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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.31
5    -----------------------------
6    
7    1.  Fixing a wrong JIT test case and some compiler warnings.
8    
9    2.  Removed a bashism from the RunTest script.
10    
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
14    
15    4.  Partial matching support is added to the JIT compiler.
16    
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
19    
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
23    
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
26    
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
29    
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
32    
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
35    
36    
37    Version 8.30 04-February-2012
38    -----------------------------
39    
40    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
41        name is defined in ctype.h.
42    
43    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
44        only in quite long subpatterns.
45    
46    3.  Removed the function pcre_info(), which has been obsolete and deprecated
47        since it was replaced by pcre_fullinfo() in February 2000.
48    
49    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
50        match a (*MARK), and the match failed at the start of the subject, a
51        reference to memory before the start of the subject could occur. This bug
52        was introduced by fix 17 of release 8.21.
53    
54    5.  A reference to an unset group with zero minimum repetition was giving
55        totally wrong answers (in non-JavaScript-compatibility mode). For example,
56        /(another)?(\1?)test/ matched against "hello world test". This bug was
57        introduced in release 8.13.
58    
59    6.  Add support for 16-bit character strings (a large amount of work involving
60        many changes and refactorings).
61    
62    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
63        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
64        from a file.
65    
66    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
67        rounding is not applied in this particular case).
68    
69    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
70        if they appear, or are escaped, in patterns.
71    
72    10. Get rid of a number of -Wunused-but-set-variable warnings.
73    
74    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
75        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
76        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
77        also returns the mark "x". This bug applied to capturing parentheses,
78        non-capturing parentheses, and atomic parentheses. It also applied to some
79        assertions.
80    
81    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
82        information out of configure.ac instead of relying on pcre.h.generic, which
83        is not stored in the repository.
84    
85    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
86        -lreadline.
87    
88    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
89    
90    15. Applied Graycode's patch to put the top-level frame on the stack rather
91        than the heap when not using the stack for recursion. This gives a
92        performance improvement in many cases when recursion is not deep.
93    
94    16. Experimental code added to "pcretest -C" to output the stack frame size.
95    
96    
97    Version 8.21 12-Dec-2011
98    ------------------------
99    
100    1.  Updating the JIT compiler.
101    
102    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
103        are added as well.
104    
105    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
106        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
107        calling _pcre_jit_exec. Some extra comments are added.
108    
109    4.  (*MARK) settings inside atomic groups that do not contain any capturing
110        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
111        was introduced by change 18 for 8.20.
112    
113    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
114        ECMA-262 standard.
115    
116    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
117        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
118        This bug was probably introduced by change 9 of 8.13.
119    
120    7.  While fixing 6 above, I noticed that a number of other items were being
121        incorrectly rejected as "not fixed length". This arose partly because newer
122        opcodes had not been added to the fixed-length checking code. I have (a)
123        corrected the bug and added tests for these items, and (b) arranged for an
124        error to occur if an unknown opcode is encountered while checking for fixed
125        length instead of just assuming "not fixed length". The items that were
126        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
127        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
128        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
129    
130    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
131        being incorrectly compiled and would have given unpredicatble results.
132    
133    9.  A possessively repeated subpattern with minimum repeat count greater than
134        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
135        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
136        the first (A) could occur when it should not.
137    
138    10. Add a cast and remove a redundant test from the code.
139    
140    11. JIT should use pcre_malloc/pcre_free for allocation.
141    
142    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
143        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
144        is anything other than /usr, -L is still shown).
145    
146    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
147    
148    14. Perl does not support \N without a following name in a [] class; PCRE now
149        also gives an error.
150    
151    15. If a forward reference was repeated with an upper limit of around 2000,
152        it caused the error "internal error: overran compiling workspace". The
153        maximum number of forward references (including repeats) was limited by the
154        internal workspace, and dependent on the LINK_SIZE. The code has been
155        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
156        the default depends on LINK_SIZE. There is a new upper limit (for safety)
157        of around 200,000 forward references. While doing this, I also speeded up
158        the filling in of repeated forward references.
159    
160    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
161        incorrectly expecting the subject to contain another "a" after the start.
162    
163    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
164        in the match, the SKIP should be ignored. This was not happening; instead
165        the SKIP was being treated as NOMATCH. For patterns such as
166        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
167        tested.
168    
169    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
170        now much more compatible with Perl, in particular in cases where the result
171        is a non-match for a non-anchored pattern. For example, if
172        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
173        "m", where previously it did not return a name. A side effect of this
174        change is that for partial matches, the last encountered mark name is
175        returned, as for non matches. A number of tests that were previously not
176        Perl-compatible have been moved into the Perl-compatible test files. The
177        refactoring has had the pleasing side effect of removing one argument from
178        the match() function, thus reducing its stack requirements.
179    
180    19. If the /S+ option was used in pcretest to study a pattern using JIT,
181        subsequent uses of /S (without +) incorrectly behaved like /S+.
182    
183    21. Retrieve executable code size support for the JIT compiler and fixing
184        some warnings.
185    
186    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
187        not work when the shorter character appeared right at the end of the
188        subject string.
189    
190    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
191        systems.
192    
193    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
194        output it when the /M option is used in pcretest.
195    
196    25. The CheckMan script was not being included in the distribution. Also, added
197        an explicit "perl" to run Perl scripts from the PrepareRelease script
198        because this is reportedly needed in Windows.
199    
200    26. If study data was being save in a file and studying had not found a set of
201        "starts with" bytes for the pattern, the data written to the file (though
202        never used) was taken from uninitialized memory and so caused valgrind to
203        complain.
204    
205    27. Updated RunTest.bat as provided by Sheri Pierce.
206    
207    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
208    
209    29. Computation of memory usage for the table of capturing group names was
210        giving an unnecessarily large value.
211    
212    
213    Version 8.20 21-Oct-2011
214    ------------------------
215    
216    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
217        a POSIX class. After further experiments with Perl, which convinced me that
218        Perl has bugs and confusions, a closing square bracket is no longer allowed
219        in a POSIX name. This bug also affected patterns with classes that started
220        with full stops.
221    
222    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
223        captured substring, but while checking the failing first alternative,
224        substring 1 is temporarily captured. If the output vector supplied to
225        pcre_exec() was not big enough for this capture, the yield of the function
226        was still zero ("insufficient space for captured substrings"). This cannot
227        be totally fixed without adding another stack variable, which seems a lot
228        of expense for a edge case. However, I have improved the situation in cases
229        such as /(a)(b)x|abc/ matched against "abc", where the return code
230        indicates that fewer than the maximum number of slots in the ovector have
231        been set.
232    
233    3.  Related to (2) above: when there are more back references in a pattern than
234        slots in the output vector, pcre_exec() uses temporary memory during
235        matching, and copies in the captures as far as possible afterwards. It was
236        using the entire output vector, but this conflicts with the specification
237        that only 2/3 is used for passing back captured substrings. Now it uses
238        only the first 2/3, for compatibility. This is, of course, another edge
239        case.
240    
241    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
242        main code base, and can be used by building with --enable-jit. When this is
243        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
244        runtime --no-jit option is given.
245    
246    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
247        ovector, the return from the function was zero, implying that there were
248        other matches that did not fit. The correct "exactly full" value is now
249        returned.
250    
251    6.  If a subpattern that was called recursively or as a subroutine contained
252        (*PRUNE) or any other control that caused it to give a non-standard return,
253        invalid errors such as "Error -26 (nested recursion at the same subject
254        position)" or even infinite loops could occur.
255    
256    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
257        computing the minimum length on reaching *ACCEPT, and so ended up with the
258        wrong value of 1 rather than 0. Further investigation indicates that
259        computing a minimum subject length in the presence of *ACCEPT is difficult
260        (think back references, subroutine calls), and so I have changed the code
261        so that no minimum is registered for a pattern that contains *ACCEPT.
262    
263    8.  If (*THEN) was present in the first (true) branch of a conditional group,
264        it was not handled as intended. [But see 16 below.]
265    
266    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
267        Sheri Pierce.
268    
269    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
270        the first byte in a match must be "a".
271    
272    11. Change 17 for 8.13 increased the recursion depth for patterns like
273        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
274        pattern contains any instances of (*THEN). If it does not, the old
275        optimizations are restored. It would be nice to do this on a per-group
276        basis, but at the moment that is not feasible.
277    
278    12. In some environments, the output of pcretest -C is CRLF terminated. This
279        broke RunTest's code that checks for the link size. A single white space
280        character after the value is now allowed for.
281    
282    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
283        For "fr", it uses the Windows-specific input and output files.
284    
285    14. If (*THEN) appeared in a group that was called recursively or as a
286        subroutine, it did not work as intended. [But see next item.]
287    
288    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
289        pattern fragments (but not containing any | characters). If A and B are
290        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
291        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
292        D. In other words, Perl considers parentheses that do not contain any |
293        characters to be part of a surrounding alternative, whereas PCRE was
294        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
295        differently. PCRE now behaves in the same way as Perl, except in the case
296        of subroutine/recursion calls such as (?1) which have in any case always
297        been different (but PCRE had them first :-).
298    
299    16. Related to 15 above: Perl does not treat the | in a conditional group as
300        creating alternatives. Such a group is treated in the same way as an
301        ordinary group without any | characters when processing (*THEN). PCRE has
302        been changed to match Perl's behaviour.
303    
304    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
305        RunGrepTest script failed.
306    
307    18. Change 22 for version 13 caused atomic groups to use more stack. This is
308        inevitable for groups that contain captures, but it can lead to a lot of
309        stack use in large patterns. The old behaviour has been restored for atomic
310        groups that do not contain any capturing parentheses.
311    
312    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
313        suppress the check for a minimum subject length at run time. (If it was
314        given to pcre_exec() or pcre_dfa_exec() it did work.)
315    
316    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
317        fail to work when decoding hex characters in data strings in EBCDIC
318        environments.
319    
320    21. It appears that in at least one Mac OS environment, the isxdigit() function
321        is implemented as a macro that evaluates to its argument more than once,
322        contravening the C 90 Standard (I haven't checked a later standard). There
323        was an instance in pcretest which caused it to go wrong when processing
324        \x{...} escapes in subject strings. The has been rewritten to avoid using
325        things like p++ in the argument of isxdigit().
326    
327    
328    Version 8.13 16-Aug-2011
329    ------------------------
330    
331    1.  The Unicode data tables have been updated to Unicode 6.0.0.
332    
333    2.  Two minor typos in pcre_internal.h have been fixed.
334    
335    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
336        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
337        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
338    
339    4.  There were a number of related bugs in the code for matching backrefences
340        caselessly in UTF-8 mode when codes for the characters concerned were
341        different numbers of bytes. For example, U+023A and U+2C65 are an upper
342        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
343        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
344        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
345        2-byte code at the end of the subject (it thought there wasn't enough data
346        left).
347    
348    5.  Comprehensive information about what went wrong is now returned by
349        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
350        as the output vector has at least 2 elements. The offset of the start of
351        the failing character and a reason code are placed in the vector.
352    
353    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
354        now returned is for the first byte of the failing character, instead of the
355        last byte inspected. This is an incompatible change, but I hope it is small
356        enough not to be a problem. It makes the returned offset consistent with
357        pcre_exec() and pcre_dfa_exec().
358    
359    7.  pcretest now gives a text phrase as well as the error number when
360        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
361        failure, the offset and reason code are output.
362    
363    8.  When \R was used with a maximizing quantifier it failed to skip backwards
364        over a \r\n pair if the subsequent match failed. Instead, it just skipped
365        back over a single character (\n). This seems wrong (because it treated the
366        two characters as a single entity when going forwards), conflicts with the
367        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
368        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
369        has been changed.
370    
371    9.  Some internal refactoring has changed the processing so that the handling
372        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
373        time (the PCRE_DOTALL option was changed this way some time ago: version
374        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
375        which was always a bit of a fudge. It also means that there is one less
376        argument for the match() function, which reduces its stack requirements
377        slightly. This change also fixes an incompatibility with Perl: the pattern
378        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
379    
380    10. More internal refactoring has drastically reduced the number of recursive
381        calls to match() for possessively repeated groups such as (abc)++ when
382        using pcre_exec().
383    
384    11. While implementing 10, a number of bugs in the handling of groups were
385        discovered and fixed:
386    
387        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
388        (a|)*(?1) gave a compile-time internal error.
389        ((a|)+)+  did not notice that the outer group could match an empty string.
390        (^a|^)+   was not marked as anchored.
391        (.*a|.*)+ was not marked as matching at start or after a newline.
392    
393    12. Yet more internal refactoring has removed another argument from the match()
394        function. Special calls to this function are now indicated by setting a
395        value in a variable in the "match data" data block.
396    
397    13. Be more explicit in pcre_study() instead of relying on "default" for
398        opcodes that mean there is no starting character; this means that when new
399        ones are added and accidentally left out of pcre_study(), testing should
400        pick them up.
401    
402    14. The -s option of pcretest has been documented for ages as being an old
403        synonym of -m (show memory usage). I have changed it to mean "force study
404        for every regex", that is, assume /S for every regex. This is similar to -i
405        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
406        using it. It makes it easier to run collections of tests with and without
407        study enabled, and thereby test pcre_study() more easily. All the standard
408        tests are now run with and without -s (but some patterns can be marked as
409        "never study" - see 20 below).
410    
411    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
412        restoration of the capturing data to the outer values was not happening
413        correctly.
414    
415    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
416        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
417        pattern had matched an empty string, and so incorrectly returned a no
418        match.
419    
420    17. There was optimizing code for the last branch of non-capturing parentheses,
421        and also for the obeyed branch of a conditional subexpression, which used
422        tail recursion to cut down on stack usage. Unfortunately, now that there is
423        the possibility of (*THEN) occurring in these branches, tail recursion is
424        no longer possible because the return has to be checked for (*THEN). These
425        two optimizations have therefore been removed. [But see 8.20/11 above.]
426    
427    18. If a pattern containing \R was studied, it was assumed that \R always
428        matched two bytes, thus causing the minimum subject length to be
429        incorrectly computed because \R can also match just one byte.
430    
431    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
432        was incorrectly computed.
433    
434    20. If /S is present twice on a test pattern in pcretest input, it now
435        *disables* studying, thereby overriding the use of -s on the command line
436        (see 14 above). This is necessary for one or two tests to keep the output
437        identical in both cases.
438    
439    21. When (*ACCEPT) was used in an assertion that matched an empty string and
440        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
441    
442    22. When an atomic group that contained a capturing parenthesis was
443        successfully matched, but the branch in which it appeared failed, the
444        capturing was not being forgotten if a higher numbered group was later
445        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
446        group 1 to "a", when in fact it should be unset. This applied to multi-
447        branched capturing and non-capturing groups, repeated or not, and also to
448        positive assertions (capturing in negative assertions does not happen
449        in PCRE) and also to nested atomic groups.
450    
451    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
452        subject after a captured substring, to make it easier to tell which of a
453        number of identical substrings has been captured.
454    
455    24. The way atomic groups are processed by pcre_exec() has been changed so that
456        if they are repeated, backtracking one repetition now resets captured
457        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
458        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
459        "aaa". Previously, it would have been "a". As part of this code
460        refactoring, the way recursive calls are handled has also been changed.
461    
462    25. If an assertion condition captured any substrings, they were not passed
463        back unless some other capturing happened later. For example, if
464        (?(?=(a))a) was matched against "a", no capturing was returned.
465    
466    26. When studying a pattern that contained subroutine calls or assertions,
467        the code for finding the minimum length of a possible match was handling
468        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
469        group 1 called group 2 while simultaneously a separate group 2 called group
470        1). A stack overflow occurred in this case. I have fixed this by limiting
471        the recursion depth to 10.
