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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.10 03 May-2010
5    ------------------------
6    
7    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
8        THEN.
9    
10    2.  (*ACCEPT) was not working when inside an atomic group.
11    
12    3.  Inside a character class, \B is treated as a literal by default, but
13        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
14        causes the error). The code is unchanged, but I tidied the documentation.
15    
16    4.  Inside a character class, PCRE always treated \R and \X as literals,
17        whereas Perl faults them if its -w option is set. I have changed PCRE so
18        that it faults them when PCRE_EXTRA is set.
19    
20    5.  Added support for \N, which always matches any character other than
21        newline. (It is the same as "." when PCRE_DOTALL is not set.)
22    
23    6.  When compiling pcregrep with newer versions of gcc which may have
24        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
25        declared with attribute warn_unused_result" were given. Just casting the
26        result to (void) does not stop the warnings; a more elaborate fudge is
27        needed. I've used a macro to implement this.
28    
29    7.  Minor change to pcretest.c to avoid a compiler warning.
30    
31    8.  Added four artifical Unicode properties to help with an option to make
32        \s etc use properties (see next item). The new properties are: Xan
33        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
34    
35    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
36        use Unicode properties. (*UCP) at the start of a pattern can be used to set
37        this option. Modified pcretest to add /W to test this facility. Added
38        REG_UCP to make it available via the POSIX interface.
39    
40    10. Added --line-buffered to pcregrep.
41    
42    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
43        studied, and the match started with a letter with a code point greater than
44        127 whose first byte was different to the first byte of the other case of
45        the letter, the other case of this starting letter was not recognized.
46    
47    
48    Version 8.02 19-Mar-2010
49    ------------------------
50    
51    1.  The Unicode data tables have been updated to Unicode 5.2.0.
52    
53    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
54        configured.
55    
56    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
57        original author of that file, following a query about its status.
58    
59    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
60        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
61    
62    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
63        quantifier applied to a forward-referencing subroutine call, could compile
64        incorrect code or give the error "internal error: previously-checked
65        referenced subpattern not found".
66    
67    6.  Both MS Visual Studio and Symbian OS have problems with initializing
68        variables to point to external functions. For these systems, therefore,
69        pcre_malloc etc. are now initialized to local functions that call the
70        relevant global functions.
71    
72    7.  There were two entries missing in the vectors called coptable and poptable
73        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
74        I've fixed the data, and added a kludgy way of testing at compile time that
75        the lengths are correct (equal to the number of opcodes).
76    
77    8.  Following on from 7, I added a similar kludge to check the length of the
78        eint vector in pcreposix.c.
79    
80    9.  Error texts for pcre_compile() are held as one long string to avoid too
81        much relocation at load time. To find a text, the string is searched,
82        counting zeros. There was no check for running off the end of the string,
83        which could happen if a new error number was added without updating the
84        string.
85    
86    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
87    
88    11. \K was not working if it appeared in an atomic group or in a group that
89        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
90        \K is "not well defined" if used in an assertion. PCRE now accepts it if
91        the assertion is positive, but not if it is negative.
92    
93    12. Change 11 fortuitously reduced the size of the stack frame used in the
94        "match()" function of pcre_exec.c by one pointer. Forthcoming
95        implementation of support for (*MARK) will need an extra pointer on the
96        stack; I have reserved it now, so that the stack frame size does not
97        decrease.
98    
99    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
100        item in branch that calls a recursion is a subroutine call - as in the
101        second branch in the above example - was incorrectly given the compile-
102        time error "recursive call could loop indefinitely" because pcre_compile()
103        was not correctly checking the subroutine for matching a non-empty string.
104    
105    14. The checks for overrunning compiling workspace could trigger after an
106        overrun had occurred. This is a "should never occur" error, but it can be
107        triggered by pathological patterns such as hundreds of nested parentheses.
108        The checks now trigger 100 bytes before the end of the workspace.
109    
110    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
111    
112    
113    Version 8.01 19-Jan-2010
114    ------------------------
115    
116    1.  If a pattern contained a conditional subpattern with only one branch (in
117        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
118        computed the wrong minimum data length (which is of course zero for such
119        subpatterns). This could cause incorrect "no match" results.
120    
121    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
122        the pattern is reset in the first branch, pcre_compile() failed with
123        "internal error: code overflow at offset...". This happened only when
124        the reset was to the original external option setting. (An optimization
125        abstracts leading options settings into an external setting, which was the
126        cause of this.)
127    
128    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
129        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
130        assertion pattern did not match (meaning that the assertion was true), it
131        was incorrectly treated as false if the SKIP had been reached during the
132        matching. This also applied to assertions used as conditions.
133    
134    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
135        assertion subpattern, including such a pattern used as a condition,
136        unpredictable results occurred, instead of the error return
137        PCRE_ERROR_DFA_UITEM.
138    
139    5.  The C++ GlobalReplace function was not working like Perl for the special
140        situation when an empty string is matched. It now does the fancy magic
141        stuff that is necessary.
142    
143    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
144        removed. (These were left over from very, very early versions of PCRE.)
