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Revision 379 - (hide annotations) (download)
Mon Mar 2 20:30:05 2009 UTC (5 years, 6 months ago) by ph10
File size: 161600 byte(s)
Lock out empty string matches in pcregrep.

1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 ph10 376 Version 7.9 xx-xxx-09
5     ---------------------
6    
7     1. When building with support for bzlib/zlib (pcregrep) and/or readline
8     (pcretest), all targets were linked against these libraries. This included
9     libpcre, libpcreposix, and libpcrecpp, even though they do not use these
10     libraries. This caused unwanted dependencies to be created. This problem
11     has been fixed, and now only pcregrep is linked with bzlib/zlib and only
12     pcretest is linked with readline.
13    
14     2. The "typedef int BOOL" in pcre_internal.h that was included inside the
15     "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
16     moved outside it again, because FALSE and TRUE are already defined in AIX,
17     but BOOL is not.
18    
19     3. The pcre_config() function was treating the PCRE_MATCH_LIMIT and
20     PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.
21    
22     4. The pcregrep documentation said spaces were inserted as well as colons (or
23     hyphens) following file names and line numbers when outputting matching
24     lines. This is not true; no spaces are inserted. I have also clarified the
25     wording for the --colour (or --color) option.
26 ph10 377
27 ph10 378 5. In pcregrep, when --colour was used with -o, the list of matching strings
28     was not coloured; this is different to GNU grep, so I have changed it to be
29     the same.
30    
31     6. When --colo(u)r was used in pcregrep, only the first matching substring in
32     each matching line was coloured. Now it goes on to look for further matches
33     of any of the test patterns, which is the same behaviour as GNU grep.
34 ph10 379
35     7. A pattern that could match an empty string could cause pcregrep to loop; it
36     doesn't make sense to accept an empty string match in pcregrep, so I have
37     locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
38     seems to be how GNU grep behaves.
39 ph10 376
40    
41 ph10 374 Version 7.8 05-Sep-08
42 ph10 349 ---------------------
43    
44     1. Replaced UCP searching code with optimized version as implemented for Ad
45     Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
46 ph10 351 stage table and inline lookup instead of a function, giving speed ups of 2
47     to 5 times on some simple patterns that I tested. Permission was given to
48     distribute the MultiStage2.py script that generates the tables (it's not in
49     the tarball, but is in the Subversion repository).
50 ph10 349
51 ph10 351 2. Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
52     scripts.
53 ph10 358
54 ph10 353 3. Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
55     a group with a zero qualifier. The result of the study could be incorrect,
56 ph10 358 or the function might crash, depending on the pattern.
57    
58     4. Caseless matching was not working for non-ASCII characters in back
59 ph10 354 references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
60 ph10 358 It now works when Unicode Property Support is available.
61    
62 ph10 355 5. In pcretest, an escape such as \x{de} in the data was always generating
63     a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
64     non-UTF-8 mode. If the value is greater than 255, it gives a warning about
65 ph10 358 truncation.
66 ph10 349
67 ph10 358 6. Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
68    
69 ph10 357 7. Added two (int) casts to pcregrep when printing the difference of two
70     pointers, in case they are 64-bit values.
71 ph10 371
72     8. Added comments about Mac OS X stack usage to the pcrestack man page and to
73     test 2 if it fails.
74    
75 ph10 359 9. Added PCRE_CALL_CONVENTION just before the names of all exported functions,
76 ph10 371 and a #define of that name to empty if it is not externally set. This is to
77     allow users of MSVC to set it if necessary.
78    
79     10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
80 ph10 359 the convenience functions in the pcre_get.c source file.
81 ph10 371
82 ph10 360 11. An option change at the start of a pattern that had top-level alternatives
83     could cause overwriting and/or a crash. This command provoked a crash in
84 ph10 371 some environments:
85    
86     printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
87    
88 ph10 360 This potential security problem was recorded as CVE-2008-2371.
89 ph10 371
90 ph10 361 12. For a pattern where the match had to start at the beginning or immediately
91     after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
92 ph10 371 pcre_dfa_exec() could read past the end of the passed subject if there was
93 ph10 361 no match. To help with detecting such bugs (e.g. with valgrind), I modified
94     pcretest so that it places the subject at the end of its malloc-ed buffer.
95 ph10 371
96 ph10 364 13. The change to pcretest in 12 above threw up a couple more cases when pcre_
97 ph10 371 exec() might read past the end of the data buffer in UTF-8 mode.
98    
99 ph10 364 14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
100 ph10 371 the data contained the byte 0x85 as part of a UTF-8 character within its
101     first line. This applied both to normal and DFA matching.
102    
103 ph10 366 15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
104 ph10 371 /^[^d]*?$/8 failed to match "abc".
105 ph10 351
106 ph10 371 16. Added a missing copyright notice to pcrecpp_internal.h.
107    
108     17. Make it more clear in the documentation that values returned from
109 ph10 368 pcre_exec() in ovector are byte offsets, not character counts.
110 ph10 357
111 ph10 371 18. Tidied a few places to stop certain compilers from issuing warnings.
112 ph10 368
113 ph10 373 19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
114     supplied by Stefan Weber. I made a further small update for 7.8 because
115 ph10 374 there is a change of source arrangements: the pcre_searchfuncs.c module is
116     replaced by pcre_ucd.c.
117 ph10 371
118 ph10 373
119 ph10 347 Version 7.7 07-May-08
120 ph10 321 ---------------------
121    
122     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
123 ph10 345 a string to a long long, pretend we don't even have a long long." This is
124 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
125 ph10 345
126 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
127     pre-7.6 versions, which defined a global no_arg variable instead of putting
128 ph10 332 it in the RE class. (See also #8 below.)
129 ph10 345
130     3. Remove a line of dead code, identified by coverity and reported by Nuno
131     Lopes.
132    
133 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
134 ph10 321
135 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
136 ph10 345 of files, instead of just to the final components.
137    
138 ph10 324 (2) If there was more than one level of directory, the subdirectories were
139     skipped unless they satisfied the include/exclude conditions. This is
140     inconsistent with GNU grep (and could even be seen as contrary to the
141     pcregrep specification - which I improved to make it absolutely clear).
142     The action now is always to scan all levels of directory, and just
143     apply the include/exclude patterns to regular files.
144 ph10 345
145 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
146 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
147    
148 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
149 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
150 ph10 326 doesn't support NULs in patterns.
151 ph10 345
152     7. Added some missing "const"s to declarations of static tables in
153     pcre_compile.c and pcre_dfa_exec.c.
154    
155 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
156 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
157 ph10 345 first patch. And a third patch - this was a messy problem.)
158 ph10 321
159 ph10 345 9. Applied Craig's patch to remove the use of push_back().
160    
161 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
162     matching function regexec().
163 ph10 345
164     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
165     which, however, unlike Perl's \g{...}, are subroutine calls, not back
166 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
167     Oniguruma does).
168 ph10 345
169     12. Previously, a group with a zero repeat such as (...){0} was completely
170 ph10 335 omitted from the compiled regex. However, this means that if the group
171     was called as a subroutine from elsewhere in the pattern, things went wrong
172 ph10 345 (an internal error was given). Such groups are now left in the compiled
173     pattern, with a new opcode that causes them to be skipped at execution
174 ph10 335 time.
175 ph10 345
176 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
177     to the way PCRE behaves:
178 ph10 345
179 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
180 ph10 345
181     (b) A back reference to an unmatched subpattern matches an empty string
182 ph10 336 (Perl fails the current match path).
183 ph10 345
184 ph10 341 (c) A data ] in a character class must be notated as \] because if the
185 ph10 345 first data character in a class is ], it defines an empty class. (In
186 ph10 341 Perl it is not possible to have an empty class.) The empty class []
187     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
188     The negative empty class [^] matches any one character, independently
189     of the DOTALL setting.
190 ph10 345
191     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
192 ph10 340 non-existent subpattern following a character class starting with ']' and
193     containing () gave an internal compiling error instead of "reference to
194     non-existent subpattern". Fortunately, when the pattern did exist, the
195 ph10 345 compiled code was correct. (When scanning forwards to check for the
196 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
197 ph10 345 the class, so got the count wrong. When actually compiling, the reference
198 ph10 340 was subsequently set up correctly.)
199 ph10 345
200 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
201 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
202     other assertions are supported. I have made pcre_dfa_exec() support
203     (*FAIL).
204    
205 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
206 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
207     cannot be changed at match time, I realized I could make a small
208     improvement to matching performance by compiling OP_ALLANY instead of
209     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
210     on the OP_ANY path.
211    
212     17. Compiling pcretest on Windows with readline support failed without the
213 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
214 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
215    
216 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
217 ph10 345 ncurses library to be included for pcretest when ReadLine support is
218     requested, but also to allow for it to be overridden. This patch came from
219     Daniel Bergström.
220 ph10 347
221 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
222 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
223     any errors with the current Unicode tables. Thanks to Peter Kankowski for
224     spotting this.
225 ph10 324
226 ph10 332
227 ph10 319 Version 7.6 28-Jan-08
228 ph10 300 ---------------------
229    
230 ph10 302 1. A character class containing a very large number of characters with
231     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
232     overflow.
233 ph10 309
234     2. Patch to cut out the "long long" test in pcrecpp_unittest when
235     HAVE_LONG_LONG is not defined.
236    
237 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
238 ph10 304 bring them up to date and include new features. This patch includes:
239 ph10 309
240 ph10 304 - Fixed PH's badly added libz and libbz2 support.