472    
473    27. Updated RunTest.bat in the distribution to the version supplied by Tom
474        Fortmann. This supports explicit test numbers on the command line, and has
475        argument validation and error reporting.
476    
477    28. An instance of \X with an unlimited repeat could fail if at any point the
478        first character it looked at was a mark character.
479    
480    29. Some minor code refactoring concerning Unicode properties and scripts
481        should reduce the stack requirement of match() slightly.
482    
483    30. Added the '=' option to pcretest to check the setting of unused capturing
484        slots at the end of the pattern, which are documented as being -1, but are
485        not included in the return count.
486    
487    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
488        compiled something random. Now it gives a compile-time error (as does
489        Perl).
490    
491    32. A *MARK encountered during the processing of a positive assertion is now
492        recorded and passed back (compatible with Perl).
493    
494    33. If --only-matching or --colour was set on a pcregrep call whose pattern
495        had alternative anchored branches, the search for a second match in a line
496        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
497        matched the line "0102" twice. The same bug affected patterns that started
498        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
499        twice.
500    
501    34. Previously, PCRE did not allow quantification of assertions. However, Perl
502        does, and because of capturing effects, quantifying parenthesized
503        assertions may at times be useful. Quantifiers are now allowed for
504        parenthesized assertions.
505    
506    35. A minor code tidy in pcre_compile() when checking options for \R usage.
507    
508    36. \g was being checked for fancy things in a character class, when it should
509        just be a literal "g".
510    
511    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
512        appearance of a nested POSIX class supersedes an apparent external class.
513        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
514        unescaped square brackets may also appear as part of class names. For
515        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
516        more like Perl. (But see 8.20/1 above.)
517    
518    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
519        was because it thought it was \N{name}, which is not supported).
520    
521    39. Add minix to OS list not supporting the -S option in pcretest.
522    
523    40. PCRE tries to detect cases of infinite recursion at compile time, but it
524        cannot analyze patterns in sufficient detail to catch mutual recursions
525        such as ((?1))((?2)). There is now a runtime test that gives an error if a
526        subgroup is called recursively as a subpattern for a second time at the
527        same position in the subject string. In previous releases this might have
528        been caught by the recursion limit, or it might have run out of stack.
529    
530    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
531        happen only once. PCRE was, however incorrectly giving a compile time error
532        "recursive call could loop indefinitely" because it cannot analyze the
533        pattern in sufficient detail. The compile time test no longer happens when
534        PCRE is compiling a conditional subpattern, but actual runaway loops are
535        now caught at runtime (see 40 above).
536    
537    42. It seems that Perl allows any characters other than a closing parenthesis
538        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
539        has been changed to be the same.
540    
541    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
542        as not to get warnings when autogen.sh is called. Also changed
543        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
544    
545    44. To help people who use pcregrep to scan files containing exceedingly long
546        lines, the following changes have been made:
547    
548        (a) The default value of the buffer size parameter has been increased from
549            8K to 20K. (The actual buffer used is three times this size.)
550    
551        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
552            PCRE is built.
553    
554        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
555            to be set at run time.
556    
557        (d) Numerical values in pcregrep options can be followed by K or M, for
558            example --buffer-size=50K.
559    
560        (e) If a line being scanned overflows pcregrep's buffer, an error is now
561            given and the return code is set to 2.
562    
563    45. Add a pointer to the latest mark to the callout data block.
564    
565    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
566        partial match of an empty string instead of no match. This was specific to
567        the use of ".".
568    
569    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
570        complete match instead of a partial match. This bug was dependent on both
571        the PCRE_UTF8 and PCRE_DOTALL options being set.
572    
573    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
574        starting byte set, because \b was not being ignored.
575    
576    
577    Version 8.12 15-Jan-2011
578    ------------------------
579    
580    1.  Fixed some typos in the markup of the man pages, and wrote a script that
581        checks for such things as part of the documentation building process.
582    
583    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
584        --match-limit and --recursion-limit options (added for 8.11). In
585        particular, this made one of the standard tests fail. (The integer value
586        went into the wrong half of a long int.)
587    
588    3.  If the --colour option was given to pcregrep with -v (invert match), it
589        did strange things, either producing crazy output, or crashing. It should,
590        of course, ignore a request for colour when reporting lines that do not
591        match.
592    
593    4.  Another pcregrep bug caused similar problems if --colour was specified with
594        -M (multiline) and the pattern match finished with a line ending.
595    
596    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
597        matched in multiline mode, the following line was shown as part of the
598        match. This seems wrong, so I have changed it.
599    
600    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
601        the check for further matches in the same line (so they could be coloured)
602        to overrun the end of the current line. If another match was found, it was
603        incorrectly shown (and then shown again when found in the next line).
604    
605    7.  If pcregrep was compiled under Windows, there was a reference to the
606        function pcregrep_exit() before it was defined. I am assuming this was
607        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
608        reported by a user. I've moved the definition above the reference.
609    
610    
611    Version 8.11 10-Dec-2010
612    ------------------------
613    
614    1.  (*THEN) was not working properly if there were untried alternatives prior
615        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
616        backtracked to try for "b" instead of moving to the next alternative branch
617        at the same level (in this case, to look for "c"). The Perl documentation
618        is clear that when (*THEN) is backtracked onto, it goes to the "next
619        alternative in the innermost enclosing group".
620    
621    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
622        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
623        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
624        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
625        (*THEN).
626    
627    3.  If \s appeared in a character class, it removed the VT character from
628        the class, even if it had been included by some previous item, for example
629        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
630        of \s, but is part of the POSIX "space" class.)
631    
632    4.  A partial match never returns an empty string (because you can always
633        match an empty string at the end of the subject); however the checking for
634        an empty string was starting at the "start of match" point. This has been
635        changed to the "earliest inspected character" point, because the returned
636        data for a partial match starts at this character. This means that, for
637        example, /(?<=abc)def/ gives a partial match for the subject "abc"
638        (previously it gave "no match").
639    
640    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
641        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
642        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
643        has an implication that the given string is incomplete (because a partial
644        match is preferred over a full match). For this reason, these items now
645        give a partial match in this situation. [Aside: previously, the one case
646        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
647        match rather than a full match, which was wrong by the old rules, but is
648        now correct.]
649    
650    6.  There was a bug in the handling of #-introduced comments, recognized when
651        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
652        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
653        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
654        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
655        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
656        places in pcre_compile().
657    
658    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
659        comments when looking ahead for named forward references to subpatterns,
660        the only newline sequence it recognized was NL. It now handles newlines
661        according to the set newline convention.
662    
663    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
664        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
665        cater for a lack of strerror(). These oversights have been fixed.
666    
667    9.  Added --match-limit and --recursion-limit to pcregrep.
668    
669    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
670    
671    11. When the -o option was used, pcregrep was setting a return code of 1, even
672        when matches were found, and --line-buffered was not being honoured.
673    
674    12. Added an optional parentheses number to the -o and --only-matching options
675        of pcregrep.
676    
677    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
678        can match an empty string. The code to do it in pcretest and pcredemo
679        needed fixing:
680    
681        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
682            only one byte after an empty string match just before CRLF (this case
683            just got forgotten; "any" and "anycrlf" were OK).
684    
685        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
686            mode when an empty string match preceded an ASCII character followed by
687            a non-ASCII character. (The code for advancing by one character rather
688            than one byte was nonsense.)
689    
690        (c) The pcredemo.c sample program did not have any code at all to handle
691            the cases when CRLF is a valid newline sequence.
692    
693    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
694        as a starting offset was within the subject string. There is now a new
695        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
696        negative or greater than the length of the string. In order to test this,
697        pcretest is extended to allow the setting of negative starting offsets.
698    
699    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
700        starting offset points to the beginning of a UTF-8 character was
701        unnecessarily clumsy. I tidied it up.
702    
703    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
704        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
705    
706    17. Nobody had reported that the --include_dir option, which was added in
707        release 7.7 should have been called --include-dir (hyphen, not underscore)
708        for compatibility with GNU grep. I have changed it to --include-dir, but
709        left --include_dir as an undocumented synonym, and the same for
710        --exclude-dir, though that is not available in GNU grep, at least as of
711        release 2.5.4.
712    
713    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
714        characters from a string of bytes) have been redefined so as not to use
715        loops, in order to improve performance in some environments. At the same
716        time, I abstracted some of the common code into auxiliary macros to save
717        repetition (this should not affect the compiled code).
718    
719    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
720        compile-time error is now given if \c is not followed by an ASCII
721        character, that is, a byte less than 128. (In EBCDIC mode, the code is
722        different, and any byte value is allowed.)
723    
724    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
725        START_OPTIMIZE option, which is now allowed at compile time - but just
726        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
727        to pcregrep and other applications that have no direct access to PCRE
728        options. The new /Y option in pcretest sets this option when calling
729        pcre_compile().
730    
731    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
732        back references. Groups containing recursive back references were forced to
733        be atomic by that change, but in the case of named groups, the amount of
734        memory required was incorrectly computed, leading to "Failed: internal
735        error: code overflow". This has been fixed.
736    
737    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
738        pcretest.c, to avoid build problems in some Borland environments.
739    
740    
741    Version 8.10 25-Jun-2010
742    ------------------------
743    
744    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
745        THEN.
746    
747    2.  (*ACCEPT) was not working when inside an atomic group.
748    
749    3.  Inside a character class, \B is treated as a literal by default, but
750        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
751        causes the error). The code is unchanged, but I tidied the documentation.
752    
753    4.  Inside a character class, PCRE always treated \R and \X as literals,
754        whereas Perl faults them if its -w option is set. I have changed PCRE so
755        that it faults them when PCRE_EXTRA is set.
756    
757    5.  Added support for \N, which always matches any character other than
758        newline. (It is the same as "." when PCRE_DOTALL is not set.)
759    
760    6.  When compiling pcregrep with newer versions of gcc which may have
761        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
762        declared with attribute warn_unused_result" were given. Just casting the
763        result to (void) does not stop the warnings; a more elaborate fudge is
764        needed. I've used a macro to implement this.
765    
766    7.  Minor change to pcretest.c to avoid a compiler warning.
767    
768    8.  Added four artifical Unicode properties to help with an option to make
769        \s etc use properties (see next item). The new properties are: Xan
770        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
771    
772    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
773        use Unicode properties. (*UCP) at the start of a pattern can be used to set
774        this option. Modified pcretest to add /W to test this facility. Added
775        REG_UCP to make it available via the POSIX interface.
776    
777    10. Added --line-buffered to pcregrep.
778    
779    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
780        studied, and the match started with a letter with a code point greater than
781        127 whose first byte was different to the first byte of the other case of
782        the letter, the other case of this starting letter was not recognized
783        (#976).
784    
785    12. If a pattern that was studied started with a repeated Unicode property
786        test, for example, \p{Nd}+, there was the theoretical possibility of
787        setting up an incorrect bitmap of starting bytes, but fortunately it could
788        not have actually happened in practice until change 8 above was made (it
789        added property types that matched character-matching opcodes).
790    
791    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
792        possible starting bytes for non-anchored patterns.
793    
794    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
795        \R, and also a number of cases that involve Unicode properties, both
796        explicit and implicit when PCRE_UCP is set.
797    
798    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
799        input, it could crash or give wrong results if characters with values
800        greater than 0xc0 were present in the subject string. (Detail: it assumed
801        UTF-8 input when processing these items.)
802    
803    16. Added a lot of (int) casts to avoid compiler warnings in systems where
804        size_t is 64-bit (#991).
805    
806    17. Added a check for running out of memory when PCRE is compiled with
807        --disable-stack-for-recursion (#990).
808    
809    18. If the last data line in a file for pcretest does not have a newline on
810        the end, a newline was missing in the output.
811    
812    19. The default pcre_chartables.c file recognizes only ASCII characters (values
813        less than 128) in its various bitmaps. However, there is a facility for
814        generating tables according to the current locale when PCRE is compiled. It
815        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
816        characters, are recognized by isspace() and therefore were getting set in
817        these tables, and indeed these tables seem to approximate to ISO 8859. This
818        caused a problem in UTF-8 mode when pcre_study() was used to create a list
819        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
820        which of course cannot start UTF-8 characters. I have changed the code so
821        that only real ASCII characters (less than 128) and the correct starting
822        bytes for UTF-8 encodings are set for characters greater than 127 when in
823        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
824        altogether.)
825    
826    20. Added the /T option to pcretest so as to be able to run tests with non-
827        standard character tables, thus making it possible to include the tests
828        used for 19 above in the standard set of tests.
829    
830    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
831        reference to a subpattern the other side of a comment that contains an
832        opening parenthesis caused either an internal compiling error, or a
833        reference to the wrong subpattern.
834    
835    
836    Version 8.02 19-Mar-2010
837    ------------------------
838    
839    1.  The Unicode data tables have been updated to Unicode 5.2.0.
840    
841    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
842        configured.
843    
844    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
845        original author of that file, following a query about its status.
846    
847    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
848        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
849    
850    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
851        quantifier applied to a forward-referencing subroutine call, could compile
852        incorrect code or give the error "internal error: previously-checked
853        referenced subpattern not found".
854    
855    6.  Both MS Visual Studio and Symbian OS have problems with initializing
856        variables to point to external functions. For these systems, therefore,
857        pcre_malloc etc. are now initialized to local functions that call the
858        relevant global functions.
859    
860    7.  There were two entries missing in the vectors called coptable and poptable
861        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
862        I've fixed the data, and added a kludgy way of testing at compile time that
863        the lengths are correct (equal to the number of opcodes).
864    
865    8.  Following on from 7, I added a similar kludge to check the length of the
866        eint vector in pcreposix.c.
867    
868    9.  Error texts for pcre_compile() are held as one long string to avoid too
869        much relocation at load time. To find a text, the string is searched,
870        counting zeros. There was no check for running off the end of the string,
871        which could happen if a new error number was added without updating the
872        string.
873    
874    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
875    
876    11. \K was not working if it appeared in an atomic group or in a group that
877        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
878        \K is "not well defined" if used in an assertion. PCRE now accepts it if
879        the assertion is positive, but not if it is negative.
880    
881    12. Change 11 fortuitously reduced the size of the stack frame used in the
882        "match()" function of pcre_exec.c by one pointer. Forthcoming
883        implementation of support for (*MARK) will need an extra pointer on the
884        stack; I have reserved it now, so that the stack frame size does not
885        decrease.
886    
887    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
888        item in branch that calls a recursion is a subroutine call - as in the
889        second branch in the above example - was incorrectly given the compile-
890        time error "recursive call could loop indefinitely" because pcre_compile()
891        was not correctly checking the subroutine for matching a non-empty string.
892    
893    14. The checks for overrunning compiling workspace could trigger after an
894        overrun had occurred. This is a "should never occur" error, but it can be
895        triggered by pathological patterns such as hundreds of nested parentheses.
896        The checks now trigger 100 bytes before the end of the workspace.
897    
898    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
899    
900    
901    Version 8.01 19-Jan-2010
902    ------------------------
903    
904    1.  If a pattern contained a conditional subpattern with only one branch (in
905        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
906        computed the wrong minimum data length (which is of course zero for such
907        subpatterns). This could cause incorrect "no match" results.
908    
909    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
910        the pattern is reset in the first branch, pcre_compile() failed with
911        "internal error: code overflow at offset...". This happened only when
912        the reset was to the original external option setting. (An optimization
913        abstracts leading options settings into an external setting, which was the
914        cause of this.)
915    
916    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
917        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
918        assertion pattern did not match (meaning that the assertion was true), it
919        was incorrectly treated as false if the SKIP had been reached during the
920        matching. This also applied to assertions used as conditions.
