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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-07  Version 8.21
5    ------------
6    
7    1.  Updating the JIT compiler.
8    
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
11    
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
15    
16    4.  Mark settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
19    
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
22    
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
26    
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
36    
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
39    
40    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
44    
45    10. Add a cast and remove a redundant test from the code.
46    
47    11. JIT should use pcre_malloc/pcre_free for allocation.
48    
49    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
50        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
51        is anything other than /usr, -L is still shown).
52    
53    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
54    
55    14. Perl does not support \N without a following name in a [] class; PCRE now
56        also gives an error.
57    
58    15. If a forward reference was repeated with an upper limit of around 2000,
59        it caused the error "internal error: overran compiling workspace". The
60        maximum number of forward references (including repeats) was limited by the
61        internal workspace, and dependent on the LINK_SIZE. The code has been
62        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
63        the default depends on LINK_SIZE. There is a new upper limit (for safety)
64        of around 200,000 forward references. While doing this, I also speeded up
65        the filling in of repeated forward references.
66    
67    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
68        incorrectly expecting the subject to contain another "a" after the start.
69    
70    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
71        in the match, the SKIP should be ignored. This was not happening; instead
72        the SKIP was being treated as NOMATCH. For patterns such as
73        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
74        tested.
75    
76    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
77        now much more compatible with Perl, in particular in cases where the result
78        is a non-match for a non-anchored pattern. For example, if
79        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
80        "m", where previously it did not return a name. A side effect of this
81        change is that for partial matches, the last encountered mark name is
82        returned, as for non matches. A number of tests that were previously not
83        Perl-compatible have been moved into the Perl-compatible test files. The
84        refactoring has had the pleasing side effect of removing one argument from
85        the match() function, thus reducing its stack requirements.
86    
87    19. If the /S+ option was used in pcretest to study a pattern using JIT,
88        subsequent uses of /S (without +) incorrectly behaved like /S+.
89    
90    
91    Version 8.20 21-Oct-2011
92    ------------------------
93    
94    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
95        a POSIX class. After further experiments with Perl, which convinced me that
96        Perl has bugs and confusions, a closing square bracket is no longer allowed
97        in a POSIX name. This bug also affected patterns with classes that started
98        with full stops.
99    
100    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
101        captured substring, but while checking the failing first alternative,
102        substring 1 is temporarily captured. If the output vector supplied to
103        pcre_exec() was not big enough for this capture, the yield of the function
104        was still zero ("insufficient space for captured substrings"). This cannot
105        be totally fixed without adding another stack variable, which seems a lot
106        of expense for a edge case. However, I have improved the situation in cases
107        such as /(a)(b)x|abc/ matched against "abc", where the return code
108        indicates that fewer than the maximum number of slots in the ovector have
109        been set.
110    
111    3.  Related to (2) above: when there are more back references in a pattern than
112        slots in the output vector, pcre_exec() uses temporary memory during
113        matching, and copies in the captures as far as possible afterwards. It was
114        using the entire output vector, but this conflicts with the specification
115        that only 2/3 is used for passing back captured substrings. Now it uses
116        only the first 2/3, for compatibility. This is, of course, another edge
117        case.
118    
119    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
120        main code base, and can be used by building with --enable-jit. When this is
121        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
122        runtime --no-jit option is given.
123    
124    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
125        ovector, the return from the function was zero, implying that there were
126        other matches that did not fit. The correct "exactly full" value is now
127        returned.
128    
129    6.  If a subpattern that was called recursively or as a subroutine contained
130        (*PRUNE) or any other control that caused it to give a non-standard return,
131        invalid errors such as "Error -26 (nested recursion at the same subject
132        position)" or even infinite loops could occur.
133    
134    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
135        computing the minimum length on reaching *ACCEPT, and so ended up with the
136        wrong value of 1 rather than 0. Further investigation indicates that
137        computing a minimum subject length in the presence of *ACCEPT is difficult
138        (think back references, subroutine calls), and so I have changed the code
139        so that no minimum is registered for a pattern that contains *ACCEPT.
140    
141    8.  If (*THEN) was present in the first (true) branch of a conditional group,
142        it was not handled as intended. [But see 16 below.]
143    
144    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
145        Sheri Pierce.
146    
147    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
148        the first byte in a match must be "a".
149    
150    11. Change 17 for 8.13 increased the recursion depth for patterns like
151        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
152        pattern contains any instances of (*THEN). If it does not, the old
153        optimizations are restored. It would be nice to do this on a per-group
154        basis, but at the moment that is not feasible.
155    
156    12. In some environments, the output of pcretest -C is CRLF terminated. This
157        broke RunTest's code that checks for the link size. A single white space
158        character after the value is now allowed for.
159    
160    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
161        For "fr", it uses the Windows-specific input and output files.
162    
163    14. If (*THEN) appeared in a group that was called recursively or as a
164        subroutine, it did not work as intended. [But see next item.]
165    
166    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
167        pattern fragments (but not containing any | characters). If A and B are
168        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
169        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
170        D. In other words, Perl considers parentheses that do not contain any |
171        characters to be part of a surrounding alternative, whereas PCRE was
172        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
173        differently. PCRE now behaves in the same way as Perl, except in the case
174        of subroutine/recursion calls such as (?1) which have in any case always
175        been different (but PCRE had them first :-).
176    
177    16. Related to 15 above: Perl does not treat the | in a conditional group as
178        creating alternatives. Such a group is treated in the same way as an
179        ordinary group without any | characters when processing (*THEN). PCRE has
180        been changed to match Perl's behaviour.
181    
182    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
183        RunGrepTest script failed.
184    
185    18. Change 22 for version 13 caused atomic groups to use more stack. This is
186        inevitable for groups that contain captures, but it can lead to a lot of
187        stack use in large patterns. The old behaviour has been restored for atomic
188        groups that do not contain any capturing parentheses.
189    
190    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
191        suppress the check for a minimum subject length at run time. (If it was
192        given to pcre_exec() or pcre_dfa_exec() it did work.)
193    
194    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
195        fail to work when decoding hex characters in data strings in EBCDIC
196        environments.
197    
198    21. It appears that in at least one Mac OS environment, the isxdigit() function
199        is implemented as a macro that evaluates to its argument more than once,
200        contravening the C 90 Standard (I haven't checked a later standard). There
201        was an instance in pcretest which caused it to go wrong when processing
202        \x{...} escapes in subject strings. The has been rewritten to avoid using
203        things like p++ in the argument of isxdigit().
204    
205    
206    Version 8.13 16-Aug-2011
207    ------------------------
208    
209    1.  The Unicode data tables have been updated to Unicode 6.0.0.
210    
211    2.  Two minor typos in pcre_internal.h have been fixed.
212    
213    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
214        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
215        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
216    
217    4.  There were a number of related bugs in the code for matching backrefences
218        caselessly in UTF-8 mode when codes for the characters concerned were
219        different numbers of bytes. For example, U+023A and U+2C65 are an upper
220        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
221        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
222        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
223        2-byte code at the end of the subject (it thought there wasn't enough data
224        left).
225    
226    5.  Comprehensive information about what went wrong is now returned by
227        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
228        as the output vector has at least 2 elements. The offset of the start of
229        the failing character and a reason code are placed in the vector.
230    
231    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
232        now returned is for the first byte of the failing character, instead of the
233        last byte inspected. This is an incompatible change, but I hope it is small
234        enough not to be a problem. It makes the returned offset consistent with
235        pcre_exec() and pcre_dfa_exec().
236    
237    7.  pcretest now gives a text phrase as well as the error number when
238        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
239        failure, the offset and reason code are output.
240    
241    8.  When \R was used with a maximizing quantifier it failed to skip backwards
242        over a \r\n pair if the subsequent match failed. Instead, it just skipped
243        back over a single character (\n). This seems wrong (because it treated the
244        two characters as a single entity when going forwards), conflicts with the
245        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
246        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
247        has been changed.
248    
249    9.  Some internal refactoring has changed the processing so that the handling
250        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
251        time (the PCRE_DOTALL option was changed this way some time ago: version
252        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
253        which was always a bit of a fudge. It also means that there is one less
254        argument for the match() function, which reduces its stack requirements
255        slightly. This change also fixes an incompatibility with Perl: the pattern
256        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
257    
258    10. More internal refactoring has drastically reduced the number of recursive
259        calls to match() for possessively repeated groups such as (abc)++ when
260        using pcre_exec().