241     - Fixed a problem with static linking.
242 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
243 ph10 304 - Fixed dftables problem and added an option.
244     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
245     HAVE_LONG_LONG.
246     - Added readline support for pcretest.
247 ph10 309 - Added an listing of the option settings after cmake has run.
248    
249 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
250     "pcre.dll" under mingw when using Configure/Make. I added stuff to
251     Makefile.am that cause it to include this special target, without
252     affecting anything else. Note that the same mingw target plus all
253     the other distribution libraries and programs are now supported
254     when configuring with CMake (see 6 below) instead of with
255     Configure/Make.
256 ph10 309
257 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
258     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
259 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
260     solves the problem, but it does no harm.
261 ph10 313
262 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
263 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
264 ph10 314 with CMake, and also correct the comment about stack recursion.
265 ph10 313
266 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
267 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
268     of a program that users should build themselves after PCRE is installed, so
269     building it automatically is not really right. What is more, it gave
270 ph10 312 trouble in some build environments.
271 ph10 300
272 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
273 ph10 308
274 ph10 319
275 ph10 298 Version 7.5 10-Jan-08
276 ph10 263 ---------------------
277    
278     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
279     values in parens when parsing an RE using the C++ wrapper."
280 ph10 286
281 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
282     Characters greater than 255 were excluded from the class instead of being
283     included.
284 ph10 286
285     3. The same bug as (2) above applied to negated POSIX classes such as
286 ph10 265 [:^space:].
287 ph10 286
288 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
289     defined or documented. It seems to have been a typo for PCRE_STATIC, so
290 ph10 286 I have changed it.
291    
292 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
293 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
294     first named subpattern whose name started with "a" (in other words, the
295 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
296     expected" is now given for (?&) (a zero-length name), and this patch also
297     makes it give the same error for \k'' (previously it complained that that
298     was a reference to a non-existent subpattern).
299 ph10 286
300 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
301 ph10 286 this is right because (?- can be followed by option settings as well as by
302 ph10 269 digits. I have, however, made the messages clearer.
303 ph10 286
304 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
305     than the number used in the conditional) now cause a compile-time error.
306     This is actually not compatible with Perl, which accepts such patterns, but
307     treats the conditional as always being FALSE (as PCRE used to), but it
308     seems to me that giving a diagnostic is better.
309 ph10 286
310 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
311 ph10 275 and messages.
312 ph10 286
313     9. Fix two occurrences of "backslash" in comments that should have been
314     "backspace".
315    
316     10. Remove two redundant lines of code that can never be obeyed (their function
317     was moved elsewhere).
318    
319     11. The program that makes PCRE's Unicode character property table had a bug
320     which caused it to generate incorrect table entries for sequences of
321 ph10 277 characters that have the same character type, but are in different scripts.
322 ph10 286 It amalgamated them into a single range, with the script of the first of
323 ph10 277 them. In other words, some characters were in the wrong script. There were
324     thirteen such cases, affecting characters in the following ranges:
325 ph10 286
326 ph10 277 U+002b0 - U+002c1
327     U+0060c - U+0060d
328 ph10 286 U+0061e - U+00612
329 ph10 277 U+0064b - U+0065e
330     U+0074d - U+0076d
331     U+01800 - U+01805
332     U+01d00 - U+01d77
333     U+01d9b - U+01dbf
334     U+0200b - U+0200f
335     U+030fc - U+030fe
336     U+03260 - U+0327f
337     U+0fb46 - U+0fbb1
338     U+10450 - U+1049d
339 ph10 286
340 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
341     compatible with GNU grep in that, if there was more than one match in a
342     line, it showed only the first of them. It now behaves in the same way as
343     GNU grep.
344 ph10 286
345     13. If the -o and -v options were combined for pcregrep, it printed a blank
346     line for every non-matching line. GNU grep prints nothing, and pcregrep now
347     does the same. The return code can be used to tell if there were any
348     non-matching lines.
349    
350 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
351    
352     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
353 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
354 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
355     and both kinds of lookbehind were skipped).
356    
357 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
358 ph10 284 inclusion of <windows.h> to before rather than after the definition of
359     INVALID_FILE_ATTRIBUTES (patch from David Byron).
360 ph10 263
361 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
362 ph10 286 character property caused pcre_compile() to compile bad code, which led at
363     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
364     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
365     caused the error; without that there was no problem.
366 ph10 263
367 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
368 ph10 286
369 ph10 289 19. Added --enable-pcretest-libreadline.
370 ph10 286
371 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
372 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
373 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
374     later patch that removed the other one (the right fix) and added unit tests
375     that check the return values (which was not done before).
376 ph10 292
377 ph10 291 21. Several CMake things:
378 ph10 287
379 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
380 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
381 ph10 288
382 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
383     linked with the newly-built libraries, not previously installed ones.
384 ph10 291
385 ph10 292 (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
386 ph10 298
387     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
388     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
389     UTF-8 newline character). The key issue is that the pattern starts .*;
390     this means that the match must be either at the beginning, or after a
391     newline. The bug was in the code for advancing after a failed match and
392     checking that the new position followed a newline. It was not taking
393 ph10 294 account of UTF-8 characters correctly.
394 ph10 298
395     23. PCRE was behaving differently from Perl in the way it recognized POSIX
396     character classes. PCRE was not treating the sequence [:...:] as a
397     character class unless the ... were all letters. Perl, however, seems to
398     allow any characters between [: and :], though of course it rejects as
399     unknown any "names" that contain non-letters, because all the known class
400     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
401     for example, whereas PCRE did not - it did not recognize a POSIX character
402     class. This seemed a bit dangerous, so the code has been changed to be
403     closer to Perl. The behaviour is not identical to Perl, because PCRE will
404     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
405     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
406     Perl does, and where it didn't before.
407    
408 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
409     Windows environments %n is disabled by default.
410 ph10 292
411    
412 ph10 260 Version 7.4 21-Sep-07
413 ph10 230 ---------------------
414    
415     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
416 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
417     LF". That isn't really right - the whole point of the change was to try to
418     help when there was an actual mention of one of the two characters. So now
419     the change happens only if \r or \n (or a literal CR or LF) character is
420 ph10 230 encountered.
421 ph10 231
422     2. The 32-bit options word was also used for 6 internal flags, but the numbers
423     of both had grown to the point where there were only 3 bits left.
424     Fortunately, there was spare space in the data structure, and so I have
425     moved the internal flags into a new 16-bit field to free up more option
426 ph10 230 bits.
427 ph10 231
428     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
429     but did not set the internal JCHANGED flag - either of these is enough to
430     control the way the "get" function works - but the PCRE_INFO_JCHANGED
431     facility is supposed to tell if (?J) was ever used, so now (?J) at the
432 ph10 230 start sets both bits.
433    
434 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
435     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
436 ph10 230
437 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
438    
439     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
440 ph10 233 compatibility, even though it is no longer used.
441 ph10 243
442     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
443 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
444 ph10 259 windows.h file is present (where different names are used). [This was
445 ph10 257 reversed later after testing - see 16 below.]
446 ph10 243
447     8. Changed all #include <config.h> to #include "config.h". There were also
448 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
449 ph10 243
450 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
451 ph10 243 sequence off the lines that it output.
452    
453     10. It was pointed out to me that arrays of string pointers cause lots of
454     relocations when a shared library is dynamically loaded. A technique of
455     using a single long string with a table of offsets can drastically reduce
456     these. I have refactored PCRE in four places to do this. The result is
457 ph10 240 dramatic:
458 ph10 243
459 ph10 240 Originally: 290
460     After changing UCP table: 187
461 ph10 243 After changing error message table: 43
462 ph10 240 After changing table of "verbs" 36
463     After changing table of Posix names 22
464 ph10 243
465 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
466 ph10 247
467 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
468 ph10 247 unicode-properties was also set.
469    
470 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
471 ph10 231
472 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
473     checked only for CRLF.
474 ph10 233
475 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
476    
477 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
478 ph10 253
479 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
480 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
481     entirely. This removes changes made in 7 above.
482 ph10 256
483 ph10 261 17. The CMake files have been updated, and there is now more information about
484     building with CMake in the NON-UNIX-USE document.
485 ph10 257
486 ph10 261
487 ph10 228 Version 7.3 28-Aug-07
488 ph10 157 ---------------------
489    
490 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
491     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
492     brackets there is not right, since it causes compilers to look for an
493     installed pcre.h, not the version that is in the source that is being
494     compiled (which of course may be different). I have changed it back to:
495 ph10 197
496 ph10 189 #include "pcre.h"
497 ph10 197
498     I have a vague recollection that the change was concerned with compiling in
499     different directories, but in the new build system, that is taken care of
500     by the VPATH setting the Makefile.
501    
502 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
503     when the subject happened to end in the byte 0x85 (e.g. if the last
504     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
505     characters but of course it shouldn't be taken as a newline when it is part
506     of another character. The bug was that, for an unlimited repeat of . in
507     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
508     characters when looking for a newline.
509 ph10 197
510     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
511    
512     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
513     in debug output.
514    
515 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
516     long printing in the pcrecpp unittest when running under MinGW.
517 ph10 189
518 ph10 197 6. ESC_K was left out of the EBCDIC table.