921    
922    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
923        assertion subpattern, including such a pattern used as a condition,
924        unpredictable results occurred, instead of the error return
925        PCRE_ERROR_DFA_UITEM.
926    
927    5.  The C++ GlobalReplace function was not working like Perl for the special
928        situation when an empty string is matched. It now does the fancy magic
929        stuff that is necessary.
930    
931    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
932        removed. (These were left over from very, very early versions of PCRE.)
933    
934    7.  Some cosmetic changes to the code to make life easier when compiling it
935        as part of something else:
936    
937        (a) Change DEBUG to PCRE_DEBUG.
938    
939        (b) In pcre_compile(), rename the member of the "branch_chain" structure
940            called "current" as "current_branch", to prevent a collision with the
941            Linux macro when compiled as a kernel module.
942    
943        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
944            prevent a collision with the Linux macro when compiled as a kernel
945            module.
946    
947    8.  In pcre_compile() there are some checks for integer overflows that used to
948        cast potentially large values to (double). This has been changed to that
949        when building, a check for int64_t is made, and if it is found, it is used
950        instead, thus avoiding the use of floating point arithmetic. (There is no
951        other use of FP in PCRE.) If int64_t is not found, the fallback is to
952        double.
953    
954    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
955        2005 (difference between two addresses compared to an unsigned value).
956    
957    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
958        custom one, because of the following reported problem in Windows:
959    
960          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
961              under Win32.
962          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
963              therefore missing the function definition.
964          - The compiler thus generates a "C" signature for the test function.
965          - The linker fails to find the "C" function.
966          - PCRE fails to configure if asked to do so against libbz2.
967    
968    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
969        messages were output:
970    
971          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
972          rerunning libtoolize, to keep the correct libtool macros in-tree.
973          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
974    
975        I have done both of these things.
976    
977    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
978        most of the time, it *can* run out if it is given a pattern that contains a
979        runaway infinite recursion. I updated the discussion in the pcrestack man
980        page.
981    
982    13. Now that we have gone to the x.xx style of version numbers, the minor
983        version may start with zero. Using 08 or 09 is a bad idea because users
984        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
985        interpreted as invalid octal numbers. I've updated the previous comment in
986        configure.ac, and also added a check that gives an error if 08 or 09 are
987        used.
988    
989    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
990        causing partial matching to fail when the end of the subject matched \W
991        in a UTF-8 pattern where \W was quantified with a minimum of 3.
992    
993    15. There were some discrepancies between the declarations in pcre_internal.h
994        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
995        their definitions. The declarations used "const uschar *" and the
996        definitions used USPTR. Even though USPTR is normally defined as "const
997        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
998        reported that: "This difference in casting confuses some C++ compilers, for
999        example, SunCC recognizes above declarations as different functions and
1000        generates broken code for hbpcre." I have changed the declarations to use
1001        USPTR.
1002    
1003    16. GNU libtool is named differently on some systems. The autogen.sh script now
1004        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1005        (FreeBSD).
1006    
1007    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1008        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1009        comment: "Figure out how to create a longlong from a string: strtoll and
1010        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1011        instance, but it only takes 2 args instead of 3!"
1012    
1013    18. A subtle bug concerned with back references has been fixed by a change of
1014        specification, with a corresponding code fix. A pattern such as
1015        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1016        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1017        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1018        same bug. Such groups have to be quantified to be useful, or contained
1019        inside another quantified group. (If there's no repetition, the reference
1020        can never match.) The problem arises because, having left the group and
1021        moved on to the rest of the pattern, a later failure that backtracks into
1022        the group uses the captured value from the final iteration of the group
1023        rather than the correct earlier one. I have fixed this in PCRE by forcing
1024        any group that contains a reference to itself to be an atomic group; that
1025        is, there cannot be any backtracking into it once it has completed. This is
1026        similar to recursive and subroutine calls.
1027    
1028    
1029    Version 8.00 19-Oct-09
1030    ----------------------
1031    
1032    1.  The table for translating pcre_compile() error codes into POSIX error codes
1033        was out-of-date, and there was no check on the pcre_compile() error code
1034        being within the table. This could lead to an OK return being given in
1035        error.
1036    
1037    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1038        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1039        in a Windows environment.
1040    
1041    3.  The pcregrep --count option prints the count for each file even when it is
1042        zero, as does GNU grep. However, pcregrep was also printing all files when
1043        --files-with-matches was added. Now, when both options are given, it prints
1044        counts only for those files that have at least one match. (GNU grep just
1045        prints the file name in this circumstance, but including the count seems
1046        more useful - otherwise, why use --count?) Also ensured that the
1047        combination -clh just lists non-zero counts, with no names.
1048    
1049    4.  The long form of the pcregrep -F option was incorrectly implemented as
1050        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1051        but it seems right to fix it, and I didn't think it was worth preserving
1052        the old behaviour.
1053    
1054    5.  The command line items --regex=pattern and --regexp=pattern were not
1055        recognized by pcregrep, which required --regex pattern or --regexp pattern
1056        (with a space rather than an '='). The man page documented the '=' forms,
1057        which are compatible with GNU grep; these now work.
1058    
1059    6.  No libpcreposix.pc file was created for pkg-config; there was just
1060        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1061    
1062    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1063        when UCP support is not needed, by modifying the Python script that
1064        generates it from Unicode data files. This should not matter if the module
1065        is correctly used as a library, but I received one complaint about 50K of
1066        unwanted data. My guess is that the person linked everything into his
1067        program rather than using a library. Anyway, it does no harm.
1068    
1069    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1070        was a minimum greater than 1 for a wide character in a possessive
1071        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1072        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1073        character. Chaos in the form of incorrect output or a compiling loop could
1074        result.
1075    
1076    9.  The restrictions on what a pattern can contain when partial matching is
1077        requested for pcre_exec() have been removed. All patterns can now be
1078        partially matched by this function. In addition, if there are at least two
1079        slots in the offset vector, the offset of the earliest inspected character
1080        for the match and the offset of the end of the subject are set in them when
1081        PCRE_ERROR_PARTIAL is returned.
1082    
1083    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1084        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1085        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1086        and may be more useful for multi-segment matching.
1087    
1088    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1089        used to be given if ever the end of the subject was reached; now it is
1090        given only if matching could not proceed because another character was
1091        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1092        string "Z", which now yields "no match" instead of "partial match". In the
1093        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1094        final character ended with (*FAIL).
1095    
1096    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1097        if the pattern had a "must contain" character that was already found in the
1098        earlier partial match, unless partial matching was again requested. For
1099        example, with the pattern /dog.(body)?/, the "must contain" character is
1100        "g". If the first part-match was for the string "dog", restarting with
1101        "sbody" failed. This bug has been fixed.
1102    
1103    13. The string returned by pcre_dfa_exec() after a partial match has been
1104        changed so that it starts at the first inspected character rather than the
1105        first character of the match. This makes a difference only if the pattern
1106        starts with a lookbehind assertion or \b or \B (\K is not supported by
1107        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1108        matching functions compatible, and I think it's the right thing to do.
1109    
1110    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1111        so that the demonstration program is easily available in environments where
1112        PCRE has not been installed from source.
1113    
1114    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1115        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1116        library.
1117    
1118    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1119        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1120        is not the first non-POSIX option to be added. Clearly some people find
1121        these options useful.
1122    
1123    17. If a caller to the POSIX matching function regexec() passes a non-zero
1124        value for nmatch with a NULL value for pmatch, the value of
1125        nmatch is forced to zero.
1126    
1127    18. RunGrepTest did not have a test for the availability of the -u option of
1128        the diff command, as RunTest does. It now checks in the same way as
1129        RunTest, and also checks for the -b option.
1130    
1131    19. If an odd number of negated classes containing just a single character
1132        interposed, within parentheses, between a forward reference to a named
1133        subpattern and the definition of the subpattern, compilation crashed with
1134        an internal error, complaining that it could not find the referenced
1135        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1136        [The bug was that it was starting one character too far in when skipping
1137        over the character class, thus treating the ] as data rather than
1138        terminating the class. This meant it could skip too much.]
1139    
1140    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1141        /g option in pcretest when the pattern contains \K, which makes it possible
1142        to have an empty string match not at the start, even when the pattern is
1143        anchored. Updated pcretest and pcredemo to use this option.
1144    
1145    21. If the maximum number of capturing subpatterns in a recursion was greater
1146        than the maximum at the outer level, the higher number was returned, but
1147        with unset values at the outer level. The correct (outer level) value is
1148        now given.
1149    
1150    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1151        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1152        make it do so. The string so far is captured, making this feature
1153        compatible with Perl.
1154    
1155    23. The tests have been re-organized, adding tests 11 and 12, to make it
1156        possible to check the Perl 5.10 features against Perl 5.10.
1157    
1158    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1159        pattern matches a fixed length string. PCRE did not allow this; now it
1160        does. Neither allows recursion.
1161    
1162    25. I finally figured out how to implement a request to provide the minimum
1163        length of subject string that was needed in order to match a given pattern.
1164        (It was back references and recursion that I had previously got hung up
1165        on.) This code has now been added to pcre_study(); it finds a lower bound
1166        to the length of subject needed. It is not necessarily the greatest lower
1167        bound, but using it to avoid searching strings that are too short does give
1168        some useful speed-ups. The value is available to calling programs via
1169        pcre_fullinfo().
1170    
1171    26. While implementing 25, I discovered to my embarrassment that pcretest had
1172        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1173        study optimizations had never been tested with that matching function.
1174        Oops. What is worse, even when it was passed study data, there was a bug in
1175        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1176        were also very few tests of studied patterns with pcre_dfa_exec().
1177    
1178    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1179        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1180        on the other side of the coin, they are no longer allowed to have different
1181        names, because these cannot be distinguished in PCRE, and this has caused
1182        confusion. (This is a difference from Perl.)
1183    
1184    28. When duplicate subpattern names are present (necessarily with different
1185        numbers, as required by 27 above), and a test is made by name in a
1186        conditional pattern, either for a subpattern having been matched, or for
1187        recursion in such a pattern, all the associated numbered subpatterns are
1188        tested, and the overall condition is true if the condition is true for any
1189        one of them. This is the way Perl works, and is also more like the way
1190        testing by number works.
1191    
1192    
1193    Version 7.9 11-Apr-09
1194    ---------------------
1195    
1196    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1197        (pcretest), all targets were linked against these libraries. This included
1198        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1199        libraries. This caused unwanted dependencies to be created. This problem
1200        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1201        pcretest is linked with readline.
1202    
1203    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1204        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1205        moved outside it again, because FALSE and TRUE are already defined in AIX,
1206        but BOOL is not.
1207    
1208    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1209        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1210    
1211    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1212        hyphens) following file names and line numbers when outputting matching
1213        lines. This is not true; no spaces are inserted. I have also clarified the
1214        wording for the --colour (or --color) option.
1215    
1216    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1217        was not coloured; this is different to GNU grep, so I have changed it to be
1218        the same.
1219    
1220    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1221        each matching line was coloured. Now it goes on to look for further matches
1222        of any of the test patterns, which is the same behaviour as GNU grep.
1223    
1224    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1225        doesn't make sense to accept an empty string match in pcregrep, so I have
1226        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1227        seems to be how GNU grep behaves.
1228    
1229    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1230        start or after a newline", because the conditional assertion was not being
1231        correctly handled. The rule now is that both the assertion and what follows
1232        in the first alternative must satisfy the test.
1233    
1234    9.  If auto-callout was enabled in a pattern with a conditional group whose
1235        condition was an assertion, PCRE could crash during matching, both with
1236        pcre_exec() and pcre_dfa_exec().
1237    
1238    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1239        used for matching.
1240    
1241    11. Unicode property support in character classes was not working for
1242        characters (bytes) greater than 127 when not in UTF-8 mode.
1243    
1244    12. Added the -M command line option to pcretest.
1245    
1246    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1247    
1248    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1249    
1250    16. Added comments and documentation about mis-use of no_arg in the C++
1251        wrapper.
1252    
1253    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1254        from Martin Jerabek that uses macro names for all relevant character and
1255        string constants.
1256    
1257    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1258        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1259        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1260        these, but not everybody uses configure.
1261    
1262    19. A conditional group that had only one branch was not being correctly
1263        recognized as an item that could match an empty string. This meant that an
1264        enclosing group might also not be so recognized, causing infinite looping
1265        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1266        with the subject "ab", where knowledge that the repeated group can match
1267        nothing is needed in order to break the loop.
1268    
1269    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1270        exec(), but without supplying a callout function, matching went wrong.
1271    
1272    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1273        leak if the size of the offset vector was greater than 30. When the vector
1274        is smaller, the saved offsets during recursion go onto a local stack
1275        vector, but for larger vectors malloc() is used. It was failing to free
1276        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1277        error, in fact).
1278    
1279    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1280        heapframe that is used only when UTF-8 support is enabled. This caused no
1281        problem, but was untidy.
1282    
1283    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1284        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1285        included within another project.
1286    
1287    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1288        slightly modified by me:
1289    
1290          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1291              not building pcregrep.
1292    
1293          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1294              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1295    
1296    25. Forward references, both numeric and by name, in patterns that made use of
1297        duplicate group numbers, could behave incorrectly or give incorrect errors,
1298        because when scanning forward to find the reference group, PCRE was not
1299        taking into account the duplicate group numbers. A pattern such as
1300        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1301    
1302    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1303        the feature of a custom pointer more persuasive (as requested by a user).
1304    
1305    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1306        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1307        pre-defined.
1308    
1309    28. Added support for (*UTF8) at the start of a pattern.
1310    
1311    29. Arrange for flags added by the "release type" setting in CMake to be shown
1312        in the configuration summary.
1313    
1314    
1315    Version 7.8 05-Sep-08
1316    ---------------------
1317    
1318    1.  Replaced UCP searching code with optimized version as implemented for Ad
1319        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1320        stage table and inline lookup instead of a function, giving speed ups of 2
1321        to 5 times on some simple patterns that I tested. Permission was given to
1322        distribute the MultiStage2.py script that generates the tables (it's not in
1323        the tarball, but is in the Subversion repository).
1324    
1325    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1326        scripts.
1327    
1328    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1329        a group with a zero qualifier. The result of the study could be incorrect,
1330        or the function might crash, depending on the pattern.
1331    
1332    4.  Caseless matching was not working for non-ASCII characters in back
1333        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1334        It now works when Unicode Property Support is available.
1335    
1336    5.  In pcretest, an escape such as \x{de} in the data was always generating
1337        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1338        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1339        truncation.
1340    
1341    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1342    
1343    7.  Added two (int) casts to pcregrep when printing the difference of two
1344        pointers, in case they are 64-bit values.
1345    
1346    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1347        test 2 if it fails.
1348    
1349    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1350        and a #define of that name to empty if it is not externally set. This is to
1351        allow users of MSVC to set it if necessary.
1352    
1353    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1354        the convenience functions in the pcre_get.c source file.
1355    
1356    11. An option change at the start of a pattern that had top-level alternatives
1357        could cause overwriting and/or a crash. This command provoked a crash in
1358        some environments:
1359    
1360          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1361    
1362        This potential security problem was recorded as CVE-2008-2371.
1363    
1364    12. For a pattern where the match had to start at the beginning or immediately
1365        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1366        pcre_dfa_exec() could read past the end of the passed subject if there was
1367        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1368        pcretest so that it places the subject at the end of its malloc-ed buffer.
1369    
1370    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1371        exec() might read past the end of the data buffer in UTF-8 mode.
1372    
1373    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1374        the data contained the byte 0x85 as part of a UTF-8 character within its
1375        first line. This applied both to normal and DFA matching.
1376    
1377    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1378        /^[^d]*?$/8 failed to match "abc".
1379    
1380    16. Added a missing copyright notice to pcrecpp_internal.h.
1381    
1382    17. Make it more clear in the documentation that values returned from
1383        pcre_exec() in ovector are byte offsets, not character counts.
