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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.9 xx-xxx-09  Version 8.02 01-Mar-2010
5    ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 5.2.0.
8    
9    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
10        configured.
11    
12    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
13        original author of that file, following a query about its status.
14    
15    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
16        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
17    
18    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
19        quantifier applied to a forward-referencing subroutine call, could compile
20        incorrect code or give the error "internal error: previously-checked
21        referenced subpattern not found".
22    
23    6.  Both MS Visual Studio and Symbian OS have problems with initializing
24        variables to point to external functions. For these systems, therefore,
25        pcre_malloc etc. are now initialized to local functions that call the
26        relevant global functions.
27    
28    7.  There were two entries missing in the vectors called coptable and poptable
29        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
30        I've fixed the data, and added a kludgy way of testing at compile time that
31        the lengths are correct (equal to the number of opcodes).
32    
33    8.  Following on from 7, I added a similar kludge to check the length of the
34        eint vector in pcreposix.c.
35    
36    9.  Error texts for pcre_compile() are held as one long string to avoid too
37        much relocation at load time. To find a text, the string is searched,
38        counting zeros. There was no check for running off the end of the string,
39        which could happen if a new error number was added without updating the
40        string.
41    
42    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
43    
44    11. \K was not working if it appeared in an atomic group or in a group that
45        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
46        \K is "not well defined" if used in an assertion. PCRE now accepts it if
47        the assertion is positive, but not if it is negative.
48    
49    12. Change 11 fortuitously reduced the size of the stack frame used in the
50        "match()" function of pcre_exec.c by one pointer. Forthcoming
51        implementation of support for (*MARK) will need an extra pointer on the
52        stack; I have reserved it now, so that the stack frame size does not
53        decrease.
54    
55    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
56        item in branch that calls a recursion is a subroutine call - as in the
57        second branch in the above example - was incorrectly given the compile-
58        time error "recursive call could loop indefinitely" because pcre_compile()
59        was not correctly checking the subroutine for matching a non-empty string.
60    
61    
62    Version 8.01 19-Jan-2010
63    ------------------------
64    
65    1.  If a pattern contained a conditional subpattern with only one branch (in
66        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
67        computed the wrong minimum data length (which is of course zero for such
68        subpatterns). This could cause incorrect "no match" results.
69    
70    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
71        the pattern is reset in the first branch, pcre_compile() failed with
72        "internal error: code overflow at offset...". This happened only when
73        the reset was to the original external option setting. (An optimization
74        abstracts leading options settings into an external setting, which was the
75        cause of this.)
76    
77    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
78        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
79        assertion pattern did not match (meaning that the assertion was true), it
80        was incorrectly treated as false if the SKIP had been reached during the
81        matching. This also applied to assertions used as conditions.
82    
83    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
84        assertion subpattern, including such a pattern used as a condition,
85        unpredictable results occurred, instead of the error return
86        PCRE_ERROR_DFA_UITEM.
87    
88    5.  The C++ GlobalReplace function was not working like Perl for the special
89        situation when an empty string is matched. It now does the fancy magic
90        stuff that is necessary.
91    
92    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
93        removed. (These were left over from very, very early versions of PCRE.)
94    
95    7.  Some cosmetic changes to the code to make life easier when compiling it
96        as part of something else:
97    
98        (a) Change DEBUG to PCRE_DEBUG.
99    
100        (b) In pcre_compile(), rename the member of the "branch_chain" structure
101            called "current" as "current_branch", to prevent a collision with the
102            Linux macro when compiled as a kernel module.
103    
104        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
105            prevent a collision with the Linux macro when compiled as a kernel
106            module.
107    
108    8.  In pcre_compile() there are some checks for integer overflows that used to
109        cast potentially large values to (double). This has been changed to that
110        when building, a check for int64_t is made, and if it is found, it is used
111        instead, thus avoiding the use of floating point arithmetic. (There is no
112        other use of FP in PCRE.) If int64_t is not found, the fallback is to
113        double.
114    
115    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
116        2005 (difference between two addresses compared to an unsigned value).
117    
118    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
119        custom one, because of the following reported problem in Windows:
120    
121          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
122              under Win32.
123          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
124              therefore missing the function definition.
125          - The compiler thus generates a "C" signature for the test function.
