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1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 nigel 5
5 nigel 35 Version 2.06 09-Jun-99
6     ----------------------
7    
8     1. Change pcretest's output for amount of store used to show just the code
9     space, because the remainder (the data block) varies in size between 32-bit and
10     64-bit systems.
11    
12     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
13     start matching at. This allows lookbehinds to work when searching for multiple
14     occurrences in a string.
15    
16     3. Added additional options to pcretest for testing multiple occurrences:
17    
18     /+ outputs the rest of the string that follows a match
19     /g loops for multiple occurrences, using the new startoffset argument
20     /G loops for multiple occurrences by passing an incremented pointer
21    
22     4. PCRE wasn't doing the "first character" optimization for patterns starting
23     with \b or \B, though it was doing it for other lookbehind assertions. That is,
24     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
25     the letter 'x'. On long subject strings, this gives a significant speed-up.
26    
27    
28 nigel 33 Version 2.05 21-Apr-99
29     ----------------------
30    
31     1. Changed the type of magic_number from int to long int so that it works
32     properly on 16-bit systems.
33    
34     2. Fixed a bug which caused patterns starting with .* not to work correctly
35     when the subject string contained newline characters. PCRE was assuming
36     anchoring for such patterns in all cases, which is not correct because .* will
37     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
38     DOTALL is set at top level; otherwise it knows that patterns starting with .*
39     must be retried after every newline in the subject.
40    
41    
42 nigel 31 Version 2.04 18-Feb-99
43     ----------------------
44    
45     1. For parenthesized subpatterns with repeats whose minimum was zero, the
46     computation of the store needed to hold the pattern was incorrect (too large).
47     If such patterns were nested a few deep, this could multiply and become a real
48     problem.
49    
50     2. Added /M option to pcretest to show the memory requirement of a specific
51     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
52    
53     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
54     compiled in such a way that the backtracking after subsequent failure was
55     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
56     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
57    
58    
59 nigel 29 Version 2.03 02-Feb-99
60     ----------------------
61    
62     1. Fixed typo and small mistake in man page.
63    
64 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
65     LICENCE file containing the conditions.
66 nigel 29
67     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
68     Perl, that is the internal \ allows the delimiter to be included in the
69     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
70     the final delimiter, add \ to the end of the pattern (to test the error).
71    
72     4. Added the convenience functions for extracting substrings after a successful
73     match. Updated pcretest to make it able to test these functions.
74    
75    
76 nigel 27 Version 2.02 14-Jan-99
77     ----------------------
78    
79     1. Initialized the working variables associated with each extraction so that
80     their saving and restoring doesn't refer to uninitialized store.
81    
82     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
83     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
84     fix the problem.
85    
86     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
87     calls, and wasn't printing the correct value for compiling calls. Increased the
88     default value of LOOPREPEAT, and the number of significant figures in the
89     times.
90    
91     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
92    
93     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
94     a building problem on Windows NT with a FAT file system.
95    
96    
97 nigel 25 Version 2.01 21-Oct-98
98     ----------------------
99    
100     1. Changed the API for pcre_compile() to allow for the provision of a pointer
101     to character tables built by pcre_maketables() in the current locale. If NULL
102     is passed, the default tables are used.
103    
104    
105 nigel 23 Version 2.00 24-Sep-98
106 nigel 21 ----------------------
107    
108 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
109     it any more.
110    
111     2. Allow quantification of (?>) groups, and make it work correctly.
112    
113     3. The first character computation wasn't working for (?>) groups.
114    
115     4. Correct the implementation of \Z (it is permitted to match on the \n at the
116     end of the subject) and add 5.005's \z, which really does match only at the
117     very end of the subject.
118    
119     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
120    
121     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
122     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
123     localized options. All options to pcre_study() were also removed.
124    
125     7. Add other new features from 5.005:
126    
127     $(?<= positive lookbehind
128     $(?<! negative lookbehind
129     (?imsx-imsx) added the unsetting capability
130     such a setting is global if at outer level; local otherwise
131     (?imsx-imsx:) non-capturing groups with option setting
132     (?(cond)re|re) conditional pattern matching
133    
134     A backreference to itself in a repeated group matches the previous
135     captured string.
136    
137     8. General tidying up of studying (both automatic and via "study")
138     consequential on the addition of new assertions.
139    
140     9. As in 5.005, unlimited repeated groups that could match an empty substring
141     are no longer faulted at compile time. Instead, the loop is forcibly broken at
142     runtime if any iteration does actually match an empty substring.
143    
144     10. Include the RunTest script in the distribution.
145    
146     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
147     discrepancies, some of which were old and were also with respect to 5.004. They
148     have now been fixed.