1384    
1385    18. Tidied a few places to stop certain compilers from issuing warnings.
1386    
1387    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1388        supplied by Stefan Weber. I made a further small update for 7.8 because
1389        there is a change of source arrangements: the pcre_searchfuncs.c module is
1390        replaced by pcre_ucd.c.
1391    
1392    
1393    Version 7.7 07-May-08
1394    ---------------------
1395    
1396    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1397        a string to a long long, pretend we don't even have a long long." This is
1398        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1399    
1400    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1401        pre-7.6 versions, which defined a global no_arg variable instead of putting
1402        it in the RE class. (See also #8 below.)
1403    
1404    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1405        Lopes.
1406    
1407    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1408    
1409        (1) The include/exclude patterns were being applied to the whole pathnames
1410            of files, instead of just to the final components.
1411    
1412        (2) If there was more than one level of directory, the subdirectories were
1413            skipped unless they satisfied the include/exclude conditions. This is
1414            inconsistent with GNU grep (and could even be seen as contrary to the
1415            pcregrep specification - which I improved to make it absolutely clear).
1416            The action now is always to scan all levels of directory, and just
1417            apply the include/exclude patterns to regular files.
1418    
1419    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1420        --exclude_dir in the tests to avoid scanning .svn directories.
1421    
1422    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1423        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1424        doesn't support NULs in patterns.
1425    
1426    7.  Added some missing "const"s to declarations of static tables in
1427        pcre_compile.c and pcre_dfa_exec.c.
1428    
1429    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1430        caused by fix #2  above. (Subsequently also a second patch to fix the
1431        first patch. And a third patch - this was a messy problem.)
1432    
1433    9.  Applied Craig's patch to remove the use of push_back().
1434    
1435    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1436        matching function regexec().
1437    
1438    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1439        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1440        references. PCRE supports relative numbers with this syntax (I don't think
1441        Oniguruma does).
1442    
1443    12. Previously, a group with a zero repeat such as (...){0} was completely
1444        omitted from the compiled regex. However, this means that if the group
1445        was called as a subroutine from elsewhere in the pattern, things went wrong
1446        (an internal error was given). Such groups are now left in the compiled
1447        pattern, with a new opcode that causes them to be skipped at execution
1448        time.
1449    
1450    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1451        to the way PCRE behaves:
1452    
1453        (a) A lone ] character is dis-allowed (Perl treats it as data).
1454    
1455        (b) A back reference to an unmatched subpattern matches an empty string
1456            (Perl fails the current match path).
1457    
1458        (c) A data ] in a character class must be notated as \] because if the
1459            first data character in a class is ], it defines an empty class. (In
1460            Perl it is not possible to have an empty class.) The empty class []
1461            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1462            The negative empty class [^] matches any one character, independently
1463            of the DOTALL setting.
1464    
1465    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1466        non-existent subpattern following a character class starting with ']' and
1467        containing () gave an internal compiling error instead of "reference to
1468        non-existent subpattern". Fortunately, when the pattern did exist, the
1469        compiled code was correct. (When scanning forwards to check for the
1470        existencd of the subpattern, it was treating the data ']' as terminating
1471        the class, so got the count wrong. When actually compiling, the reference
1472        was subsequently set up correctly.)
1473    
1474    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1475        it was being rejected as not supported by pcre_dfa_exec(), even though
1476        other assertions are supported. I have made pcre_dfa_exec() support
1477        (*FAIL).
1478    
1479    16. The implementation of 13c above involved the invention of a new opcode,
1480        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1481        cannot be changed at match time, I realized I could make a small
1482        improvement to matching performance by compiling OP_ALLANY instead of
1483        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1484        on the OP_ANY path.
1485    
1486    17. Compiling pcretest on Windows with readline support failed without the
1487        following two fixes: (1) Make the unistd.h include conditional on
1488        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1489    
1490    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1491        ncurses library to be included for pcretest when ReadLine support is
1492        requested, but also to allow for it to be overridden. This patch came from
1493        Daniel Bergström.
1494    
1495    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1496        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1497        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1498        spotting this.
1499    
1500    
1501    Version 7.6 28-Jan-08
1502    ---------------------
1503    
1504    1.  A character class containing a very large number of characters with
1505        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1506        overflow.
1507    
1508    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1509        HAVE_LONG_LONG is not defined.
1510    
1511    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1512        bring them up to date and include new features. This patch includes:
1513    
1514        - Fixed PH's badly added libz and libbz2 support.
1515        - Fixed a problem with static linking.
1516        - Added pcredemo. [But later removed - see 7 below.]
1517        - Fixed dftables problem and added an option.
1518        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1519            HAVE_LONG_LONG.
1520        - Added readline support for pcretest.
1521        - Added an listing of the option settings after cmake has run.
1522    
1523    4.  A user submitted a patch to Makefile that makes it easy to create
1524        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1525        Makefile.am that cause it to include this special target, without
1526        affecting anything else. Note that the same mingw target plus all
1527        the other distribution libraries and programs are now supported
1528        when configuring with CMake (see 6 below) instead of with
1529        Configure/Make.
1530    
1531    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1532        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1533        exported in the Windows port". It has not yet been confirmed that the patch
1534        solves the problem, but it does no harm.
1535    
1536    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1537        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1538        with CMake, and also correct the comment about stack recursion.
1539    
1540    7.  Remove the automatic building of pcredemo from the ./configure system and
1541        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1542        of a program that users should build themselves after PCRE is installed, so
1543        building it automatically is not really right. What is more, it gave
1544        trouble in some build environments.
1545    
1546    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1547    
1548    
1549    Version 7.5 10-Jan-08
1550    ---------------------
1551    
1552    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1553        values in parens when parsing an RE using the C++ wrapper."
1554    
1555    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1556        Characters greater than 255 were excluded from the class instead of being
1557        included.
1558    
1559    3.  The same bug as (2) above applied to negated POSIX classes such as
1560        [:^space:].
1561    
1562    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1563        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1564        I have changed it.
1565    
1566    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1567        first named subpattern) and a construct such as (?&a) would reference the
1568        first named subpattern whose name started with "a" (in other words, the
1569        length check was missing). Both these problems are fixed. "Subpattern name
1570        expected" is now given for (?&) (a zero-length name), and this patch also
1571        makes it give the same error for \k'' (previously it complained that that
1572        was a reference to a non-existent subpattern).
1573    
1574    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1575        this is right because (?- can be followed by option settings as well as by
1576        digits. I have, however, made the messages clearer.
1577    
1578    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1579        than the number used in the conditional) now cause a compile-time error.
1580        This is actually not compatible with Perl, which accepts such patterns, but
1581        treats the conditional as always being FALSE (as PCRE used to), but it
1582        seems to me that giving a diagnostic is better.
1583    
1584    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1585        and messages.
1586    
1587    9.  Fix two occurrences of "backslash" in comments that should have been
1588        "backspace".
1589    
1590    10. Remove two redundant lines of code that can never be obeyed (their function
1591        was moved elsewhere).
1592    
1593    11. The program that makes PCRE's Unicode character property table had a bug
1594        which caused it to generate incorrect table entries for sequences of
1595        characters that have the same character type, but are in different scripts.
1596        It amalgamated them into a single range, with the script of the first of
1597        them. In other words, some characters were in the wrong script. There were
1598        thirteen such cases, affecting characters in the following ranges:
1599    
1600          U+002b0 - U+002c1
1601          U+0060c - U+0060d
1602          U+0061e - U+00612
1603          U+0064b - U+0065e
1604          U+0074d - U+0076d
1605          U+01800 - U+01805
1606          U+01d00 - U+01d77
1607          U+01d9b - U+01dbf
1608          U+0200b - U+0200f
1609          U+030fc - U+030fe
1610          U+03260 - U+0327f
1611          U+0fb46 - U+0fbb1
1612          U+10450 - U+1049d
1613    
1614    12. The -o option (show only the matching part of a line) for pcregrep was not
1615        compatible with GNU grep in that, if there was more than one match in a
1616        line, it showed only the first of them. It now behaves in the same way as
1617        GNU grep.
1618    
1619    13. If the -o and -v options were combined for pcregrep, it printed a blank
1620        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1621        does the same. The return code can be used to tell if there were any
1622        non-matching lines.
1623    
1624    14. Added --file-offsets and --line-offsets to pcregrep.
1625    
1626    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1627        infinitely looping recursion. The bug was that positive lookaheads were not
1628        being skipped when checking for a possible empty match (negative lookaheads
1629        and both kinds of lookbehind were skipped).
1630    
1631    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1632        inclusion of <windows.h> to before rather than after the definition of
1633        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1634    
1635    17. Specifying a possessive quantifier with a specific limit for a Unicode
1636        character property caused pcre_compile() to compile bad code, which led at
1637        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1638        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1639        caused the error; without that there was no problem.
1640    
1641    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1642    
1643    19. Added --enable-pcretest-libreadline.
1644    
1645    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1646        RE::GlobalReplace(). As a result, the number of replacements returned was
1647        double what it should be. I removed one of the increments, but Craig sent a
1648        later patch that removed the other one (the right fix) and added unit tests
1649        that check the return values (which was not done before).
1650    
1651    21. Several CMake things:
1652    
1653        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1654            the names libpcre and libpcreposix, not just pcre and pcreposix.
1655    
1656        (2) The above change means that pcretest and pcregrep are now correctly
1657            linked with the newly-built libraries, not previously installed ones.
1658    
1659        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1660    
1661    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1662        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1663        UTF-8 newline character). The key issue is that the pattern starts .*;
1664        this means that the match must be either at the beginning, or after a
1665        newline. The bug was in the code for advancing after a failed match and
1666        checking that the new position followed a newline. It was not taking
1667        account of UTF-8 characters correctly.
1668    
1669    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1670        character classes. PCRE was not treating the sequence [:...:] as a
1671        character class unless the ... were all letters. Perl, however, seems to
1672        allow any characters between [: and :], though of course it rejects as
1673        unknown any "names" that contain non-letters, because all the known class
1674        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1675        for example, whereas PCRE did not - it did not recognize a POSIX character
1676        class. This seemed a bit dangerous, so the code has been changed to be
1677        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1678        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1679        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1680        Perl does, and where it didn't before.
1681    
1682    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1683        Windows environments %n is disabled by default.
1684    
1685    
1686    Version 7.4 21-Sep-07
1687    ---------------------
1688    
1689    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1690        means that a class such as [\s] counted as "explicit reference to CR or
1691        LF". That isn't really right - the whole point of the change was to try to
1692        help when there was an actual mention of one of the two characters. So now
1693        the change happens only if \r or \n (or a literal CR or LF) character is
1694        encountered.
1695    
1696    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1697        of both had grown to the point where there were only 3 bits left.
1698        Fortunately, there was spare space in the data structure, and so I have
1699        moved the internal flags into a new 16-bit field to free up more option
1700        bits.
1701    
1702    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1703        but did not set the internal JCHANGED flag - either of these is enough to
1704        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1705        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1706        start sets both bits.
1707    
1708    4.  Added options (at build time, compile time, exec time) to change \R from
1709        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1710    
1711    5.  doc/pcresyntax.html was missing from the distribution.
1712    
1713    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1714        compatibility, even though it is no longer used.
1715    
1716    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1717        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1718        windows.h file is present (where different names are used). [This was
1719        reversed later after testing - see 16 below.]
1720    
1721    8.  Changed all #include <config.h> to #include "config.h". There were also
1722        some further <pcre.h> cases that I changed to "pcre.h".
1723    
1724    9.  When pcregrep was used with the --colour option, it missed the line ending
1725        sequence off the lines that it output.
1726    
1727    10. It was pointed out to me that arrays of string pointers cause lots of
1728        relocations when a shared library is dynamically loaded. A technique of
1729        using a single long string with a table of offsets can drastically reduce
1730        these. I have refactored PCRE in four places to do this. The result is
1731        dramatic:
1732    
1733          Originally:                          290
1734          After changing UCP table:            187
1735          After changing error message table:   43
1736          After changing table of "verbs"       36
1737          After changing table of Posix names   22
1738    
1739        Thanks to the folks working on Gregex for glib for this insight.
1740    
1741    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1742        unicode-properties was also set.
1743    
1744    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1745    
1746    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1747        checked only for CRLF.
1748    
1749    14. Added casts to pcretest.c to avoid compiler warnings.
1750    
1751    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1752    
1753    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1754        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1755        entirely. This removes changes made in 7 above.
1756    
1757    17. The CMake files have been updated, and there is now more information about
1758        building with CMake in the NON-UNIX-USE document.
1759    
1760    
1761    Version 7.3 28-Aug-07
1762    ---------------------
1763    
1764     1. In the rejigging of the build system that eventually resulted in 7.1, the
1765        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1766        brackets there is not right, since it causes compilers to look for an
1767        installed pcre.h, not the version that is in the source that is being
1768        compiled (which of course may be different). I have changed it back to:
1769    
1770          #include "pcre.h"
1771    
1772        I have a vague recollection that the change was concerned with compiling in
1773        different directories, but in the new build system, that is taken care of
1774        by the VPATH setting the Makefile.
1775    
1776     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1777        when the subject happened to end in the byte 0x85 (e.g. if the last
1778        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1779        characters but of course it shouldn't be taken as a newline when it is part
1780        of another character. The bug was that, for an unlimited repeat of . in
1781        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1782        characters when looking for a newline.
1783    
1784     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1785    
1786     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1787        in debug output.
1788    
1789     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1790        long printing in the pcrecpp unittest when running under MinGW.
1791    
1792     6. ESC_K was left out of the EBCDIC table.
1793    
1794     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1795        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1796        limit also applies to "virtual nesting" when a pattern is recursive, and in
1797        this case 1000 isn't so big. I have been able to remove this limit at the
1798        expense of backing off one optimization in certain circumstances. Normally,
1799        when pcre_exec() would call its internal match() function recursively and
1800        immediately return the result unconditionally, it uses a "tail recursion"
1801        feature to save stack. However, when a subpattern that can match an empty
1802        string has an unlimited repetition quantifier, it no longer makes this
1803        optimization. That gives it a stack frame in which to save the data for
1804        checking that an empty string has been matched. Previously this was taken
1805        from the 1000-entry workspace that had been reserved. So now there is no
1806        explicit limit, but more stack is used.
1807    
1808     8. Applied Daniel's patches to solve problems with the import/export magic
1809        syntax that is required for Windows, and which was going wrong for the
1810        pcreposix and pcrecpp parts of the library. These were overlooked when this
1811        problem was solved for the main library.
1812    
1813     9. There were some crude static tests to avoid integer overflow when computing
1814        the size of patterns that contain repeated groups with explicit upper
1815        limits. As the maximum quantifier is 65535, the maximum group length was
1816        set at 30,000 so that the product of these two numbers did not overflow a
1817        32-bit integer. However, it turns out that people want to use groups that
1818        are longer than 30,000 bytes (though not repeat them that many times).
1819        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1820        made it possible to implement the integer overflow checks in a much more
1821        dynamic way, which I have now done. The artificial limitation on group
1822        length has been removed - we now have only the limit on the total length of
1823        the compiled pattern, which depends on the LINK_SIZE setting.
1824    
1825    10. Fixed a bug in the documentation for get/copy named substring when
1826        duplicate names are permitted. If none of the named substrings are set, the
1827        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1828        empty string.
1829    
1830    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1831        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1832        because the ] is interpreted as the first data character and the
1833        terminating ] is not found. PCRE has been made compatible with Perl in this
1834        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1835        cause memory overwriting.
1836    
1837    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1838        string has been matched (to stop an infinite loop). It was not recognizing
1839        a conditional subpattern that could match an empty string if that
1840        subpattern was within another subpattern. For example, it looped when
1841        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1842        condition was not nested. This bug has been fixed.