519 ph10 189
520 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
521     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
522     limit also applies to "virtual nesting" when a pattern is recursive, and in
523     this case 1000 isn't so big. I have been able to remove this limit at the
524     expense of backing off one optimization in certain circumstances. Normally,
525     when pcre_exec() would call its internal match() function recursively and
526     immediately return the result unconditionally, it uses a "tail recursion"
527     feature to save stack. However, when a subpattern that can match an empty
528     string has an unlimited repetition quantifier, it no longer makes this
529     optimization. That gives it a stack frame in which to save the data for
530     checking that an empty string has been matched. Previously this was taken
531     from the 1000-entry workspace that had been reserved. So now there is no
532     explicit limit, but more stack is used.
533 ph10 189
534 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
535     syntax that is required for Windows, and which was going wrong for the
536     pcreposix and pcrecpp parts of the library. These were overlooked when this
537     problem was solved for the main library.
538 ph10 197
539 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
540     the size of patterns that contain repeated groups with explicit upper
541     limits. As the maximum quantifier is 65535, the maximum group length was
542     set at 30,000 so that the product of these two numbers did not overflow a
543     32-bit integer. However, it turns out that people want to use groups that
544     are longer than 30,000 bytes (though not repeat them that many times).
545     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
546     made it possible to implement the integer overflow checks in a much more
547     dynamic way, which I have now done. The artificial limitation on group
548     length has been removed - we now have only the limit on the total length of
549     the compiled pattern, which depends on the LINK_SIZE setting.
550 ph10 208
551     10. Fixed a bug in the documentation for get/copy named substring when
552     duplicate names are permitted. If none of the named substrings are set, the
553     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
554     empty string.
555    
556     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
557     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
558     because the ] is interpreted as the first data character and the
559     terminating ] is not found. PCRE has been made compatible with Perl in this
560     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
561     cause memory overwriting.
562    
563 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
564     string has been matched (to stop an infinite loop). It was not recognizing
565 ph10 208 a conditional subpattern that could match an empty string if that
566 ph10 206 subpattern was within another subpattern. For example, it looped when
567 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
568 ph10 206 condition was not nested. This bug has been fixed.
569 ph10 208
570 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
571     past the start of the subject in the presence of bytes with the top bit
572     set, for example "\x8aBCD".
573 ph10 211
574 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
575     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
576 ph10 200
577 ph10 211 14. Optimized (?!) to (*FAIL).
578 ph10 202
579 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
580     This restricts code points to be within the range 0 to 0x10FFFF, excluding
581     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
582     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
583     does: it's just the validity check that is more restrictive.
584 ph10 220
585     16. Inserted checks for integer overflows during escape sequence (backslash)
586     processing, and also fixed erroneous offset values for syntax errors during
587     backslash processing.
588    
589 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
590 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
591    
592 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
593     caused an overrun.
594 ph10 220
595     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
596     something other than just ASCII characters) inside a group that had an
597     unlimited repeat caused a loop at compile time (while checking to see
598     whether the group could match an empty string).
599    
600 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
601     [\P{Any}] did so. (Error in the code for printing property names.)
602 ph10 210
603 ph10 220 21. An orphan \E inside a character class could cause a crash.
604    
605     22. A repeated capturing bracket such as (A)? could cause a wild memory
606 ph10 218 reference during compilation.
607 ph10 220
608     23. There are several functions in pcre_compile() that scan along a compiled
609     expression for various reasons (e.g. to see if it's fixed length for look
610 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
611 ph10 220 present in the pattern. These operators have additional parameters compared
612     with \d, etc, and these were not being taken into account when moving along
613 ph10 218 the compiled data. Specifically:
614 ph10 220
615     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
616     length.
617    
618     (b) An item such as \pL+ within a repeated group could cause crashes or
619 ph10 218 loops.
620 ph10 220
621 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
622 ph10 220 "reference to non-existent subpattern" error.
623    
624 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
625    
626 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
627 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
628 ph10 211
629 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
630 ph10 218
631 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
632 ph10 223 character were causing crashes (broken optimization).
633 ph10 227
634 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
635 ph10 227 \p or \P) caused a compile-time loop.
636    
637 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
638     break. For example, the unstudied pattern [\r\n]A does not match the string
639     "\r\nA" because change 7.0/46 below moves the current point on by two
640     characters after failing to match at the start. However, the pattern \nA
641 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
642     the same is true. There doesn't seem any very clean way out of this, but
643     what I have chosen to do makes the common cases work: PCRE now takes note
644     of whether there can be an explicit match for \r or \n anywhere in the
645     pattern, and if so, 7.0/46 no longer applies. As part of this change,
646     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
647     pattern has explicit CR or LF references.
648 ph10 222
649 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
650 ph10 223
651 ph10 227
652 ph10 189 Version 7.2 19-Jun-07
653     ---------------------
654    
655 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
656     which is apparently normally available under Windows.
657 ph10 159
658     2. Re-jig the pcregrep tests with different newline settings in an attempt
659     to make them independent of the local environment's newline setting.
660 ph10 157
661 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
662 ph10 165
663 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
664     was not 2, because the output contained actual offsets. The recent new
665 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
666     usable with all link sizes.
667    
668 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
669     stack recursion. This gives a massive performance boost under BSD, but just
670 ph10 165 a small improvement under Linux. However, it saves one field in the frame
671 ph10 164 in all cases.
672 ph10 172
673 ph10 166 6. Added more features from the forthcoming Perl 5.10:
674 ph10 172
675 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
676     recursion call. It refers to the nth most recently opened parentheses.
677 ph10 172
678 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
679 ph10 172 to be opened parentheses.
680    
681     (c) Conditions that refer to capturing parentheses can be specified
682 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
683 ph10 172
684 ph10 168 (d) \K resets the start of the current match so that everything before
685 ph10 172 is not part of it.
686    
687 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
688 ph10 172
689 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
690 ph10 172 reference syntax.
691 ph10 182
692 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
693 ph10 182 alternative starts with the same number.
694 ph10 172
695 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
696    
697 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
698     PCRE_INFO_JCHANGED.
699    
700     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
701     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
702 ph10 170 for detecting groups that can match an empty string.
703 ph10 159
704 ph10 172 9. A pattern with a very large number of alternatives (more than several
705     hundred) was running out of internal workspace during the pre-compile
706     phase, where pcre_compile() figures out how much memory will be needed. A
707     bit of new cunning has reduced the workspace needed for groups with
708     alternatives. The 1000-alternative test pattern now uses 12 bytes of
709     workspace instead of running out of the 4096 that are available.
710 ph10 182
711 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
712 ph10 172
713 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
714     The report of the bug said:
715 ph10 182
716 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
717     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
718 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
719 ph10 185
720 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
721 ph10 185 it matched the wrong number of bytes.
722 ph10 172
723 ph10 179
724 ph10 155 Version 7.1 24-Apr-07
725 ph10 98 ---------------------
726    
727 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
728 ph10 122 that is more "standard", making use of automake and other Autotools. There
729 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
730     on this.
731 ph10 111
732     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
733     for recursive directory scanning broke on some systems because the files
734     are not scanned in any specific order and on different systems the order
735     was different. A call to "sort" has been inserted into RunGrepTest for the
736     approprate test as a short-term fix. In the longer term there may be an
737 ph10 100 alternative.
738 ph10 111
739 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
740 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
741     people do their own conversions for various reasons). The problems
742     concerned the use of low-level troff macros .br and .in. I have therefore
743     removed all such uses from the man pages (some were redundant, some could
744 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
745     HTML has been updated to handle .nf/.fi and to complain if it encounters
746     .br or .in.
747 ph10 111
748 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
749 ph10 123 arranged for config.h to be included in the distribution, with the name
750 ph10 111 config.h.generic, for the benefit of those who have to compile without
751     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
752    
753     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
754     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
755 ph10 127 makevp.bat for the current PCRE, using the additional files
756 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
757 ph10 111
758     6. A Windows user reported a minor discrepancy with test 2, which turned out
759     to be caused by a trailing space on an input line that had got lost in his
760 ph10 102 copy. The trailing space was an accident, so I've just removed it.
761 ph10 111
762 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
763 ph10 111 that is needed.
764    
765 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
766     as "const" (a) because they are and (b) because it helps the PHP
767     maintainers who have recently made a script to detect big data structures
768 ph10 111 in the php code that should be moved to the .rodata section. I remembered
769     to update Builducptable as well, so it won't revert if ucptable.h is ever
770 ph10 105 re-created.
771 ph10 111
772     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
773 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
774 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
775     support is not required. This saves 1.5-2K of code, which is important in
776 ph10 107 some applications.
777 ph10 111
778 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
779 ph10 111 so as not to refer to the tables, even though these functions will never be
780     called when UTF-8 support is disabled. Otherwise there are problems with a
781     shared library.
782    
783 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
784    
785     (a) It was defining its arguments as char * instead of void *.
786    
787 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
788     a long time ago when I wrote it, but is no longer the case.
789    
790 ph10 118 The emulated memove() is provided for those environments that have neither
791 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
792 ph10 118 is clearly not the case, as these two bugs were recently reported.
793 ph10 123
794 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
795 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
796     pages, and it removes trailing spaces from listed files. It also creates
797     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
798     case, it wraps all the #defines with #ifndefs. This script should be run
799 ph10 111 before "make dist".
800 ph10 123
801 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
802     with Unicode property support.
