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1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 nigel 5
5 nigel 37 Version 2.07 29-Jul-99
6     ----------------------
7    
8     1. The documentation is now supplied in plain text form and HTML as well as in
9     the form of man page sources.
10    
11     2. C++ compilers don't like assigning (void *) values to other pointer types.
12     In particular this affects malloc(). Although there is no problem in Standard
13     C, I've put in casts to keep C++ compilers happy.
14    
15     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
16     should be (const char *).
17    
18     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
19     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
20     However, I haven't made this a standard facility. The documentation doesn't
21     mention it, and the Makefile doesn't support it.
22    
23     5. The Makefile now contains an "install" target, with editable destinations at
24     the top of the file. The pcretest program is not installed.
25    
26     6. pgrep -V now gives the PCRE version number and date.
27    
28     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
29     causing the entire string to be ignored, instead of just the last character.
30    
31     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
32     non-matching string, it can take a very, very long time, even for strings of
33     quite modest length, because of the nested recursion. PCRE now does better in
34     some of these cases. It does this by remembering the last required literal
35     character in the pattern, and pre-searching the subject to ensure it is present
36     before running the real match. In other words, it applies a heuristic to detect
37     some types of certain failure quickly, and in the above example, if presented
38     with a string that has no trailing " it gives "no match" very quickly.
39    
40     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
41     other alternatives are tried instead.
42    
43    
44 nigel 35 Version 2.06 09-Jun-99
45     ----------------------
46    
47     1. Change pcretest's output for amount of store used to show just the code
48     space, because the remainder (the data block) varies in size between 32-bit and
49     64-bit systems.
50    
51     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
52     start matching at. This allows lookbehinds to work when searching for multiple
53     occurrences in a string.
54    
55     3. Added additional options to pcretest for testing multiple occurrences:
56    
57     /+ outputs the rest of the string that follows a match
58     /g loops for multiple occurrences, using the new startoffset argument
59     /G loops for multiple occurrences by passing an incremented pointer
60    
61     4. PCRE wasn't doing the "first character" optimization for patterns starting
62     with \b or \B, though it was doing it for other lookbehind assertions. That is,
63     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
64     the letter 'x'. On long subject strings, this gives a significant speed-up.
65    
66    
67 nigel 33 Version 2.05 21-Apr-99
68     ----------------------
69    
70     1. Changed the type of magic_number from int to long int so that it works
71     properly on 16-bit systems.
72    
73     2. Fixed a bug which caused patterns starting with .* not to work correctly
74     when the subject string contained newline characters. PCRE was assuming
75     anchoring for such patterns in all cases, which is not correct because .* will
76     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
77     DOTALL is set at top level; otherwise it knows that patterns starting with .*
78     must be retried after every newline in the subject.
79    
80    
81 nigel 31 Version 2.04 18-Feb-99
82     ----------------------
83    
84     1. For parenthesized subpatterns with repeats whose minimum was zero, the
85     computation of the store needed to hold the pattern was incorrect (too large).
86     If such patterns were nested a few deep, this could multiply and become a real
87     problem.
88    
89     2. Added /M option to pcretest to show the memory requirement of a specific
90     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
91    
92     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
93     compiled in such a way that the backtracking after subsequent failure was
94     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
95     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
96    
97    
98 nigel 29 Version 2.03 02-Feb-99
99     ----------------------
100    
101     1. Fixed typo and small mistake in man page.
102    
103 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
104     LICENCE file containing the conditions.
105 nigel 29
106     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
107     Perl, that is the internal \ allows the delimiter to be included in the
108     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
109     the final delimiter, add \ to the end of the pattern (to test the error).
110    
111     4. Added the convenience functions for extracting substrings after a successful
112     match. Updated pcretest to make it able to test these functions.
113    
114    
115 nigel 27 Version 2.02 14-Jan-99
116     ----------------------
117    
118     1. Initialized the working variables associated with each extraction so that
119     their saving and restoring doesn't refer to uninitialized store.
120    
121     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
122     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
123     fix the problem.
124    
125     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
126     calls, and wasn't printing the correct value for compiling calls. Increased the
127     default value of LOOPREPEAT, and the number of significant figures in the
128     times.
129    
130     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
131    
132     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
133     a building problem on Windows NT with a FAT file system.
134    
135    
136 nigel 25 Version 2.01 21-Oct-98
137     ----------------------
138    
139     1. Changed the API for pcre_compile() to allow for the provision of a pointer
140     to character tables built by pcre_maketables() in the current locale. If NULL
141     is passed, the default tables are used.
142    
143    
144 nigel 23 Version 2.00 24-Sep-98
145 nigel 21 ----------------------
146    
147 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
148     it any more.
149    
150     2. Allow quantification of (?>) groups, and make it work correctly.
151    
152     3. The first character computation wasn't working for (?>) groups.
153    
154     4. Correct the implementation of \Z (it is permitted to match on the \n at the
155     end of the subject) and add 5.005's \z, which really does match only at the
156     very end of the subject.
157    
158     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
159    
160     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
161     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
162     localized options. All options to pcre_study() were also removed.