1843    
1844    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1845        past the start of the subject in the presence of bytes with the top bit
1846        set, for example "\x8aBCD".
1847    
1848    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1849        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1850    
1851    14. Optimized (?!) to (*FAIL).
1852    
1853    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1854        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1855        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1856        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1857        does: it's just the validity check that is more restrictive.
1858    
1859    16. Inserted checks for integer overflows during escape sequence (backslash)
1860        processing, and also fixed erroneous offset values for syntax errors during
1861        backslash processing.
1862    
1863    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1864        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1865    
1866    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1867        caused an overrun.
1868    
1869    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1870        something other than just ASCII characters) inside a group that had an
1871        unlimited repeat caused a loop at compile time (while checking to see
1872        whether the group could match an empty string).
1873    
1874    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1875        [\P{Any}] did so. (Error in the code for printing property names.)
1876    
1877    21. An orphan \E inside a character class could cause a crash.
1878    
1879    22. A repeated capturing bracket such as (A)? could cause a wild memory
1880        reference during compilation.
1881    
1882    23. There are several functions in pcre_compile() that scan along a compiled
1883        expression for various reasons (e.g. to see if it's fixed length for look
1884        behind). There were bugs in these functions when a repeated \p or \P was
1885        present in the pattern. These operators have additional parameters compared
1886        with \d, etc, and these were not being taken into account when moving along
1887        the compiled data. Specifically:
1888    
1889        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1890            length.
1891    
1892        (b) An item such as \pL+ within a repeated group could cause crashes or
1893            loops.
1894    
1895        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1896            "reference to non-existent subpattern" error.
1897    
1898        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1899    
1900    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1901        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1902    
1903    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1904    
1905    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1906        character were causing crashes (broken optimization).
1907    
1908    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1909        \p or \P) caused a compile-time loop.
1910    
1911    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1912        break. For example, the unstudied pattern [\r\n]A does not match the string
1913        "\r\nA" because change 7.0/46 below moves the current point on by two
1914        characters after failing to match at the start. However, the pattern \nA
1915        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1916        the same is true. There doesn't seem any very clean way out of this, but
1917        what I have chosen to do makes the common cases work: PCRE now takes note
1918        of whether there can be an explicit match for \r or \n anywhere in the
1919        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1920        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1921        pattern has explicit CR or LF references.
1922    
1923    29. Added (*CR) etc for changing newline setting at start of pattern.
1924    
1925    
1926    Version 7.2 19-Jun-07
1927    ---------------------
1928    
1929     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1930        which is apparently normally available under Windows.
1931    
1932     2. Re-jig the pcregrep tests with different newline settings in an attempt
1933        to make them independent of the local environment's newline setting.
1934    
1935     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1936    
1937     4. Some of the "internals" tests were previously cut out when the link size
1938        was not 2, because the output contained actual offsets. The recent new
1939        "Z" feature of pcretest means that these can be cut out, making the tests
1940        usable with all link sizes.
1941    
1942     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1943        stack recursion. This gives a massive performance boost under BSD, but just
1944        a small improvement under Linux. However, it saves one field in the frame
1945        in all cases.
1946    
1947     6. Added more features from the forthcoming Perl 5.10:
1948    
1949        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1950            recursion call. It refers to the nth most recently opened parentheses.
1951    
1952        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1953            to be opened parentheses.
1954    
1955        (c) Conditions that refer to capturing parentheses can be specified
1956            relatively, for example, (?(-2)... or (?(+3)...
1957    
1958        (d) \K resets the start of the current match so that everything before
1959            is not part of it.
1960    
1961        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1962    
1963        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1964            reference syntax.
1965    
1966        (g) (?| introduces a group in which the numbering of parentheses in each
1967            alternative starts with the same number.
1968    
1969        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1970    
1971     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1972        PCRE_INFO_JCHANGED.
1973    
1974     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1975        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1976        for detecting groups that can match an empty string.
1977    
1978     9. A pattern with a very large number of alternatives (more than several
1979        hundred) was running out of internal workspace during the pre-compile
1980        phase, where pcre_compile() figures out how much memory will be needed. A
1981        bit of new cunning has reduced the workspace needed for groups with
1982        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1983        workspace instead of running out of the 4096 that are available.
1984    
1985    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1986    
1987    11. Applied patch from Google to remove an optimization that didn't quite work.
1988        The report of the bug said:
1989    
1990          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1991          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1992          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1993    
1994    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1995        it matched the wrong number of bytes.
1996    
1997    
1998    Version 7.1 24-Apr-07
1999    ---------------------
2000    
2001     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
2002        that is more "standard", making use of automake and other Autotools. There
2003        is some re-arrangement of the files and adjustment of comments consequent
2004        on this.
2005    
2006     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
2007        for recursive directory scanning broke on some systems because the files
2008        are not scanned in any specific order and on different systems the order
2009        was different. A call to "sort" has been inserted into RunGrepTest for the
2010        approprate test as a short-term fix. In the longer term there may be an
2011        alternative.
2012    
2013     3. I had an email from Eric Raymond about problems translating some of PCRE's
2014        man pages to HTML (despite the fact that I distribute HTML pages, some
2015        people do their own conversions for various reasons). The problems
2016        concerned the use of low-level troff macros .br and .in. I have therefore
2017        removed all such uses from the man pages (some were redundant, some could
2018        be replaced by .nf/.fi pairs). The 132html script that I use to generate
2019        HTML has been updated to handle .nf/.fi and to complain if it encounters
2020        .br or .in.
2021    
2022     4. Updated comments in configure.ac that get placed in config.h.in and also
2023        arranged for config.h to be included in the distribution, with the name
2024        config.h.generic, for the benefit of those who have to compile without
2025        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
2026    
2027     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
2028        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
2029        makevp.bat for the current PCRE, using the additional files
2030        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
2031    
2032     6. A Windows user reported a minor discrepancy with test 2, which turned out
2033        to be caused by a trailing space on an input line that had got lost in his
2034        copy. The trailing space was an accident, so I've just removed it.
2035    
2036     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
2037        that is needed.
2038    
2039     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
2040        as "const" (a) because they are and (b) because it helps the PHP
2041        maintainers who have recently made a script to detect big data structures
2042        in the php code that should be moved to the .rodata section. I remembered
2043        to update Builducptable as well, so it won't revert if ucptable.h is ever
2044        re-created.
2045    
2046     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
2047        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
2048        order to be able to cut out the UTF-8 tables in the latter when UTF-8
2049        support is not required. This saves 1.5-2K of code, which is important in
2050        some applications.
2051    
2052        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
2053        so as not to refer to the tables, even though these functions will never be
2054        called when UTF-8 support is disabled. Otherwise there are problems with a
2055        shared library.
2056    
2057    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
2058    
2059        (a) It was defining its arguments as char * instead of void *.
2060    
2061        (b) It was assuming that all moves were upwards in memory; this was true
2062            a long time ago when I wrote it, but is no longer the case.
2063    
2064        The emulated memove() is provided for those environments that have neither
2065        memmove() nor bcopy(). I didn't think anyone used it these days, but that
2066        is clearly not the case, as these two bugs were recently reported.
2067    
2068    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
2069        and Detrail to create the HTML documentation, the .txt form of the man
2070        pages, and it removes trailing spaces from listed files. It also creates
2071        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
2072        case, it wraps all the #defines with #ifndefs. This script should be run
2073        before "make dist".
2074    
2075    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
2076        with Unicode property support.
2077    
2078        (a) For a maximizing quantifier, if the two different cases of the
2079            character were of different lengths in their UTF-8 codings (there are
2080            some cases like this - I found 11), and the matching function had to
2081            back up over a mixture of the two cases, it incorrectly assumed they
2082            were both the same length.
2083    
2084        (b) When PCRE was configured to use the heap rather than the stack for
2085            recursion during matching, it was not correctly preserving the data for
2086            the other case of a UTF-8 character when checking ahead for a match
2087            while processing a minimizing repeat. If the check also involved
2088            matching a wide character, but failed, corruption could cause an
2089            erroneous result when trying to check for a repeat of the original
2090            character.
2091    
2092    13. Some tidying changes to the testing mechanism:
2093    
2094        (a) The RunTest script now detects the internal link size and whether there
2095            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
2096            values substituted by "configure". (The RunGrepTest script already did
2097            this for UTF-8.) The configure.ac script no longer substitutes the
2098            relevant variables.
2099    
2100        (b) The debugging options /B and /D in pcretest show the compiled bytecode
2101            with length and offset values. This means that the output is different
2102            for different internal link sizes. Test 2 is skipped for link sizes
2103            other than 2 because of this, bypassing the problem. Unfortunately,
2104            there was also a test in test 3 (the locale tests) that used /B and
2105            failed for link sizes other than 2. Rather than cut the whole test out,
2106            I have added a new /Z option to pcretest that replaces the length and
2107            offset values with spaces. This is now used to make test 3 independent
2108            of link size. (Test 2 will be tidied up later.)
2109    
2110    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
2111        segmentation fault instead of returning the appropriate error message.
2112    
2113    15. In multiline mode when the newline sequence was set to "any", the pattern
2114        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
2115        This doesn't seem right; it now treats the CRLF combination as the line
2116        ending, and so does not match in that case. It's only a pattern such as ^$
2117        that would hit this one: something like ^ABC$ would have failed after \r
2118        and then tried again after \r\n.
2119    
2120    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
2121        in an attempt to make files that differ only in their line terminators
2122        compare equal. This works on Linux.
2123    
2124    17. Under certain error circumstances pcregrep might try to free random memory
2125        as it exited. This is now fixed, thanks to valgrind.
2126    
2127    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
2128        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
2129        was because its rules for how to advance for /g after matching an empty
2130        string at the end of a line did not allow for this case. They now check for
2131        it specially.
2132    
2133    20. pcretest is supposed to handle patterns and data of any length, by
2134        extending its buffers when necessary. It was getting this wrong when the
2135        buffer for a data line had to be extended.
2136    
2137    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
2138        CRLF as a newline sequence.
2139    
2140    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
2141        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
2142        I have nevertheless tidied it up.
2143    
2144    23. Added some casts to kill warnings from HP-UX ia64 compiler.
2145    
2146    24. Added a man page for pcre-config.
2147    
2148    
2149    Version 7.0 19-Dec-06
2150    ---------------------
2151    
2152     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
2153        moving to gcc 4.1.1.
2154    
2155     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
2156        sys/time.h, which is documented as needed for this function. It doesn't
2157        seem to matter on Linux, but it showed up on some releases of OS X.
2158    
2159     3. It seems that there are systems where bytes whose values are greater than
2160        127 match isprint() in the "C" locale. The "C" locale should be the
2161        default when a C program starts up. In most systems, only ASCII printing
2162        characters match isprint(). This difference caused the output from pcretest
2163        to vary, making some of the tests fail. I have changed pcretest so that:
2164    
2165        (a) When it is outputting text in the compiled version of a pattern, bytes
2166            other than 32-126 are always shown as hex escapes.
2167    
2168        (b) When it is outputting text that is a matched part of a subject string,
2169            it does the same, unless a different locale has been set for the match
2170            (using the /L modifier). In this case, it uses isprint() to decide.
2171    
2172     4. Fixed a major bug that caused incorrect computation of the amount of memory
2173        required for a compiled pattern when options that changed within the
2174        pattern affected the logic of the preliminary scan that determines the
2175        length. The relevant options are -x, and -i in UTF-8 mode. The result was
2176        that the computed length was too small. The symptoms of this bug were
2177        either the PCRE error "internal error: code overflow" from pcre_compile(),
2178        or a glibc crash with a message such as "pcretest: free(): invalid next
2179        size (fast)". Examples of patterns that provoked this bug (shown in
2180        pcretest format) are:
2181    
2182          /(?-x: )/x
2183          /(?x)(?-x: \s*#\s*)/
2184          /((?i)[\x{c0}])/8
2185          /(?i:[\x{c0}])/8
2186    
2187        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
2188        is now done differently.
2189    
2190     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
2191        wrapper classes; (b) implement a new function in the C++ scanner that is
2192        more efficient than the old way of doing things because it avoids levels of
2193        recursion in the regex matching; (c) add a paragraph to the documentation
2194        for the FullMatch() function.
2195    
2196     6. The escape sequence \n was being treated as whatever was defined as
2197        "newline". Not only was this contrary to the documentation, which states
2198        that \n is character 10 (hex 0A), but it also went horribly wrong when
2199        "newline" was defined as CRLF. This has been fixed.
2200    
2201     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
2202        was being set to -1 for the "end of line" case (supposedly a value that no
2203        character can have). Though this value is never used (the check for end of
2204        line is "zero bytes in current character"), it caused compiler complaints.
2205        I've changed it to 0xffffffff.
2206    
2207     8. In pcre_version.c, the version string was being built by a sequence of
2208        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
2209        string (as it is for production releases) called a macro with an empty
2210        argument. The C standard says the result of this is undefined. The gcc
2211        compiler treats it as an empty string (which was what was wanted) but it is
2212        reported that Visual C gives an error. The source has been hacked around to
2213        avoid this problem.
2214    
2215     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
2216        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
2217        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
2218        of them did).
2219    
2220    10. Originally, pcretest opened its input and output without "b"; then I was
2221        told that "b" was needed in some environments, so it was added for release
2222        5.0 to both the input and output. (It makes no difference on Unix-like
2223        systems.) Later I was told that it is wrong for the input on Windows. I've
2224        now abstracted the modes into two macros, to make it easier to fiddle with
2225        them, and removed "b" from the input mode under Windows.
2226    
2227    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
2228    
2229    12. Added -help and --help to pcretest as an official way of being reminded
2230        of the options.
2231    
2232    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
2233        and pcrecpp.cc because they annoy compilers at high warning levels.
2234    
2235    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
2236    
2237    15. Fixed an occurrence of == in configure.ac that should have been = (shell
2238        scripts are not C programs :-) and which was not noticed because it works
2239        on Linux.
2240    
2241    16. pcretest is supposed to handle any length of pattern and data line (as one
2242        line or as a continued sequence of lines) by extending its input buffer if
2243        necessary. This feature was broken for very long pattern lines, leading to
2244        a string of junk being passed to pcre_compile() if the pattern was longer
2245        than about 50K.
2246    
2247    17. I have done a major re-factoring of the way pcre_compile() computes the
2248        amount of memory needed for a compiled pattern. Previously, there was code
2249        that made a preliminary scan of the pattern in order to do this. That was
2250        OK when PCRE was new, but as the facilities have expanded, it has become
2251        harder and harder to keep it in step with the real compile phase, and there
2252        have been a number of bugs (see for example, 4 above). I have now found a
2253        cunning way of running the real compile function in a "fake" mode that
2254        enables it to compute how much memory it would need, while actually only
2255        ever using a few hundred bytes of working memory and without too many
2256        tests of the mode. This should make future maintenance and development
2257        easier. A side effect of this work is that the limit of 200 on the nesting
2258        depth of parentheses has been removed (though this was never a serious
2259        limitation, I suspect). However, there is a downside: pcre_compile() now
2260        runs more slowly than before (30% or more, depending on the pattern). I
2261        hope this isn't a big issue. There is no effect on runtime performance.
2262    
2263    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
2264        newline (only possible for the last line of a file) and it was a
2265        pattern that set a locale (followed by /Lsomething), pcretest crashed.
2266    
2267    19. Added additional timing features to pcretest. (1) The -tm option now times
2268        matching only, not compiling. (2) Both -t and -tm can be followed, as a
2269        separate command line item, by a number that specifies the number of
2270        repeats to use when timing. The default is 50000; this gives better
2271        precision, but takes uncomfortably long for very large patterns.
