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revision 3 by nigel, Sat Feb 24 21:38:01 2007 UTC revision 47 by nigel, Sat Feb 24 21:39:29 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    
5    Version 3.2 12-May-00
6    ---------------------
7    
8    This is purely a bug fixing release.
9    
10    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
11    of ZA. This was just one example of several cases that could provoke this bug,
12    which was introduced by change 9 of version 2.00. The code for breaking
13    infinite loops after an iteration that matches an empty string was't working
14    correctly.
15    
16    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
17    when matched against abbab (for example). After matching an empty string, it
18    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
19    caused it to match further down the string than it should.
20    
21    3. The code contained an inclusion of sys/types.h. It isn't clear why this
22    was there because it doesn't seem to be needed, and it causes trouble on some
23    systems, as it is not a Standard C header. It has been removed.
24    
25    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
26    were reported on the Macintosh. The changes were from
27    
28      while ((c = *(++ptr)) != 0 && c != '\n');
29    to
30      while ((c = *(++ptr)) != 0 && c != '\n') ;
31    
32    Totally extraordinary, but if that's what it takes...
33    
34    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
35    available. Added HAVE_BCOPY and an autoconf test for it; if neither
36    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
37    assumes the way PCRE uses memmove() (always moving upwards).
38    
39    6. PCRE is being used in one environment where strchr() is not available. There
40    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
41    faster code anyway.
42    
43    
44    Version 3.1 09-Feb-00
45    ---------------------
46    
47    The only change in this release is the fixing of some bugs in Makefile.in for
48    the "install" target:
49    
50    (1) It was failing to install pcreposix.h.
51    
52    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
53    
54    
55    Version 3.0 01-Feb-00
56    ---------------------
57    
58    1. Add support for the /+ modifier to perltest (to output $` like it does in
59    pcretest).
60    
61    2. Add support for the /g modifier to perltest.
62    
63    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
64    matches null strings.
65    
66    4. Fix perltest so that it doesn't do unwanted things when fed an empty
67    pattern. Perl treats empty patterns specially - it reuses the most recent
68    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
69    effect.
70    
71    5. The POSIX interface was broken in that it was just handing over the POSIX
72    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
73    required a bigger vector, with some working space on the end. This means that
74    the POSIX wrapper now has to get and free some memory, and copy the results.
75    
76    6. Added some simple autoconf support, placing the test data and the
77    documentation in separate directories, re-organizing some of the
78    information files, and making it build pcre-config (a GNU standard). Also added
79    libtool support for building PCRE as a shared library, which is now the
80    default.
81    
82    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
83    09 are not valid octal constants. Single digits will be used for minor values
84    less than 10.
85    
86    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
87    existing programs that set these in the POSIX interface can use PCRE without
88    modification.
89    
90    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
91    return all that pcre_info() returns, plus additional data. The pcre_info()
92    function is retained for compatibility, but is considered to be obsolete.
93    
94    10. Added experimental recursion feature (?R) to handle one common case that
95    Perl 5.6 will be able to do with (?p{...}).
96    
97    11. Added support for POSIX character classes like [:alpha:], which Perl is
98    adopting.
99    
100    
101    Version 2.08 31-Aug-99
102    ----------------------
103    
104    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
105    trying to match at the startoffset position, but instead was moving forward to
106    the next newline as if a previous match had failed.
107    
108    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
109    and could get into a loop if a null string was matched other than at the start
110    of the subject.
111    
112    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
113    be distinguished at compile time, and for completeness also added PCRE_DATE.
114    
115    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
116    in GnuWin32 environments.
117    
118    
119    Version 2.07 29-Jul-99
120    ----------------------
121    
122    1. The documentation is now supplied in plain text form and HTML as well as in
123    the form of man page sources.
124    
125    2. C++ compilers don't like assigning (void *) values to other pointer types.
126    In particular this affects malloc(). Although there is no problem in Standard
127    C, I've put in casts to keep C++ compilers happy.
128    
129    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
130    should be (const char *).
131    
132    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
133    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
134    However, I haven't made this a standard facility. The documentation doesn't
135    mention it, and the Makefile doesn't support it.
136    
137    5. The Makefile now contains an "install" target, with editable destinations at
138    the top of the file. The pcretest program is not installed.
139    
140    6. pgrep -V now gives the PCRE version number and date.
141    
142    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
143    causing the entire string to be ignored, instead of just the last character.
144    
145    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
146    non-matching string, it can take a very, very long time, even for strings of
147    quite modest length, because of the nested recursion. PCRE now does better in
148    some of these cases. It does this by remembering the last required literal
149    character in the pattern, and pre-searching the subject to ensure it is present
150    before running the real match. In other words, it applies a heuristic to detect
151    some types of certain failure quickly, and in the above example, if presented
152    with a string that has no trailing " it gives "no match" very quickly.