803 ph10 123
804     (a) For a maximizing quantifier, if the two different cases of the
805     character were of different lengths in their UTF-8 codings (there are
806     some cases like this - I found 11), and the matching function had to
807 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
808     were both the same length.
809 ph10 123
810     (b) When PCRE was configured to use the heap rather than the stack for
811     recursion during matching, it was not correctly preserving the data for
812     the other case of a UTF-8 character when checking ahead for a match
813     while processing a minimizing repeat. If the check also involved
814 ph10 115 matching a wide character, but failed, corruption could cause an
815     erroneous result when trying to check for a repeat of the original
816     character.
817 ph10 123
818 ph10 116 13. Some tidying changes to the testing mechanism:
819 ph10 98
820 ph10 116 (a) The RunTest script now detects the internal link size and whether there
821     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
822 ph10 123 values substituted by "configure". (The RunGrepTest script already did
823     this for UTF-8.) The configure.ac script no longer substitutes the
824     relevant variables.
825    
826 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
827     with length and offset values. This means that the output is different
828     for different internal link sizes. Test 2 is skipped for link sizes
829     other than 2 because of this, bypassing the problem. Unfortunately,
830     there was also a test in test 3 (the locale tests) that used /B and
831 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
832     I have added a new /Z option to pcretest that replaces the length and
833     offset values with spaces. This is now used to make test 3 independent
834 ph10 122 of link size. (Test 2 will be tidied up later.)
835 ph10 123
836     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
837 ph10 122 segmentation fault instead of returning the appropriate error message.
838 ph10 134
839 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
840 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
841     This doesn't seem right; it now treats the CRLF combination as the line
842     ending, and so does not match in that case. It's only a pattern such as ^$
843     that would hit this one: something like ^ABC$ would have failed after \r
844     and then tried again after \r\n.
845    
846 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
847 ph10 134 in an attempt to make files that differ only in their line terminators
848     compare equal. This works on Linux.
849 ph10 142
850 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
851     as it exited. This is now fixed, thanks to valgrind.
852 ph10 142
853 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
854 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
855     was because its rules for how to advance for /g after matching an empty
856 ph10 143 string at the end of a line did not allow for this case. They now check for
857     it specially.
858 ph10 150
859     20. pcretest is supposed to handle patterns and data of any length, by
860     extending its buffers when necessary. It was getting this wrong when the
861 ph10 147 buffer for a data line had to be extended.
862 ph10 150
863 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
864 ph10 150 CRLF as a newline sequence.
865 ph10 152
866 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
867 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
868     I have nevertheless tidied it up.
869 ph10 111
870 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
871 ph10 123
872 ph10 153 24. Added a man page for pcre-config.
873 ph10 152
874 ph10 153
875 nigel 93 Version 7.0 19-Dec-06
876     ---------------------
877    
878     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
879     moving to gcc 4.1.1.
880    
881     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
882     sys/time.h, which is documented as needed for this function. It doesn't
883     seem to matter on Linux, but it showed up on some releases of OS X.
884    
885     3. It seems that there are systems where bytes whose values are greater than
886     127 match isprint() in the "C" locale. The "C" locale should be the
887     default when a C program starts up. In most systems, only ASCII printing
888     characters match isprint(). This difference caused the output from pcretest
889     to vary, making some of the tests fail. I have changed pcretest so that:
890    
891     (a) When it is outputting text in the compiled version of a pattern, bytes
892     other than 32-126 are always shown as hex escapes.
893    
894     (b) When it is outputting text that is a matched part of a subject string,
895     it does the same, unless a different locale has been set for the match
896     (using the /L modifier). In this case, it uses isprint() to decide.
897    
898     4. Fixed a major bug that caused incorrect computation of the amount of memory
899     required for a compiled pattern when options that changed within the
900     pattern affected the logic of the preliminary scan that determines the
901     length. The relevant options are -x, and -i in UTF-8 mode. The result was
902     that the computed length was too small. The symptoms of this bug were
903     either the PCRE error "internal error: code overflow" from pcre_compile(),
904     or a glibc crash with a message such as "pcretest: free(): invalid next
905     size (fast)". Examples of patterns that provoked this bug (shown in
906     pcretest format) are:
907    
908     /(?-x: )/x
909     /(?x)(?-x: \s*#\s*)/
910     /((?i)[\x{c0}])/8
911     /(?i:[\x{c0}])/8
912    
913     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
914     is now done differently.
915    
916     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
917     wrapper classes; (b) implement a new function in the C++ scanner that is
918     more efficient than the old way of doing things because it avoids levels of
919     recursion in the regex matching; (c) add a paragraph to the documentation
920     for the FullMatch() function.
921    
922     6. The escape sequence \n was being treated as whatever was defined as
923     "newline". Not only was this contrary to the documentation, which states
924     that \n is character 10 (hex 0A), but it also went horribly wrong when
925     "newline" was defined as CRLF. This has been fixed.
926    
927     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
928     was being set to -1 for the "end of line" case (supposedly a value that no
929     character can have). Though this value is never used (the check for end of
930     line is "zero bytes in current character"), it caused compiler complaints.
931     I've changed it to 0xffffffff.
932    
933     8. In pcre_version.c, the version string was being built by a sequence of
934     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
935     string (as it is for production releases) called a macro with an empty
936     argument. The C standard says the result of this is undefined. The gcc
937     compiler treats it as an empty string (which was what was wanted) but it is
938     reported that Visual C gives an error. The source has been hacked around to
939     avoid this problem.
940    
941     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
942     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
943     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
944     of them did).
945    
946     10. Originally, pcretest opened its input and output without "b"; then I was
947     told that "b" was needed in some environments, so it was added for release
948     5.0 to both the input and output. (It makes no difference on Unix-like
949     systems.) Later I was told that it is wrong for the input on Windows. I've
950     now abstracted the modes into two macros, to make it easier to fiddle with
951     them, and removed "b" from the input mode under Windows.
952    
953     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
954    
955     12. Added -help and --help to pcretest as an official way of being reminded
956     of the options.
957    
958     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
959     and pcrecpp.cc because they annoy compilers at high warning levels.
960    
961     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
962    
963     15. Fixed an occurrence of == in configure.ac that should have been = (shell
964     scripts are not C programs :-) and which was not noticed because it works
965     on Linux.
966    
967     16. pcretest is supposed to handle any length of pattern and data line (as one
968     line or as a continued sequence of lines) by extending its input buffer if
969     necessary. This feature was broken for very long pattern lines, leading to
970     a string of junk being passed to pcre_compile() if the pattern was longer
971     than about 50K.
972    
973     17. I have done a major re-factoring of the way pcre_compile() computes the
974     amount of memory needed for a compiled pattern. Previously, there was code
975     that made a preliminary scan of the pattern in order to do this. That was
976     OK when PCRE was new, but as the facilities have expanded, it has become
977     harder and harder to keep it in step with the real compile phase, and there
978     have been a number of bugs (see for example, 4 above). I have now found a
979     cunning way of running the real compile function in a "fake" mode that
980     enables it to compute how much memory it would need, while actually only
981     ever using a few hundred bytes of working memory and without too many
982     tests of the mode. This should make future maintenance and development
983     easier. A side effect of this work is that the limit of 200 on the nesting
984     depth of parentheses has been removed (though this was never a serious
985     limitation, I suspect). However, there is a downside: pcre_compile() now
986     runs more slowly than before (30% or more, depending on the pattern). I
987     hope this isn't a big issue. There is no effect on runtime performance.
988    
989     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
990     newline (only possible for the last line of a file) and it was a
991     pattern that set a locale (followed by /Lsomething), pcretest crashed.
992    
993     19. Added additional timing features to pcretest. (1) The -tm option now times
994     matching only, not compiling. (2) Both -t and -tm can be followed, as a
995     separate command line item, by a number that specifies the number of
996     repeats to use when timing. The default is 50000; this gives better
997     precision, but takes uncomfortably long for very large patterns.
998    
999     20. Extended pcre_study() to be more clever in cases where a branch of a
1000     subpattern has no definite first character. For example, (a*|b*)[cd] would
1001     previously give no result from pcre_study(). Now it recognizes that the
1002     first character must be a, b, c, or d.
1003    
1004     21. There was an incorrect error "recursive call could loop indefinitely" if
1005     a subpattern (or the entire pattern) that was being tested for matching an
1006     empty string contained only one non-empty item after a nested subpattern.
1007     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1008     incorrectly, because the \d was being skipped in the check.
1009    
1010     22. The pcretest program now has a new pattern option /B and a command line
1011     option -b, which is equivalent to adding /B to every pattern. This causes
1012     it to show the compiled bytecode, without the additional information that
1013     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1014     is the same as /B/I).
1015    
1016     23. A new optimization is now able automatically to treat some sequences such
1017     as a*b as a*+b. More specifically, if something simple (such as a character
1018     or a simple class like \d) has an unlimited quantifier, and is followed by
1019     something that cannot possibly match the quantified thing, the quantifier
1020     is automatically "possessified".
1021    
1022     24. A recursive reference to a subpattern whose number was greater than 39
1023     went wrong under certain circumstances in UTF-8 mode. This bug could also
1024     have affected the operation of pcre_study().