163    
164     7. Add other new features from 5.005:
165    
166     $(?<= positive lookbehind
167     $(?<! negative lookbehind
168     (?imsx-imsx) added the unsetting capability
169     such a setting is global if at outer level; local otherwise
170     (?imsx-imsx:) non-capturing groups with option setting
171     (?(cond)re|re) conditional pattern matching
172    
173     A backreference to itself in a repeated group matches the previous
174     captured string.
175    
176     8. General tidying up of studying (both automatic and via "study")
177     consequential on the addition of new assertions.
178    
179     9. As in 5.005, unlimited repeated groups that could match an empty substring
180     are no longer faulted at compile time. Instead, the loop is forcibly broken at
181     runtime if any iteration does actually match an empty substring.
182    
183     10. Include the RunTest script in the distribution.
184    
185     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
186     discrepancies, some of which were old and were also with respect to 5.004. They
187     have now been fixed.
188    
189    
190     Version 1.09 28-Apr-98
191     ----------------------
192    
193 nigel 21 1. A negated single character class followed by a quantifier with a minimum
194     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
195     program crashes, or just wrong answers. This did not apply to negated classes
196     containing more than one character, or to minima other than one.
197    
198    
199 nigel 19 Version 1.08 27-Mar-98
200     ----------------------
201    
202     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
203    
204     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
205     latter must appear before anything that relies on it in the pattern.
206    
207    
208 nigel 17 Version 1.07 16-Feb-98
209     ----------------------
210    
211     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
212     repeat of a potentially empty string).
213    
214    
215 nigel 15 Version 1.06 23-Jan-98
216     ----------------------
217    
218     1. Added Markus Oberhumer's little patches for C++.
219    
220     2. Literal strings longer than 255 characters were broken.
221    
222    
223 nigel 13 Version 1.05 23-Dec-97
224     ----------------------
225    
226     1. Negated character classes containing more than one character were failing if
227     PCRE_CASELESS was set at run time.
228    
229    
230 nigel 11 Version 1.04 19-Dec-97
231     ----------------------
232    
233     1. Corrected the man page, where some "const" qualifiers had been omitted.
234    
235     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
236     input syntax.
237    
238     3. Fixed memory leak which occurred when a regex with back references was
239     matched with an offsets vector that wasn't big enough. The temporary memory
240     that is used in this case wasn't being freed if the match failed.
241    
242     4. Tidied pcretest to ensure it frees memory that it gets.
243    
244     5. Temporary memory was being obtained in the case where the passed offsets
245     vector was exactly big enough.
246    
247     6. Corrected definition of offsetof() from change 5 below.
248    
249     7. I had screwed up change 6 below and broken the rules for the use of
250     setjmp(). Now fixed.
251    
252    
253 nigel 9 Version 1.03 18-Dec-97
254     ----------------------
255    
256     1. A erroneous regex with a missing opening parenthesis was correctly
257     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
258     on some systems.
259    
260     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
261     it was reported that one broken compiler failed on the former because "code" is
262     also an independent variable.
263    
264     3. The erroneous regex a[]b caused an array overrun reference.
265    
266     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
267     fail on data ending with that character. (It was going on too far, and checking
268     the next character, typically a binary zero.) This was specific to the
269     optimized code for single-character negative classes.
270    
271     5. Added a contributed patch from the TIN world which does the following:
272    
273     + Add an undef for memmove, in case the the system defines a macro for it.
274    
275     + Add a definition of offsetof(), in case there isn't one. (I don't know
276     the reason behind this - offsetof() is part of the ANSI standard - but
277     it does no harm).
278    
279     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
280     most of the places where whitespace preceded '#'. I have given up and
281     allowed the remaining 2 cases to be at the margin.
282    
283     + Rename some variables in pcre to eliminate shadowing. This seems very
284     pedantic, but does no harm, of course.
285    
286     6. Moved the call to setjmp() into its own function, to get rid of warnings
287     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
288    
289     7. Constructs such as \d{8,} were compiling into the equivalent of
290 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
291 nigel 9 outcome, but in this particular case used more store than had been allocated,
292     which caused the bug to be discovered because it threw up an internal error.
293    
294     8. The debugging code in both pcre and pcretest for outputting the compiled
295     form of a regex was going wrong in the case of back references followed by
296     curly-bracketed repeats.
297    
298    
299 nigel 7 Version 1.02 12-Dec-97
300     ----------------------
301    
302     1. Typos in pcre.3 and comments in the source fixed.
303    
304     2. Applied a contributed patch to get rid of places where it used to remove
305     'const' from variables, and fixed some signed/unsigned and uninitialized
306     variable warnings.
307    
308     3. Added the "runtest" target to Makefile.
309    
310     4. Set default compiler flag to -O2 rather than just -O.
311    
312    
313 nigel 5 Version 1.01 19-Nov-97
314     ----------------------
315    
316     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
317     like /([ab]*)*/, that is, for classes with more than one character in them.
318    
319     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
320     as /((?>a*))*/ (a PCRE_EXTRA facility).
321    
322    
323     Version 1.00 18-Nov-97
324     ----------------------
325    
326     1. Added compile-time macros to support systems such as SunOS4 which don't have
327     memmove() or strerror() but have other things that can be used instead.