126          - The linker fails to find the "C" function.
127          - PCRE fails to configure if asked to do so against libbz2.
128    
129    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
130        messages were output:
131    
132          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
133          rerunning libtoolize, to keep the correct libtool macros in-tree.
134          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
135    
136        I have done both of these things.
137    
138    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
139        most of the time, it *can* run out if it is given a pattern that contains a
140        runaway infinite recursion. I updated the discussion in the pcrestack man
141        page.
142    
143    13. Now that we have gone to the x.xx style of version numbers, the minor
144        version may start with zero. Using 08 or 09 is a bad idea because users
145        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
146        interpreted as invalid octal numbers. I've updated the previous comment in
147        configure.ac, and also added a check that gives an error if 08 or 09 are
148        used.
149    
150    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
151        causing partial matching to fail when the end of the subject matched \W
152        in a UTF-8 pattern where \W was quantified with a minimum of 3.
153    
154    15. There were some discrepancies between the declarations in pcre_internal.h
155        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
156        their definitions. The declarations used "const uschar *" and the
157        definitions used USPTR. Even though USPTR is normally defined as "const
158        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
159        reported that: "This difference in casting confuses some C++ compilers, for
160        example, SunCC recognizes above declarations as different functions and
161        generates broken code for hbpcre." I have changed the declarations to use
162        USPTR.
163    
164    16. GNU libtool is named differently on some systems. The autogen.sh script now
165        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
166        (FreeBSD).
167    
168    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
169        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
170        comment: "Figure out how to create a longlong from a string: strtoll and
171        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
172        instance, but it only takes 2 args instead of 3!"
173    
174    18. A subtle bug concerned with back references has been fixed by a change of
175        specification, with a corresponding code fix. A pattern such as
176        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
177        refers, was giving matches when it shouldn't. For example, xa=xaaa would
178        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
179        same bug. Such groups have to be quantified to be useful, or contained
180        inside another quantified group. (If there's no repetition, the reference
181        can never match.) The problem arises because, having left the group and
182        moved on to the rest of the pattern, a later failure that backtracks into
183        the group uses the captured value from the final iteration of the group
184        rather than the correct earlier one. I have fixed this in PCRE by forcing
185        any group that contains a reference to itself to be an atomic group; that
186        is, there cannot be any backtracking into it once it has completed. This is
187        similar to recursive and subroutine calls.
188    
189    
190    Version 8.00 19-Oct-09
191    ----------------------
192    
193    1.  The table for translating pcre_compile() error codes into POSIX error codes
194        was out-of-date, and there was no check on the pcre_compile() error code
195        being within the table. This could lead to an OK return being given in
196        error.
197    
198    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
199        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
200        in a Windows environment.
201    
202    3.  The pcregrep --count option prints the count for each file even when it is
203        zero, as does GNU grep. However, pcregrep was also printing all files when
204        --files-with-matches was added. Now, when both options are given, it prints
205        counts only for those files that have at least one match. (GNU grep just
206        prints the file name in this circumstance, but including the count seems
207        more useful - otherwise, why use --count?) Also ensured that the
208        combination -clh just lists non-zero counts, with no names.
209    
210    4.  The long form of the pcregrep -F option was incorrectly implemented as
211        --fixed_strings instead of --fixed-strings. This is an incompatible change,
212        but it seems right to fix it, and I didn't think it was worth preserving
213        the old behaviour.
214    
215    5.  The command line items --regex=pattern and --regexp=pattern were not
216        recognized by pcregrep, which required --regex pattern or --regexp pattern
217        (with a space rather than an '='). The man page documented the '=' forms,
218        which are compatible with GNU grep; these now work.
219    
220    6.  No libpcreposix.pc file was created for pkg-config; there was just
221        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
222    
223    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
224        when UCP support is not needed, by modifying the Python script that
225        generates it from Unicode data files. This should not matter if the module
226        is correctly used as a library, but I received one complaint about 50K of
227        unwanted data. My guess is that the person linked everything into his
228        program rather than using a library. Anyway, it does no harm.
229    
230    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
231        was a minimum greater than 1 for a wide character in a possessive
232        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
233        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
234        character. Chaos in the form of incorrect output or a compiling loop could
235        result.