1025    
1026     25. Realized that a little bit of performance could be had by replacing
1027     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1028    
1029     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1030    
1031     27. Possessive quantifiers such as a++ were previously implemented by turning
1032     them into atomic groups such as ($>a+). Now they have their own opcodes,
1033     which improves performance. This includes the automatically created ones
1034     from 23 above.
1035    
1036     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1037     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1038     the first matched character to be a colon. This applied both to named and
1039     numbered groups.
1040    
1041     29. The ucpinternal.h header file was missing its idempotency #ifdef.
1042    
1043     30. I was sent a "project" file called libpcre.a.dev which I understand makes
1044     building PCRE on Windows easier, so I have included it in the distribution.
1045    
1046     31. There is now a check in pcretest against a ridiculously large number being
1047     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1048     loop, the loop is abandoned.
1049    
1050     32. Forward references to subpatterns in conditions such as (?(2)...) where
1051     subpattern 2 is defined later cause pcre_compile() to search forwards in
1052     the pattern for the relevant set of parentheses. This search went wrong
1053     when there were unescaped parentheses in a character class, parentheses
1054     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1055    
1056     33. "Subroutine" calls and backreferences were previously restricted to
1057     referencing subpatterns earlier in the regex. This restriction has now
1058     been removed.
1059    
1060     34. Added a number of extra features that are going to be in Perl 5.10. On the
1061     whole, these are just syntactic alternatives for features that PCRE had
1062     previously implemented using the Python syntax or my own invention. The
1063     other formats are all retained for compatibility.
1064    
1065     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1066     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1067     also .NET compatible.
1068    
1069     (b) A recursion or subroutine call to a named group can now be defined as
1070     (?&name) as well as (?P>name).
1071    
1072     (c) A backreference to a named group can now be defined as \k<name> or
1073     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1074     5.10, are also .NET compatible.
1075    
1076     (d) A conditional reference to a named group can now use the syntax
1077     (?(<name>) or (?('name') as well as (?(name).
1078    
1079     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1080     groups (named and numbered) that are never evaluated inline, but can be
1081     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1082     is always false. There may be only one alternative in such a group.
1083    
1084     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1085     as the simple (?(R). The condition is true only if the most recent
1086     recursion is that of the given number or name. It does not search out
1087     through the entire recursion stack.
1088    
1089     (g) The escape \gN or \g{N} has been added, where N is a positive or
1090     negative number, specifying an absolute or relative reference.
1091    
1092     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1093     some "unreachable code" warnings.
1094    
1095     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1096     things, this adds five new scripts.
1097    
1098     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1099     There were also incompatibilities regarding the handling of \Q..\E inside
1100     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1101     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1102    
1103     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1104     matches an empty string, and forcibly breaks the loop. There were bugs in
1105     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1106     against aaaa the result was just "a" rather than "aaaa", for example. Two
1107     separate and independent bugs (that affected different cases) have been
1108     fixed.
1109    
1110     39. Refactored the code to abolish the use of different opcodes for small
1111     capturing bracket numbers. This is a tidy that I avoided doing when I
1112     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1113     The new approach is not only tidier, it makes it possible to reduce the
1114     memory needed to fix the previous bug (38).
1115    
1116     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1117     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1118     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1119     mode.
1120    
1121     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1122     report.
1123    
1124     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1125     copy construction and assignment in the C++ wrapper.
1126    
1127     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1128     couple of bugs that could have given wrong results in the "--newline=crlf"
1129     case.
1130    
1131     44. Added a number of casts and did some reorganization of signed/unsigned int
1132     variables following suggestions from Dair Grant. Also renamed the variable
1133     "this" as "item" because it is a C++ keyword.
1134    
1135     45. Arranged for dftables to add
1136    
1137     #include "pcre_internal.h"
1138    
1139     to pcre_chartables.c because without it, gcc 4.x may remove the array
1140     definition from the final binary if PCRE is built into a static library and
1141     dead code stripping is activated.
1142    
1143     46. For an unanchored pattern, if a match attempt fails at the start of a
1144     newline sequence, and the newline setting is CRLF or ANY, and the next two
1145     characters are CRLF, advance by two characters instead of one.
1146    
1147    
1148 nigel 91 Version 6.7 04-Jul-06
1149     ---------------------
1150    
1151     1. In order to handle tests when input lines are enormously long, pcretest has
1152     been re-factored so that it automatically extends its buffers when
1153     necessary. The code is crude, but this _is_ just a test program. The
1154     default size has been increased from 32K to 50K.
1155    
1156     2. The code in pcre_study() was using the value of the re argument before
1157     testing it for NULL. (Of course, in any sensible call of the function, it
1158     won't be NULL.)
1159    
1160     3. The memmove() emulation function in pcre_internal.h, which is used on
1161     systems that lack both memmove() and bcopy() - that is, hardly ever -
1162     was missing a "static" storage class specifier.
1163    
1164     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1165     containing an extended class (one that cannot be represented by a bitmap
1166     because it contains high-valued characters or Unicode property items, e.g.
1167     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1168     pattern, but PCRE should not loop if you do not (it no longer does).
1169     [Detail: two cases were found: (a) a repeated subpattern containing an
1170     extended class; (b) a recursive reference to a subpattern that followed a
1171     previous extended class. It wasn't skipping over the extended class
1172     correctly when UTF-8 mode was not set.]
1173    
1174     5. A negated single-character class was not being recognized as fixed-length
1175     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1176     compile error "lookbehind assertion is not fixed length".
1177    
1178     6. The RunPerlTest auxiliary script was showing an unexpected difference
1179     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1180     write a Perl script that can interpret lines of an input file either as
1181     byte characters or as UTF-8, which is what "perltest" was being required to
1182     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1183     can't do is switch easily at run time between having the "use utf8;" pragma
1184     or not. In the end, I fudged it by using the RunPerlTest script to insert
1185     "use utf8;" explicitly for the UTF-8 tests.
1186    
1187     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1188     the end of the subject string, contrary to the documentation and to what
1189     Perl does. This was true of both matching functions. Now it matches only at
1190     the start of the subject and immediately after *internal* newlines.
1191    
1192     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1193     a pointer to an int instead of a pointer to an unsigned long int. This
1194     caused problems on 64-bit systems.
1195    
1196     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1197     instance of the 'standard' template library not being so standard".
1198    
1199     10. There was no check on the number of named subpatterns nor the maximum
1200     length of a subpattern name. The product of these values is used to compute
1201     the size of the memory block for a compiled pattern. By supplying a very
1202     long subpattern name and a large number of named subpatterns, the size
1203     computation could be caused to overflow. This is now prevented by limiting
1204     the length of names to 32 characters, and the number of named subpatterns
1205     to 10,000.
1206    
1207     11. Subpatterns that are repeated with specific counts have to be replicated in
1208     the compiled pattern. The size of memory for this was computed from the
1209     length of the subpattern and the repeat count. The latter is limited to
1210     65535, but there was no limit on the former, meaning that integer overflow
1211     could in principle occur. The compiled length of a repeated subpattern is
1212     now limited to 30,000 bytes in order to prevent this.
1213    
1214     12. Added the optional facility to have named substrings with the same name.
1215    
1216     13. Added the ability to use a named substring as a condition, using the
1217     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1218     are numbers (not recommended). Forward references are permitted.
1219    
1220     14. Added forward references in named backreferences (if you see what I mean).
1221    
1222     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1223     pattern could run off the end of the subject. For example, the pattern
1224     "(?s)(.{1,5})"8 did this with the subject "ab".
1225    
1226     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1227     PCRE_CASELESS was set when matching characters that were quantified with ?
1228     or *.
1229    
1230     17. A character class other than a single negated character that had a minimum
1231     but no maximum quantifier - for example [ab]{6,} - was not handled
1232     correctly by pce_dfa_exec(). It would match only one character.
1233    
1234     18. A valid (though odd) pattern that looked like a POSIX character
1235     class but used an invalid character after [ (for example [[,abc,]]) caused
1236     pcre_compile() to give the error "Failed: internal error: code overflow" or
1237     in some cases to crash with a glibc free() error. This could even happen if
1238     the pattern terminated after [[ but there just happened to be a sequence of
1239     letters, a binary zero, and a closing ] in the memory that followed.
1240    
1241     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1242     over the years. Originally (before any Unicode support), just the bottom 8
1243     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1244     output from "man perlunicode" includes this:
1245    
1246     The regular expression compiler produces polymorphic opcodes. That
1247     is, the pattern adapts to the data and automatically switches to
1248     the Unicode character scheme when presented with Unicode data--or
1249     instead uses a traditional byte scheme when presented with byte
1250     data.
1251    
1252     Sadly, a wide octal escape does not cause a switch, and in a string with
1253     no other multibyte characters, these octal escapes are treated as before.
1254     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1255     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1256     Unicode string.
1257    
1258     I have not perpetrated such confusion in PCRE. Up till now, it took just
1259     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1260     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1261     translate to the appropriate multibyte character.
1262    
1263     29. Applied some refactoring to reduce the number of warnings from Microsoft
1264     and Borland compilers. This has included removing the fudge introduced
1265     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1266     a warning about an unused variable.
1267    
1268     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1269     characters since release 4.0, because Perl (from release 5.004) does not.
1270     [Or at least, is documented not to: some releases seem to be in conflict
1271     with the documentation.] However, when a pattern was studied with
1272     pcre_study() and all its branches started with \s, PCRE still included VT
1273     as a possible starting character. Of course, this did no harm; it just
1274     caused an unnecessary match attempt.