261    
262    11. While implementing 10, a number of bugs in the handling of groups were
263        discovered and fixed:
264    
265        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
266        (a|)*(?1) gave a compile-time internal error.
267        ((a|)+)+  did not notice that the outer group could match an empty string.
268        (^a|^)+   was not marked as anchored.
269        (.*a|.*)+ was not marked as matching at start or after a newline.
270    
271    12. Yet more internal refactoring has removed another argument from the match()
272        function. Special calls to this function are now indicated by setting a
273        value in a variable in the "match data" data block.
274    
275    13. Be more explicit in pcre_study() instead of relying on "default" for
276        opcodes that mean there is no starting character; this means that when new
277        ones are added and accidentally left out of pcre_study(), testing should
278        pick them up.
279    
280    14. The -s option of pcretest has been documented for ages as being an old
281        synonym of -m (show memory usage). I have changed it to mean "force study
282        for every regex", that is, assume /S for every regex. This is similar to -i
283        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
284        using it. It makes it easier to run collections of tests with and without
285        study enabled, and thereby test pcre_study() more easily. All the standard
286        tests are now run with and without -s (but some patterns can be marked as
287        "never study" - see 20 below).
288    
289    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
290        restoration of the capturing data to the outer values was not happening
291        correctly.
292    
293    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
294        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
295        pattern had matched an empty string, and so incorrectly returned a no
296        match.
297    
298    17. There was optimizing code for the last branch of non-capturing parentheses,
299        and also for the obeyed branch of a conditional subexpression, which used
300        tail recursion to cut down on stack usage. Unfortunately, now that there is
301        the possibility of (*THEN) occurring in these branches, tail recursion is
302        no longer possible because the return has to be checked for (*THEN). These
303        two optimizations have therefore been removed. [But see 8.20/11 above.]
304    
305    18. If a pattern containing \R was studied, it was assumed that \R always
306        matched two bytes, thus causing the minimum subject length to be
307        incorrectly computed because \R can also match just one byte.
308    
309    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
310        was incorrectly computed.
311    
312    20. If /S is present twice on a test pattern in pcretest input, it now
313        *disables* studying, thereby overriding the use of -s on the command line
314        (see 14 above). This is necessary for one or two tests to keep the output
315        identical in both cases.
316    
317    21. When (*ACCEPT) was used in an assertion that matched an empty string and
318        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
319    
320    22. When an atomic group that contained a capturing parenthesis was
321        successfully matched, but the branch in which it appeared failed, the
322        capturing was not being forgotten if a higher numbered group was later
323        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
324        group 1 to "a", when in fact it should be unset. This applied to multi-
325        branched capturing and non-capturing groups, repeated or not, and also to
326        positive assertions (capturing in negative assertions does not happen
327        in PCRE) and also to nested atomic groups.
328    
329    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
330        subject after a captured substring, to make it easier to tell which of a
331        number of identical substrings has been captured.
332    
333    24. The way atomic groups are processed by pcre_exec() has been changed so that
334        if they are repeated, backtracking one repetition now resets captured
335        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
336        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
337        "aaa". Previously, it would have been "a". As part of this code
338        refactoring, the way recursive calls are handled has also been changed.
339    
340    25. If an assertion condition captured any substrings, they were not passed
341        back unless some other capturing happened later. For example, if
342        (?(?=(a))a) was matched against "a", no capturing was returned.
343    
344    26. When studying a pattern that contained subroutine calls or assertions,
345        the code for finding the minimum length of a possible match was handling
346        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
347        group 1 called group 2 while simultaneously a separate group 2 called group
348        1). A stack overflow occurred in this case. I have fixed this by limiting
349        the recursion depth to 10.
350    
351    27. Updated RunTest.bat in the distribution to the version supplied by Tom
352        Fortmann. This supports explicit test numbers on the command line, and has
353        argument validation and error reporting.
354    
355    28. An instance of \X with an unlimited repeat could fail if at any point the
356        first character it looked at was a mark character.
357    
358    29. Some minor code refactoring concerning Unicode properties and scripts
359        should reduce the stack requirement of match() slightly.
360    
361    30. Added the '=' option to pcretest to check the setting of unused capturing
362        slots at the end of the pattern, which are documented as being -1, but are
363        not included in the return count.
364    
365    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
366        compiled something random. Now it gives a compile-time error (as does
367        Perl).
368    
369    32. A *MARK encountered during the processing of a positive assertion is now
370        recorded and passed back (compatible with Perl).
371    
372    33. If --only-matching or --colour was set on a pcregrep call whose pattern
373        had alternative anchored branches, the search for a second match in a line
374        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
375        matched the line "0102" twice. The same bug affected patterns that started
376        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
377        twice.
378    
379    34. Previously, PCRE did not allow quantification of assertions. However, Perl
380        does, and because of capturing effects, quantifying parenthesized
381        assertions may at times be useful. Quantifiers are now allowed for
382        parenthesized assertions.
383    
384    35. A minor code tidy in pcre_compile() when checking options for \R usage.
385    
386    36. \g was being checked for fancy things in a character class, when it should
387        just be a literal "g".
388    
389    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
390        appearance of a nested POSIX class supersedes an apparent external class.
391        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
392        unescaped square brackets may also appear as part of class names. For
393        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
394        more like Perl. (But see 8.20/1 above.)
395    
396    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
397        was because it thought it was \N{name}, which is not supported).
398    
399    39. Add minix to OS list not supporting the -S option in pcretest.
400    
401    40. PCRE tries to detect cases of infinite recursion at compile time, but it
402        cannot analyze patterns in sufficient detail to catch mutual recursions
403        such as ((?1))((?2)). There is now a runtime test that gives an error if a
404        subgroup is called recursively as a subpattern for a second time at the
405        same position in the subject string. In previous releases this might have
406        been caught by the recursion limit, or it might have run out of stack.
407    
408    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
409        happen only once. PCRE was, however incorrectly giving a compile time error
410        "recursive call could loop indefinitely" because it cannot analyze the
411        pattern in sufficient detail. The compile time test no longer happens when
412        PCRE is compiling a conditional subpattern, but actual runaway loops are
413        now caught at runtime (see 40 above).
414    
415    42. It seems that Perl allows any characters other than a closing parenthesis
416        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
417        has been changed to be the same.
418    
419    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
420        as not to get warnings when autogen.sh is called. Also changed
421        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
422    
423    44. To help people who use pcregrep to scan files containing exceedingly long
424        lines, the following changes have been made:
425    
426        (a) The default value of the buffer size parameter has been increased from
427            8K to 20K. (The actual buffer used is three times this size.)
428    
429        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
430            PCRE is built.
431    
432        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
433            to be set at run time.
434    
435        (d) Numerical values in pcregrep options can be followed by K or M, for
436            example --buffer-size=50K.
437    
438        (e) If a line being scanned overflows pcregrep's buffer, an error is now
439            given and the return code is set to 2.
440    
441    45. Add a pointer to the latest mark to the callout data block.
442    
443    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
444        partial match of an empty string instead of no match. This was specific to
445        the use of ".".
446    
447    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
448        complete match instead of a partial match. This bug was dependent on both
449        the PCRE_UTF8 and PCRE_DOTALL options being set.
450    
451    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
452        starting byte set, because \b was not being ignored.
453    
454    
455    Version 8.12 15-Jan-2011
456    ------------------------
457    
458    1.  Fixed some typos in the markup of the man pages, and wrote a script that
459        checks for such things as part of the documentation building process.
460    
461    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
462        --match-limit and --recursion-limit options (added for 8.11). In
463        particular, this made one of the standard tests fail. (The integer value
464        went into the wrong half of a long int.)
465    
466    3.  If the --colour option was given to pcregrep with -v (invert match), it
467        did strange things, either producing crazy output, or crashing. It should,
468        of course, ignore a request for colour when reporting lines that do not
469        match.
470    
471    4.  Another pcregrep bug caused similar problems if --colour was specified with
472        -M (multiline) and the pattern match finished with a line ending.
473    
474    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
475        matched in multiline mode, the following line was shown as part of the
476        match. This seems wrong, so I have changed it.
477    
478    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
479        the check for further matches in the same line (so they could be coloured)
480        to overrun the end of the current line. If another match was found, it was
481        incorrectly shown (and then shown again when found in the next line).