145    
146    7.  Some cosmetic changes to the code to make life easier when compiling it
147        as part of something else:
148    
149        (a) Change DEBUG to PCRE_DEBUG.
150    
151        (b) In pcre_compile(), rename the member of the "branch_chain" structure
152            called "current" as "current_branch", to prevent a collision with the
153            Linux macro when compiled as a kernel module.
154    
155        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
156            prevent a collision with the Linux macro when compiled as a kernel
157            module.
158    
159    8.  In pcre_compile() there are some checks for integer overflows that used to
160        cast potentially large values to (double). This has been changed to that
161        when building, a check for int64_t is made, and if it is found, it is used
162        instead, thus avoiding the use of floating point arithmetic. (There is no
163        other use of FP in PCRE.) If int64_t is not found, the fallback is to
164        double.
165    
166    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
167        2005 (difference between two addresses compared to an unsigned value).
168    
169    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
170        custom one, because of the following reported problem in Windows:
171    
172          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
173              under Win32.
174          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
175              therefore missing the function definition.
176          - The compiler thus generates a "C" signature for the test function.
177          - The linker fails to find the "C" function.
178          - PCRE fails to configure if asked to do so against libbz2.
179    
180    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
181        messages were output:
182    
183          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
184          rerunning libtoolize, to keep the correct libtool macros in-tree.
185          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
186    
187        I have done both of these things.
188    
189    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
190        most of the time, it *can* run out if it is given a pattern that contains a
191        runaway infinite recursion. I updated the discussion in the pcrestack man
192        page.
193    
194    13. Now that we have gone to the x.xx style of version numbers, the minor
195        version may start with zero. Using 08 or 09 is a bad idea because users
196        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
197        interpreted as invalid octal numbers. I've updated the previous comment in
198        configure.ac, and also added a check that gives an error if 08 or 09 are
199        used.
200    
201    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
202        causing partial matching to fail when the end of the subject matched \W
203        in a UTF-8 pattern where \W was quantified with a minimum of 3.
204    
205    15. There were some discrepancies between the declarations in pcre_internal.h
206        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
207        their definitions. The declarations used "const uschar *" and the
208        definitions used USPTR. Even though USPTR is normally defined as "const
209        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
210        reported that: "This difference in casting confuses some C++ compilers, for
211        example, SunCC recognizes above declarations as different functions and
212        generates broken code for hbpcre." I have changed the declarations to use
213        USPTR.
214    
215    16. GNU libtool is named differently on some systems. The autogen.sh script now
216        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
217        (FreeBSD).
218    
219    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
220        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
221        comment: "Figure out how to create a longlong from a string: strtoll and
222        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
223        instance, but it only takes 2 args instead of 3!"
224    
225    18. A subtle bug concerned with back references has been fixed by a change of
226        specification, with a corresponding code fix. A pattern such as
227        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
228        refers, was giving matches when it shouldn't. For example, xa=xaaa would
229        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
230        same bug. Such groups have to be quantified to be useful, or contained
231        inside another quantified group. (If there's no repetition, the reference
232        can never match.) The problem arises because, having left the group and
233        moved on to the rest of the pattern, a later failure that backtracks into
234        the group uses the captured value from the final iteration of the group
235        rather than the correct earlier one. I have fixed this in PCRE by forcing
236        any group that contains a reference to itself to be an atomic group; that
237        is, there cannot be any backtracking into it once it has completed. This is
238        similar to recursive and subroutine calls.
239    
240    
241    Version 8.00 19-Oct-09
242  ----------------------  ----------------------
243    
244  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
245      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
246      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
247      error.      error.
248    
249  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
250      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
251      in a Windows environment.      in a Windows environment.
252    
253  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
254      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
255      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
256      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
257      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
258      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
259      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
260    
261  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
262      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
263      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
264      the old behaviour.      the old behaviour.
265    
266  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
267      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
268      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
269      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
270    
271  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
272      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
273    
274  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
275      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
276      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
277      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
278      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
279      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
280    
281  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
282      was a minimum greater than 1 for a wide character in a possessive      was a minimum greater than 1 for a wide character in a possessive
283      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
284      which had an unlimited repeat of a nested, fixed maximum repeat of a wide      which had an unlimited repeat of a nested, fixed maximum repeat of a wide
285      character. Chaos in the form of incorrect output or a compiling loop could      character. Chaos in the form of incorrect output or a compiling loop could
286      result.      result.
287    
288  9.  The restrictions on what a pattern can contain when partial matching is  9.  The restrictions on what a pattern can contain when partial matching is
289      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
290      partially matched by this function. In addition, if there are at least two      partially matched by this function. In addition, if there are at least two
291      slots in the offset vector, the offsets of the first-encountered partial      slots in the offset vector, the offset of the earliest inspected character
292      match are set in them when PCRE_ERROR_PARTIAL is returned.      for the match and the offset of the end of the subject are set in them when
293        PCRE_ERROR_PARTIAL is returned.
294    
295  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
296      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
297      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
298      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
299      pcre_exec().  