328    
329     2. Arranged that "make clean" removes the executables.
330    
331    
332 nigel 3 Version 0.99 27-Oct-97
333     ----------------------
334    
335     1. Fixed bug in code for optimizing classes with only one character. It was
336     initializing a 32-byte map regardless, which could cause it to run off the end
337     of the memory it had got.
338    
339     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
340    
341    
342     Version 0.98 22-Oct-97
343     ----------------------
344    
345     1. Fixed bug in code for handling temporary memory usage when there are more
346     back references than supplied space in the ovector. This could cause segfaults.
347    
348    
349     Version 0.97 21-Oct-97
350     ----------------------
351    
352     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
353    
354     2. Optimized negated single characters not to use a bit map.
355    
356     3. Brought error texts together as macro definitions; clarified some of them;
357     fixed one that was wrong - it said "range out of order" when it meant "invalid
358     escape sequence".
359    
360     4. Changed some char * arguments to const char *.
361    
362     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
363    
364     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
365     pcretest.
366    
367    
368     Version 0.96 16-Oct-97
369     ----------------------
370    
371     1. Added a simple "pgrep" utility to the distribution.
372    
373     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
374     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
375     where "ddd" means "one or more decimal digits".
376    
377     3. Fixed serious bug. If a pattern had a back reference, but the call to
378     pcre_exec() didn't supply a large enough ovector to record the related
379     identifying subpattern, the match always failed. PCRE now remembers the number
380     of the largest back reference, and gets some temporary memory in which to save
381     the offsets during matching if necessary, in order to ensure that
382     backreferences always work.
383    
384     4. Increased the compatibility with Perl in a number of ways:
385    
386     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
387     to request this handling. The option can be set at compile or exec time.
388    
389     (b) $ matches before a terminating newline by default; an option
390     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
391     mode). The option can be set at compile or exec time.
392    
393     (c) The handling of \ followed by a digit other than 0 is now supposed to be
394     the same as Perl's. If the decimal number it represents is less than 10
395     or there aren't that many previous left capturing parentheses, an octal
396     escape is read. Inside a character class, it's always an octal escape,
397     even if it is a single digit.
398    
399     (d) An escaped but undefined alphabetic character is taken as a literal,
400     unless PCRE_EXTRA is set. Currently this just reserves the remaining
401     escapes.
402    
403     (e) {0} is now permitted. (The previous item is removed from the compiled
404     pattern).
405    
406     5. Changed all the names of code files so that the basic parts are no longer
407     than 10 characters, and abolished the teeny "globals.c" file.
408    
409     6. Changed the handling of character classes; they are now done with a 32-byte
410     bit map always.
411    
412     7. Added the -d and /D options to pcretest to make it possible to look at the
413     internals of compilation without having to recompile pcre.
414    
415    
416     Version 0.95 23-Sep-97
417     ----------------------
418    
419     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
420     \x20 at the start of a run of normal characters. These were being treated as
421     real characters, instead of the source characters being re-checked.
422    
423    
424     Version 0.94 18-Sep-97
425     ----------------------
426    
427     1. The functions are now thread-safe, with the caveat that the global variables
428     containing pointers to malloc() and free() or alternative functions are the
429     same for all threads.
430    
431     2. Get pcre_study() to generate a bitmap of initial characters for non-
432     anchored patterns when this is possible, and use it if passed to pcre_exec().
433    
434    
435     Version 0.93 15-Sep-97
436     ----------------------
437    
438     1. /(b)|(:+)/ was computing an incorrect first character.
439    
440     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
441     but not actually doing anything yet.
442    
443     3. Treat "-" characters in classes that cannot be part of ranges as literals,
444     as Perl does (e.g. [-az] or [az-]).
445    
446     4. Set the anchored flag if a branch starts with .* or .*? because that tests
447     all possible positions.
448    
449     5. Split up into different modules to avoid including unneeded functions in a
450     compiled binary. However, compile and exec are still in one module. The "study"
451     function is split off.
452    
453     6. The character tables are now in a separate module whose source is generated
454     by an auxiliary program - but can then be edited by hand if required. There are
455     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
456     toupper() in the code.
457    
458     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
459     make them global. Abolish the function for setting them, as the caller can now
460     set them directly.
461    
462    
463     Version 0.92 11-Sep-97
464     ----------------------
465    
466     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
467     (e.g. /a{1,3}/) was broken (I mis-optimized it).
468    
469     2. Caseless matching was not working in character classes if the characters in
470     the pattern were in upper case.
471    
472     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
473    
474     4. Make PCRE_ANCHORED public and accept as a compile option.
475    
476     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
477     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
478     pass them.
479    
480     6. Give an error if bad option bits passed at compile or run time.
481    
482     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
483     pcretest to cause it to pass that flag.
484    
485     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
486     options, and the first character, if set.
487    
488     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
489    
490    
491     Version 0.91 10-Sep-97
492     ----------------------
493    
494     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
495     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
496    
497     2. PCRE was looping on encountering an indefinitely repeated back reference to
498     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
499     Perl does - treats the match as successful.
500    
501     ****

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