1507        a different (DFA) algorithm. Although it is slower than the original
1508        function, it does have some advantages for certain types of matching
1509        problem.
1510    
1511     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1512        including restarting after a partial match.
1513    
1514     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1515        defined when compiling for Windows was sent to me. I have put it into the
1516        code, though I have no means of testing or verifying it.
1517    
1518     7. Added the pcre_refcount() auxiliary function.
1519    
1520     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1521        match before or at the first newline in the subject string. In pcretest,
1522        the /f option on a pattern can be used to set this.
1523    
1524     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1525        would behave wrongly. This has been present in PCRE since release 4.0.
1526    
1527    10. A number of changes to the pcregrep command:
1528    
1529        (a) Refactored how -x works; insert ^(...)$ instead of setting
1530            PCRE_ANCHORED and checking the length, in preparation for adding
1531            something similar for -w.
1532    
1533        (b) Added the -w (match as a word) option.
1534    
1535        (c) Refactored the way lines are read and buffered so as to have more
1536            than one at a time available.
1537    
1538        (d) Implemented a pcregrep test script.
1539    
1540        (e) Added the -M (multiline match) option. This allows patterns to match
1541            over several lines of the subject. The buffering ensures that at least
1542            8K, or the rest of the document (whichever is the shorter) is available
1543            for matching (and similarly the previous 8K for lookbehind assertions).
1544    
1545        (f) Changed the --help output so that it now says
1546    
1547              -w, --word-regex(p)
1548    
1549            instead of two lines, one with "regex" and the other with "regexp"
1550            because that confused at least one person since the short forms are the
1551            same. (This required a bit of code, as the output is generated
1552            automatically from a table. It wasn't just a text change.)
1553    
1554        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1555            option but starts with a hyphen. Could be a pattern or a path name
1556            starting with a hyphen, for instance.
1557    
1558        (h) "-" can be given as a file name to represent stdin.
1559    
1560        (i) When file names are being printed, "(standard input)" is used for
1561            the standard input, for compatibility with GNU grep. Previously
1562            "<stdin>" was used.
1563    
1564        (j) The option --label=xxx can be used to supply a name to be used for
1565            stdin when file names are being printed. There is no short form.
1566    
1567        (k) Re-factored the options decoding logic because we are going to add
1568            two more options that take data. Such options can now be given in four
1569            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1570    
1571        (l) Added the -A, -B, and -C options for requesting that lines of context
1572            around matches be printed.
1573    
1574        (m) Added the -L option to print the names of files that do not contain
1575            any matching lines, that is, the complement of -l.
1576    
1577        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1578            continue to scan other files.
1579    
1580        (o) The -s option was incorrectly implemented. For compatibility with other
1581            greps, it now suppresses the error message for a non-existent or non-
1582            accessible file (but not the return code). There is a new option called
1583            -q that suppresses the output of matching lines, which was what -s was
1584            previously doing.
1585    
1586        (p) Added --include and --exclude options to specify files for inclusion
1587            and exclusion when recursing.
1588    
1589    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1590        Hopefully, it now does.
1591    
1592    12. Missing cast in pcre_study().
1593    
1594    13. Added an "uninstall" target to the makefile.
1595    
1596    14. Replaced "extern" in the function prototypes in Makefile.in with
1597        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1598        world, but is set differently for Windows.
1599    
1600    15. Added a second compiling function called pcre_compile2(). The only
1601        difference is that it has an extra argument, which is a pointer to an
1602        integer error code. When there is a compile-time failure, this is set
1603        non-zero, in addition to the error test pointer being set to point to an
1604        error message. The new argument may be NULL if no error number is required
1605        (but then you may as well call pcre_compile(), which is now just a
1606        wrapper). This facility is provided because some applications need a
1607        numeric error indication, but it has also enabled me to tidy up the way
1608        compile-time errors are handled in the POSIX wrapper.
1609    
1610    16. Added VPATH=.libs to the makefile; this should help when building with one
1611        prefix path and installing with another. (Or so I'm told by someone who
1612        knows more about this stuff than I do.)
1613    
1614    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1615        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1616        match everything, including newlines. This is not POSIX-compatible, but
1617        somebody wanted the feature. From pcretest it can be activated by using
1618        both the P and the s flags.
1619    
1620    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1621    
1622    19. libpcre.pc was being incorrectly installed as executable.
1623    
1624    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1625        it now also looks for '\r' so that it will work unmodified on Windows.
1626    
1627    21. Added Google's contributed C++ wrapper to the distribution.
1628    
1629    22. Added some untidy missing memory free() calls in pcretest, to keep
1630        Electric Fence happy when testing.
1631    
1632    
1633    
1634    Version 5.0 13-Sep-04
1635    ---------------------
1636    
1637     1. Internal change: literal characters are no longer packed up into items
1638        containing multiple characters in a single byte-string. Each character
1639        is now matched using a separate opcode. However, there may be more than one
1640        byte in the character in UTF-8 mode.
1641    
1642     2. The pcre_callout_block structure has two new fields: pattern_position and
1643        next_item_length. These contain the offset in the pattern to the next match
1644        item, and its length, respectively.
1645    
1646     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1647        insertion of callouts before each pattern item. Added the /C option to
1648        pcretest to make use of this.
1649    
1650     4. On the advice of a Windows user, the lines
1651    
1652          #if defined(_WIN32) || defined(WIN32)
1653          _setmode( _fileno( stdout ), 0x8000 );
1654          #endif  /* defined(_WIN32) || defined(WIN32) */
1655    
1656        have been added to the source of pcretest. This apparently does useful
1657        magic in relation to line terminators.
1658    
1659     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1660        for the benefit of those environments where the "b" makes a difference.
1661    
1662     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1663        to know about it. I have put a hack into configure.in that adds in code
1664        to set GCC=yes if CC=icc. This seems to end up at a point in the
1665        generated configure script that is early enough to affect the setting of
1666        compiler options, which is what is needed, but I have no means of testing
1667        whether it really works. (The user who reported this had patched the
1668        generated configure script, which of course I cannot do.)
1669    
1670        LATER: After change 22 below (new libtool files), the configure script
1671        seems to know about icc (and also ecc). Therefore, I have commented out
1672        this hack in configure.in.
1673    
1674     7. Added support for pkg-config (2 patches were sent in).