1275    
1276     22. Removed a now-redundant internal flag bit that recorded the fact that case
1277     dependency changed within the pattern. This was once needed for "required
1278     byte" processing, but is no longer used. This recovers a now-scarce options
1279     bit. Also moved the least significant internal flag bit to the most-
1280     significant bit of the word, which was not previously used (hangover from
1281     the days when it was an int rather than a uint) to free up another bit for
1282     the future.
1283    
1284     23. Added support for CRLF line endings as well as CR and LF. As well as the
1285     default being selectable at build time, it can now be changed at runtime
1286     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1287     specify that it is scanning data with non-default line endings.
1288    
1289     24. Changed the definition of CXXLINK to make it agree with the definition of
1290     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1291    
1292     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1293     recursions. This makes a big different to stack usage for some patterns.
1294    
1295     26. If a subpattern containing a named recursion or subroutine reference such
1296     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1297     the space required for the compiled pattern went wrong and gave too small a
1298     value. Depending on the environment, this could lead to "Failed: internal
1299     error: code overflow at offset 49" or "glibc detected double free or
1300     corruption" errors.
1301    
1302     27. Applied patches from Google (a) to support the new newline modes and (b) to
1303     advance over multibyte UTF-8 characters in GlobalReplace.
1304    
1305     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1306     difference for some implementation of PCRE in some Windows version.
1307    
1308     29. Added some extra testing facilities to pcretest:
1309    
1310     \q<number> in a data line sets the "match limit" value
1311     \Q<number> in a data line sets the "match recursion limt" value
1312     -S <number> sets the stack size, where <number> is in megabytes
1313    
1314     The -S option isn't available for Windows.
1315    
1316    
1317 nigel 89 Version 6.6 06-Feb-06
1318     ---------------------
1319    
1320     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1321     in pcreposix.h. I have copied the definition from pcre.h.
1322    
1323     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1324     because pcre.h is no longer a built file.
1325    
1326     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1327     not normally included in the compiled code.
1328    
1329    
1330 nigel 87 Version 6.5 01-Feb-06
1331     ---------------------
1332    
1333     1. When using the partial match feature with pcre_dfa_exec(), it was not
1334     anchoring the second and subsequent partial matches at the new starting
1335     point. This could lead to incorrect results. For example, with the pattern
1336     /1234/, partially matching against "123" and then "a4" gave a match.
1337    
1338     2. Changes to pcregrep:
1339    
1340     (a) All non-match returns from pcre_exec() were being treated as failures
1341     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1342     error message is output. Some extra information is given for the
1343     PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1344     probably the only errors that are likely to be caused by users (by
1345     specifying a regex that has nested indefinite repeats, for instance).
1346     If there are more than 20 of these errors, pcregrep is abandoned.
1347    
1348     (b) A binary zero was treated as data while matching, but terminated the
1349     output line if it was written out. This has been fixed: binary zeroes
1350     are now no different to any other data bytes.
1351    
1352     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1353     used to set a locale for matching. The --locale=xxxx long option has
1354     been added (no short equivalent) to specify a locale explicitly on the
1355     pcregrep command, overriding the environment variables.
1356    
1357     (d) When -B was used with -n, some line numbers in the output were one less
1358     than they should have been.
1359    
1360     (e) Added the -o (--only-matching) option.
1361    
1362     (f) If -A or -C was used with -c (count only), some lines of context were
1363     accidentally printed for the final match.
1364    
1365     (g) Added the -H (--with-filename) option.
1366    
1367     (h) The combination of options -rh failed to suppress file names for files
1368     that were found from directory arguments.
1369    
1370     (i) Added the -D (--devices) and -d (--directories) options.
1371    
1372     (j) Added the -F (--fixed-strings) option.
1373    
1374     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1375    
1376     (l) Added the --colo(u)r option.
1377    
1378     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1379     is not present by default.
1380    
1381     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1382     items such as (?R) or (?1), when the recursion could match a number of
1383     alternatives. If it matched one of the alternatives, but subsequently,
1384     outside the recursion, there was a failure, the code tried to back up into
1385     the recursion. However, because of the way PCRE is implemented, this is not
1386     possible, and the result was an incorrect result from the match.
1387    
1388     In order to prevent this happening, the specification of recursion has
1389     been changed so that all such subpatterns are automatically treated as
1390     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1391    
1392     4. I had overlooked the fact that, in some locales, there are characters for
1393     which isalpha() is true but neither isupper() nor islower() are true. In
1394     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1395     and ordfeminine) are like this. This affected the treatment of \w and \W
1396     when they appeared in character classes, but not when they appeared outside
1397     a character class. The bit map for "word" characters is now created
1398     separately from the results of isalnum() instead of just taking it from the
1399     upper, lower, and digit maps. (Plus the underscore character, of course.)
1400    
1401     5. The above bug also affected the handling of POSIX character classes such as
1402     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1403     permanent tables. Instead, the bit maps for such a class were previously
1404     created as the appropriate unions of the upper, lower, and digit bitmaps.
1405     Now they are created by subtraction from the [[:word:]] class, which has
1406     its own bitmap.
1407    
1408     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1409     It is created by subtracting the vertical space characters (\x09, \x0a,
1410     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1411     subtraction was done in the overall bitmap for a character class, meaning
1412     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1413     be recognized. This bug has been fixed.
1414    
1415     7. Patches from the folks at Google:
1416    
1417     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1418     real life, but is still worth protecting against".
1419    
1420     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1421     regular expressions".
1422    
1423     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1424     have it.
1425    
1426     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1427     "configure" and the latter not, in order to fix a problem somebody had
1428     with compiling the Arg class on HP-UX.
1429    
1430     (e) Improve the error-handling of the C++ wrapper a little bit.
1431    
1432     (f) New tests for checking recursion limiting.
1433    
1434     8. The pcre_memmove() function, which is used only if the environment does not
1435     have a standard memmove() function (and is therefore rarely compiled),
1436     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1437     returning a result (though PCRE never actually uses the result).
1438    
1439     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1440     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1441     returned instead of calling malloc() with an overflowing number that would
1442     most likely cause subsequent chaos.
1443    
1444     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1445    
1446     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1447     with this option is matched, the nmatch and pmatch options of regexec() are
1448     ignored.
1449    
1450     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1451     provided in case anyone wants to the the POSIX interface with UTF-8
1452     strings.
1453    
1454     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1455     C++ linking (needed for some HP-UX environments).
1456    
1457     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1458     (unused parameter) and in the pcre_printint() function (omitted "default"
1459     switch label when the default is to do nothing).
1460    
1461     15. Added some code to make it possible, when PCRE is compiled as a C++
1462     library, to replace subject pointers for pcre_exec() with a smart pointer
1463     class, thus making it possible to process discontinuous strings.
1464    
1465     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1466     much the same function. They were added by different people who were trying
1467     to make PCRE easy to compile on non-Unix systems. It has been suggested
1468     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1469     for compiling on Windows systems. I have therefore replaced it with
1470     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1471     defaults to "extern" for C or "extern C" for C++, which works fine on
1472     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1473     SCOPE with something explicit in config.h. In addition:
1474    
1475     (a) pcreposix.h still had just "extern" instead of either of these macros;
1476     I have replaced it with PCRE_DATA_SCOPE.
1477    
1478     (b) Functions such as _pcre_xclass(), which are internal to the library,
1479     but external in the C sense, all had PCRE_EXPORT in their definitions.
1480     This is apparently wrong for the Windows case, so I have removed it.
1481     (It makes no difference on Unix-like systems.)
1482    
1483     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1484     of recursive calls to match(). This is different to MATCH_LIMIT because
1485     that limits the total number of calls to match(), not all of which increase
1486     the depth of recursion. Limiting the recursion depth limits the amount of
1487     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1488     when PCRE is compiled, and changed at run time. A patch from Google adds
1489     this functionality to the C++ interface.
1490    
1491     18. Changes to the handling of Unicode character properties:
1492    
1493     (a) Updated the table to Unicode 4.1.0.
1494    
1495     (b) Recognize characters that are not in the table as "Cn" (undefined).
1496    
1497     (c) I revised the way the table is implemented to a much improved format
1498     which includes recognition of ranges. It now supports the ranges that
1499     are defined in UnicodeData.txt, and it also amalgamates other
1500     characters into ranges. This has reduced the number of entries in the
1501     table from around 16,000 to around 3,000, thus reducing its size
1502     considerably. I realized I did not need to use a tree structure after
1503     all - a binary chop search is just as efficient. Having reduced the
1504     number of entries, I extended their size from 6 bytes to 8 bytes to
1505     allow for more data.
1506    
1507     (d) Added support for Unicode script names via properties such as \p{Han}.
1508    
1509     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1510     matching that character.
1511    
1512     20. When matching a repeated Unicode property with a minimum greater than zero,
1513     (for example \pL{2,}), PCRE could look past the end of the subject if it
1514     reached it while seeking the minimum number of characters. This could
1515     happen only if some of the characters were more than one byte long, because
1516     there is a check for at least the minimum number of bytes.
1517    
1518     21. Refactored the implementation of \p and \P so as to be more general, to
1519     allow for more different types of property in future. This has changed the
1520     compiled form incompatibly. Anybody with saved compiled patterns that use
1521     \p or \P will have to recompile them.
1522    
1523     22. Added "Any" and "L&" to the supported property types.
