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

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