1675    
1676     8. Negated POSIX character classes that used a combination of internal tables
1677        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1678        [[:^ascii]]. Typically, they would match almost any characters. The other
1679        POSIX classes were not broken in this way.
1680    
1681     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1682        to find the match, as PCRE was deluded into thinking that the match had to
1683        start at the start point or following a newline. The same bug applied to
1684        patterns with negative forward assertions or any backward assertions
1685        preceding ".*" at the start, unless the pattern required a fixed first
1686        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1687    
1688    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1689        starting at the last subject character, bytes beyond the end of the subject
1690        string were read.
1691    
1692    11. Renamed the variable "class" as "classbits" to make life easier for C++
1693        users. (Previously there was a macro definition, but it apparently wasn't
1694        enough.)
1695    
1696    12. Added the new field "tables" to the extra data so that tables can be passed
1697        in at exec time, or the internal tables can be re-selected. This allows
1698        a compiled regex to be saved and re-used at a later time by a different
1699        program that might have everything at different addresses.
1700    
1701    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1702        -R library as well as a -L library.
1703    
1704    14. The debugging options of pcretest (-d on the command line or D on a
1705        pattern) showed incorrect output for anything following an extended class
1706        that contained multibyte characters and which was followed by a quantifier.
1707    
1708    15. Added optional support for general category Unicode character properties
1709        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1710        support. It adds about 90K to the size of the library. The meanings of the
1711        inbuilt class escapes such as \d and \s have NOT been changed.
1712    
1713    16. Updated pcredemo.c to include calls to free() to release the memory for the
1714        compiled pattern.
1715    
1716    17. The generated file chartables.c was being created in the source directory
1717        instead of in the building directory. This caused the build to fail if the
1718        source directory was different from the building directory, and was
1719        read-only.
1720    
1721    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1722        file. No doubt somebody will tell me if they don't make sense... Also added
1723        Dan Mooney's comments about building on OpenVMS.
1724    
1725    19. Added support for partial matching via the PCRE_PARTIAL option for
1726        pcre_exec() and the \P data escape in pcretest.
1727    
1728    20. Extended pcretest with 3 new pattern features:
1729    
1730        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1731              write the compiled pattern to the file whose name is "rest-of-line".
1732              This is a straight binary dump of the data, with the saved pointer to
1733              the character tables forced to be NULL. The study data, if any, is
1734              written too. After writing, pcretest reads a new pattern.
1735    
1736        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1737              compiled pattern from the given file. There must not be any
1738              occurrences of "<" in the file name (pretty unlikely); if there are,
1739              pcretest will instead treat the initial "<" as a pattern delimiter.
1740              After reading in the pattern, pcretest goes on to read data lines as
1741              usual.
1742    
1743        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1744              and 16-bit fields in a compiled pattern, to simulate a pattern that
1745              was compiled on a host of opposite endianness.
1746    
1747    21. The pcre-exec() function can now cope with patterns that were compiled on
1748        hosts of opposite endianness, with this restriction:
1749    
1750          As for any compiled expression that is saved and used later, the tables
1751          pointer field cannot be preserved; the extra_data field in the arguments
1752          to pcre_exec() should be used to pass in a tables address if a value
1753          other than the default internal tables were used at compile time.
1754    
1755    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1756        now diagnosed as an error. Previously, most of the time, a negative number
1757        would have been treated as zero, but if in addition "ovector" was passed as
1758        NULL, a crash could occur.
1759    
1760    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1761        new versions from the libtool 1.5 distribution (the last one is a copy of
1762        a file called libtool.m4). This seems to have fixed the need to patch
1763        "configure" to support Darwin 1.3 (which I used to do). However, I still
1764        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1765        workstation).
1766    
1767    24. Changed the PCRE licence to be the more standard "BSD" licence.
1768    
1769    
1770    Version 4.5 01-Dec-03
1771    ---------------------
1772    
1773     1. There has been some re-arrangement of the code for the match() function so
1774        that it can be compiled in a version that does not call itself recursively.
1775        Instead, it keeps those local variables that need separate instances for
1776        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1777        needs to "recurse". Keeping track of where control must go is done by means
1778        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1779        hide most of the details from the main code, and operates only if
1780        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1781        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1782        operating.
1783    
1784        To make it easier for callers to provide specially tailored get/free
1785        functions for this usage, two new functions, pcre_stack_malloc, and
1786        pcre_stack_free, are used. They are always called in strict stacking order,
1787        and the size of block requested is always the same.
1788    
1789        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1790        PCRE has been compiled to use the stack or the heap for recursion. The
1791        -C option of pcretest uses this to show which version is compiled.
1792    
1793        A new data escape \S, is added to pcretest; it causes the amounts of store
1794        obtained and freed by both kinds of malloc/free at match time to be added
1795        to the output.
1796    
1797     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1798        what's available on my current Linux desktop machine.
1799    
1800     3. When matching a UTF-8 string, the test for a valid string at the start has
1801        been extended. If start_offset is not zero, PCRE now checks that it points
1802        to a byte that is the start of a UTF-8 character. If not, it returns
1803        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1804        this is necessary because there may be backward assertions in the pattern.
1805        When matching the same subject several times, it may save resources to use
1806        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1807    
1808     4. The code for checking the validity of UTF-8 strings has been tightened so
1809        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1810        containing "overlong sequences".
1811    
1812     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1813        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1814        should have been "&", but it just so happened that all the cases this let
1815        through by mistake were picked up later in the function.
1816    
1817     6. I had used a variable called "isblank" - this is a C99 function, causing
1818        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1819    
1820     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1821        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1822        so the version is shown; (c) stop "make test" echoing "./RunTest".
1823    
1824     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1825    
1826     9. The prototype for memmove() for systems that don't have it was using
1827        size_t, but the inclusion of the header that defines size_t was later. I've
1828        moved the #includes for the C headers earlier to avoid this.
1829    
1830    10. Added some adjustments to the code to make it easier to compiler on certain
1831        special systems:
1832    
1833          (a) Some "const" qualifiers were missing.
1834          (b) Added the macro EXPORT before all exported functions; by default this
1835              is defined to be empty.
1836          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1837              that it reads its output file name as an argument instead of writing
1838              to the standard output and assuming this can be redirected.
1839    
1840    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1841        class containing characters with values greater than 255, PCRE compilation
1842        went into a loop.