1524    
1525     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1526     but give a compile time error if the value is greater than 0xff.
1527    
1528     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1529     accidentally not being installed or uninstalled.
1530    
1531     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1532     made were to insert the current release number. This seemed silly, because
1533     it made things harder for people building PCRE on systems that don't run
1534     "configure". I have turned pcre.h into a distributed file, no longer built
1535     by "configure", with the version identification directly included. There is
1536     no longer a pcre.h.in file.
1537    
1538     However, this change necessitated a change to the pcre-config script as
1539     well. It is built from pcre-config.in, and one of the substitutions was the
1540     release number. I have updated configure.ac so that ./configure now finds
1541     the release number by grepping pcre.h.
1542    
1543     26. Added the ability to run the tests under valgrind.
1544    
1545    
1546 nigel 85 Version 6.4 05-Sep-05
1547     ---------------------
1548    
1549     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1550     "--" to be printed when multiple files were scanned, even when none of the
1551     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1552     consider it to be a bug, and have restored the previous behaviour.
1553    
1554     2. A couple of code tidies to get rid of compiler warnings.
1555    
1556     3. The pcretest program used to cheat by referring to symbols in the library
1557     whose names begin with _pcre_. These are internal symbols that are not
1558     really supposed to be visible externally, and in some environments it is
1559     possible to suppress them. The cheating is now confined to including
1560     certain files from the library's source, which is a bit cleaner.
1561    
1562     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1563     file's purpose clearer.
1564    
1565     5. Reorganized pcre_ucp_findchar().
1566    
1567    
1568 nigel 83 Version 6.3 15-Aug-05
1569     ---------------------
1570    
1571     1. The file libpcre.pc.in did not have general read permission in the tarball.
1572    
1573     2. There were some problems when building without C++ support:
1574    
1575     (a) If C++ support was not built, "make install" and "make test" still
1576     tried to test it.
1577    
1578     (b) There were problems when the value of CXX was explicitly set. Some
1579     changes have been made to try to fix these, and ...
1580    
1581     (c) --disable-cpp can now be used to explicitly disable C++ support.
1582    
1583     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1584     backslash in a target when C++ was disabled. This confuses some
1585     versions of "make", apparently. Using an intermediate variable solves
1586     this. (Same for CPP_LOBJ.)
1587    
1588     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1589     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1590     necessary on certain architectures.
1591    
1592     4. Added a setting of -export-symbols-regex to the link command to remove
1593     those symbols that are exported in the C sense, but actually are local
1594     within the library, and not documented. Their names all begin with
1595     "_pcre_". This is not a perfect job, because (a) we have to except some
1596     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1597     available (and never for static libraries). I have made a note to try to
1598     find a way round (a) in the future.
1599    
1600    
1601 nigel 81 Version 6.2 01-Aug-05
1602     ---------------------
1603    
1604     1. There was no test for integer overflow of quantifier values. A construction
1605     such as {1111111111111111} would give undefined results. What is worse, if
1606     a minimum quantifier for a parenthesized subpattern overflowed and became
1607     negative, the calculation of the memory size went wrong. This could have
1608     led to memory overwriting.
1609    
1610     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1611    
1612     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1613     operating environments where this matters.
1614    
1615     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1616     PCRE options from within the C++ wrapper.
1617    
1618     5. Named capturing subpatterns were not being correctly counted when a pattern
1619     was compiled. This caused two problems: (a) If there were more than 100
1620     such subpatterns, the calculation of the memory needed for the whole
1621     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1622     back references of the form \12, where the number was greater than 9, were
1623     not recognized as back references, even though there were sufficient
1624     previous subpatterns.
1625    
1626     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1627     versions of gcc, e.g. 2.95.4.
1628    
1629    
1630 nigel 79 Version 6.1 21-Jun-05
1631     ---------------------
1632    
1633     1. There was one reference to the variable "posix" in pcretest.c that was not
1634     surrounded by "#if !defined NOPOSIX".
1635    
1636     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1637     the cross-check on the old pcre_info() function, for the benefit of the
1638     cut-down version of PCRE that is currently imported into Exim.
1639    
1640     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1641     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1642     patterns that start (?i) but I don't think that matters. The use of (?i) is
1643     just an example; this all applies to the other options as well.
1644    
1645     4. Since libtool seems to echo the compile commands it is issuing, the output
1646     from "make" can be reduced a bit by putting "@" in front of each libtool
1647     compile command.
1648    
1649     5. Patch from the folks at Google for configure.in to be a bit more thorough
1650     in checking for a suitable C++ installation before trying to compile the
1651     C++ stuff. This should fix a reported problem when a compiler was present,
1652     but no suitable headers.
1653    
1654     6. The man pages all had just "PCRE" as their title. I have changed them to
1655     be the relevant file name. I have also arranged that these names are
1656     retained in the file doc/pcre.txt, which is a concatenation in text format
1657     of all the man pages except the little individual ones for each function.
1658    
1659     7. The NON-UNIX-USE file had not been updated for the different set of source
1660     files that come with release 6. I also added a few comments about the C++
1661     wrapper.
1662    
1663    
1664 nigel 77 Version 6.0 07-Jun-05
1665     ---------------------
1666    
1667     1. Some minor internal re-organization to help with my DFA experiments.
1668    
1669     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1670     didn't matter for the library itself when fully configured, but did matter
1671     when compiling without UCP support, or within Exim, where the ucp files are
1672     not imported.
1673    
1674     3. Refactoring of the library code to split up the various functions into
1675     different source modules. The addition of the new DFA matching code (see
1676     below) to a single monolithic source would have made it really too
1677     unwieldy, quite apart from causing all the code to be include in a
1678     statically linked application, when only some functions are used. This is
1679     relevant even without the DFA addition now that patterns can be compiled in
1680     one application and matched in another.
1681    
1682     The downside of splitting up is that there have to be some external
1683     functions and data tables that are used internally in different modules of
1684     the library but which are not part of the API. These have all had their
1685     names changed to start with "_pcre_" so that they are unlikely to clash
1686     with other external names.
1687    
1688     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1689     a different (DFA) algorithm. Although it is slower than the original
1690     function, it does have some advantages for certain types of matching
1691     problem.
1692    
1693     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1694     including restarting after a partial match.
1695    
1696     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1697     defined when compiling for Windows was sent to me. I have put it into the
1698     code, though I have no means of testing or verifying it.
1699    
1700     7. Added the pcre_refcount() auxiliary function.
1701    
1702     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1703     match before or at the first newline in the subject string. In pcretest,
1704     the /f option on a pattern can be used to set this.
1705    
1706     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1707     would behave wrongly. This has been present in PCRE since release 4.0.
1708    
1709     10. A number of changes to the pcregrep command:
1710    
1711     (a) Refactored how -x works; insert ^(...)$ instead of setting
1712     PCRE_ANCHORED and checking the length, in preparation for adding
1713     something similar for -w.
1714    
1715     (b) Added the -w (match as a word) option.
1716    
1717     (c) Refactored the way lines are read and buffered so as to have more
1718     than one at a time available.
1719    
1720     (d) Implemented a pcregrep test script.
1721    
1722     (e) Added the -M (multiline match) option. This allows patterns to match
1723     over several lines of the subject. The buffering ensures that at least
1724     8K, or the rest of the document (whichever is the shorter) is available
1725     for matching (and similarly the previous 8K for lookbehind assertions).
1726    
1727     (f) Changed the --help output so that it now says
1728    
1729     -w, --word-regex(p)
1730    
1731     instead of two lines, one with "regex" and the other with "regexp"
1732     because that confused at least one person since the short forms are the
1733     same. (This required a bit of code, as the output is generated
1734     automatically from a table. It wasn't just a text change.)
1735    
1736     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1737     option but starts with a hyphen. Could be a pattern or a path name
1738     starting with a hyphen, for instance.
1739    
1740     (h) "-" can be given as a file name to represent stdin.
1741    
1742     (i) When file names are being printed, "(standard input)" is used for
1743     the standard input, for compatibility with GNU grep. Previously
1744     "<stdin>" was used.
1745    
1746     (j) The option --label=xxx can be used to supply a name to be used for
1747     stdin when file names are being printed. There is no short form.
1748    
1749     (k) Re-factored the options decoding logic because we are going to add
1750     two more options that take data. Such options can now be given in four
1751     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1752    
1753     (l) Added the -A, -B, and -C options for requesting that lines of context
1754     around matches be printed.
1755    
1756     (m) Added the -L option to print the names of files that do not contain
1757     any matching lines, that is, the complement of -l.
1758    
1759     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1760     continue to scan other files.
1761    
1762     (o) The -s option was incorrectly implemented. For compatibility with other
1763     greps, it now suppresses the error message for a non-existent or non-
1764     accessible file (but not the return code). There is a new option called
1765     -q that suppresses the output of matching lines, which was what -s was
1766     previously doing.
1767    
1768     (p) Added --include and --exclude options to specify files for inclusion
1769     and exclusion when recursing.
1770    
1771     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1772     Hopefully, it now does.
1773    
1774     12. Missing cast in pcre_study().
1775    
1776     13. Added an "uninstall" target to the makefile.
1777    
1778     14. Replaced "extern" in the function prototypes in Makefile.in with
1779     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1780     world, but is set differently for Windows.