482    
483    7.  If pcregrep was compiled under Windows, there was a reference to the
484        function pcregrep_exit() before it was defined. I am assuming this was
485        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
486        reported by a user. I've moved the definition above the reference.
487    
488    
489    Version 8.11 10-Dec-2010
490    ------------------------
491    
492    1.  (*THEN) was not working properly if there were untried alternatives prior
493        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
494        backtracked to try for "b" instead of moving to the next alternative branch
495        at the same level (in this case, to look for "c"). The Perl documentation
496        is clear that when (*THEN) is backtracked onto, it goes to the "next
497        alternative in the innermost enclosing group".
498    
499    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
500        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
501        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
502        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
503        (*THEN).
504    
505    3.  If \s appeared in a character class, it removed the VT character from
506        the class, even if it had been included by some previous item, for example
507        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
508        of \s, but is part of the POSIX "space" class.)
509    
510    4.  A partial match never returns an empty string (because you can always
511        match an empty string at the end of the subject); however the checking for
512        an empty string was starting at the "start of match" point. This has been
513        changed to the "earliest inspected character" point, because the returned
514        data for a partial match starts at this character. This means that, for
515        example, /(?<=abc)def/ gives a partial match for the subject "abc"
516        (previously it gave "no match").
517    
518    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
519        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
520        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
521        has an implication that the given string is incomplete (because a partial
522        match is preferred over a full match). For this reason, these items now
523        give a partial match in this situation. [Aside: previously, the one case
524        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
525        match rather than a full match, which was wrong by the old rules, but is
526        now correct.]
527    
528    6.  There was a bug in the handling of #-introduced comments, recognized when
529        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
530        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
531        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
532        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
533        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
534        places in pcre_compile().
535    
536    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
537        comments when looking ahead for named forward references to subpatterns,
538        the only newline sequence it recognized was NL. It now handles newlines
539        according to the set newline convention.
540    
541    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
542        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
543        cater for a lack of strerror(). These oversights have been fixed.
544    
545    9.  Added --match-limit and --recursion-limit to pcregrep.
546    
547    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
548    
549    11. When the -o option was used, pcregrep was setting a return code of 1, even
550        when matches were found, and --line-buffered was not being honoured.
551    
552    12. Added an optional parentheses number to the -o and --only-matching options
553        of pcregrep.
554    
555    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
556        can match an empty string. The code to do it in pcretest and pcredemo
557        needed fixing:
558    
559        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
560            only one byte after an empty string match just before CRLF (this case
561            just got forgotten; "any" and "anycrlf" were OK).
562    
563        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
564            mode when an empty string match preceded an ASCII character followed by
565            a non-ASCII character. (The code for advancing by one character rather
566            than one byte was nonsense.)
567    
568        (c) The pcredemo.c sample program did not have any code at all to handle
569            the cases when CRLF is a valid newline sequence.
570    
571    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
572        as a starting offset was within the subject string. There is now a new
573        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
574        negative or greater than the length of the string. In order to test this,
575        pcretest is extended to allow the setting of negative starting offsets.
576    
577    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
578        starting offset points to the beginning of a UTF-8 character was
579        unnecessarily clumsy. I tidied it up.
580    
581    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
582        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
583    
584    17. Nobody had reported that the --include_dir option, which was added in
585        release 7.7 should have been called --include-dir (hyphen, not underscore)
586        for compatibility with GNU grep. I have changed it to --include-dir, but
587        left --include_dir as an undocumented synonym, and the same for
588        --exclude-dir, though that is not available in GNU grep, at least as of
589        release 2.5.4.
590    
591    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
592        characters from a string of bytes) have been redefined so as not to use
593        loops, in order to improve performance in some environments. At the same
594        time, I abstracted some of the common code into auxiliary macros to save
595        repetition (this should not affect the compiled code).
596    
597    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
598        compile-time error is now given if \c is not followed by an ASCII
599        character, that is, a byte less than 128. (In EBCDIC mode, the code is
600        different, and any byte value is allowed.)
601    
602    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
603        START_OPTIMIZE option, which is now allowed at compile time - but just
604        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
605        to pcregrep and other applications that have no direct access to PCRE
606        options. The new /Y option in pcretest sets this option when calling
607        pcre_compile().
608    
609    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
610        back references. Groups containing recursive back references were forced to
611        be atomic by that change, but in the case of named groups, the amount of
612        memory required was incorrectly computed, leading to "Failed: internal
613        error: code overflow". This has been fixed.
614    
615    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
616        pcretest.c, to avoid build problems in some Borland environments.
617    
618    
619    Version 8.10 25-Jun-2010
620    ------------------------
621    
622    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
623        THEN.
624    
625    2.  (*ACCEPT) was not working when inside an atomic group.
626    
627    3.  Inside a character class, \B is treated as a literal by default, but
628        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
629        causes the error). The code is unchanged, but I tidied the documentation.
630    
631    4.  Inside a character class, PCRE always treated \R and \X as literals,
632        whereas Perl faults them if its -w option is set. I have changed PCRE so
633        that it faults them when PCRE_EXTRA is set.
634    
635    5.  Added support for \N, which always matches any character other than
636        newline. (It is the same as "." when PCRE_DOTALL is not set.)
637    
638    6.  When compiling pcregrep with newer versions of gcc which may have
639        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
640        declared with attribute warn_unused_result" were given. Just casting the
641        result to (void) does not stop the warnings; a more elaborate fudge is
642        needed. I've used a macro to implement this.
643    
644    7.  Minor change to pcretest.c to avoid a compiler warning.
645    
646    8.  Added four artifical Unicode properties to help with an option to make
647        \s etc use properties (see next item). The new properties are: Xan
648        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
649    
650    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
651        use Unicode properties. (*UCP) at the start of a pattern can be used to set
652        this option. Modified pcretest to add /W to test this facility. Added
653        REG_UCP to make it available via the POSIX interface.
654    
655    10. Added --line-buffered to pcregrep.
656    
657    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
658        studied, and the match started with a letter with a code point greater than
659        127 whose first byte was different to the first byte of the other case of
660        the letter, the other case of this starting letter was not recognized
661        (#976).
662    
663    12. If a pattern that was studied started with a repeated Unicode property
664        test, for example, \p{Nd}+, there was the theoretical possibility of
665        setting up an incorrect bitmap of starting bytes, but fortunately it could
666        not have actually happened in practice until change 8 above was made (it
667        added property types that matched character-matching opcodes).
668    
669    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
670        possible starting bytes for non-anchored patterns.
671    
672    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
673        \R, and also a number of cases that involve Unicode properties, both
674        explicit and implicit when PCRE_UCP is set.
675    
676    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
677        input, it could crash or give wrong results if characters with values
678        greater than 0xc0 were present in the subject string. (Detail: it assumed
679        UTF-8 input when processing these items.)
680    
681    16. Added a lot of (int) casts to avoid compiler warnings in systems where
682        size_t is 64-bit (#991).
683    
684    17. Added a check for running out of memory when PCRE is compiled with
685        --disable-stack-for-recursion (#990).
686    
687    18. If the last data line in a file for pcretest does not have a newline on
688        the end, a newline was missing in the output.
689    
690    19. The default pcre_chartables.c file recognizes only ASCII characters (values
691        less than 128) in its various bitmaps. However, there is a facility for
692        generating tables according to the current locale when PCRE is compiled. It
693        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
694        characters, are recognized by isspace() and therefore were getting set in
695        these tables, and indeed these tables seem to approximate to ISO 8859. This
696        caused a problem in UTF-8 mode when pcre_study() was used to create a list
697        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
698        which of course cannot start UTF-8 characters. I have changed the code so
699        that only real ASCII characters (less than 128) and the correct starting
700        bytes for UTF-8 encodings are set for characters greater than 127 when in
701        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
702        altogether.)
703    
704    20. Added the /T option to pcretest so as to be able to run tests with non-
705        standard character tables, thus making it possible to include the tests
706        used for 19 above in the standard set of tests.
707    
708    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
709        reference to a subpattern the other side of a comment that contains an
710        opening parenthesis caused either an internal compiling error, or a
711        reference to the wrong subpattern.
712    
713    
714    Version 8.02 19-Mar-2010
715    ------------------------
716    
717    1.  The Unicode data tables have been updated to Unicode 5.2.0.
718    
719    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
720        configured.
721    
722    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
723        original author of that file, following a query about its status.