1843    
1844    12. A recursive reference to a subpattern that was within another subpattern
1845        that had a minimum quantifier of zero caused PCRE to crash. For example,
1846        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1847        recursion. If the recursively-called subpattern itself had a zero repeat,
1848        that was OK.
1849    
1850    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1851        buffer into which it was copied (for escape processing) was still set at
1852        1024, so long lines caused crashes.
1853    
1854    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1855        "internal error: code overflow...". This applied to any character class
1856        that was followed by a possessive quantifier.
1857    
1858    15. Modified the Makefile to add libpcre.la as a prerequisite for
1859        libpcreposix.la because I was told this is needed for a parallel build to
1860        work.
1861    
1862    16. If a pattern that contained .* following optional items at the start was
1863        studied, the wrong optimizing data was generated, leading to matching
1864        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1865        matching string must start with a or b or c. The correct conclusion for
1866        this pattern is that a match can start with any character.
1867    
1868    
1869    Version 4.4 13-Aug-03
1870    ---------------------
1871    
1872     1. In UTF-8 mode, a character class containing characters with values between
1873        127 and 255 was not handled correctly if the compiled pattern was studied.
1874        In fixing this, I have also improved the studying algorithm for such
1875        classes (slightly).
1876    
1877     2. Three internal functions had redundant arguments passed to them. Removal
1878        might give a very teeny performance improvement.
1879    
1880     3. Documentation bug: the value of the capture_top field in a callout is *one
1881        more than* the number of the hightest numbered captured substring.
1882    
1883     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1884        in incorrectly linking with a previously installed version. They now link
1885        explicitly with libpcre.la.
1886    
1887     5. configure.in no longer needs to recognize Cygwin specially.
1888    
1889     6. A problem in pcre.in for Windows platforms is fixed.
1890    
1891     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1892        pcretest, it used to include the size of the study block as part of its
1893        output. Unfortunately, the structure contains a field that has a different
1894        size on different hardware architectures. This meant that the tests that
1895        showed this size failed. As the block is currently always of a fixed size,
1896        this information isn't actually particularly useful in pcretest output, so
1897        I have just removed it.
1898    
1899     8. Three pre-processor statements accidentally did not start in column 1.
1900        Sadly, there are *still* compilers around that complain, even though
1901        standard C has not required this for well over a decade. Sigh.
1902    
1903     9. In pcretest, the code for checking callouts passed small integers in the
1904        callout_data field, which is a void * field. However, some picky compilers
1905        complained about the casts involved for this on 64-bit systems. Now
1906        pcretest passes the address of the small integer instead, which should get
1907        rid of the warnings.
1908    
1909    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1910        both compile and run time, and gives an error if an invalid UTF-8 sequence
1911        is found. There is a option for disabling this check in cases where the
1912        string is known to be correct and/or the maximum performance is wanted.
1913    
1914    11. In response to a bug report, I changed one line in Makefile.in from
1915    
1916            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1917        to
1918            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1919    
1920        to look similar to other lines, but I have no way of telling whether this
1921        is the right thing to do, as I do not use Windows. No doubt I'll get told
1922        if it's wrong...
1923    
1924    
1925    Version 4.3 21-May-03
1926    ---------------------
1927    
1928    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1929       Makefile.
1930    
1931    2. Some refactoring to improve the quality of the code:
1932    
1933       (i)   The utf8_table... variables are now declared "const".
1934    
1935       (ii)  The code for \cx, which used the "case flipping" table to upper case
1936             lower case letters, now just substracts 32. This is ASCII-specific,
1937             but the whole concept of \cx is ASCII-specific, so it seems
1938             reasonable.
1939    
1940       (iii) PCRE was using its character types table to recognize decimal and
1941             hexadecimal digits in the pattern. This is silly, because it handles
1942             only 0-9, a-f, and A-F, but the character types table is locale-
1943             specific, which means strange things might happen. A private
1944             table is now used for this - though it costs 256 bytes, a table is
1945             much faster than multiple explicit tests. Of course, the standard
1946             character types table is still used for matching digits in subject
1947             strings against \d.
1948    
1949       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1950             ending in _t are). So I've renamed it as ESC_tee.
1951    
1952    3. The first argument for regexec() in the POSIX wrapper should have been
1953       defined as "const".
1954    
1955    4. Changed pcretest to use malloc() for its buffers so that they can be
1956       Electric Fenced for debugging.
1957    
1958    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1959       to read one or more bytes before the start of the subject string. Often this
1960       had no effect on PCRE's behaviour, but in some circumstances it could
1961       provoke a segmentation fault.
1962    
1963    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1964       to try to read one or more bytes before the start of the subject string.
1965    
1966    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1967       UTF-8 support could misbehave in various ways if the subject string
1968       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1969       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1970       back over UTF-8 characters.)
1971    
1972    
1973    Version 4.2 14-Apr-03
1974    ---------------------
1975    
1976    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1977    
1978    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1979         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1980         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1981         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1982         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1983           and BUILD_EXEEXT
1984         Note: automatic setting of the BUILD variables is not yet working
1985         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1986           compile-time but not at link-time
1987         [LINK]: use for linking executables only
1988         make different versions for Windows and non-Windows
1989         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1990           libraries
1991         [LINK_FOR_BUILD]: new variable
1992         [OBJEXT]: use throughout
1993         [EXEEXT]: use throughout
1994         <winshared>: new target
1995         <wininstall>: new target
1996         <dftables.o>: use native compiler
1997         <dftables>: use native linker
1998         <install>: handle Windows platform correctly
1999         <clean>: ditto
2000         <check>: ditto
2001         copy DLL to top builddir before testing
2002    
2003       As part of these changes, -no-undefined was removed again. This was reported
2004       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2005       in any case.
2006    
2007    3. Some tidies to get rid of compiler warnings:
2008    
2009       . In the match_data structure, match_limit was an unsigned long int, whereas
2010         match_call_count was an int. I've made them both unsigned long ints.
2011    
2012       . In pcretest the fact that a const uschar * doesn't automatically cast to
2013         a void * provoked a warning.
2014    
2015       . Turning on some more compiler warnings threw up some "shadow" variables
2016         and a few more missing casts.
2017    
2018    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2019       option, a class that contained a single character with a value between 128
2020       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2021    
2022    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2023       option, a class that contained several characters, but with at least one
2024       whose value was between 128 and 255 caused PCRE to crash.