2272    
2273    20. Extended pcre_study() to be more clever in cases where a branch of a
2274        subpattern has no definite first character. For example, (a*|b*)[cd] would
2275        previously give no result from pcre_study(). Now it recognizes that the
2276        first character must be a, b, c, or d.
2277    
2278    21. There was an incorrect error "recursive call could loop indefinitely" if
2279        a subpattern (or the entire pattern) that was being tested for matching an
2280        empty string contained only one non-empty item after a nested subpattern.
2281        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
2282        incorrectly, because the \d was being skipped in the check.
2283    
2284    22. The pcretest program now has a new pattern option /B and a command line
2285        option -b, which is equivalent to adding /B to every pattern. This causes
2286        it to show the compiled bytecode, without the additional information that
2287        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
2288        is the same as /B/I).
2289    
2290    23. A new optimization is now able automatically to treat some sequences such
2291        as a*b as a*+b. More specifically, if something simple (such as a character
2292        or a simple class like \d) has an unlimited quantifier, and is followed by
2293        something that cannot possibly match the quantified thing, the quantifier
2294        is automatically "possessified".
2295    
2296    24. A recursive reference to a subpattern whose number was greater than 39
2297        went wrong under certain circumstances in UTF-8 mode. This bug could also
2298        have affected the operation of pcre_study().
2299    
2300    25. Realized that a little bit of performance could be had by replacing
2301        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
2302    
2303    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
2304    
2305    27. Possessive quantifiers such as a++ were previously implemented by turning
2306        them into atomic groups such as ($>a+). Now they have their own opcodes,
2307        which improves performance. This includes the automatically created ones
2308        from 23 above.
2309    
2310    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
2311        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
2312        the first matched character to be a colon. This applied both to named and
2313        numbered groups.
2314    
2315    29. The ucpinternal.h header file was missing its idempotency #ifdef.
2316    
2317    30. I was sent a "project" file called libpcre.a.dev which I understand makes
2318        building PCRE on Windows easier, so I have included it in the distribution.
2319    
2320    31. There is now a check in pcretest against a ridiculously large number being
2321        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
2322        loop, the loop is abandoned.
2323    
2324    32. Forward references to subpatterns in conditions such as (?(2)...) where
2325        subpattern 2 is defined later cause pcre_compile() to search forwards in
2326        the pattern for the relevant set of parentheses. This search went wrong
2327        when there were unescaped parentheses in a character class, parentheses
2328        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2329    
2330    33. "Subroutine" calls and backreferences were previously restricted to
2331        referencing subpatterns earlier in the regex. This restriction has now
2332        been removed.
2333    
2334    34. Added a number of extra features that are going to be in Perl 5.10. On the
2335        whole, these are just syntactic alternatives for features that PCRE had
2336        previously implemented using the Python syntax or my own invention. The
2337        other formats are all retained for compatibility.
2338    
2339        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2340            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2341            also .NET compatible.
2342    
2343        (b) A recursion or subroutine call to a named group can now be defined as
2344            (?&name) as well as (?P>name).
2345    
2346        (c) A backreference to a named group can now be defined as \k<name> or
2347            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2348            5.10, are also .NET compatible.
2349    
2350        (d) A conditional reference to a named group can now use the syntax
2351            (?(<name>) or (?('name') as well as (?(name).
2352    
2353        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2354            groups (named and numbered) that are never evaluated inline, but can be
2355            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2356            is always false. There may be only one alternative in such a group.
2357    
2358        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2359            as the simple (?(R). The condition is true only if the most recent
2360            recursion is that of the given number or name. It does not search out
2361            through the entire recursion stack.
2362    
2363        (g) The escape \gN or \g{N} has been added, where N is a positive or
2364            negative number, specifying an absolute or relative reference.
2365    
2366    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2367        some "unreachable code" warnings.
2368    
2369    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2370        things, this adds five new scripts.
2371    
2372    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2373        There were also incompatibilities regarding the handling of \Q..\E inside
2374        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2375        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2376    
2377    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2378        matches an empty string, and forcibly breaks the loop. There were bugs in
2379        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2380        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2381        separate and independent bugs (that affected different cases) have been
2382        fixed.
2383    
2384    39. Refactored the code to abolish the use of different opcodes for small
2385        capturing bracket numbers. This is a tidy that I avoided doing when I
2386        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2387        The new approach is not only tidier, it makes it possible to reduce the
2388        memory needed to fix the previous bug (38).
2389    
2390    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2391        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2392        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2393        mode.
2394    
2395    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2396        report.
2397    
2398    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2399        copy construction and assignment in the C++ wrapper.
2400    
2401    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2402        couple of bugs that could have given wrong results in the "--newline=crlf"
2403        case.
2404    
2405    44. Added a number of casts and did some reorganization of signed/unsigned int
2406        variables following suggestions from Dair Grant. Also renamed the variable
2407        "this" as "item" because it is a C++ keyword.
2408    
2409    45. Arranged for dftables to add
2410    
2411          #include "pcre_internal.h"
2412    
2413        to pcre_chartables.c because without it, gcc 4.x may remove the array
2414        definition from the final binary if PCRE is built into a static library and
2415        dead code stripping is activated.
2416    
2417    46. For an unanchored pattern, if a match attempt fails at the start of a
2418        newline sequence, and the newline setting is CRLF or ANY, and the next two
2419        characters are CRLF, advance by two characters instead of one.
2420    
2421    
2422    Version 6.7 04-Jul-06
2423    ---------------------
2424    
2425     1. In order to handle tests when input lines are enormously long, pcretest has
2426        been re-factored so that it automatically extends its buffers when
2427        necessary. The code is crude, but this _is_ just a test program. The
2428        default size has been increased from 32K to 50K.
2429    
2430     2. The code in pcre_study() was using the value of the re argument before
2431        testing it for NULL. (Of course, in any sensible call of the function, it
2432        won't be NULL.)
2433    
2434     3. The memmove() emulation function in pcre_internal.h, which is used on
2435        systems that lack both memmove() and bcopy() - that is, hardly ever -
2436        was missing a "static" storage class specifier.
2437    
2438     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2439        containing an extended class (one that cannot be represented by a bitmap
2440        because it contains high-valued characters or Unicode property items, e.g.
2441        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2442        pattern, but PCRE should not loop if you do not (it no longer does).
2443        [Detail: two cases were found: (a) a repeated subpattern containing an
2444        extended class; (b) a recursive reference to a subpattern that followed a
2445        previous extended class. It wasn't skipping over the extended class
2446        correctly when UTF-8 mode was not set.]
2447    
2448     5. A negated single-character class was not being recognized as fixed-length
2449        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2450        compile error "lookbehind assertion is not fixed length".
2451    
2452     6. The RunPerlTest auxiliary script was showing an unexpected difference
2453        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2454        write a Perl script that can interpret lines of an input file either as
2455        byte characters or as UTF-8, which is what "perltest" was being required to
2456        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2457        can't do is switch easily at run time between having the "use utf8;" pragma
2458        or not. In the end, I fudged it by using the RunPerlTest script to insert
2459        "use utf8;" explicitly for the UTF-8 tests.
2460    
2461     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2462        the end of the subject string, contrary to the documentation and to what
2463        Perl does. This was true of both matching functions. Now it matches only at
2464        the start of the subject and immediately after *internal* newlines.
2465    
2466     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2467        a pointer to an int instead of a pointer to an unsigned long int. This
2468        caused problems on 64-bit systems.
2469    
2470     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2471        instance of the 'standard' template library not being so standard".
2472    
2473    10. There was no check on the number of named subpatterns nor the maximum
2474        length of a subpattern name. The product of these values is used to compute
2475        the size of the memory block for a compiled pattern. By supplying a very
2476        long subpattern name and a large number of named subpatterns, the size
2477        computation could be caused to overflow. This is now prevented by limiting
2478        the length of names to 32 characters, and the number of named subpatterns
2479        to 10,000.
2480    
2481    11. Subpatterns that are repeated with specific counts have to be replicated in
2482        the compiled pattern. The size of memory for this was computed from the
2483        length of the subpattern and the repeat count. The latter is limited to
2484        65535, but there was no limit on the former, meaning that integer overflow
2485        could in principle occur. The compiled length of a repeated subpattern is
2486        now limited to 30,000 bytes in order to prevent this.
2487    
2488    12. Added the optional facility to have named substrings with the same name.
2489    
2490    13. Added the ability to use a named substring as a condition, using the
2491        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2492        are numbers (not recommended). Forward references are permitted.
2493    
2494    14. Added forward references in named backreferences (if you see what I mean).
2495    
2496    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2497        pattern could run off the end of the subject. For example, the pattern
2498        "(?s)(.{1,5})"8 did this with the subject "ab".
2499    
2500    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2501        PCRE_CASELESS was set when matching characters that were quantified with ?
2502        or *.
2503    
2504    17. A character class other than a single negated character that had a minimum
2505        but no maximum quantifier - for example [ab]{6,} - was not handled
2506        correctly by pce_dfa_exec(). It would match only one character.
2507    
2508    18. A valid (though odd) pattern that looked like a POSIX character
2509        class but used an invalid character after [ (for example [[,abc,]]) caused
2510        pcre_compile() to give the error "Failed: internal error: code overflow" or
2511        in some cases to crash with a glibc free() error. This could even happen if
2512        the pattern terminated after [[ but there just happened to be a sequence of
2513        letters, a binary zero, and a closing ] in the memory that followed.
2514    
2515    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2516        over the years. Originally (before any Unicode support), just the bottom 8
2517        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2518        output from "man perlunicode" includes this:
2519    
2520          The regular expression compiler produces polymorphic opcodes.  That
2521          is, the pattern adapts to the data and automatically switches to
2522          the Unicode character scheme when presented with Unicode data--or
2523          instead uses a traditional byte scheme when presented with byte
2524          data.
2525    
2526        Sadly, a wide octal escape does not cause a switch, and in a string with
2527        no other multibyte characters, these octal escapes are treated as before.
2528        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2529        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2530        Unicode string.
2531    
2532        I have not perpetrated such confusion in PCRE. Up till now, it took just
2533        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2534        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2535        translate to the appropriate multibyte character.
2536    
2537    29. Applied some refactoring to reduce the number of warnings from Microsoft
2538        and Borland compilers. This has included removing the fudge introduced
2539        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2540        a warning about an unused variable.
2541    
2542    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2543        characters since release 4.0, because Perl (from release 5.004) does not.
2544        [Or at least, is documented not to: some releases seem to be in conflict
2545        with the documentation.] However, when a pattern was studied with
2546        pcre_study() and all its branches started with \s, PCRE still included VT
2547        as a possible starting character. Of course, this did no harm; it just
2548        caused an unnecessary match attempt.
2549    
2550    22. Removed a now-redundant internal flag bit that recorded the fact that case
2551        dependency changed within the pattern. This was once needed for "required
2552        byte" processing, but is no longer used. This recovers a now-scarce options
2553        bit. Also moved the least significant internal flag bit to the most-
2554        significant bit of the word, which was not previously used (hangover from
2555        the days when it was an int rather than a uint) to free up another bit for
2556        the future.
2557    
2558    23. Added support for CRLF line endings as well as CR and LF. As well as the
2559        default being selectable at build time, it can now be changed at runtime
2560        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2561        specify that it is scanning data with non-default line endings.
2562    
2563    24. Changed the definition of CXXLINK to make it agree with the definition of
2564        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2565    
2566    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2567        recursions. This makes a big different to stack usage for some patterns.
2568    
2569    26. If a subpattern containing a named recursion or subroutine reference such
2570        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2571        the space required for the compiled pattern went wrong and gave too small a
2572        value. Depending on the environment, this could lead to "Failed: internal
2573        error: code overflow at offset 49" or "glibc detected double free or
2574        corruption" errors.
2575    
2576    27. Applied patches from Google (a) to support the new newline modes and (b) to
2577        advance over multibyte UTF-8 characters in GlobalReplace.
2578    
2579    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2580        difference for some implementation of PCRE in some Windows version.
2581    
2582    29. Added some extra testing facilities to pcretest:
2583    
2584        \q<number>   in a data line sets the "match limit" value
2585        \Q<number>   in a data line sets the "match recursion limt" value
2586        -S <number>  sets the stack size, where <number> is in megabytes
2587    
2588        The -S option isn't available for Windows.
2589    
2590    
2591    Version 6.6 06-Feb-06
2592    ---------------------
2593    
2594     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2595        in pcreposix.h. I have copied the definition from pcre.h.
2596    
2597     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2598        because pcre.h is no longer a built file.
2599    
2600     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2601        not normally included in the compiled code.
2602    
2603    
2604    Version 6.5 01-Feb-06
2605    ---------------------
2606    
2607     1. When using the partial match feature with pcre_dfa_exec(), it was not
2608        anchoring the second and subsequent partial matches at the new starting
2609        point. This could lead to incorrect results. For example, with the pattern
2610        /1234/, partially matching against "123" and then "a4" gave a match.
2611    
2612     2. Changes to pcregrep:
2613    
2614        (a) All non-match returns from pcre_exec() were being treated as failures
2615            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2616            error message is output. Some extra information is given for the
2617            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2618            probably the only errors that are likely to be caused by users (by
2619            specifying a regex that has nested indefinite repeats, for instance).
2620            If there are more than 20 of these errors, pcregrep is abandoned.
2621    
2622        (b) A binary zero was treated as data while matching, but terminated the
2623            output line if it was written out. This has been fixed: binary zeroes
2624            are now no different to any other data bytes.
2625    
2626        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2627            used to set a locale for matching. The --locale=xxxx long option has
2628            been added (no short equivalent) to specify a locale explicitly on the
2629            pcregrep command, overriding the environment variables.
2630    
2631        (d) When -B was used with -n, some line numbers in the output were one less
2632            than they should have been.
2633    
2634        (e) Added the -o (--only-matching) option.
2635    
2636        (f) If -A or -C was used with -c (count only), some lines of context were
2637            accidentally printed for the final match.
2638    
2639        (g) Added the -H (--with-filename) option.
2640    
2641        (h) The combination of options -rh failed to suppress file names for files
2642            that were found from directory arguments.
2643    
2644        (i) Added the -D (--devices) and -d (--directories) options.
2645    
2646        (j) Added the -F (--fixed-strings) option.
2647    
2648        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2649    
2650        (l) Added the --colo(u)r option.
2651    
2652        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2653            is not present by default.
2654    
2655     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2656        items such as (?R) or (?1), when the recursion could match a number of
2657        alternatives. If it matched one of the alternatives, but subsequently,
2658        outside the recursion, there was a failure, the code tried to back up into
2659        the recursion. However, because of the way PCRE is implemented, this is not
2660        possible, and the result was an incorrect result from the match.
2661    
2662        In order to prevent this happening, the specification of recursion has
2663        been changed so that all such subpatterns are automatically treated as
2664        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2665    
2666     4. I had overlooked the fact that, in some locales, there are characters for
2667        which isalpha() is true but neither isupper() nor islower() are true. In
2668        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2669        and ordfeminine) are like this. This affected the treatment of \w and \W
2670        when they appeared in character classes, but not when they appeared outside
2671        a character class. The bit map for "word" characters is now created
2672        separately from the results of isalnum() instead of just taking it from the
2673        upper, lower, and digit maps. (Plus the underscore character, of course.)
2674    
2675     5. The above bug also affected the handling of POSIX character classes such as
2676        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2677        permanent tables. Instead, the bit maps for such a class were previously
2678        created as the appropriate unions of the upper, lower, and digit bitmaps.
2679        Now they are created by subtraction from the [[:word:]] class, which has
2680        its own bitmap.
2681    
2682     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2683        It is created by subtracting the vertical space characters (\x09, \x0a,
2684        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2685        subtraction was done in the overall bitmap for a character class, meaning
2686        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2687        be recognized. This bug has been fixed.