724    
725    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
726        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
727    
728    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
729        quantifier applied to a forward-referencing subroutine call, could compile
730        incorrect code or give the error "internal error: previously-checked
731        referenced subpattern not found".
732    
733    6.  Both MS Visual Studio and Symbian OS have problems with initializing
734        variables to point to external functions. For these systems, therefore,
735        pcre_malloc etc. are now initialized to local functions that call the
736        relevant global functions.
737    
738    7.  There were two entries missing in the vectors called coptable and poptable
739        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
740        I've fixed the data, and added a kludgy way of testing at compile time that
741        the lengths are correct (equal to the number of opcodes).
742    
743    8.  Following on from 7, I added a similar kludge to check the length of the
744        eint vector in pcreposix.c.
745    
746    9.  Error texts for pcre_compile() are held as one long string to avoid too
747        much relocation at load time. To find a text, the string is searched,
748        counting zeros. There was no check for running off the end of the string,
749        which could happen if a new error number was added without updating the
750        string.
751    
752    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
753    
754    11. \K was not working if it appeared in an atomic group or in a group that
755        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
756        \K is "not well defined" if used in an assertion. PCRE now accepts it if
757        the assertion is positive, but not if it is negative.
758    
759    12. Change 11 fortuitously reduced the size of the stack frame used in the
760        "match()" function of pcre_exec.c by one pointer. Forthcoming
761        implementation of support for (*MARK) will need an extra pointer on the
762        stack; I have reserved it now, so that the stack frame size does not
763        decrease.
764    
765    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
766        item in branch that calls a recursion is a subroutine call - as in the
767        second branch in the above example - was incorrectly given the compile-
768        time error "recursive call could loop indefinitely" because pcre_compile()
769        was not correctly checking the subroutine for matching a non-empty string.
770    
771    14. The checks for overrunning compiling workspace could trigger after an
772        overrun had occurred. This is a "should never occur" error, but it can be
773        triggered by pathological patterns such as hundreds of nested parentheses.
774        The checks now trigger 100 bytes before the end of the workspace.
775    
776    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
777    
778    
779    Version 8.01 19-Jan-2010
780    ------------------------
781    
782    1.  If a pattern contained a conditional subpattern with only one branch (in
783        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
784        computed the wrong minimum data length (which is of course zero for such
785        subpatterns). This could cause incorrect "no match" results.
786    
787    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
788        the pattern is reset in the first branch, pcre_compile() failed with
789        "internal error: code overflow at offset...". This happened only when
790        the reset was to the original external option setting. (An optimization
791        abstracts leading options settings into an external setting, which was the
792        cause of this.)
793    
794    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
795        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
796        assertion pattern did not match (meaning that the assertion was true), it
797        was incorrectly treated as false if the SKIP had been reached during the
798        matching. This also applied to assertions used as conditions.
799    
800    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
801        assertion subpattern, including such a pattern used as a condition,
802        unpredictable results occurred, instead of the error return
803        PCRE_ERROR_DFA_UITEM.
804    
805    5.  The C++ GlobalReplace function was not working like Perl for the special
806        situation when an empty string is matched. It now does the fancy magic
807        stuff that is necessary.
808    
809    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
810        removed. (These were left over from very, very early versions of PCRE.)
811    
812    7.  Some cosmetic changes to the code to make life easier when compiling it
813        as part of something else:
814    
815        (a) Change DEBUG to PCRE_DEBUG.
816    
817        (b) In pcre_compile(), rename the member of the "branch_chain" structure
818            called "current" as "current_branch", to prevent a collision with the
819            Linux macro when compiled as a kernel module.
820    
821        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
822            prevent a collision with the Linux macro when compiled as a kernel
823            module.
824    
825    8.  In pcre_compile() there are some checks for integer overflows that used to
826        cast potentially large values to (double). This has been changed to that
827        when building, a check for int64_t is made, and if it is found, it is used
828        instead, thus avoiding the use of floating point arithmetic. (There is no
829        other use of FP in PCRE.) If int64_t is not found, the fallback is to
830        double.
831    
832    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
833        2005 (difference between two addresses compared to an unsigned value).
834    
835    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
836        custom one, because of the following reported problem in Windows:
837    
838          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
839              under Win32.
840          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
841              therefore missing the function definition.
842          - The compiler thus generates a "C" signature for the test function.
843          - The linker fails to find the "C" function.
844          - PCRE fails to configure if asked to do so against libbz2.
845    
846    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
847        messages were output:
848    
849          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
850          rerunning libtoolize, to keep the correct libtool macros in-tree.
851          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
852    
853        I have done both of these things.
854    
855    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
856        most of the time, it *can* run out if it is given a pattern that contains a
857        runaway infinite recursion. I updated the discussion in the pcrestack man
858        page.
859    
860    13. Now that we have gone to the x.xx style of version numbers, the minor
861        version may start with zero. Using 08 or 09 is a bad idea because users
862        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
863        interpreted as invalid octal numbers. I've updated the previous comment in
864        configure.ac, and also added a check that gives an error if 08 or 09 are
865        used.
866    
867    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
868        causing partial matching to fail when the end of the subject matched \W
869        in a UTF-8 pattern where \W was quantified with a minimum of 3.
870    
871    15. There were some discrepancies between the declarations in pcre_internal.h
872        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
873        their definitions. The declarations used "const uschar *" and the
874        definitions used USPTR. Even though USPTR is normally defined as "const
875        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
876        reported that: "This difference in casting confuses some C++ compilers, for
877        example, SunCC recognizes above declarations as different functions and
878        generates broken code for hbpcre." I have changed the declarations to use
879        USPTR.
880    
881    16. GNU libtool is named differently on some systems. The autogen.sh script now
882        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
883        (FreeBSD).
884    
885    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
886        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
887        comment: "Figure out how to create a longlong from a string: strtoll and
888        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
889        instance, but it only takes 2 args instead of 3!"
890    
891    18. A subtle bug concerned with back references has been fixed by a change of
892        specification, with a corresponding code fix. A pattern such as
893        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
894        refers, was giving matches when it shouldn't. For example, xa=xaaa would
895        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
896        same bug. Such groups have to be quantified to be useful, or contained
897        inside another quantified group. (If there's no repetition, the reference
898        can never match.) The problem arises because, having left the group and
899        moved on to the rest of the pattern, a later failure that backtracks into
900        the group uses the captured value from the final iteration of the group
901        rather than the correct earlier one. I have fixed this in PCRE by forcing
902        any group that contains a reference to itself to be an atomic group; that
903        is, there cannot be any backtracking into it once it has completed. This is
904        similar to recursive and subroutine calls.
905    
906    
907    Version 8.00 19-Oct-09
908    ----------------------
909    
910    1.  The table for translating pcre_compile() error codes into POSIX error codes
911        was out-of-date, and there was no check on the pcre_compile() error code
912        being within the table. This could lead to an OK return being given in
913        error.
914    
915    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
916        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
917        in a Windows environment.
918    
919    3.  The pcregrep --count option prints the count for each file even when it is
920        zero, as does GNU grep. However, pcregrep was also printing all files when
921        --files-with-matches was added. Now, when both options are given, it prints
922        counts only for those files that have at least one match. (GNU grep just
923        prints the file name in this circumstance, but including the count seems
924        more useful - otherwise, why use --count?) Also ensured that the
925        combination -clh just lists non-zero counts, with no names.
926    
927    4.  The long form of the pcregrep -F option was incorrectly implemented as
928        --fixed_strings instead of --fixed-strings. This is an incompatible change,
929        but it seems right to fix it, and I didn't think it was worth preserving
930        the old behaviour.
931    
932    5.  The command line items --regex=pattern and --regexp=pattern were not
933        recognized by pcregrep, which required --regex pattern or --regexp pattern
934        (with a space rather than an '='). The man page documented the '=' forms,
935        which are compatible with GNU grep; these now work.
936    
937    6.  No libpcreposix.pc file was created for pkg-config; there was just
938        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
939    
940    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
941        when UCP support is not needed, by modifying the Python script that
942        generates it from Unicode data files. This should not matter if the module
943        is correctly used as a library, but I received one complaint about 50K of
944        unwanted data. My guess is that the person linked everything into his
945        program rather than using a library. Anyway, it does no harm.
946    
947    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
948        was a minimum greater than 1 for a wide character in a possessive
949        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
950        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
951        character. Chaos in the form of incorrect output or a compiling loop could
952        result.