2025    
2026    
2027    Version 4.1 12-Mar-03
2028    ---------------------
2029    
2030    1. Compiling with gcc -pedantic found a couple of places where casts were
2031    needed, and a string in dftables.c that was longer than standard compilers are
2032    required to support.
2033    
2034    2. Compiling with Sun's compiler found a few more places where the code could
2035    be tidied up in order to avoid warnings.
2036    
2037    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2038    first of these names is deprecated in the latest Autoconf in favour of the name
2039    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2040    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2041    analogy I have changed it to CFLAGS_FOR_BUILD.
2042    
2043    4. Added -no-undefined to the linking command in the Makefile, because this is
2044    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2045    linking step for the pcreposix library.
2046    
2047    5. PCRE was failing to diagnose the case of two named groups with the same
2048    name.
2049    
2050    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2051    literal character that is needed in the subject for a match, and scans along to
2052    ensure that it is present before embarking on the full matching process. This
2053    saves time in cases of nested unlimited repeats that are never going to match.
2054    Problem: the scan can take a lot of time if the subject is very long (e.g.
2055    megabytes), thus penalizing straightforward matches. It is now done only if the
2056    amount of subject to be scanned is less than 1000 bytes.
2057    
2058    7. A lesser problem with the same optimization is that it was recording the
2059    first character of an anchored pattern as "needed", thus provoking a search
2060    right along the subject, even when the first match of the pattern was going to
2061    fail. The "needed" character is now not set for anchored patterns, unless it
2062    follows something in the pattern that is of non-fixed length. Thus, it still
2063    fulfils its original purpose of finding quick non-matches in cases of nested
2064    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2065    
2066    
2067    Version 4.0 17-Feb-03
2068    ---------------------
2069    
2070    1. If a comment in an extended regex that started immediately after a meta-item
2071    extended to the end of string, PCRE compiled incorrect data. This could lead to
2072    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2073    
2074    2. Moved to autoconf 2.53 and libtool 1.4.2.
2075    
2076    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2077    the special perltest8 script is no longer needed - all the tests can be run
2078    from a single perltest script.
2079    
2080    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2081    by \s. It has now been removed in PCRE. This means it isn't recognized as
2082    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2083    class [:space:] *does* include VT, thereby creating a mess.
2084    
2085    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2086    space and tab.
2087    
2088    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2089    its new features into the main test script, reducing the number of scripts.
2090    
2091    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2092    were backward compatible, and made the (?i) apply to the whole pattern, as if
2093    /i were given. Now it behaves more logically, and applies the option setting
2094    only to what follows. PCRE has been changed to follow suit. However, if it
2095    finds options settings right at the start of the pattern, it extracts them into
2096    the global options, as before. Thus, they show up in the info data.
2097    
2098    8. Added support for the \Q...\E escape sequence. Characters in between are
2099    treated as literals. This is slightly different from Perl in that $ and @ are
2100    also handled as literals inside the quotes. In Perl, they will cause variable
2101    interpolation. Note the following examples:
2102    
2103        Pattern            PCRE matches      Perl matches
2104    
2105        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2106        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2107        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2108    
2109    For compatibility with Perl, \Q...\E sequences are recognized inside character
2110    classes as well as outside them.
2111    
2112    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2113    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2114    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2115    signed/unsigned warnings.
2116    
2117    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2118    option for pcretest, so I've replaced it by a simple function that does just
2119    that job.
2120    
2121    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2122    "pcregrep -".
2123    
2124    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2125    Java package. This provides some syntactic sugar for simple cases of what my
2126    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2127    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2128    item, you can use this simplified notation. Note that only makes sense with
2129    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2130    greediness, whatever the setting of the PCRE_UNGREEDY option.
2131    
2132    13. A change of greediness default within a pattern was not taking effect at
2133    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2134    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2135    was abstracted outside.
2136    
2137    14. PCRE now supports the \G assertion. It is true when the current matching
2138    position is at the start point of the match. This differs from \A when the
2139    starting offset is non-zero. Used with the /g option of pcretest (or similar
2140    code), it works in the same way as it does for Perl's /g option. If all
2141    alternatives of a regex begin with \G, the expression is anchored to the start
2142    match position, and the "anchored" flag is set in the compiled expression.
2143    
2144    15. Some bugs concerning the handling of certain option changes within patterns
2145    have been fixed. These applied to options other than (?ims). For example,
2146    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2147    been the other way round. Some of this was related to change 7 above.
2148    
2149    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2150    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2151    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2152    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2153    
2154    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2155    mode. Unlike ".", it always matches newline, whatever the setting of
2156    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2157    assertions. Perl allows it, but it doesn't (in general) work because it can't
2158    calculate the length of the lookbehind. At least, that's the case for Perl
2159    5.8.0 - I've been told they are going to document that it doesn't work in
2160    future.
2161    
2162    18. Added an error diagnosis for escapes that PCRE does not support: these are
2163    \L, \l, \N, \P, \p, \U, \u, and \X.
2164    
2165    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2166    reading past the end of the pattern in cases such as /[abcd/.
2167    
2168    20. PCRE was getting more memory than necessary for patterns with classes that
2169    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2170    
2171    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2172    compiling PCRE for use with Virtual Pascal.
2173    
2174    22. Small fix to the Makefile to make it work properly if the build is done
2175    outside the source tree.
2176    
2177    23. Added a new extension: a condition to go with recursion. If a conditional
2178    subpattern starts with (?(R) the "true" branch is used if recursion has
2179    happened, whereas the "false" branch is used only at the top level.
2180    
2181    24. When there was a very long string of literal characters (over 255 bytes
2182    without UTF support, over 250 bytes with UTF support), the computation of how
2183    much memory was required could be incorrect, leading to segfaults or other
2184    strange effects.
2185    
2186    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2187    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2188    there was a subsequent back reference to those brackets. This meant that, for
2189    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2190    possible to check for precisely this case. All we can do is abandon the
2191    optimization if .* occurs inside capturing brackets when there are any back
2192    references whatsoever. (See below for a better fix that came later.)
2193    
2194    26. The handling of the optimization for finding the first character of a
2195    non-anchored pattern, and for finding a character that is required later in the
2196    match were failing in some cases. This didn't break the matching; it just
2197    failed to optimize when it could. The way this is done has been re-implemented.