153    
154    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
155    other alternatives are tried instead.
156    
157    
158    Version 2.06 09-Jun-99
159    ----------------------
160    
161    1. Change pcretest's output for amount of store used to show just the code
162    space, because the remainder (the data block) varies in size between 32-bit and
163    64-bit systems.
164    
165    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
166    start matching at. This allows lookbehinds to work when searching for multiple
167    occurrences in a string.
168    
169    3. Added additional options to pcretest for testing multiple occurrences:
170    
171       /+   outputs the rest of the string that follows a match
172       /g   loops for multiple occurrences, using the new startoffset argument
173       /G   loops for multiple occurrences by passing an incremented pointer
174    
175    4. PCRE wasn't doing the "first character" optimization for patterns starting
176    with \b or \B, though it was doing it for other lookbehind assertions. That is,
177    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
178    the letter 'x'. On long subject strings, this gives a significant speed-up.
179    
180    
181    Version 2.05 21-Apr-99
182    ----------------------
183    
184    1. Changed the type of magic_number from int to long int so that it works
185    properly on 16-bit systems.
186    
187    2. Fixed a bug which caused patterns starting with .* not to work correctly
188    when the subject string contained newline characters. PCRE was assuming
189    anchoring for such patterns in all cases, which is not correct because .* will
190    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
191    DOTALL is set at top level; otherwise it knows that patterns starting with .*
192    must be retried after every newline in the subject.
193    
194    
195    Version 2.04 18-Feb-99
196    ----------------------
197    
198    1. For parenthesized subpatterns with repeats whose minimum was zero, the
199    computation of the store needed to hold the pattern was incorrect (too large).
200    If such patterns were nested a few deep, this could multiply and become a real
201    problem.
202    
203    2. Added /M option to pcretest to show the memory requirement of a specific
204    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
205    
206    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
207    compiled in such a way that the backtracking after subsequent failure was
208    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
209    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
210    
211    
212    Version 2.03 02-Feb-99
213    ----------------------
214    
215    1. Fixed typo and small mistake in man page.
216    
217    2. Added 4th condition (GPL supersedes if conflict) and created separate
218    LICENCE file containing the conditions.
219    
220    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
221    Perl, that is the internal \ allows the delimiter to be included in the
222    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
223    the final delimiter, add \ to the end of the pattern (to test the error).
224    
225    4. Added the convenience functions for extracting substrings after a successful
226    match. Updated pcretest to make it able to test these functions.
227    
228    
229    Version 2.02 14-Jan-99
230    ----------------------
231    
232    1. Initialized the working variables associated with each extraction so that
233    their saving and restoring doesn't refer to uninitialized store.
234    
235    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
236    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
237    fix the problem.
238    
239    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
240    calls, and wasn't printing the correct value for compiling calls. Increased the
241    default value of LOOPREPEAT, and the number of significant figures in the
242    times.
243    
244    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
245    
246    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
247    a building problem on Windows NT with a FAT file system.
248    
249    
250    Version 2.01 21-Oct-98
251    ----------------------
252    
253    1. Changed the API for pcre_compile() to allow for the provision of a pointer
254    to character tables built by pcre_maketables() in the current locale. If NULL
255    is passed, the default tables are used.
256    
257    
258    Version 2.00 24-Sep-98
259    ----------------------
260    
261    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
262    it any more.
263    
264    2. Allow quantification of (?>) groups, and make it work correctly.
265    
266    3. The first character computation wasn't working for (?>) groups.
267    
268    4. Correct the implementation of \Z (it is permitted to match on the \n at the
269    end of the subject) and add 5.005's \z, which really does match only at the
270    very end of the subject.
271    
272    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
273    
274    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
275    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
276    localized options. All options to pcre_study() were also removed.
277    
278    7. Add other new features from 5.005:
279    
280       $(?<=           positive lookbehind
281       $(?<!           negative lookbehind
282       (?imsx-imsx)    added the unsetting capability
283                       such a setting is global if at outer level; local otherwise
284       (?imsx-imsx:)   non-capturing groups with option setting
285       (?(cond)re|re)  conditional pattern matching
286    
287       A backreference to itself in a repeated group matches the previous
288       captured string.
289    
290    8. General tidying up of studying (both automatic and via "study")
291    consequential on the addition of new assertions.
292    
293    9. As in 5.005, unlimited repeated groups that could match an empty substring
294    are no longer faulted at compile time. Instead, the loop is forcibly broken at
295    runtime if any iteration does actually match an empty substring.