953    
954    9.  The restrictions on what a pattern can contain when partial matching is
955        requested for pcre_exec() have been removed. All patterns can now be
956        partially matched by this function. In addition, if there are at least two
957        slots in the offset vector, the offset of the earliest inspected character
958        for the match and the offset of the end of the subject are set in them when
959        PCRE_ERROR_PARTIAL is returned.
960    
961    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
962        synonymous with PCRE_PARTIAL, for backwards compatibility, and
963        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
964        and may be more useful for multi-segment matching.
965    
966    11. Partial matching with pcre_exec() is now more intuitive. A partial match
967        used to be given if ever the end of the subject was reached; now it is
968        given only if matching could not proceed because another character was
969        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
970        string "Z", which now yields "no match" instead of "partial match". In the
971        case of pcre_dfa_exec(), "no match" is given if every matching path for the
972        final character ended with (*FAIL).
973    
974    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
975        if the pattern had a "must contain" character that was already found in the
976        earlier partial match, unless partial matching was again requested. For
977        example, with the pattern /dog.(body)?/, the "must contain" character is
978        "g". If the first part-match was for the string "dog", restarting with
979        "sbody" failed. This bug has been fixed.
980    
981    13. The string returned by pcre_dfa_exec() after a partial match has been
982        changed so that it starts at the first inspected character rather than the
983        first character of the match. This makes a difference only if the pattern
984        starts with a lookbehind assertion or \b or \B (\K is not supported by
985        pcre_dfa_exec()). It's an incompatible change, but it makes the two
986        matching functions compatible, and I think it's the right thing to do.
987    
988    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
989        so that the demonstration program is easily available in environments where
990        PCRE has not been installed from source.
991    
992    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
993        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
994        library.
995    
996    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
997        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
998        is not the first non-POSIX option to be added. Clearly some people find
999        these options useful.
1000    
1001    17. If a caller to the POSIX matching function regexec() passes a non-zero
1002        value for nmatch with a NULL value for pmatch, the value of
1003        nmatch is forced to zero.
1004    
1005    18. RunGrepTest did not have a test for the availability of the -u option of
1006        the diff command, as RunTest does. It now checks in the same way as
1007        RunTest, and also checks for the -b option.
1008    
1009    19. If an odd number of negated classes containing just a single character
1010        interposed, within parentheses, between a forward reference to a named
1011        subpattern and the definition of the subpattern, compilation crashed with
1012        an internal error, complaining that it could not find the referenced
1013        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1014        [The bug was that it was starting one character too far in when skipping
1015        over the character class, thus treating the ] as data rather than
1016        terminating the class. This meant it could skip too much.]
1017    
1018    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1019        /g option in pcretest when the pattern contains \K, which makes it possible
1020        to have an empty string match not at the start, even when the pattern is
1021        anchored. Updated pcretest and pcredemo to use this option.
1022    
1023    21. If the maximum number of capturing subpatterns in a recursion was greater
1024        than the maximum at the outer level, the higher number was returned, but
1025        with unset values at the outer level. The correct (outer level) value is
1026        now given.
1027    
1028    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1029        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1030        make it do so. The string so far is captured, making this feature
1031        compatible with Perl.
1032    
1033    23. The tests have been re-organized, adding tests 11 and 12, to make it
1034        possible to check the Perl 5.10 features against Perl 5.10.
1035    
1036    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1037        pattern matches a fixed length string. PCRE did not allow this; now it
1038        does. Neither allows recursion.
1039    
1040    25. I finally figured out how to implement a request to provide the minimum
1041        length of subject string that was needed in order to match a given pattern.
1042        (It was back references and recursion that I had previously got hung up
1043        on.) This code has now been added to pcre_study(); it finds a lower bound
1044        to the length of subject needed. It is not necessarily the greatest lower
1045        bound, but using it to avoid searching strings that are too short does give
1046        some useful speed-ups. The value is available to calling programs via
1047        pcre_fullinfo().
1048    
1049    26. While implementing 25, I discovered to my embarrassment that pcretest had
1050        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1051        study optimizations had never been tested with that matching function.
1052        Oops. What is worse, even when it was passed study data, there was a bug in
1053        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1054        were also very few tests of studied patterns with pcre_dfa_exec().
1055    
1056    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1057        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1058        on the other side of the coin, they are no longer allowed to have different
1059        names, because these cannot be distinguished in PCRE, and this has caused
1060        confusion. (This is a difference from Perl.)
1061    
1062    28. When duplicate subpattern names are present (necessarily with different
1063        numbers, as required by 27 above), and a test is made by name in a
1064        conditional pattern, either for a subpattern having been matched, or for
1065        recursion in such a pattern, all the associated numbered subpatterns are
1066        tested, and the overall condition is true if the condition is true for any
1067        one of them. This is the way Perl works, and is also more like the way
1068        testing by number works.
1069    
1070    
1071    Version 7.9 11-Apr-09
1072    ---------------------
1073    
1074    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1075        (pcretest), all targets were linked against these libraries. This included
1076        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1077        libraries. This caused unwanted dependencies to be created. This problem
1078        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1079        pcretest is linked with readline.
1080    
1081    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1082        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1083        moved outside it again, because FALSE and TRUE are already defined in AIX,
1084        but BOOL is not.
1085    
1086    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1087        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1088    
1089    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1090        hyphens) following file names and line numbers when outputting matching
1091        lines. This is not true; no spaces are inserted. I have also clarified the
1092        wording for the --colour (or --color) option.
1093    
1094    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1095        was not coloured; this is different to GNU grep, so I have changed it to be
1096        the same.
1097    
1098    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1099        each matching line was coloured. Now it goes on to look for further matches
1100        of any of the test patterns, which is the same behaviour as GNU grep.
1101    
1102    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1103        doesn't make sense to accept an empty string match in pcregrep, so I have
1104        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1105        seems to be how GNU grep behaves.
1106    
1107    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1108        start or after a newline", because the conditional assertion was not being
1109        correctly handled. The rule now is that both the assertion and what follows
1110        in the first alternative must satisfy the test.
1111    
1112    9.  If auto-callout was enabled in a pattern with a conditional group whose
1113        condition was an assertion, PCRE could crash during matching, both with
1114        pcre_exec() and pcre_dfa_exec().
1115    
1116    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1117        used for matching.
1118    
1119    11. Unicode property support in character classes was not working for
1120        characters (bytes) greater than 127 when not in UTF-8 mode.
1121    
1122    12. Added the -M command line option to pcretest.
1123    
1124    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1125    
1126    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1127    
1128    16. Added comments and documentation about mis-use of no_arg in the C++
1129        wrapper.
1130    
1131    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1132        from Martin Jerabek that uses macro names for all relevant character and
1133        string constants.
1134    
1135    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1136        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1137        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1138        these, but not everybody uses configure.
1139    
1140    19. A conditional group that had only one branch was not being correctly
1141        recognized as an item that could match an empty string. This meant that an
1142        enclosing group might also not be so recognized, causing infinite looping
1143        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1144        with the subject "ab", where knowledge that the repeated group can match
1145        nothing is needed in order to break the loop.
1146    
1147    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1148        exec(), but without supplying a callout function, matching went wrong.
1149    
1150    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1151        leak if the size of the offset vector was greater than 30. When the vector
1152        is smaller, the saved offsets during recursion go onto a local stack
1153        vector, but for larger vectors malloc() is used. It was failing to free
1154        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1155        error, in fact).
1156    
1157    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1158        heapframe that is used only when UTF-8 support is enabled. This caused no
1159        problem, but was untidy.
1160    
1161    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1162        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1163        included within another project.
1164    
1165    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1166        slightly modified by me:
1167    
1168          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1169              not building pcregrep.
1170    
1171          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1172              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1173    
1174    25. Forward references, both numeric and by name, in patterns that made use of
1175        duplicate group numbers, could behave incorrectly or give incorrect errors,
1176        because when scanning forward to find the reference group, PCRE was not
1177        taking into account the duplicate group numbers. A pattern such as
1178        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1179    
1180    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1181        the feature of a custom pointer more persuasive (as requested by a user).
1182    
1183    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1184        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1185        pre-defined.
1186    
1187    28. Added support for (*UTF8) at the start of a pattern.
1188    
1189    29. Arrange for flags added by the "release type" setting in CMake to be shown
1190        in the configuration summary.