2198    
2199    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2200    
2201    28. Added a new feature that provides some of the functionality that Perl
2202    provides with (?{...}). The facility is termed a "callout". The way it is done
2203    in PCRE is for the caller to provide an optional function, by setting
2204    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2205    global variable. By default it is unset, which disables all calling out. To get
2206    the function called, the regex must include (?C) at appropriate points. This
2207    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2208    This provides a means of identifying different callout points. When PCRE
2209    reaches such a point in the regex, if pcre_callout has been set, the external
2210    function is called. It is provided with data in a structure called
2211    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2212    matching continues; if it returns a non-zero value, the match at the current
2213    point fails. However, backtracking will occur if possible. [This was changed
2214    later and other features added - see item 49 below.]
2215    
2216    29. pcretest is upgraded to test the callout functionality. It provides a
2217    callout function that displays information. By default, it shows the start of
2218    the match and the current position in the text. There are some new data escapes
2219    to vary what happens:
2220    
2221        \C+         in addition, show current contents of captured substrings
2222        \C-         do not supply a callout function
2223        \C!n        return 1 when callout number n is reached
2224        \C!n!m      return 1 when callout number n is reached for the mth time
2225    
2226    30. If pcregrep was called with the -l option and just a single file name, it
2227    output "<stdin>" if a match was found, instead of the file name.
2228    
2229    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2230    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2231    pcre_exec(). This saves a malloc/free per call. The default value of
2232    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2233    when configuring.
2234    
2235    32. The default maximum size of a compiled pattern is 64K. There have been a
2236    few cases of people hitting this limit. The code now uses macros to handle the
2237    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2238    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2239    configuring. Tests 2 and 5 work only with 2-byte links because they output
2240    debugging information about compiled patterns.
2241    
2242    33. Internal code re-arrangements:
2243    
2244    (a) Moved the debugging function for printing out a compiled regex into
2245        its own source file (printint.c) and used #include to pull it into
2246        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2247        separate copies.
2248    
2249    (b) Defined the list of op-code names for debugging as a macro in
2250        internal.h so that it is next to the definition of the opcodes.
2251    
2252    (c) Defined a table of op-code lengths for simpler skipping along compiled
2253        code. This is again a macro in internal.h so that it is next to the
2254        definition of the opcodes.
2255    
2256    34. Added support for recursive calls to individual subpatterns, along the
2257    lines of Robin Houston's patch (but implemented somewhat differently).
2258    
2259    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2260    allow it to read and process whole directories in Win32. This code was
2261    contributed by Lionel Fourquaux; it has not been tested by me.
2262    
2263    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2264    used to name a group. Names consist of alphanumerics and underscores, and must
2265    be unique. Back references use the syntax (?P=name) and recursive calls use
2266    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2267    numbers. The function pcre_fullinfo() can be used after compilation to extract
2268    a name/number map. There are three relevant calls:
2269    
2270      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2271      PCRE_INFO_NAMECOUNT            yields the number of entries
2272      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2273    
2274    The map is a vector of fixed-size entries. The size of each entry depends on
2275    the length of the longest name used. The first two bytes of each entry are the
2276    group number, most significant byte first. There follows the corresponding
2277    name, zero terminated. The names are in alphabetical order.
2278    
2279    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2280    case instead of 255. Making it the same both with and without UTF-8 support
2281    means that the same test output works with both.
2282    
2283    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2284    calling malloc() with a zero argument.
2285    
2286    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2287    optimization. I've improved things by keeping a bitmap of backreferences with
2288    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2289    fact referenced, the optimization can be applied. It is unlikely that a
2290    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2291    the match to follow \n) will appear inside brackets with a number greater than
2292    31, but if it does, any back reference > 31 suppresses the optimization.
2293    
2294    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2295    of disabling numbered capturing parentheses. Any opening parenthesis that is
2296    not followed by ? behaves as if it were followed by ?: but named parentheses
2297    can still be used for capturing (and they will acquire numbers in the usual
2298    way).
2299    
2300    41. Redesigned the return codes from the match() function into yes/no/error so
2301    that errors can be passed back from deep inside the nested calls. A malloc
2302    failure while inside a recursive subpattern call now causes the
2303    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2304    
2305    42. It is now possible to set a limit on the number of times the match()
2306    function is called in a call to pcre_exec(). This facility makes it possible to
2307    limit the amount of recursion and backtracking, though not in a directly
2308    obvious way, because the match() function is used in a number of different
2309    circumstances. The count starts from zero for each position in the subject
2310    string (for non-anchored patterns). The default limit is, for compatibility, a
2311    large number, namely 10 000 000. You can change this in two ways:
2312    
2313    (a) When configuring PCRE before making, you can use --with-match-limit=n
2314        to set a default value for the compiled library.
2315    
2316    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2317        a different value is set. See 45 below.
2318    
2319    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2320    
2321    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2322    of things that can be changed at compile time. The first argument specifies
2323    what is wanted and the second points to where the information is to be placed.
2324    The current list of available information is:
2325    
2326      PCRE_CONFIG_UTF8
2327    
2328    The output is an integer that is set to one if UTF-8 support is available;
2329    otherwise it is set to zero.
2330    
2331      PCRE_CONFIG_NEWLINE
2332    
2333    The output is an integer that it set to the value of the code that is used for
2334    newline. It is either LF (10) or CR (13).
2335    
2336      PCRE_CONFIG_LINK_SIZE
2337    
2338    The output is an integer that contains the number of bytes used for internal
2339    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2340    
2341      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2342    
2343    The output is an integer that contains the threshold above which the POSIX
2344    interface uses malloc() for output vectors. See item 31 above.
2345    
2346      PCRE_CONFIG_MATCH_LIMIT
2347    
2348    The output is an unsigned integer that contains the default limit of the number
2349    of match() calls in a pcre_exec() execution. See 42 above.
2350    
2351    44. pcretest has been upgraded by the addition of the -C option. This causes it
2352    to extract all the available output from the new pcre_config() function, and to
2353    output it. The program then exits immediately.
2354    
2355    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2356    order to support additional features. One way would have been to define
2357    pcre_exec2() (for example) with extra arguments, but this would not have been
2358    extensible, and would also have required all calls to the original function to
2359    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2360    is used for passing in "extra" data from pcre_study().