2688    
2689     7. Patches from the folks at Google:
2690    
2691          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2692          real life, but is still worth protecting against".
2693    
2694          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2695          regular expressions".
2696    
2697          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2698          have it.
2699    
2700          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2701          "configure" and the latter not, in order to fix a problem somebody had
2702          with compiling the Arg class on HP-UX.
2703    
2704          (e) Improve the error-handling of the C++ wrapper a little bit.
2705    
2706          (f) New tests for checking recursion limiting.
2707    
2708     8. The pcre_memmove() function, which is used only if the environment does not
2709        have a standard memmove() function (and is therefore rarely compiled),
2710        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2711        returning a result (though PCRE never actually uses the result).
2712    
2713     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2714        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2715        returned instead of calling malloc() with an overflowing number that would
2716        most likely cause subsequent chaos.
2717    
2718    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2719    
2720    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2721        with this option is matched, the nmatch and pmatch options of regexec() are
2722        ignored.
2723    
2724    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2725        provided in case anyone wants to the the POSIX interface with UTF-8
2726        strings.
2727    
2728    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2729        C++ linking (needed for some HP-UX environments).
2730    
2731    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2732        (unused parameter) and in the pcre_printint() function (omitted "default"
2733        switch label when the default is to do nothing).
2734    
2735    15. Added some code to make it possible, when PCRE is compiled as a C++
2736        library, to replace subject pointers for pcre_exec() with a smart pointer
2737        class, thus making it possible to process discontinuous strings.
2738    
2739    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2740        much the same function. They were added by different people who were trying
2741        to make PCRE easy to compile on non-Unix systems. It has been suggested
2742        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2743        for compiling on Windows systems. I have therefore replaced it with
2744        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2745        defaults to "extern" for C or "extern C" for C++, which works fine on
2746        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2747        SCOPE with something explicit in config.h. In addition:
2748    
2749        (a) pcreposix.h still had just "extern" instead of either of these macros;
2750            I have replaced it with PCRE_DATA_SCOPE.
2751    
2752        (b) Functions such as _pcre_xclass(), which are internal to the library,
2753            but external in the C sense, all had PCRE_EXPORT in their definitions.
2754            This is apparently wrong for the Windows case, so I have removed it.
2755            (It makes no difference on Unix-like systems.)
2756    
2757    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2758        of recursive calls to match(). This is different to MATCH_LIMIT because
2759        that limits the total number of calls to match(), not all of which increase
2760        the depth of recursion. Limiting the recursion depth limits the amount of
2761        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2762        when PCRE is compiled, and changed at run time. A patch from Google adds
2763        this functionality to the C++ interface.
2764    
2765    18. Changes to the handling of Unicode character properties:
2766    
2767        (a) Updated the table to Unicode 4.1.0.
2768    
2769        (b) Recognize characters that are not in the table as "Cn" (undefined).
2770    
2771        (c) I revised the way the table is implemented to a much improved format
2772            which includes recognition of ranges. It now supports the ranges that
2773            are defined in UnicodeData.txt, and it also amalgamates other
2774            characters into ranges. This has reduced the number of entries in the
2775            table from around 16,000 to around 3,000, thus reducing its size
2776            considerably. I realized I did not need to use a tree structure after
2777            all - a binary chop search is just as efficient. Having reduced the
2778            number of entries, I extended their size from 6 bytes to 8 bytes to
2779            allow for more data.
2780    
2781        (d) Added support for Unicode script names via properties such as \p{Han}.
2782    
2783    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2784        matching that character.
2785    
2786    20. When matching a repeated Unicode property with a minimum greater than zero,
2787        (for example \pL{2,}), PCRE could look past the end of the subject if it
2788        reached it while seeking the minimum number of characters. This could
2789        happen only if some of the characters were more than one byte long, because
2790        there is a check for at least the minimum number of bytes.
2791    
2792    21. Refactored the implementation of \p and \P so as to be more general, to
2793        allow for more different types of property in future. This has changed the
2794        compiled form incompatibly. Anybody with saved compiled patterns that use
2795        \p or \P will have to recompile them.
2796    
2797    22. Added "Any" and "L&" to the supported property types.
2798    
2799    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2800        but give a compile time error if the value is greater than 0xff.
2801    
2802    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2803        accidentally not being installed or uninstalled.
2804    
2805    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2806        made were to insert the current release number. This seemed silly, because
2807        it made things harder for people building PCRE on systems that don't run
2808        "configure". I have turned pcre.h into a distributed file, no longer built
2809        by "configure", with the version identification directly included. There is
2810        no longer a pcre.h.in file.
2811    
2812        However, this change necessitated a change to the pcre-config script as
2813        well. It is built from pcre-config.in, and one of the substitutions was the
2814        release number. I have updated configure.ac so that ./configure now finds
2815        the release number by grepping pcre.h.
2816    
2817    26. Added the ability to run the tests under valgrind.
2818    
2819    
2820    Version 6.4 05-Sep-05
2821    ---------------------
2822    
2823     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2824        "--" to be printed when multiple files were scanned, even when none of the
2825        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2826        consider it to be a bug, and have restored the previous behaviour.
2827    
2828     2. A couple of code tidies to get rid of compiler warnings.
2829    
2830     3. The pcretest program used to cheat by referring to symbols in the library
2831        whose names begin with _pcre_. These are internal symbols that are not
2832        really supposed to be visible externally, and in some environments it is
2833        possible to suppress them. The cheating is now confined to including
2834        certain files from the library's source, which is a bit cleaner.
2835    
2836     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2837        file's purpose clearer.
2838    
2839     5. Reorganized pcre_ucp_findchar().
2840    
2841    
2842    Version 6.3 15-Aug-05
2843    ---------------------
2844    
2845     1. The file libpcre.pc.in did not have general read permission in the tarball.
2846    
2847     2. There were some problems when building without C++ support:
2848    
2849        (a) If C++ support was not built, "make install" and "make test" still
2850            tried to test it.
2851    
2852        (b) There were problems when the value of CXX was explicitly set. Some
2853            changes have been made to try to fix these, and ...
2854    
2855        (c) --disable-cpp can now be used to explicitly disable C++ support.
2856    
2857        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2858            backslash in a target when C++ was disabled. This confuses some
2859            versions of "make", apparently. Using an intermediate variable solves
2860            this. (Same for CPP_LOBJ.)
2861    
2862     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2863        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2864        necessary on certain architectures.
2865    
2866     4. Added a setting of -export-symbols-regex to the link command to remove
2867        those symbols that are exported in the C sense, but actually are local
2868        within the library, and not documented. Their names all begin with
2869        "_pcre_". This is not a perfect job, because (a) we have to except some
2870        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2871        available (and never for static libraries). I have made a note to try to
2872        find a way round (a) in the future.
2873    
2874    
2875    Version 6.2 01-Aug-05
2876    ---------------------
2877    
2878     1. There was no test for integer overflow of quantifier values. A construction
2879        such as {1111111111111111} would give undefined results. What is worse, if
2880        a minimum quantifier for a parenthesized subpattern overflowed and became
2881        negative, the calculation of the memory size went wrong. This could have
2882        led to memory overwriting.
2883    
2884     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2885    
2886     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2887        operating environments where this matters.
2888    
2889     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2890        PCRE options from within the C++ wrapper.
2891    
2892     5. Named capturing subpatterns were not being correctly counted when a pattern
2893        was compiled. This caused two problems: (a) If there were more than 100
2894        such subpatterns, the calculation of the memory needed for the whole
2895        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2896        back references of the form \12, where the number was greater than 9, were
2897        not recognized as back references, even though there were sufficient
2898        previous subpatterns.
2899    
2900     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2901        versions of gcc, e.g. 2.95.4.
2902    
2903    
2904    Version 6.1 21-Jun-05
2905    ---------------------
2906    
2907     1. There was one reference to the variable "posix" in pcretest.c that was not
2908        surrounded by "#if !defined NOPOSIX".
2909    
2910     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2911        the cross-check on the old pcre_info() function, for the benefit of the
2912        cut-down version of PCRE that is currently imported into Exim.
2913    
2914     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2915        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2916        patterns that start (?i) but I don't think that matters. The use of (?i) is
2917        just an example; this all applies to the other options as well.
2918    
2919     4. Since libtool seems to echo the compile commands it is issuing, the output
2920        from "make" can be reduced a bit by putting "@" in front of each libtool
2921        compile command.
2922    
2923     5. Patch from the folks at Google for configure.in to be a bit more thorough
2924        in checking for a suitable C++ installation before trying to compile the
2925        C++ stuff. This should fix a reported problem when a compiler was present,
2926        but no suitable headers.
2927    
2928     6. The man pages all had just "PCRE" as their title. I have changed them to
2929        be the relevant file name. I have also arranged that these names are
2930        retained in the file doc/pcre.txt, which is a concatenation in text format
2931        of all the man pages except the little individual ones for each function.
2932    
2933     7. The NON-UNIX-USE file had not been updated for the different set of source
2934        files that come with release 6. I also added a few comments about the C++
2935        wrapper.
2936    
2937    
2938    Version 6.0 07-Jun-05
2939    ---------------------
2940    
2941     1. Some minor internal re-organization to help with my DFA experiments.
2942    
2943     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2944        didn't matter for the library itself when fully configured, but did matter
2945        when compiling without UCP support, or within Exim, where the ucp files are
2946        not imported.
2947    
2948     3. Refactoring of the library code to split up the various functions into
2949        different source modules. The addition of the new DFA matching code (see
2950        below) to a single monolithic source would have made it really too
2951        unwieldy, quite apart from causing all the code to be include in a
2952        statically linked application, when only some functions are used. This is
2953        relevant even without the DFA addition now that patterns can be compiled in
2954        one application and matched in another.
2955    
2956        The downside of splitting up is that there have to be some external
2957        functions and data tables that are used internally in different modules of
2958        the library but which are not part of the API. These have all had their
2959        names changed to start with "_pcre_" so that they are unlikely to clash
2960        with other external names.
2961    
2962     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2963        a different (DFA) algorithm. Although it is slower than the original
2964        function, it does have some advantages for certain types of matching
2965        problem.
2966    
2967     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2968        including restarting after a partial match.
2969    
2970     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2971        defined when compiling for Windows was sent to me. I have put it into the
2972        code, though I have no means of testing or verifying it.
2973    
2974     7. Added the pcre_refcount() auxiliary function.
2975    
2976     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2977        match before or at the first newline in the subject string. In pcretest,
2978        the /f option on a pattern can be used to set this.
2979    
2980     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2981        would behave wrongly. This has been present in PCRE since release 4.0.
2982    
2983    10. A number of changes to the pcregrep command:
2984    
2985        (a) Refactored how -x works; insert ^(...)$ instead of setting
2986            PCRE_ANCHORED and checking the length, in preparation for adding
2987            something similar for -w.
2988    
2989        (b) Added the -w (match as a word) option.
2990    
2991        (c) Refactored the way lines are read and buffered so as to have more
2992            than one at a time available.
2993    
2994        (d) Implemented a pcregrep test script.
2995    
2996        (e) Added the -M (multiline match) option. This allows patterns to match
2997            over several lines of the subject. The buffering ensures that at least
2998            8K, or the rest of the document (whichever is the shorter) is available
2999            for matching (and similarly the previous 8K for lookbehind assertions).
3000    
3001        (f) Changed the --help output so that it now says
3002    
3003              -w, --word-regex(p)
3004    
3005            instead of two lines, one with "regex" and the other with "regexp"
3006            because that confused at least one person since the short forms are the
3007            same. (This required a bit of code, as the output is generated
3008            automatically from a table. It wasn't just a text change.)
3009    
3010        (g) -- can be used to terminate pcregrep options if the next thing isn't an
3011            option but starts with a hyphen. Could be a pattern or a path name
3012            starting with a hyphen, for instance.
3013    
3014        (h) "-" can be given as a file name to represent stdin.
3015    
3016        (i) When file names are being printed, "(standard input)" is used for
3017            the standard input, for compatibility with GNU grep. Previously
3018            "<stdin>" was used.
3019    
3020        (j) The option --label=xxx can be used to supply a name to be used for
3021            stdin when file names are being printed. There is no short form.
3022    
3023        (k) Re-factored the options decoding logic because we are going to add
3024            two more options that take data. Such options can now be given in four
3025            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
3026    
3027        (l) Added the -A, -B, and -C options for requesting that lines of context
3028            around matches be printed.
3029    
3030        (m) Added the -L option to print the names of files that do not contain
3031            any matching lines, that is, the complement of -l.
3032    
3033        (n) The return code is 2 if any file cannot be opened, but pcregrep does
3034            continue to scan other files.
3035    
3036        (o) The -s option was incorrectly implemented. For compatibility with other
3037            greps, it now suppresses the error message for a non-existent or non-
3038            accessible file (but not the return code). There is a new option called
3039            -q that suppresses the output of matching lines, which was what -s was
3040            previously doing.
3041    
3042        (p) Added --include and --exclude options to specify files for inclusion
3043            and exclusion when recursing.
3044    
3045    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
3046        Hopefully, it now does.
3047    
3048    12. Missing cast in pcre_study().
3049    
3050    13. Added an "uninstall" target to the makefile.
3051    
3052    14. Replaced "extern" in the function prototypes in Makefile.in with
3053        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
3054        world, but is set differently for Windows.
3055    
3056    15. Added a second compiling function called pcre_compile2(). The only
3057        difference is that it has an extra argument, which is a pointer to an
3058        integer error code. When there is a compile-time failure, this is set
3059        non-zero, in addition to the error test pointer being set to point to an
3060        error message. The new argument may be NULL if no error number is required
3061        (but then you may as well call pcre_compile(), which is now just a
3062        wrapper). This facility is provided because some applications need a
3063        numeric error indication, but it has also enabled me to tidy up the way
3064        compile-time errors are handled in the POSIX wrapper.
3065    
3066    16. Added VPATH=.libs to the makefile; this should help when building with one
3067        prefix path and installing with another. (Or so I'm told by someone who
3068        knows more about this stuff than I do.)
3069    
3070    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
3071        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
3072        match everything, including newlines. This is not POSIX-compatible, but
3073        somebody wanted the feature. From pcretest it can be activated by using
3074        both the P and the s flags.
3075    
3076    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
3077    
3078    19. libpcre.pc was being incorrectly installed as executable.
3079    
3080    20. A couple of places in pcretest check for end-of-line by looking for '\n';
3081        it now also looks for '\r' so that it will work unmodified on Windows.
3082    
3083    21. Added Google's contributed C++ wrapper to the distribution.
3084    
3085    22. Added some untidy missing memory free() calls in pcretest, to keep
3086        Electric Fence happy when testing.
3087    
3088    
3089    
3090    Version 5.0 13-Sep-04
3091    ---------------------
3092    
3093     1. Internal change: literal characters are no longer packed up into items
3094        containing multiple characters in a single byte-string. Each character
3095        is now matched using a separate opcode. However, there may be more than one
3096        byte in the character in UTF-8 mode.
3097    
3098     2. The pcre_callout_block structure has two new fields: pattern_position and
3099        next_item_length. These contain the offset in the pattern to the next match
3100        item, and its length, respectively.
3101    
3102     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
3103        insertion of callouts before each pattern item. Added the /C option to
3104        pcretest to make use of this.
3105    
3106     4. On the advice of a Windows user, the lines
3107    
3108          #if defined(_WIN32) || defined(WIN32)
3109          _setmode( _fileno( stdout ), 0x8000 );
3110          #endif  /* defined(_WIN32) || defined(WIN32) */
3111    
3112        have been added to the source of pcretest. This apparently does useful
3113        magic in relation to line terminators.