236    
237    9.  The restrictions on what a pattern can contain when partial matching is
238        requested for pcre_exec() have been removed. All patterns can now be
239        partially matched by this function. In addition, if there are at least two
240        slots in the offset vector, the offset of the earliest inspected character
241        for the match and the offset of the end of the subject are set in them when
242        PCRE_ERROR_PARTIAL is returned.
243    
244    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
245        synonymous with PCRE_PARTIAL, for backwards compatibility, and
246        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
247        and may be more useful for multi-segment matching.
248    
249    11. Partial matching with pcre_exec() is now more intuitive. A partial match
250        used to be given if ever the end of the subject was reached; now it is
251        given only if matching could not proceed because another character was
252        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
253        string "Z", which now yields "no match" instead of "partial match". In the
254        case of pcre_dfa_exec(), "no match" is given if every matching path for the
255        final character ended with (*FAIL).
256    
257    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
258        if the pattern had a "must contain" character that was already found in the
259        earlier partial match, unless partial matching was again requested. For
260        example, with the pattern /dog.(body)?/, the "must contain" character is
261        "g". If the first part-match was for the string "dog", restarting with
262        "sbody" failed. This bug has been fixed.
263    
264    13. The string returned by pcre_dfa_exec() after a partial match has been
265        changed so that it starts at the first inspected character rather than the
266        first character of the match. This makes a difference only if the pattern
267        starts with a lookbehind assertion or \b or \B (\K is not supported by
268        pcre_dfa_exec()). It's an incompatible change, but it makes the two
269        matching functions compatible, and I think it's the right thing to do.
270    
271    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
272        so that the demonstration program is easily available in environments where
273        PCRE has not been installed from source.
274    
275    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
276        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
277        library.
278    
279    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
280        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
281        is not the first non-POSIX option to be added. Clearly some people find
282        these options useful.
283    
284    17. If a caller to the POSIX matching function regexec() passes a non-zero
285        value for nmatch with a NULL value for pmatch, the value of
286        nmatch is forced to zero.
287    
288    18. RunGrepTest did not have a test for the availability of the -u option of
289        the diff command, as RunTest does. It now checks in the same way as
290        RunTest, and also checks for the -b option.
291    
292    19. If an odd number of negated classes containing just a single character
293        interposed, within parentheses, between a forward reference to a named
294        subpattern and the definition of the subpattern, compilation crashed with
295        an internal error, complaining that it could not find the referenced
296        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
297        [The bug was that it was starting one character too far in when skipping
298        over the character class, thus treating the ] as data rather than
299        terminating the class. This meant it could skip too much.]
300    
301    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
302        /g option in pcretest when the pattern contains \K, which makes it possible
303        to have an empty string match not at the start, even when the pattern is
304        anchored. Updated pcretest and pcredemo to use this option.
305    
306    21. If the maximum number of capturing subpatterns in a recursion was greater
307        than the maximum at the outer level, the higher number was returned, but
308        with unset values at the outer level. The correct (outer level) value is
309        now given.
310    
311    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
312        PCRE did not set those parentheses (unlike Perl). I have now found a way to
313        make it do so. The string so far is captured, making this feature
314        compatible with Perl.
315    
316    23. The tests have been re-organized, adding tests 11 and 12, to make it
317        possible to check the Perl 5.10 features against Perl 5.10.
318    
319    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
320        pattern matches a fixed length string. PCRE did not allow this; now it
321        does. Neither allows recursion.
322    
323    25. I finally figured out how to implement a request to provide the minimum
324        length of subject string that was needed in order to match a given pattern.
325        (It was back references and recursion that I had previously got hung up
326        on.) This code has now been added to pcre_study(); it finds a lower bound
327        to the length of subject needed. It is not necessarily the greatest lower
328        bound, but using it to avoid searching strings that are too short does give
329        some useful speed-ups. The value is available to calling programs via
330        pcre_fullinfo().
331    
332    26. While implementing 25, I discovered to my embarrassment that pcretest had
333        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
334        study optimizations had never been tested with that matching function.
335        Oops. What is worse, even when it was passed study data, there was a bug in
336        pcre_dfa_exec() that meant it never actually used it. Double oops. There
337        were also very few tests of studied patterns with pcre_dfa_exec().