2361    
2362    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2363    contains the following fields:
2364    
2365      flags         a bitmap indicating which of the following fields are set
2366      study_data    opaque data from pcre_study()
2367      match_limit   a way of specifying a limit on match() calls for a specific
2368                      call to pcre_exec()
2369      callout_data  data for callouts (see 49 below)
2370    
2371    The flag bits are also defined in pcre.h, and are
2372    
2373      PCRE_EXTRA_STUDY_DATA
2374      PCRE_EXTRA_MATCH_LIMIT
2375      PCRE_EXTRA_CALLOUT_DATA
2376    
2377    The pcre_study() function now returns one of these new pcre_extra blocks, with
2378    the actual study data pointed to by the study_data field, and the
2379    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2380    before. That is, this change is entirely upwards-compatible and requires no
2381    change to existing code.
2382    
2383    If you want to pass in additional data to pcre_exec(), you can either place it
2384    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2385    block.
2386    
2387    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2388    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2389    times with different match limits, until it finds the minimum value needed for
2390    pcre_exec() to complete. The value is then output. This can be instructive; for
2391    most simple matches the number is quite small, but for pathological cases it
2392    gets very large very quickly.
2393    
2394    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2395    returns the size of the data block pointed to by the study_data field in a
2396    pcre_extra block, that is, the value that was passed as the argument to
2397    pcre_malloc() when PCRE was getting memory in which to place the information
2398    created by pcre_study(). The fourth argument should point to a size_t variable.
2399    pcretest has been extended so that this information is shown after a successful
2400    pcre_study() call when information about the compiled regex is being displayed.
2401    
2402    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2403    because what follows is always an absolute path. (Later: it turns out that this
2404    is more than cosmetic for MinGW, because it doesn't like empty path
2405    components.)
2406    
2407    49. Some changes have been made to the callout feature (see 28 above):
2408    
2409    (i)  A callout function now has three choices for what it returns:
2410    
2411           0  =>  success, carry on matching
2412         > 0  =>  failure at this point, but backtrack if possible
2413         < 0  =>  serious error, return this value from pcre_exec()
2414    
2415         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2416         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2417         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2418         use by callout functions. It will never be used by PCRE itself.
2419    
2420    (ii) The pcre_extra structure (see 45 above) has a void * field called
2421         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2422         pcre_callout_block structure has a field of the same name. The contents of
2423         the field passed in the pcre_extra structure are passed to the callout
2424         function in the corresponding field in the callout block. This makes it
2425         easier to use the same callout-containing regex from multiple threads. For
2426         testing, the pcretest program has a new data escape
2427    
2428           \C*n        pass the number n (may be negative) as callout_data
2429    
2430         If the callout function in pcretest receives a non-zero value as
2431         callout_data, it returns that value.
2432    
2433    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2434    there were some redundant $(CFLAGS) in commands that are now specified as
2435    $(LINK), which already includes $(CFLAGS).
2436    
2437    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2438    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2439    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2440    one-byte characters throughout. Note that case-insensitive matching applies
2441    only to characters whose values are less than 256. PCRE doesn't support the
2442    notion of cases for higher-valued characters.
2443    
2444    (i)   A character class whose characters are all within 0-255 is handled as
2445          a bit map, and the map is inverted for negative classes. Previously, a
2446          character > 255 always failed to match such a class; however it should
2447          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2448    
2449    (ii)  A negated character class with a single character < 255 is coded as
2450          "not this character" (OP_NOT). This wasn't working properly when the test
2451          character was multibyte, either singly or repeated.
2452    
2453    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2454          mode, for example: \x{100}{2,3}.
2455    
2456    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2457          singly or repeated) now correctly test multibyte characters. However,
2458          PCRE doesn't recognize any characters with values greater than 255 as
2459          digits, spaces, or word characters. Such characters always match \D, \S,
2460          and \W, and never match \d, \s, or \w.
2461    
2462    (v)   Classes may now contain characters and character ranges with values
2463          greater than 255. For example: [ab\x{100}-\x{400}].
2464    
2465    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2466          PCRE in UTF-8 mode.
2467    
2468    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2469    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2470    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2471    value.)
2472    
2473    53. The single man page has become too large. I have therefore split it up into
2474    a number of separate man pages. These also give rise to individual HTML pages;
2475    these are now put in a separate directory, and there is an index.html page that
2476    lists them all. Some hyperlinking between the pages has been installed.
2477    
2478    54. Added convenience functions for handling named capturing parentheses.
2479    
2480    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2481    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2482    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2483    are faulted.
2484    
2485    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2486    calling configure. These values are used when compiling the dftables.c program
2487    which is run to generate the source of the default character tables. They
2488    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2489    you will need to set these values.
2490    
2491    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2492    
2493    
2494    Version 3.9 02-Jan-02
2495    ---------------------
2496    
2497    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2498    
2499    2. If --disable-static was given, the building process failed when trying to
2500    build pcretest and pcregrep. (For some reason it was using libtool to compile
2501    them, which is not right, as they aren't part of the library.)
2502    
2503    
2504    Version 3.8 18-Dec-01
2505    ---------------------
2506    
2507    1. The experimental UTF-8 code was completely screwed up. It was packing the
2508    bytes in the wrong order. How dumb can you get?
2509    
2510    
2511    Version 3.7 29-Oct-01
2512    ---------------------
2513    
2514    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2515    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2516    this didn't happen under Solaris 8, where I normally test things.
2517    
2518    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2519    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2520    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2521    this fix an hour or so after the initial 3.7 release.)
2522    
2523    
2524    Version 3.6 23-Oct-01
2525    ---------------------
2526    
2527    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2528    offsets passed as NULL with zero offset count.
2529    
2530    2. The config.guess and config.sub files had not been updated when I moved to
2531    the latest autoconf.
2532    
2533    
2534    Version 3.5 15-Aug-01
2535    ---------------------
2536    
2537    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2538    had been forgotten.
2539    
2540    2. By using declared but undefined structures, we can avoid using "void"
2541    definitions in pcre.h while keeping the internal definitions of the structures
2542    private.
2543    
2544    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2545    user point of view, this means that both static and shared libraries are built
2546    by default, but this can be individually controlled. More of the work of
2547    handling this static/shared cases is now inside libtool instead of PCRE's make
2548    file.
2549    
2550    4. The pcretest utility is now installed along with pcregrep because it is
2551    useful for users (to test regexs) and by doing this, it automatically gets
2552    relinked by libtool. The documentation has been turned into a man page, so
2553    there are now .1, .txt, and .html versions in /doc.