1191    
1192    
1193    Version 7.8 05-Sep-08
1194    ---------------------
1195    
1196    1.  Replaced UCP searching code with optimized version as implemented for Ad
1197        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1198        stage table and inline lookup instead of a function, giving speed ups of 2
1199        to 5 times on some simple patterns that I tested. Permission was given to
1200        distribute the MultiStage2.py script that generates the tables (it's not in
1201        the tarball, but is in the Subversion repository).
1202    
1203    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1204        scripts.
1205    
1206    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1207        a group with a zero qualifier. The result of the study could be incorrect,
1208        or the function might crash, depending on the pattern.
1209    
1210    4.  Caseless matching was not working for non-ASCII characters in back
1211        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1212        It now works when Unicode Property Support is available.
1213    
1214    5.  In pcretest, an escape such as \x{de} in the data was always generating
1215        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1216        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1217        truncation.
1218    
1219    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1220    
1221    7.  Added two (int) casts to pcregrep when printing the difference of two
1222        pointers, in case they are 64-bit values.
1223    
1224    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1225        test 2 if it fails.
1226    
1227    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1228        and a #define of that name to empty if it is not externally set. This is to
1229        allow users of MSVC to set it if necessary.
1230    
1231    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1232        the convenience functions in the pcre_get.c source file.
1233    
1234    11. An option change at the start of a pattern that had top-level alternatives
1235        could cause overwriting and/or a crash. This command provoked a crash in
1236        some environments:
1237    
1238          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1239    
1240        This potential security problem was recorded as CVE-2008-2371.
1241    
1242    12. For a pattern where the match had to start at the beginning or immediately
1243        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1244        pcre_dfa_exec() could read past the end of the passed subject if there was
1245        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1246        pcretest so that it places the subject at the end of its malloc-ed buffer.
1247    
1248    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1249        exec() might read past the end of the data buffer in UTF-8 mode.
1250    
1251    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1252        the data contained the byte 0x85 as part of a UTF-8 character within its
1253        first line. This applied both to normal and DFA matching.
1254    
1255    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1256        /^[^d]*?$/8 failed to match "abc".
1257    
1258    16. Added a missing copyright notice to pcrecpp_internal.h.
1259    
1260    17. Make it more clear in the documentation that values returned from
1261        pcre_exec() in ovector are byte offsets, not character counts.
1262    
1263    18. Tidied a few places to stop certain compilers from issuing warnings.
1264    
1265    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1266        supplied by Stefan Weber. I made a further small update for 7.8 because
1267        there is a change of source arrangements: the pcre_searchfuncs.c module is
1268        replaced by pcre_ucd.c.
1269    
1270    
1271    Version 7.7 07-May-08
1272    ---------------------
1273    
1274    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1275        a string to a long long, pretend we don't even have a long long." This is
1276        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1277    
1278    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1279        pre-7.6 versions, which defined a global no_arg variable instead of putting
1280        it in the RE class. (See also #8 below.)
1281    
1282    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1283        Lopes.
1284    
1285    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1286    
1287        (1) The include/exclude patterns were being applied to the whole pathnames
1288            of files, instead of just to the final components.
1289    
1290        (2) If there was more than one level of directory, the subdirectories were
1291            skipped unless they satisfied the include/exclude conditions. This is
1292            inconsistent with GNU grep (and could even be seen as contrary to the
1293            pcregrep specification - which I improved to make it absolutely clear).
1294            The action now is always to scan all levels of directory, and just
1295            apply the include/exclude patterns to regular files.
1296    
1297    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1298        --exclude_dir in the tests to avoid scanning .svn directories.
1299    
1300    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1301        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1302        doesn't support NULs in patterns.
1303    
1304    7.  Added some missing "const"s to declarations of static tables in
1305        pcre_compile.c and pcre_dfa_exec.c.
1306    
1307    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1308        caused by fix #2  above. (Subsequently also a second patch to fix the
1309        first patch. And a third patch - this was a messy problem.)
1310    
1311    9.  Applied Craig's patch to remove the use of push_back().
1312    
1313    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1314        matching function regexec().
1315    
1316    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1317        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1318        references. PCRE supports relative numbers with this syntax (I don't think
1319        Oniguruma does).
1320    
1321    12. Previously, a group with a zero repeat such as (...){0} was completely
1322        omitted from the compiled regex. However, this means that if the group
1323        was called as a subroutine from elsewhere in the pattern, things went wrong
1324        (an internal error was given). Such groups are now left in the compiled
1325        pattern, with a new opcode that causes them to be skipped at execution
1326        time.
1327    
1328    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1329        to the way PCRE behaves:
1330    
1331        (a) A lone ] character is dis-allowed (Perl treats it as data).
1332    
1333        (b) A back reference to an unmatched subpattern matches an empty string
1334            (Perl fails the current match path).
1335    
1336        (c) A data ] in a character class must be notated as \] because if the
1337            first data character in a class is ], it defines an empty class. (In
1338            Perl it is not possible to have an empty class.) The empty class []
1339            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1340            The negative empty class [^] matches any one character, independently
1341            of the DOTALL setting.
1342    
1343    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1344        non-existent subpattern following a character class starting with ']' and
1345        containing () gave an internal compiling error instead of "reference to
1346        non-existent subpattern". Fortunately, when the pattern did exist, the
1347        compiled code was correct. (When scanning forwards to check for the
1348        existencd of the subpattern, it was treating the data ']' as terminating
1349        the class, so got the count wrong. When actually compiling, the reference
1350        was subsequently set up correctly.)
1351    
1352    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1353        it was being rejected as not supported by pcre_dfa_exec(), even though
1354        other assertions are supported. I have made pcre_dfa_exec() support
1355        (*FAIL).
1356    
1357    16. The implementation of 13c above involved the invention of a new opcode,
1358        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1359        cannot be changed at match time, I realized I could make a small
1360        improvement to matching performance by compiling OP_ALLANY instead of
1361        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1362        on the OP_ANY path.
1363    
1364    17. Compiling pcretest on Windows with readline support failed without the
1365        following two fixes: (1) Make the unistd.h include conditional on
1366        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1367    
1368    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1369        ncurses library to be included for pcretest when ReadLine support is
1370        requested, but also to allow for it to be overridden. This patch came from
1371        Daniel Bergström.
1372    
1373    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1374        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1375        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1376        spotting this.
1377    
1378    
1379    Version 7.6 28-Jan-08
1380    ---------------------
1381    
1382    1.  A character class containing a very large number of characters with
1383        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1384        overflow.
1385    
1386    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1387        HAVE_LONG_LONG is not defined.
1388    
1389    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1390        bring them up to date and include new features. This patch includes:
1391    
1392        - Fixed PH's badly added libz and libbz2 support.
1393        - Fixed a problem with static linking.
1394        - Added pcredemo. [But later removed - see 7 below.]
1395        - Fixed dftables problem and added an option.
1396        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1397            HAVE_LONG_LONG.
1398        - Added readline support for pcretest.
1399        - Added an listing of the option settings after cmake has run.
1400    
1401    4.  A user submitted a patch to Makefile that makes it easy to create
1402        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1403        Makefile.am that cause it to include this special target, without
1404        affecting anything else. Note that the same mingw target plus all
1405        the other distribution libraries and programs are now supported
1406        when configuring with CMake (see 6 below) instead of with
1407        Configure/Make.
1408    
1409    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1410        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1411        exported in the Windows port". It has not yet been confirmed that the patch
1412        solves the problem, but it does no harm.
1413    
1414    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1415        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1416        with CMake, and also correct the comment about stack recursion.
1417    
1418    7.  Remove the automatic building of pcredemo from the ./configure system and
1419        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1420        of a program that users should build themselves after PCRE is installed, so
1421        building it automatically is not really right. What is more, it gave
1422        trouble in some build environments.
1423    
1424    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1425    
1426    
1427    Version 7.5 10-Jan-08
1428    ---------------------
1429    
1430    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1431        values in parens when parsing an RE using the C++ wrapper."
1432    
1433    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1434        Characters greater than 255 were excluded from the class instead of being
1435        included.
1436    
1437    3.  The same bug as (2) above applied to negated POSIX classes such as
1438        [:^space:].
1439    
1440    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1441        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1442        I have changed it.