338    
339    27. If (?| is used to create subpatterns with duplicate numbers, they are now
340        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
341        on the other side of the coin, they are no longer allowed to have different
342        names, because these cannot be distinguished in PCRE, and this has caused
343        confusion. (This is a difference from Perl.)
344    
345    28. When duplicate subpattern names are present (necessarily with different
346        numbers, as required by 27 above), and a test is made by name in a
347        conditional pattern, either for a subpattern having been matched, or for
348        recursion in such a pattern, all the associated numbered subpatterns are
349        tested, and the overall condition is true if the condition is true for any
350        one of them. This is the way Perl works, and is also more like the way
351        testing by number works.
352    
353    
354    Version 7.9 11-Apr-09
355  ---------------------  ---------------------
356    
357  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
# Line 17  Version 7.9 xx-xxx-09 Line 367  Version 7.9 xx-xxx-09
367      but BOOL is not.      but BOOL is not.
368    
369  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
370      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
371    
372  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
373      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
# Line 42  Version 7.9 xx-xxx-09 Line 392  Version 7.9 xx-xxx-09
392      correctly handled. The rule now is that both the assertion and what follows      correctly handled. The rule now is that both the assertion and what follows
393      in the first alternative must satisfy the test.      in the first alternative must satisfy the test.
394    
395  9.  If auto-callout was enabled in a pattern with a conditional group whose  9.  If auto-callout was enabled in a pattern with a conditional group whose
396      condition was an assertion, PCRE could crash during matching, both with      condition was an assertion, PCRE could crash during matching, both with
397      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
398    
# Line 64  Version 7.9 xx-xxx-09 Line 414  Version 7.9 xx-xxx-09
414  17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch  17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
415      from Martin Jerabek that uses macro names for all relevant character and      from Martin Jerabek that uses macro names for all relevant character and
416      string constants.      string constants.
417    
418  18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and  18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
419      SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without      SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
420      SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of      SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
421      these, but not everybody uses configure.      these, but not everybody uses configure.
422    
423  19. A conditional group that had only one branch was not being correctly  19. A conditional group that had only one branch was not being correctly
424      recognized as an item that could match an empty string. This meant that an      recognized as an item that could match an empty string. This meant that an
425      enclosing group might also not be so recognized, causing infinite looping      enclosing group might also not be so recognized, causing infinite looping
426      (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$      (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
427      with the subject "ab", where knowledge that the repeated group can match      with the subject "ab", where knowledge that the repeated group can match
428      nothing is needed in order to break the loop.      nothing is needed in order to break the loop.
429    
430  20. If a pattern that was compiled with callouts was matched using pcre_dfa_  20. If a pattern that was compiled with callouts was matched using pcre_dfa_
431      exec(), but without supplying a callout function, matching went wrong.      exec(), but without supplying a callout function, matching went wrong.
432    
433    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
434        leak if the size of the offset vector was greater than 30. When the vector
435        is smaller, the saved offsets during recursion go onto a local stack
436        vector, but for larger vectors malloc() is used. It was failing to free
437        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
438        error, in fact).
439    
440    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
441        heapframe that is used only when UTF-8 support is enabled. This caused no
442        problem, but was untidy.
443    
444    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
445        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
446        included within another project.
447    
448    24. Steven Van Ingelgem's patches to add more options to the CMake support,
449        slightly modified by me:
450    
451          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
452              not building pcregrep.
453    
454          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
455              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
456    
457    25. Forward references, both numeric and by name, in patterns that made use of
458        duplicate group numbers, could behave incorrectly or give incorrect errors,
459        because when scanning forward to find the reference group, PCRE was not
460        taking into account the duplicate group numbers. A pattern such as
461        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
462    
463    26. Changed a few more instances of "const unsigned char *" to USPTR, making
464        the feature of a custom pointer more persuasive (as requested by a user).
465    
466    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
467        pcretest.c, inside #ifndefs, because it seems they are sometimes already
468        pre-defined.
469    
470    28. Added support for (*UTF8) at the start of a pattern.
471    
472    29. Arrange for flags added by the "release type" setting in CMake to be shown
473        in the configuration summary.
474    
475    
476  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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