2554    
2555    5. Upgrades to pcregrep:
2556       (i)   Added long-form option names like gnu grep.
2557       (ii)  Added --help to list all options with an explanatory phrase.
2558       (iii) Added -r, --recursive to recurse into sub-directories.
2559       (iv)  Added -f, --file to read patterns from a file.
2560    
2561    6. pcre_exec() was referring to its "code" argument before testing that
2562    argument for NULL (and giving an error if it was NULL).
2563    
2564    7. Upgraded Makefile.in to allow for compiling in a different directory from
2565    the source directory.
2566    
2567    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2568    options bits, the pointer it was passed was to an int instead of to an unsigned
2569    long int. This mattered only on 64-bit systems.
2570    
2571    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2572    generated) instead of pcre.in, which it its source. Also made the same change
2573    in several of the .c files.
2574    
2575    10. A new release of gcc defines printf() as a macro, which broke pcretest
2576    because it had an ifdef in the middle of a string argument for printf(). Fixed
2577    by using separate calls to printf().
2578    
2579    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2580    script, to force use of CR or LF instead of \n in the source. On non-Unix
2581    systems, the value can be set in config.h.
2582    
2583    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2584    absolute limit. Changed the text of the error message to make this clear, and
2585    likewise updated the man page.
2586    
2587    13. The limit of 99 on the number of capturing subpatterns has been removed.
2588    The new limit is 65535, which I hope will not be a "real" limit.
2589    
2590    
2591    Version 3.4 22-Aug-00
2592    ---------------------
2593    
2594    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2595    
2596    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2597    
2598    
2599    Version 3.3 01-Aug-00
2600    ---------------------
2601    
2602    1. If an octal character was given, but the value was greater than \377, it
2603    was not getting masked to the least significant bits, as documented. This could
2604    lead to crashes in some systems.
2605    
2606    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2607    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2608    
2609    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2610    These just pass their arguments on to (pcre_free)(), but they are provided
2611    because some uses of PCRE bind it to non-C systems that can call its functions,
2612    but cannot call free() or pcre_free() directly.
2613    
2614    4. Add "make test" as a synonym for "make check". Corrected some comments in
2615    the Makefile.
2616    
2617    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2618    Makefile.
2619    
2620    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2621    command called pgrep for grepping around the active processes.
2622    
2623    7. Added the beginnings of support for UTF-8 character strings.
2624    
2625    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2626    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2627    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2628    out for the ar command.)
2629    
2630    
2631    Version 3.2 12-May-00
2632    ---------------------
2633    
2634    This is purely a bug fixing release.
2635    
2636    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2637    of ZA. This was just one example of several cases that could provoke this bug,
2638    which was introduced by change 9 of version 2.00. The code for breaking
2639    infinite loops after an iteration that matches an empty string was't working
2640    correctly.
2641    
2642    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2643    when matched against abbab (for example). After matching an empty string, it
2644    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2645    caused it to match further down the string than it should.
2646    
2647    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2648    was there because it doesn't seem to be needed, and it causes trouble on some
2649    systems, as it is not a Standard C header. It has been removed.
2650    
2651    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2652    were reported on the Macintosh. The changes were from
2653    
2654      while ((c = *(++ptr)) != 0 && c != '\n');
2655    to
2656      while ((c = *(++ptr)) != 0 && c != '\n') ;
2657    
2658    Totally extraordinary, but if that's what it takes...
2659    
2660    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2661    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2662    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2663    assumes the way PCRE uses memmove() (always moving upwards).
2664    
2665    6. PCRE is being used in one environment where strchr() is not available. There
2666    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2667    faster code anyway.
2668    
2669    
2670    Version 3.1 09-Feb-00
2671    ---------------------
2672    
2673    The only change in this release is the fixing of some bugs in Makefile.in for
2674    the "install" target:
2675    
2676    (1) It was failing to install pcreposix.h.
2677    
2678    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2679    
2680    
2681    Version 3.0 01-Feb-00
2682    ---------------------
2683    
2684    1. Add support for the /+ modifier to perltest (to output $` like it does in
2685    pcretest).
2686    
2687    2. Add support for the /g modifier to perltest.
2688    
2689    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2690    matches null strings.
2691    
2692    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2693    pattern. Perl treats empty patterns specially - it reuses the most recent
2694    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2695    effect.
2696    
2697    5. The POSIX interface was broken in that it was just handing over the POSIX
2698    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2699    required a bigger vector, with some working space on the end. This means that
2700    the POSIX wrapper now has to get and free some memory, and copy the results.
2701    
2702    6. Added some simple autoconf support, placing the test data and the
2703    documentation in separate directories, re-organizing some of the
2704    information files, and making it build pcre-config (a GNU standard). Also added
2705    libtool support for building PCRE as a shared library, which is now the
2706    default.
2707    
2708    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2709    09 are not valid octal constants. Single digits will be used for minor values
2710    less than 10.
2711    
2712    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2713    existing programs that set these in the POSIX interface can use PCRE without
2714    modification.
2715    
2716    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2717    return all that pcre_info() returns, plus additional data. The pcre_info()
2718    function is retained for compatibility, but is considered to be obsolete.
2719    
2720    10. Added experimental recursion feature (?R) to handle one common case that
2721    Perl 5.6 will be able to do with (?p{...}).
2722    
2723    11. Added support for POSIX character classes like [:alpha:], which Perl is
2724    adopting.
2725    
2726    
2727    Version 2.08 31-Aug-99
2728    ----------------------
2729    
2730    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2731    trying to match at the startoffset position, but instead was moving forward to
2732    the next newline as if a previous match had failed.
2733    
2734    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2735    and could get into a loop if a null string was matched other than at the start
2736    of the subject.
2737    
2738    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2739    be distinguished at compile time, and for completeness also added PCRE_DATE.
2740    
2741    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2742    in GnuWin32 environments.
2743    
2744    
2745    Version 2.07 29-Jul-99
2746    ----------------------
2747    
2748    1. The documentation is now supplied in plain text form and HTML as well as in
2749    the form of man page sources.
2750    
2751    2. C++ compilers don't like assigning (void *) values to other pointer types.
2752    In particular this affects malloc(). Although there is no problem in Standard
2753    C, I've put in casts to keep C++ compilers happy.
2754    
2755    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2756    should be (const char *).