300    11. Partial matching with pcre_exec() is now more intuitive. A partial match
301  11. Partial matching with pcre_exec() is now more intuitive. A partial match      used to be given if ever the end of the subject was reached; now it is
302      used to be given if ever the end of the subject was reached; now it is      given only if matching could not proceed because another character was
303      given only if matching could not proceed because another character was      needed. This makes a difference in some odd cases such as Z(*FAIL) with the
304      needed. This makes a difference in some odd cases such as Z(*FAIL) with the      string "Z", which now yields "no match" instead of "partial match". In the
305      string "Z", which now yields "no match" instead of "partial match". In the      case of pcre_dfa_exec(), "no match" is given if every matching path for the
306      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
307      final character ended with (*FAIL).  
   
308  12. Restarting a match using pcre_dfa_exec() after a partial match did not work  12. Restarting a match using pcre_dfa_exec() after a partial match did not work
309      if the pattern had a "must contain" character that was already found in the      if the pattern had a "must contain" character that was already found in the
310      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
311      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
312      "g". If the first part-match was for the string "dog", restarting with      "g". If the first part-match was for the string "dog", restarting with
313      "sbody" failed.      "sbody" failed. This bug has been fixed.
314    
315  13. Added a pcredemo man page, created automatically from the pcredemo.c file,  13. The string returned by pcre_dfa_exec() after a partial match has been
316      so that the demonstration program is easily available in environments where      changed so that it starts at the first inspected character rather than the
317      PCRE has not been installed from source.      first character of the match. This makes a difference only if the pattern
318        starts with a lookbehind assertion or \b or \B (\K is not supported by
319  14. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,      pcre_dfa_exec()). It's an incompatible change, but it makes the two
320        matching functions compatible, and I think it's the right thing to do.
321    
322    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
323        so that the demonstration program is easily available in environments where
324        PCRE has not been installed from source.
325    
326    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
327      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
328      library.      library.
329    
330    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
331        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
332        is not the first non-POSIX option to be added. Clearly some people find
333        these options useful.
334    
335    17. If a caller to the POSIX matching function regexec() passes a non-zero
336        value for nmatch with a NULL value for pmatch, the value of
337        nmatch is forced to zero.
338    
339    18. RunGrepTest did not have a test for the availability of the -u option of
340        the diff command, as RunTest does. It now checks in the same way as
341        RunTest, and also checks for the -b option.
342    
343    19. If an odd number of negated classes containing just a single character
344        interposed, within parentheses, between a forward reference to a named
345        subpattern and the definition of the subpattern, compilation crashed with
346        an internal error, complaining that it could not find the referenced
347        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
348        [The bug was that it was starting one character too far in when skipping
349        over the character class, thus treating the ] as data rather than
350        terminating the class. This meant it could skip too much.]
351    
352    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
353        /g option in pcretest when the pattern contains \K, which makes it possible
354        to have an empty string match not at the start, even when the pattern is
355        anchored. Updated pcretest and pcredemo to use this option.
356    
357    21. If the maximum number of capturing subpatterns in a recursion was greater
358        than the maximum at the outer level, the higher number was returned, but
359        with unset values at the outer level. The correct (outer level) value is
360        now given.
361    
362    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
363        PCRE did not set those parentheses (unlike Perl). I have now found a way to
364        make it do so. The string so far is captured, making this feature
365        compatible with Perl.
366    
367    23. The tests have been re-organized, adding tests 11 and 12, to make it
368        possible to check the Perl 5.10 features against Perl 5.10.
369    
370    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
371        pattern matches a fixed length string. PCRE did not allow this; now it
372        does. Neither allows recursion.
373    
374    25. I finally figured out how to implement a request to provide the minimum
375        length of subject string that was needed in order to match a given pattern.
376        (It was back references and recursion that I had previously got hung up
377        on.) This code has now been added to pcre_study(); it finds a lower bound
378        to the length of subject needed. It is not necessarily the greatest lower
379        bound, but using it to avoid searching strings that are too short does give
380        some useful speed-ups. The value is available to calling programs via
381        pcre_fullinfo().
382    
383    26. While implementing 25, I discovered to my embarrassment that pcretest had
384        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
385        study optimizations had never been tested with that matching function.
386        Oops. What is worse, even when it was passed study data, there was a bug in
387        pcre_dfa_exec() that meant it never actually used it. Double oops. There
388        were also very few tests of studied patterns with pcre_dfa_exec().
389    
390    27. If (?| is used to create subpatterns with duplicate numbers, they are now
391        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
392        on the other side of the coin, they are no longer allowed to have different
393        names, because these cannot be distinguished in PCRE, and this has caused
394        confusion. (This is a difference from Perl.)
395    
396    28. When duplicate subpattern names are present (necessarily with different
397        numbers, as required by 27 above), and a test is made by name in a
398        conditional pattern, either for a subpattern having been matched, or for
399        recursion in such a pattern, all the associated numbered subpatterns are
400        tested, and the overall condition is true if the condition is true for any
401        one of them. This is the way Perl works, and is also more like the way
402        testing by number works.
403    
404    
405  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
406  ---------------------  ---------------------

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