1443    
1444    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1445        first named subpattern) and a construct such as (?&a) would reference the
1446        first named subpattern whose name started with "a" (in other words, the
1447        length check was missing). Both these problems are fixed. "Subpattern name
1448        expected" is now given for (?&) (a zero-length name), and this patch also
1449        makes it give the same error for \k'' (previously it complained that that
1450        was a reference to a non-existent subpattern).
1451    
1452    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1453        this is right because (?- can be followed by option settings as well as by
1454        digits. I have, however, made the messages clearer.
1455    
1456    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1457        than the number used in the conditional) now cause a compile-time error.
1458        This is actually not compatible with Perl, which accepts such patterns, but
1459        treats the conditional as always being FALSE (as PCRE used to), but it
1460        seems to me that giving a diagnostic is better.
1461    
1462    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1463        and messages.
1464    
1465    9.  Fix two occurrences of "backslash" in comments that should have been
1466        "backspace".
1467    
1468    10. Remove two redundant lines of code that can never be obeyed (their function
1469        was moved elsewhere).
1470    
1471    11. The program that makes PCRE's Unicode character property table had a bug
1472        which caused it to generate incorrect table entries for sequences of
1473        characters that have the same character type, but are in different scripts.
1474        It amalgamated them into a single range, with the script of the first of
1475        them. In other words, some characters were in the wrong script. There were
1476        thirteen such cases, affecting characters in the following ranges:
1477    
1478          U+002b0 - U+002c1
1479          U+0060c - U+0060d
1480          U+0061e - U+00612
1481          U+0064b - U+0065e
1482          U+0074d - U+0076d
1483          U+01800 - U+01805
1484          U+01d00 - U+01d77
1485          U+01d9b - U+01dbf
1486          U+0200b - U+0200f
1487          U+030fc - U+030fe
1488          U+03260 - U+0327f
1489          U+0fb46 - U+0fbb1
1490          U+10450 - U+1049d
1491    
1492    12. The -o option (show only the matching part of a line) for pcregrep was not
1493        compatible with GNU grep in that, if there was more than one match in a
1494        line, it showed only the first of them. It now behaves in the same way as
1495        GNU grep.
1496    
1497    13. If the -o and -v options were combined for pcregrep, it printed a blank
1498        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1499        does the same. The return code can be used to tell if there were any
1500        non-matching lines.
1501    
1502    14. Added --file-offsets and --line-offsets to pcregrep.
1503    
1504    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1505        infinitely looping recursion. The bug was that positive lookaheads were not
1506        being skipped when checking for a possible empty match (negative lookaheads
1507        and both kinds of lookbehind were skipped).
1508    
1509    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1510        inclusion of <windows.h> to before rather than after the definition of
1511        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1512    
1513    17. Specifying a possessive quantifier with a specific limit for a Unicode
1514        character property caused pcre_compile() to compile bad code, which led at
1515        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1516        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1517        caused the error; without that there was no problem.
1518    
1519    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1520    
1521    19. Added --enable-pcretest-libreadline.
1522    
1523    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1524        RE::GlobalReplace(). As a result, the number of replacements returned was
1525        double what it should be. I removed one of the increments, but Craig sent a
1526        later patch that removed the other one (the right fix) and added unit tests
1527        that check the return values (which was not done before).
1528    
1529    21. Several CMake things:
1530    
1531        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1532            the names libpcre and libpcreposix, not just pcre and pcreposix.
1533    
1534        (2) The above change means that pcretest and pcregrep are now correctly
1535            linked with the newly-built libraries, not previously installed ones.
1536    
1537        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1538    
1539    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1540        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1541        UTF-8 newline character). The key issue is that the pattern starts .*;
1542        this means that the match must be either at the beginning, or after a
1543        newline. The bug was in the code for advancing after a failed match and
1544        checking that the new position followed a newline. It was not taking
1545        account of UTF-8 characters correctly.
1546    
1547    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1548        character classes. PCRE was not treating the sequence [:...:] as a
1549        character class unless the ... were all letters. Perl, however, seems to
1550        allow any characters between [: and :], though of course it rejects as
1551        unknown any "names" that contain non-letters, because all the known class
1552        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1553        for example, whereas PCRE did not - it did not recognize a POSIX character
1554        class. This seemed a bit dangerous, so the code has been changed to be
1555        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1556        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1557        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1558        Perl does, and where it didn't before.
1559    
1560    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1561        Windows environments %n is disabled by default.
1562    
1563    
1564    Version 7.4 21-Sep-07
1565    ---------------------
1566    
1567    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1568        means that a class such as [\s] counted as "explicit reference to CR or
1569        LF". That isn't really right - the whole point of the change was to try to
1570        help when there was an actual mention of one of the two characters. So now
1571        the change happens only if \r or \n (or a literal CR or LF) character is
1572        encountered.
1573    
1574    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1575        of both had grown to the point where there were only 3 bits left.
1576        Fortunately, there was spare space in the data structure, and so I have
1577        moved the internal flags into a new 16-bit field to free up more option
1578        bits.
1579    
1580    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1581        but did not set the internal JCHANGED flag - either of these is enough to
1582        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1583        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1584        start sets both bits.
1585    
1586    4.  Added options (at build time, compile time, exec time) to change \R from
1587        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1588    
1589    5.  doc/pcresyntax.html was missing from the distribution.
1590    
1591    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1592        compatibility, even though it is no longer used.
1593    
1594    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1595        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1596        windows.h file is present (where different names are used). [This was
1597        reversed later after testing - see 16 below.]
1598    
1599    8.  Changed all #include <config.h> to #include "config.h". There were also
1600        some further <pcre.h> cases that I changed to "pcre.h".
1601    
1602    9.  When pcregrep was used with the --colour option, it missed the line ending
1603        sequence off the lines that it output.
1604    
1605    10. It was pointed out to me that arrays of string pointers cause lots of
1606        relocations when a shared library is dynamically loaded. A technique of
1607        using a single long string with a table of offsets can drastically reduce
1608        these. I have refactored PCRE in four places to do this. The result is
1609        dramatic:
1610    
1611          Originally:                          290
1612          After changing UCP table:            187
1613          After changing error message table:   43
1614          After changing table of "verbs"       36
1615          After changing table of Posix names   22
1616    
1617        Thanks to the folks working on Gregex for glib for this insight.
1618    
1619    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1620        unicode-properties was also set.
1621    
1622    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1623    
1624    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1625        checked only for CRLF.
1626    
1627    14. Added casts to pcretest.c to avoid compiler warnings.
1628    
1629    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1630    
1631    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1632        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1633        entirely. This removes changes made in 7 above.
1634    
1635    17. The CMake files have been updated, and there is now more information about
1636        building with CMake in the NON-UNIX-USE document.
1637    
1638    
1639    Version 7.3 28-Aug-07
1640    ---------------------
1641    
1642     1. In the rejigging of the build system that eventually resulted in 7.1, the
1643        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1644        brackets there is not right, since it causes compilers to look for an
1645        installed pcre.h, not the version that is in the source that is being
1646        compiled (which of course may be different). I have changed it back to:
1647    
1648          #include "pcre.h"
1649    
1650        I have a vague recollection that the change was concerned with compiling in
1651        different directories, but in the new build system, that is taken care of
1652        by the VPATH setting the Makefile.
1653    
1654     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1655        when the subject happened to end in the byte 0x85 (e.g. if the last
1656        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1657        characters but of course it shouldn't be taken as a newline when it is part
1658        of another character. The bug was that, for an unlimited repeat of . in
1659        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1660        characters when looking for a newline.
1661    
1662     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1663    
1664     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1665        in debug output.
1666    
1667     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1668        long printing in the pcrecpp unittest when running under MinGW.
1669    
1670     6. ESC_K was left out of the EBCDIC table.
1671    
1672     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1673        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1674        limit also applies to "virtual nesting" when a pattern is recursive, and in
1675        this case 1000 isn't so big. I have been able to remove this limit at the
1676        expense of backing off one optimization in certain circumstances. Normally,
1677        when pcre_exec() would call its internal match() function recursively and
1678        immediately return the result unconditionally, it uses a "tail recursion"
1679        feature to save stack. However, when a subpattern that can match an empty
1680        string has an unlimited repetition quantifier, it no longer makes this
1681        optimization. That gives it a stack frame in which to save the data for
1682        checking that an empty string has been matched. Previously this was taken
1683        from the 1000-entry workspace that had been reserved. So now there is no
1684        explicit limit, but more stack is used.