2757    
2758    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2759    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2760    However, I haven't made this a standard facility. The documentation doesn't
2761    mention it, and the Makefile doesn't support it.
2762    
2763    5. The Makefile now contains an "install" target, with editable destinations at
2764    the top of the file. The pcretest program is not installed.
2765    
2766    6. pgrep -V now gives the PCRE version number and date.
2767    
2768    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2769    causing the entire string to be ignored, instead of just the last character.
2770    
2771    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2772    non-matching string, it can take a very, very long time, even for strings of
2773    quite modest length, because of the nested recursion. PCRE now does better in
2774    some of these cases. It does this by remembering the last required literal
2775    character in the pattern, and pre-searching the subject to ensure it is present
2776    before running the real match. In other words, it applies a heuristic to detect
2777    some types of certain failure quickly, and in the above example, if presented
2778    with a string that has no trailing " it gives "no match" very quickly.
2779    
2780    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2781    other alternatives are tried instead.
2782    
2783    
2784    Version 2.06 09-Jun-99
2785    ----------------------
2786    
2787    1. Change pcretest's output for amount of store used to show just the code
2788    space, because the remainder (the data block) varies in size between 32-bit and
2789    64-bit systems.
2790    
2791    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2792    start matching at. This allows lookbehinds to work when searching for multiple
2793    occurrences in a string.
2794    
2795    3. Added additional options to pcretest for testing multiple occurrences:
2796    
2797       /+   outputs the rest of the string that follows a match
2798       /g   loops for multiple occurrences, using the new startoffset argument
2799       /G   loops for multiple occurrences by passing an incremented pointer
2800    
2801    4. PCRE wasn't doing the "first character" optimization for patterns starting
2802    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2803    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2804    the letter 'x'. On long subject strings, this gives a significant speed-up.
2805    
2806    
2807    Version 2.05 21-Apr-99
2808    ----------------------
2809    
2810    1. Changed the type of magic_number from int to long int so that it works
2811    properly on 16-bit systems.
2812    
2813    2. Fixed a bug which caused patterns starting with .* not to work correctly
2814    when the subject string contained newline characters. PCRE was assuming
2815    anchoring for such patterns in all cases, which is not correct because .* will
2816    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2817    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2818    must be retried after every newline in the subject.
2819    
2820    
2821    Version 2.04 18-Feb-99
2822    ----------------------
2823    
2824    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2825    computation of the store needed to hold the pattern was incorrect (too large).
2826    If such patterns were nested a few deep, this could multiply and become a real
2827    problem.
2828    
2829    2. Added /M option to pcretest to show the memory requirement of a specific
2830    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2831    
2832    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2833    compiled in such a way that the backtracking after subsequent failure was
2834    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2835    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2836    
2837    
2838    Version 2.03 02-Feb-99
2839    ----------------------
2840    
2841    1. Fixed typo and small mistake in man page.
2842    
2843    2. Added 4th condition (GPL supersedes if conflict) and created separate
2844    LICENCE file containing the conditions.
2845    
2846    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2847    Perl, that is the internal \ allows the delimiter to be included in the
2848    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2849    the final delimiter, add \ to the end of the pattern (to test the error).
2850    
2851    4. Added the convenience functions for extracting substrings after a successful
2852    match. Updated pcretest to make it able to test these functions.
2853    
2854    
2855    Version 2.02 14-Jan-99
2856    ----------------------
2857    
2858    1. Initialized the working variables associated with each extraction so that
2859    their saving and restoring doesn't refer to uninitialized store.
2860    
2861    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2862    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2863    fix the problem.
2864    
2865    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2866    calls, and wasn't printing the correct value for compiling calls. Increased the
2867    default value of LOOPREPEAT, and the number of significant figures in the
2868    times.
2869    
2870    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2871    
2872    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2873    a building problem on Windows NT with a FAT file system.
2874    
2875    
2876    Version 2.01 21-Oct-98
2877    ----------------------
2878    
2879    1. Changed the API for pcre_compile() to allow for the provision of a pointer
2880    to character tables built by pcre_maketables() in the current locale. If NULL
2881    is passed, the default tables are used.
2882    
2883    
2884    Version 2.00 24-Sep-98
2885    ----------------------
2886    
2887    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2888    it any more.
2889    
2890    2. Allow quantification of (?>) groups, and make it work correctly.
2891    
2892    3. The first character computation wasn't working for (?>) groups.
2893    
2894    4. Correct the implementation of \Z (it is permitted to match on the \n at the
2895    end of the subject) and add 5.005's \z, which really does match only at the
2896    very end of the subject.
2897    
2898    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2899    
2900    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2901    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2902    localized options. All options to pcre_study() were also removed.
2903    
2904    7. Add other new features from 5.005:
2905    
2906       $(?<=           positive lookbehind
2907       $(?<!           negative lookbehind
2908       (?imsx-imsx)    added the unsetting capability
2909                       such a setting is global if at outer level; local otherwise
2910       (?imsx-imsx:)   non-capturing groups with option setting
2911       (?(cond)re|re)  conditional pattern matching
2912    
2913       A backreference to itself in a repeated group matches the previous
2914       captured string.
2915    
2916    8. General tidying up of studying (both automatic and via "study")
2917    consequential on the addition of new assertions.
2918    
2919    9. As in 5.005, unlimited repeated groups that could match an empty substring
2920    are no longer faulted at compile time. Instead, the loop is forcibly broken at
2921    runtime if any iteration does actually match an empty substring.
2922    
2923    10. Include the RunTest script in the distribution.
2924    
2925    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2926    discrepancies, some of which were old and were also with respect to 5.004. They
2927    have now been fixed.
2928    
2929    
2930    Version 1.09 28-Apr-98
2931    ----------------------
2932    
2933    1. A negated single character class followed by a quantifier with a minimum
2934    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
2935    program crashes, or just wrong answers. This did not apply to negated classes
2936    containing more than one character, or to minima other than one.
2937    
2938    
2939    Version 1.08 27-Mar-98
2940    ----------------------
2941    
2942    1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2943    
2944    2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2945    latter must appear before anything that relies on it in the pattern.
2946    
2947    
2948  Version 1.07 16-Feb-98  Version 1.07 16-Feb-98
2949  ----------------------  ----------------------

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