149    
150    
151     Version 1.09 28-Apr-98
152     ----------------------
153    
154 nigel 21 1. A negated single character class followed by a quantifier with a minimum
155     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
156     program crashes, or just wrong answers. This did not apply to negated classes
157     containing more than one character, or to minima other than one.
158    
159    
160 nigel 19 Version 1.08 27-Mar-98
161     ----------------------
162    
163     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
164    
165     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
166     latter must appear before anything that relies on it in the pattern.
167    
168    
169 nigel 17 Version 1.07 16-Feb-98
170     ----------------------
171    
172     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
173     repeat of a potentially empty string).
174    
175    
176 nigel 15 Version 1.06 23-Jan-98
177     ----------------------
178    
179     1. Added Markus Oberhumer's little patches for C++.
180    
181     2. Literal strings longer than 255 characters were broken.
182    
183    
184 nigel 13 Version 1.05 23-Dec-97
185     ----------------------
186    
187     1. Negated character classes containing more than one character were failing if
188     PCRE_CASELESS was set at run time.
189    
190    
191 nigel 11 Version 1.04 19-Dec-97
192     ----------------------
193    
194     1. Corrected the man page, where some "const" qualifiers had been omitted.
195    
196     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
197     input syntax.
198    
199     3. Fixed memory leak which occurred when a regex with back references was
200     matched with an offsets vector that wasn't big enough. The temporary memory
201     that is used in this case wasn't being freed if the match failed.
202    
203     4. Tidied pcretest to ensure it frees memory that it gets.
204    
205     5. Temporary memory was being obtained in the case where the passed offsets
206     vector was exactly big enough.
207    
208     6. Corrected definition of offsetof() from change 5 below.
209    
210     7. I had screwed up change 6 below and broken the rules for the use of
211     setjmp(). Now fixed.
212    
213    
214 nigel 9 Version 1.03 18-Dec-97
215     ----------------------
216    
217     1. A erroneous regex with a missing opening parenthesis was correctly
218     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
219     on some systems.
220    
221     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
222     it was reported that one broken compiler failed on the former because "code" is
223     also an independent variable.
224    
225     3. The erroneous regex a[]b caused an array overrun reference.
226    
227     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
228     fail on data ending with that character. (It was going on too far, and checking
229     the next character, typically a binary zero.) This was specific to the
230     optimized code for single-character negative classes.
231    
232     5. Added a contributed patch from the TIN world which does the following:
233    
234     + Add an undef for memmove, in case the the system defines a macro for it.
235    
236     + Add a definition of offsetof(), in case there isn't one. (I don't know
237     the reason behind this - offsetof() is part of the ANSI standard - but
238     it does no harm).
239    
240     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
241     most of the places where whitespace preceded '#'. I have given up and
242     allowed the remaining 2 cases to be at the margin.
243    
244     + Rename some variables in pcre to eliminate shadowing. This seems very
245     pedantic, but does no harm, of course.
246    
247     6. Moved the call to setjmp() into its own function, to get rid of warnings
248     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
249    
250     7. Constructs such as \d{8,} were compiling into the equivalent of
251 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
252 nigel 9 outcome, but in this particular case used more store than had been allocated,
253     which caused the bug to be discovered because it threw up an internal error.
254    
255     8. The debugging code in both pcre and pcretest for outputting the compiled
256     form of a regex was going wrong in the case of back references followed by
257     curly-bracketed repeats.
258    
259    
260 nigel 7 Version 1.02 12-Dec-97
261     ----------------------
262    
263     1. Typos in pcre.3 and comments in the source fixed.
264    
265     2. Applied a contributed patch to get rid of places where it used to remove
266     'const' from variables, and fixed some signed/unsigned and uninitialized
267     variable warnings.
268    
269     3. Added the "runtest" target to Makefile.
270    
271     4. Set default compiler flag to -O2 rather than just -O.
272    
273    
274 nigel 5 Version 1.01 19-Nov-97
275     ----------------------
276    
277     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
278     like /([ab]*)*/, that is, for classes with more than one character in them.
279    
280     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
281     as /((?>a*))*/ (a PCRE_EXTRA facility).
282    
283    
284     Version 1.00 18-Nov-97
285     ----------------------
286    
287     1. Added compile-time macros to support systems such as SunOS4 which don't have
288     memmove() or strerror() but have other things that can be used instead.
289    
290     2. Arranged that "make clean" removes the executables.
291    
292    
293 nigel 3 Version 0.99 27-Oct-97
294     ----------------------
295    
296     1. Fixed bug in code for optimizing classes with only one character. It was
297     initializing a 32-byte map regardless, which could cause it to run off the end
298     of the memory it had got.