296    
297    10. Include the RunTest script in the distribution.
298    
299    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
300    discrepancies, some of which were old and were also with respect to 5.004. They
301    have now been fixed.
302    
303    
304    Version 1.09 28-Apr-98
305    ----------------------
306    
307    1. A negated single character class followed by a quantifier with a minimum
308    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
309    program crashes, or just wrong answers. This did not apply to negated classes
310    containing more than one character, or to minima other than one.
311    
312    
313    Version 1.08 27-Mar-98
314    ----------------------
315    
316    1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
317    
318    2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
319    latter must appear before anything that relies on it in the pattern.
320    
321    
322    Version 1.07 16-Feb-98
323    ----------------------
324    
325    1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
326    repeat of a potentially empty string).
327    
328    
329    Version 1.06 23-Jan-98
330    ----------------------
331    
332    1. Added Markus Oberhumer's little patches for C++.
333    
334    2. Literal strings longer than 255 characters were broken.
335    
336    
337    Version 1.05 23-Dec-97
338    ----------------------
339    
340    1. Negated character classes containing more than one character were failing if
341    PCRE_CASELESS was set at run time.
342    
343    
344    Version 1.04 19-Dec-97
345    ----------------------
346    
347    1. Corrected the man page, where some "const" qualifiers had been omitted.
348    
349    2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
350    input syntax.
351    
352    3. Fixed memory leak which occurred when a regex with back references was
353    matched with an offsets vector that wasn't big enough. The temporary memory
354    that is used in this case wasn't being freed if the match failed.
355    
356    4. Tidied pcretest to ensure it frees memory that it gets.
357    
358    5. Temporary memory was being obtained in the case where the passed offsets
359    vector was exactly big enough.
360    
361    6. Corrected definition of offsetof() from change 5 below.
362    
363    7. I had screwed up change 6 below and broken the rules for the use of
364    setjmp(). Now fixed.
365    
366    
367    Version 1.03 18-Dec-97
368    ----------------------
369    
370    1. A erroneous regex with a missing opening parenthesis was correctly
371    diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
372    on some systems.
373    
374    2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
375    it was reported that one broken compiler failed on the former because "code" is
376    also an independent variable.
377    
378    3. The erroneous regex a[]b caused an array overrun reference.
379    
380    4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
381    fail on data ending with that character. (It was going on too far, and checking
382    the next character, typically a binary zero.) This was specific to the
383    optimized code for single-character negative classes.
384    
385    5. Added a contributed patch from the TIN world which does the following:
386    
387      + Add an undef for memmove, in case the the system defines a macro for it.
388    
389      + Add a definition of offsetof(), in case there isn't one. (I don't know
390        the reason behind this - offsetof() is part of the ANSI standard - but
391        it does no harm).
392    
393      + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
394        most of the places where whitespace preceded '#'. I have given up and
395        allowed the remaining 2 cases to be at the margin.
396    
397      + Rename some variables in pcre to eliminate shadowing. This seems very
398        pedantic, but does no harm, of course.
399    
400    6. Moved the call to setjmp() into its own function, to get rid of warnings
401    from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
402    
403    7. Constructs such as \d{8,} were compiling into the equivalent of
404    \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
405    outcome, but in this particular case used more store than had been allocated,
406    which caused the bug to be discovered because it threw up an internal error.
407    
408    8. The debugging code in both pcre and pcretest for outputting the compiled
409    form of a regex was going wrong in the case of back references followed by
410    curly-bracketed repeats.
411    
412    
413    Version 1.02 12-Dec-97
414    ----------------------
415    
416    1. Typos in pcre.3 and comments in the source fixed.
417    
418    2. Applied a contributed patch to get rid of places where it used to remove
419    'const' from variables, and fixed some signed/unsigned and uninitialized
420    variable warnings.
421    
422    3. Added the "runtest" target to Makefile.
423    
424    4. Set default compiler flag to -O2 rather than just -O.
425    
426    
427    Version 1.01 19-Nov-97
428    ----------------------
429    
430    1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
431    like /([ab]*)*/, that is, for classes with more than one character in them.
432    
433    2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
434    as /((?>a*))*/ (a PCRE_EXTRA facility).
435    
436    
437    Version 1.00 18-Nov-97
438    ----------------------
439    
440    1. Added compile-time macros to support systems such as SunOS4 which don't have
441    memmove() or strerror() but have other things that can be used instead.
442    
443    2. Arranged that "make clean" removes the executables.
444    
445    
446  Version 0.99 27-Oct-97  Version 0.99 27-Oct-97
447  ----------------------  ----------------------
448    

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