3114    
3115     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
3116        for the benefit of those environments where the "b" makes a difference.
3117    
3118     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
3119        to know about it. I have put a hack into configure.in that adds in code
3120        to set GCC=yes if CC=icc. This seems to end up at a point in the
3121        generated configure script that is early enough to affect the setting of
3122        compiler options, which is what is needed, but I have no means of testing
3123        whether it really works. (The user who reported this had patched the
3124        generated configure script, which of course I cannot do.)
3125    
3126        LATER: After change 22 below (new libtool files), the configure script
3127        seems to know about icc (and also ecc). Therefore, I have commented out
3128        this hack in configure.in.
3129    
3130     7. Added support for pkg-config (2 patches were sent in).
3131    
3132     8. Negated POSIX character classes that used a combination of internal tables
3133        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
3134        [[:^ascii]]. Typically, they would match almost any characters. The other
3135        POSIX classes were not broken in this way.
3136    
3137     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
3138        to find the match, as PCRE was deluded into thinking that the match had to
3139        start at the start point or following a newline. The same bug applied to
3140        patterns with negative forward assertions or any backward assertions
3141        preceding ".*" at the start, unless the pattern required a fixed first
3142        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
3143    
3144    10. In UTF-8 mode, when moving forwards in the subject after a failed match
3145        starting at the last subject character, bytes beyond the end of the subject
3146        string were read.
3147    
3148    11. Renamed the variable "class" as "classbits" to make life easier for C++
3149        users. (Previously there was a macro definition, but it apparently wasn't
3150        enough.)
3151    
3152    12. Added the new field "tables" to the extra data so that tables can be passed
3153        in at exec time, or the internal tables can be re-selected. This allows
3154        a compiled regex to be saved and re-used at a later time by a different
3155        program that might have everything at different addresses.
3156    
3157    13. Modified the pcre-config script so that, when run on Solaris, it shows a
3158        -R library as well as a -L library.
3159    
3160    14. The debugging options of pcretest (-d on the command line or D on a
3161        pattern) showed incorrect output for anything following an extended class
3162        that contained multibyte characters and which was followed by a quantifier.
3163    
3164    15. Added optional support for general category Unicode character properties
3165        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
3166        support. It adds about 90K to the size of the library. The meanings of the
3167        inbuilt class escapes such as \d and \s have NOT been changed.
3168    
3169    16. Updated pcredemo.c to include calls to free() to release the memory for the
3170        compiled pattern.
3171    
3172    17. The generated file chartables.c was being created in the source directory
3173        instead of in the building directory. This caused the build to fail if the
3174        source directory was different from the building directory, and was
3175        read-only.
3176    
3177    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
3178        file. No doubt somebody will tell me if they don't make sense... Also added
3179        Dan Mooney's comments about building on OpenVMS.
3180    
3181    19. Added support for partial matching via the PCRE_PARTIAL option for
3182        pcre_exec() and the \P data escape in pcretest.
3183    
3184    20. Extended pcretest with 3 new pattern features:
3185    
3186        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
3187              write the compiled pattern to the file whose name is "rest-of-line".
3188              This is a straight binary dump of the data, with the saved pointer to
3189              the character tables forced to be NULL. The study data, if any, is
3190              written too. After writing, pcretest reads a new pattern.
3191    
3192        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
3193              compiled pattern from the given file. There must not be any
3194              occurrences of "<" in the file name (pretty unlikely); if there are,
3195              pcretest will instead treat the initial "<" as a pattern delimiter.
3196              After reading in the pattern, pcretest goes on to read data lines as
3197              usual.
3198    
3199        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
3200              and 16-bit fields in a compiled pattern, to simulate a pattern that
3201              was compiled on a host of opposite endianness.
3202    
3203    21. The pcre-exec() function can now cope with patterns that were compiled on
3204        hosts of opposite endianness, with this restriction:
3205    
3206          As for any compiled expression that is saved and used later, the tables
3207          pointer field cannot be preserved; the extra_data field in the arguments
3208          to pcre_exec() should be used to pass in a tables address if a value
3209          other than the default internal tables were used at compile time.
3210    
3211    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
3212        now diagnosed as an error. Previously, most of the time, a negative number
3213        would have been treated as zero, but if in addition "ovector" was passed as
3214        NULL, a crash could occur.
3215    
3216    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
3217        new versions from the libtool 1.5 distribution (the last one is a copy of
3218        a file called libtool.m4). This seems to have fixed the need to patch
3219        "configure" to support Darwin 1.3 (which I used to do). However, I still
3220        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
3221        workstation).
3222    
3223    24. Changed the PCRE licence to be the more standard "BSD" licence.
3224    
3225    
3226    Version 4.5 01-Dec-03
3227    ---------------------
3228    
3229     1. There has been some re-arrangement of the code for the match() function so
3230        that it can be compiled in a version that does not call itself recursively.
3231        Instead, it keeps those local variables that need separate instances for
3232        each "recursion" in a frame on the heap, and gets/frees frames whenever it
3233        needs to "recurse". Keeping track of where control must go is done by means
3234        of setjmp/longjmp. The whole thing is implemented by a set of macros that
3235        hide most of the details from the main code, and operates only if
3236        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
3237        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
3238        operating.
3239    
3240        To make it easier for callers to provide specially tailored get/free
3241        functions for this usage, two new functions, pcre_stack_malloc, and
3242        pcre_stack_free, are used. They are always called in strict stacking order,
3243        and the size of block requested is always the same.
3244    
3245        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
3246        PCRE has been compiled to use the stack or the heap for recursion. The
3247        -C option of pcretest uses this to show which version is compiled.
3248    
3249        A new data escape \S, is added to pcretest; it causes the amounts of store
3250        obtained and freed by both kinds of malloc/free at match time to be added
3251        to the output.
3252    
3253     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
3254        what's available on my current Linux desktop machine.
3255    
3256     3. When matching a UTF-8 string, the test for a valid string at the start has
3257        been extended. If start_offset is not zero, PCRE now checks that it points
3258        to a byte that is the start of a UTF-8 character. If not, it returns
3259        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
3260        this is necessary because there may be backward assertions in the pattern.
3261        When matching the same subject several times, it may save resources to use
3262        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
3263    
3264     4. The code for checking the validity of UTF-8 strings has been tightened so
3265        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
3266        containing "overlong sequences".
3267    
3268     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
3269        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
3270        should have been "&", but it just so happened that all the cases this let
3271        through by mistake were picked up later in the function.
3272    
3273     6. I had used a variable called "isblank" - this is a C99 function, causing
3274        some compilers to warn. To avoid this, I renamed it (as "blankclass").
3275    
3276     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
3277        prompting; (b) run "./pcretest /dev/null" at the start of the test script
3278        so the version is shown; (c) stop "make test" echoing "./RunTest".
3279    
3280     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
3281    
3282     9. The prototype for memmove() for systems that don't have it was using
3283        size_t, but the inclusion of the header that defines size_t was later. I've
3284        moved the #includes for the C headers earlier to avoid this.
3285    
3286    10. Added some adjustments to the code to make it easier to compiler on certain
3287        special systems:
3288    
3289          (a) Some "const" qualifiers were missing.
3290          (b) Added the macro EXPORT before all exported functions; by default this
3291              is defined to be empty.
3292          (c) Changed the dftables auxiliary program (that builds chartables.c) so
3293              that it reads its output file name as an argument instead of writing
3294              to the standard output and assuming this can be redirected.
3295    
3296    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
3297        class containing characters with values greater than 255, PCRE compilation
3298        went into a loop.
3299    
3300    12. A recursive reference to a subpattern that was within another subpattern
3301        that had a minimum quantifier of zero caused PCRE to crash. For example,
3302        (x(y(?2))z)? provoked this bug with a subject that got as far as the
3303        recursion. If the recursively-called subpattern itself had a zero repeat,
3304        that was OK.
3305    
3306    13. In pcretest, the buffer for reading a data line was set at 30K, but the
3307        buffer into which it was copied (for escape processing) was still set at
3308        1024, so long lines caused crashes.
3309    
3310    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
3311        "internal error: code overflow...". This applied to any character class
3312        that was followed by a possessive quantifier.
3313    
3314    15. Modified the Makefile to add libpcre.la as a prerequisite for
3315        libpcreposix.la because I was told this is needed for a parallel build to
3316        work.
3317    
3318    16. If a pattern that contained .* following optional items at the start was
3319        studied, the wrong optimizing data was generated, leading to matching
3320        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
3321        matching string must start with a or b or c. The correct conclusion for
3322        this pattern is that a match can start with any character.
3323    
3324    
3325    Version 4.4 13-Aug-03
3326    ---------------------
3327    
3328     1. In UTF-8 mode, a character class containing characters with values between
3329        127 and 255 was not handled correctly if the compiled pattern was studied.
3330        In fixing this, I have also improved the studying algorithm for such
3331        classes (slightly).
3332    
3333     2. Three internal functions had redundant arguments passed to them. Removal
3334        might give a very teeny performance improvement.
3335    
3336     3. Documentation bug: the value of the capture_top field in a callout is *one
3337        more than* the number of the hightest numbered captured substring.
3338    
3339     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
3340        in incorrectly linking with a previously installed version. They now link
3341        explicitly with libpcre.la.
3342    
3343     5. configure.in no longer needs to recognize Cygwin specially.
3344    
3345     6. A problem in pcre.in for Windows platforms is fixed.
3346    
3347     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
3348        pcretest, it used to include the size of the study block as part of its
3349        output. Unfortunately, the structure contains a field that has a different
3350        size on different hardware architectures. This meant that the tests that
3351        showed this size failed. As the block is currently always of a fixed size,
3352        this information isn't actually particularly useful in pcretest output, so
3353        I have just removed it.
3354    
3355     8. Three pre-processor statements accidentally did not start in column 1.
3356        Sadly, there are *still* compilers around that complain, even though
3357        standard C has not required this for well over a decade. Sigh.
3358    
3359     9. In pcretest, the code for checking callouts passed small integers in the
3360        callout_data field, which is a void * field. However, some picky compilers
3361        complained about the casts involved for this on 64-bit systems. Now
3362        pcretest passes the address of the small integer instead, which should get
3363        rid of the warnings.
3364    
3365    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
3366        both compile and run time, and gives an error if an invalid UTF-8 sequence
3367        is found. There is a option for disabling this check in cases where the
3368        string is known to be correct and/or the maximum performance is wanted.
3369    
3370    11. In response to a bug report, I changed one line in Makefile.in from
3371    
3372            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
3373        to
3374            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
3375    
3376        to look similar to other lines, but I have no way of telling whether this
3377        is the right thing to do, as I do not use Windows. No doubt I'll get told
3378        if it's wrong...
3379    
3380    
3381    Version 4.3 21-May-03
3382    ---------------------
3383    
3384    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
3385       Makefile.
3386    
3387    2. Some refactoring to improve the quality of the code:
3388    
3389       (i)   The utf8_table... variables are now declared "const".
3390    
3391       (ii)  The code for \cx, which used the "case flipping" table to upper case
3392             lower case letters, now just substracts 32. This is ASCII-specific,
3393             but the whole concept of \cx is ASCII-specific, so it seems
3394             reasonable.
3395    
3396       (iii) PCRE was using its character types table to recognize decimal and
3397             hexadecimal digits in the pattern. This is silly, because it handles
3398             only 0-9, a-f, and A-F, but the character types table is locale-
3399             specific, which means strange things might happen. A private
3400             table is now used for this - though it costs 256 bytes, a table is
3401             much faster than multiple explicit tests. Of course, the standard
3402             character types table is still used for matching digits in subject
3403             strings against \d.
3404    
3405       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
3406             ending in _t are). So I've renamed it as ESC_tee.
3407    
3408    3. The first argument for regexec() in the POSIX wrapper should have been
3409       defined as "const".
3410    
3411    4. Changed pcretest to use malloc() for its buffers so that they can be
3412       Electric Fenced for debugging.
3413    
3414    5. There were several places in the code where, in UTF-8 mode, PCRE would try
3415       to read one or more bytes before the start of the subject string. Often this
3416       had no effect on PCRE's behaviour, but in some circumstances it could
3417       provoke a segmentation fault.
3418    
3419    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
3420       to try to read one or more bytes before the start of the subject string.
3421    
3422    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
3423       UTF-8 support could misbehave in various ways if the subject string
3424       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
3425       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
3426       back over UTF-8 characters.)
3427    
3428    
3429    Version 4.2 14-Apr-03
3430    ---------------------
3431    
3432    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
3433    
3434    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
3435         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
3436         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
3437         [WIN_PREFIX]: new variable, "cyg" for Cygwin
3438         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
3439           and BUILD_EXEEXT
3440         Note: automatic setting of the BUILD variables is not yet working
3441         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
3442           compile-time but not at link-time
3443         [LINK]: use for linking executables only
3444         make different versions for Windows and non-Windows
3445         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
3446           libraries
3447         [LINK_FOR_BUILD]: new variable
3448         [OBJEXT]: use throughout
3449         [EXEEXT]: use throughout
3450         <winshared>: new target
3451         <wininstall>: new target
3452         <dftables.o>: use native compiler
3453         <dftables>: use native linker
3454         <install>: handle Windows platform correctly
3455         <clean>: ditto
3456         <check>: ditto
3457         copy DLL to top builddir before testing
3458    
3459       As part of these changes, -no-undefined was removed again. This was reported
3460       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
3461       in any case.
3462    
3463    3. Some tidies to get rid of compiler warnings:
3464    
3465       . In the match_data structure, match_limit was an unsigned long int, whereas
3466         match_call_count was an int. I've made them both unsigned long ints.
3467    
3468       . In pcretest the fact that a const uschar * doesn't automatically cast to
3469         a void * provoked a warning.
3470    
3471       . Turning on some more compiler warnings threw up some "shadow" variables
3472         and a few more missing casts.
3473    
3474    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
3475       option, a class that contained a single character with a value between 128
3476       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
3477    
3478    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
3479       option, a class that contained several characters, but with at least one
3480       whose value was between 128 and 255 caused PCRE to crash.
3481    
3482    
3483    Version 4.1 12-Mar-03
3484    ---------------------
3485    
3486    1. Compiling with gcc -pedantic found a couple of places where casts were
3487    needed, and a string in dftables.c that was longer than standard compilers are
3488    required to support.
3489    
3490    2. Compiling with Sun's compiler found a few more places where the code could
3491    be tidied up in order to avoid warnings.
3492    
3493    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
3494    first of these names is deprecated in the latest Autoconf in favour of the name
3495    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
3496    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
3497    analogy I have changed it to CFLAGS_FOR_BUILD.
3498    
3499    4. Added -no-undefined to the linking command in the Makefile, because this is
3500    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
3501    linking step for the pcreposix library.
3502    
3503    5. PCRE was failing to diagnose the case of two named groups with the same
3504    name.
3505    
3506    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
3507    literal character that is needed in the subject for a match, and scans along to
3508    ensure that it is present before embarking on the full matching process. This
3509    saves time in cases of nested unlimited repeats that are never going to match.
3510    Problem: the scan can take a lot of time if the subject is very long (e.g.
3511    megabytes), thus penalizing straightforward matches. It is now done only if the
3512    amount of subject to be scanned is less than 1000 bytes.
3513    
3514    7. A lesser problem with the same optimization is that it was recording the
3515    first character of an anchored pattern as "needed", thus provoking a search
3516    right along the subject, even when the first match of the pattern was going to
3517    fail. The "needed" character is now not set for anchored patterns, unless it
3518    follows something in the pattern that is of non-fixed length. Thus, it still
3519    fulfils its original purpose of finding quick non-matches in cases of nested
3520    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
3521    
3522    
3523    Version 4.0 17-Feb-03
3524    ---------------------
3525