1685    
1686     8. Applied Daniel's patches to solve problems with the import/export magic
1687        syntax that is required for Windows, and which was going wrong for the
1688        pcreposix and pcrecpp parts of the library. These were overlooked when this
1689        problem was solved for the main library.
1690    
1691     9. There were some crude static tests to avoid integer overflow when computing
1692        the size of patterns that contain repeated groups with explicit upper
1693        limits. As the maximum quantifier is 65535, the maximum group length was
1694        set at 30,000 so that the product of these two numbers did not overflow a
1695        32-bit integer. However, it turns out that people want to use groups that
1696        are longer than 30,000 bytes (though not repeat them that many times).
1697        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1698        made it possible to implement the integer overflow checks in a much more
1699        dynamic way, which I have now done. The artificial limitation on group
1700        length has been removed - we now have only the limit on the total length of
1701        the compiled pattern, which depends on the LINK_SIZE setting.
1702    
1703    10. Fixed a bug in the documentation for get/copy named substring when
1704        duplicate names are permitted. If none of the named substrings are set, the
1705        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1706        empty string.
1707    
1708    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1709        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1710        because the ] is interpreted as the first data character and the
1711        terminating ] is not found. PCRE has been made compatible with Perl in this
1712        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1713        cause memory overwriting.
1714    
1715    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1716        string has been matched (to stop an infinite loop). It was not recognizing
1717        a conditional subpattern that could match an empty string if that
1718        subpattern was within another subpattern. For example, it looped when
1719        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1720        condition was not nested. This bug has been fixed.
1721    
1722    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1723        past the start of the subject in the presence of bytes with the top bit
1724        set, for example "\x8aBCD".
1725    
1726    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1727        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1728    
1729    14. Optimized (?!) to (*FAIL).
1730    
1731    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1732        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1733        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1734        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1735        does: it's just the validity check that is more restrictive.
1736    
1737    16. Inserted checks for integer overflows during escape sequence (backslash)
1738        processing, and also fixed erroneous offset values for syntax errors during
1739        backslash processing.
1740    
1741    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1742        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1743    
1744    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1745        caused an overrun.
1746    
1747    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1748        something other than just ASCII characters) inside a group that had an
1749        unlimited repeat caused a loop at compile time (while checking to see
1750        whether the group could match an empty string).
1751    
1752    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1753        [\P{Any}] did so. (Error in the code for printing property names.)
1754    
1755    21. An orphan \E inside a character class could cause a crash.
1756    
1757    22. A repeated capturing bracket such as (A)? could cause a wild memory
1758        reference during compilation.
1759    
1760    23. There are several functions in pcre_compile() that scan along a compiled
1761        expression for various reasons (e.g. to see if it's fixed length for look
1762        behind). There were bugs in these functions when a repeated \p or \P was
1763        present in the pattern. These operators have additional parameters compared
1764        with \d, etc, and these were not being taken into account when moving along
1765        the compiled data. Specifically:
1766    
1767        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1768            length.
1769    
1770        (b) An item such as \pL+ within a repeated group could cause crashes or
1771            loops.
1772    
1773        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1774            "reference to non-existent subpattern" error.
1775    
1776        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1777    
1778    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1779        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1780    
1781    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1782    
1783    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1784        character were causing crashes (broken optimization).
1785    
1786    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1787        \p or \P) caused a compile-time loop.
1788    
1789    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1790        break. For example, the unstudied pattern [\r\n]A does not match the string
1791        "\r\nA" because change 7.0/46 below moves the current point on by two
1792        characters after failing to match at the start. However, the pattern \nA
1793        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1794        the same is true. There doesn't seem any very clean way out of this, but
1795        what I have chosen to do makes the common cases work: PCRE now takes note
1796        of whether there can be an explicit match for \r or \n anywhere in the
1797        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1798        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1799        pattern has explicit CR or LF references.
1800    
1801    29. Added (*CR) etc for changing newline setting at start of pattern.
1802    
1803    
1804    Version 7.2 19-Jun-07
1805    ---------------------
1806    
1807     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1808        which is apparently normally available under Windows.
1809    
1810     2. Re-jig the pcregrep tests with different newline settings in an attempt
1811        to make them independent of the local environment's newline setting.
1812    
1813     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1814    
1815     4. Some of the "internals" tests were previously cut out when the link size
1816        was not 2, because the output contained actual offsets. The recent new
1817        "Z" feature of pcretest means that these can be cut out, making the tests
1818        usable with all link sizes.
1819    
1820     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1821        stack recursion. This gives a massive performance boost under BSD, but just
1822        a small improvement under Linux. However, it saves one field in the frame
1823        in all cases.
1824    
1825     6. Added more features from the forthcoming Perl 5.10:
1826    
1827        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1828            recursion call. It refers to the nth most recently opened parentheses.
1829    
1830        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1831            to be opened parentheses.
1832    
1833        (c) Conditions that refer to capturing parentheses can be specified
1834            relatively, for example, (?(-2)... or (?(+3)...
1835    
1836        (d) \K resets the start of the current match so that everything before
1837            is not part of it.
1838    
1839        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1840    
1841        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1842            reference syntax.
1843    
1844        (g) (?| introduces a group in which the numbering of parentheses in each
1845            alternative starts with the same number.
1846    
1847        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1848    
1849     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1850        PCRE_INFO_JCHANGED.
1851    
1852     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1853        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1854        for detecting groups that can match an empty string.
1855    
1856     9. A pattern with a very large number of alternatives (more than several
1857        hundred) was running out of internal workspace during the pre-compile
1858        phase, where pcre_compile() figures out how much memory will be needed. A
1859        bit of new cunning has reduced the workspace needed for groups with
1860        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1861        workspace instead of running out of the 4096 that are available.
1862    
1863    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1864    
1865    11. Applied patch from Google to remove an optimization that didn't quite work.
1866        The report of the bug said:
1867    
1868          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1869          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1870          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1871    
1872    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1873        it matched the wrong number of bytes.
1874    
1875    
1876    Version 7.1 24-Apr-07
1877  ---------------------  ---------------------
1878    
1879   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 33  Version 7.1 12-Mar-07 Line 1905  Version 7.1 12-Mar-07
1905   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1906      Weber: (1) pcre_internal.h was missing some function renames; (2) updated      Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1907      makevp.bat for the current PCRE, using the additional files      makevp.bat for the current PCRE, using the additional files
1908      makevp-compile.txt, makevp-linklib.txt, and pcregexp.pas.      makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1909    
1910   6. A Windows user reported a minor discrepancy with test 2, which turned out   6. A Windows user reported a minor discrepancy with test 2, which turned out
1911      to be caused by a trailing space on an input line that had got lost in his      to be caused by a trailing space on an input line that had got lost in his
# Line 116  Version 7.1 12-Mar-07 Line 1988  Version 7.1 12-Mar-07
1988  14. If erroroffset was passed as NULL to pcre_compile, it provoked a  14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1989      segmentation fault instead of returning the appropriate error message.      segmentation fault instead of returning the appropriate error message.
1990    
1991    15. In multiline mode when the newline sequence was set to "any", the pattern
1992        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1993        This doesn't seem right; it now treats the CRLF combination as the line
1994        ending, and so does not match in that case. It's only a pattern such as ^$
1995        that would hit this one: something like ^ABC$ would have failed after \r
1996        and then tried again after \r\n.
1997    
1998    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1999        in an attempt to make files that differ only in their line terminators
2000        compare equal. This works on Linux.
2001    
2002    17. Under certain error circumstances pcregrep might try to free random memory
2003        as it exited. This is now fixed, thanks to valgrind.
2004    
2005    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
2006        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
2007        was because its rules for how to advance for /g after matching an empty
2008        string at the end of a line did not allow for this case. They now check for
2009        it specially.
2010    
2011    20. pcretest is supposed to handle patterns and data of any length, by
2012        extending its buffers when necessary. It was getting this wrong when the
2013        buffer for a data line had to be extended.
2014    
2015    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
2016        CRLF as a newline sequence.
2017    
2018    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
2019        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
2020        I have nevertheless tidied it up.
2021    
2022    23. Added some casts to kill warnings from HP-UX ia64 compiler.
2023    
2024    24. Added a man page for pcre-config.
2025    
2026    
2027  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
2028  ---------------------  ---------------------

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