299    
300     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
301    
302    
303     Version 0.98 22-Oct-97
304     ----------------------
305    
306     1. Fixed bug in code for handling temporary memory usage when there are more
307     back references than supplied space in the ovector. This could cause segfaults.
308    
309    
310     Version 0.97 21-Oct-97
311     ----------------------
312    
313     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
314    
315     2. Optimized negated single characters not to use a bit map.
316    
317     3. Brought error texts together as macro definitions; clarified some of them;
318     fixed one that was wrong - it said "range out of order" when it meant "invalid
319     escape sequence".
320    
321     4. Changed some char * arguments to const char *.
322    
323     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
324    
325     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
326     pcretest.
327    
328    
329     Version 0.96 16-Oct-97
330     ----------------------
331    
332     1. Added a simple "pgrep" utility to the distribution.
333    
334     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
335     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
336     where "ddd" means "one or more decimal digits".
337    
338     3. Fixed serious bug. If a pattern had a back reference, but the call to
339     pcre_exec() didn't supply a large enough ovector to record the related
340     identifying subpattern, the match always failed. PCRE now remembers the number
341     of the largest back reference, and gets some temporary memory in which to save
342     the offsets during matching if necessary, in order to ensure that
343     backreferences always work.
344    
345     4. Increased the compatibility with Perl in a number of ways:
346    
347     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
348     to request this handling. The option can be set at compile or exec time.
349    
350     (b) $ matches before a terminating newline by default; an option
351     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
352     mode). The option can be set at compile or exec time.
353    
354     (c) The handling of \ followed by a digit other than 0 is now supposed to be
355     the same as Perl's. If the decimal number it represents is less than 10
356     or there aren't that many previous left capturing parentheses, an octal
357     escape is read. Inside a character class, it's always an octal escape,
358     even if it is a single digit.
359    
360     (d) An escaped but undefined alphabetic character is taken as a literal,
361     unless PCRE_EXTRA is set. Currently this just reserves the remaining
362     escapes.
363    
364     (e) {0} is now permitted. (The previous item is removed from the compiled
365     pattern).
366    
367     5. Changed all the names of code files so that the basic parts are no longer
368     than 10 characters, and abolished the teeny "globals.c" file.
369    
370     6. Changed the handling of character classes; they are now done with a 32-byte
371     bit map always.
372    
373     7. Added the -d and /D options to pcretest to make it possible to look at the
374     internals of compilation without having to recompile pcre.
375    
376    
377     Version 0.95 23-Sep-97
378     ----------------------
379    
380     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
381     \x20 at the start of a run of normal characters. These were being treated as
382     real characters, instead of the source characters being re-checked.
383    
384    
385     Version 0.94 18-Sep-97
386     ----------------------
387    
388     1. The functions are now thread-safe, with the caveat that the global variables
389     containing pointers to malloc() and free() or alternative functions are the
390     same for all threads.
391    
392     2. Get pcre_study() to generate a bitmap of initial characters for non-
393     anchored patterns when this is possible, and use it if passed to pcre_exec().
394    
395    
396     Version 0.93 15-Sep-97
397     ----------------------
398    
399     1. /(b)|(:+)/ was computing an incorrect first character.
400    
401     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
402     but not actually doing anything yet.
403    
404     3. Treat "-" characters in classes that cannot be part of ranges as literals,
405     as Perl does (e.g. [-az] or [az-]).
406    
407     4. Set the anchored flag if a branch starts with .* or .*? because that tests
408     all possible positions.
409    
410     5. Split up into different modules to avoid including unneeded functions in a
411     compiled binary. However, compile and exec are still in one module. The "study"
412     function is split off.
413    
414     6. The character tables are now in a separate module whose source is generated
415     by an auxiliary program - but can then be edited by hand if required. There are
416     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
417     toupper() in the code.
418    
419     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
420     make them global. Abolish the function for setting them, as the caller can now
421     set them directly.
422    
423    
424     Version 0.92 11-Sep-97
425     ----------------------
426    
427     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
428     (e.g. /a{1,3}/) was broken (I mis-optimized it).
429    
430     2. Caseless matching was not working in character classes if the characters in
431     the pattern were in upper case.
432    
433     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
434    
435     4. Make PCRE_ANCHORED public and accept as a compile option.
436    
437     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
438     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
439     pass them.
440    
441     6. Give an error if bad option bits passed at compile or run time.
442    
443     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
444     pcretest to cause it to pass that flag.
445    
446     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
447     options, and the first character, if set.
448    
449     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
450    
451    
452     Version 0.91 10-Sep-97
453     ----------------------
454    
455     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
456     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
457    
458     2. PCRE was looping on encountering an indefinitely repeated back reference to
459     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
460     Perl does - treats the match as successful.
461    
462     ****

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