1781    
1782     15. Added a second compiling function called pcre_compile2(). The only
1783     difference is that it has an extra argument, which is a pointer to an
1784     integer error code. When there is a compile-time failure, this is set
1785     non-zero, in addition to the error test pointer being set to point to an
1786     error message. The new argument may be NULL if no error number is required
1787     (but then you may as well call pcre_compile(), which is now just a
1788     wrapper). This facility is provided because some applications need a
1789     numeric error indication, but it has also enabled me to tidy up the way
1790     compile-time errors are handled in the POSIX wrapper.
1791    
1792     16. Added VPATH=.libs to the makefile; this should help when building with one
1793     prefix path and installing with another. (Or so I'm told by someone who
1794     knows more about this stuff than I do.)
1795    
1796     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1797     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1798     match everything, including newlines. This is not POSIX-compatible, but
1799     somebody wanted the feature. From pcretest it can be activated by using
1800     both the P and the s flags.
1801    
1802     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1803    
1804     19. libpcre.pc was being incorrectly installed as executable.
1805    
1806     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1807     it now also looks for '\r' so that it will work unmodified on Windows.
1808    
1809     21. Added Google's contributed C++ wrapper to the distribution.
1810    
1811     22. Added some untidy missing memory free() calls in pcretest, to keep
1812     Electric Fence happy when testing.
1813    
1814    
1815    
1816 nigel 75 Version 5.0 13-Sep-04
1817     ---------------------
1818    
1819     1. Internal change: literal characters are no longer packed up into items
1820     containing multiple characters in a single byte-string. Each character
1821     is now matched using a separate opcode. However, there may be more than one
1822     byte in the character in UTF-8 mode.
1823    
1824     2. The pcre_callout_block structure has two new fields: pattern_position and
1825     next_item_length. These contain the offset in the pattern to the next match
1826     item, and its length, respectively.
1827    
1828     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1829     insertion of callouts before each pattern item. Added the /C option to
1830     pcretest to make use of this.
1831    
1832     4. On the advice of a Windows user, the lines
1833    
1834     #if defined(_WIN32) || defined(WIN32)
1835     _setmode( _fileno( stdout ), 0x8000 );
1836     #endif /* defined(_WIN32) || defined(WIN32) */
1837    
1838     have been added to the source of pcretest. This apparently does useful
1839     magic in relation to line terminators.
1840    
1841     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1842     for the benefit of those environments where the "b" makes a difference.
1843    
1844     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1845     to know about it. I have put a hack into configure.in that adds in code
1846     to set GCC=yes if CC=icc. This seems to end up at a point in the
1847     generated configure script that is early enough to affect the setting of
1848     compiler options, which is what is needed, but I have no means of testing
1849     whether it really works. (The user who reported this had patched the
1850     generated configure script, which of course I cannot do.)
1851    
1852     LATER: After change 22 below (new libtool files), the configure script
1853     seems to know about icc (and also ecc). Therefore, I have commented out
1854     this hack in configure.in.
1855    
1856     7. Added support for pkg-config (2 patches were sent in).
1857    
1858     8. Negated POSIX character classes that used a combination of internal tables
1859     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1860     [[:^ascii]]. Typically, they would match almost any characters. The other
1861     POSIX classes were not broken in this way.
1862    
1863     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1864     to find the match, as PCRE was deluded into thinking that the match had to
1865     start at the start point or following a newline. The same bug applied to
1866     patterns with negative forward assertions or any backward assertions
1867     preceding ".*" at the start, unless the pattern required a fixed first
1868     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1869    
1870     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1871     starting at the last subject character, bytes beyond the end of the subject
1872     string were read.
1873    
1874     11. Renamed the variable "class" as "classbits" to make life easier for C++
1875     users. (Previously there was a macro definition, but it apparently wasn't
1876     enough.)
1877    
1878     12. Added the new field "tables" to the extra data so that tables can be passed
1879     in at exec time, or the internal tables can be re-selected. This allows
1880     a compiled regex to be saved and re-used at a later time by a different
1881     program that might have everything at different addresses.
1882    
1883     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1884     -R library as well as a -L library.
1885    
1886     14. The debugging options of pcretest (-d on the command line or D on a
1887     pattern) showed incorrect output for anything following an extended class
1888     that contained multibyte characters and which was followed by a quantifier.
1889    
1890     15. Added optional support for general category Unicode character properties
1891     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1892     support. It adds about 90K to the size of the library. The meanings of the
1893     inbuilt class escapes such as \d and \s have NOT been changed.
1894    
1895     16. Updated pcredemo.c to include calls to free() to release the memory for the
1896     compiled pattern.
1897    
1898     17. The generated file chartables.c was being created in the source directory
1899     instead of in the building directory. This caused the build to fail if the
1900     source directory was different from the building directory, and was
1901     read-only.
1902    
1903     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1904     file. No doubt somebody will tell me if they don't make sense... Also added
1905     Dan Mooney's comments about building on OpenVMS.
1906    
1907     19. Added support for partial matching via the PCRE_PARTIAL option for
1908     pcre_exec() and the \P data escape in pcretest.
1909    
1910     20. Extended pcretest with 3 new pattern features:
1911    
1912     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1913     write the compiled pattern to the file whose name is "rest-of-line".
1914     This is a straight binary dump of the data, with the saved pointer to
1915     the character tables forced to be NULL. The study data, if any, is
1916     written too. After writing, pcretest reads a new pattern.
1917    
1918     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1919     compiled pattern from the given file. There must not be any
1920     occurrences of "<" in the file name (pretty unlikely); if there are,
1921     pcretest will instead treat the initial "<" as a pattern delimiter.
1922     After reading in the pattern, pcretest goes on to read data lines as
1923     usual.
1924    
1925     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1926     and 16-bit fields in a compiled pattern, to simulate a pattern that
1927     was compiled on a host of opposite endianness.
1928    
1929     21. The pcre-exec() function can now cope with patterns that were compiled on
1930     hosts of opposite endianness, with this restriction:
1931    
1932     As for any compiled expression that is saved and used later, the tables
1933     pointer field cannot be preserved; the extra_data field in the arguments
1934     to pcre_exec() should be used to pass in a tables address if a value
1935     other than the default internal tables were used at compile time.
1936    
1937     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1938     now diagnosed as an error. Previously, most of the time, a negative number
1939     would have been treated as zero, but if in addition "ovector" was passed as
1940     NULL, a crash could occur.
1941    
1942     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1943     new versions from the libtool 1.5 distribution (the last one is a copy of
1944     a file called libtool.m4). This seems to have fixed the need to patch
1945     "configure" to support Darwin 1.3 (which I used to do). However, I still
1946     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1947     workstation).
1948    
1949     24. Changed the PCRE licence to be the more standard "BSD" licence.
1950    
1951    
1952 nigel 73 Version 4.5 01-Dec-03
1953     ---------------------
1954    
1955     1. There has been some re-arrangement of the code for the match() function so
1956     that it can be compiled in a version that does not call itself recursively.
1957     Instead, it keeps those local variables that need separate instances for
1958     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1959     needs to "recurse". Keeping track of where control must go is done by means
1960     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1961     hide most of the details from the main code, and operates only if
1962     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1963     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1964     operating.
1965    
1966     To make it easier for callers to provide specially tailored get/free
1967     functions for this usage, two new functions, pcre_stack_malloc, and
1968     pcre_stack_free, are used. They are always called in strict stacking order,
1969     and the size of block requested is always the same.
1970    
1971     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1972     PCRE has been compiled to use the stack or the heap for recursion. The
1973     -C option of pcretest uses this to show which version is compiled.
1974    
1975     A new data escape \S, is added to pcretest; it causes the amounts of store
1976     obtained and freed by both kinds of malloc/free at match time to be added
1977     to the output.
1978    
1979     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1980     what's available on my current Linux desktop machine.
1981    
1982     3. When matching a UTF-8 string, the test for a valid string at the start has
1983     been extended. If start_offset is not zero, PCRE now checks that it points
1984     to a byte that is the start of a UTF-8 character. If not, it returns
1985     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1986     this is necessary because there may be backward assertions in the pattern.
1987     When matching the same subject several times, it may save resources to use
1988     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1989    
1990     4. The code for checking the validity of UTF-8 strings has been tightened so
1991     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1992     containing "overlong sequences".
1993    
1994     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1995     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1996     should have been "&", but it just so happened that all the cases this let
1997     through by mistake were picked up later in the function.
1998    
1999     6. I had used a variable called "isblank" - this is a C99 function, causing
2000     some compilers to warn. To avoid this, I renamed it (as "blankclass").
2001    
2002     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2003     prompting; (b) run "./pcretest /dev/null" at the start of the test script
2004     so the version is shown; (c) stop "make test" echoing "./RunTest".
2005    
2006     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2007    
2008     9. The prototype for memmove() for systems that don't have it was using
2009     size_t, but the inclusion of the header that defines size_t was later. I've
2010     moved the #includes for the C headers earlier to avoid this.
2011    
2012     10. Added some adjustments to the code to make it easier to compiler on certain
2013     special systems:
2014    
2015     (a) Some "const" qualifiers were missing.
2016     (b) Added the macro EXPORT before all exported functions; by default this
2017     is defined to be empty.
2018     (c) Changed the dftables auxiliary program (that builds chartables.c) so
2019     that it reads its output file name as an argument instead of writing
2020     to the standard output and assuming this can be redirected.
2021    
2022     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2023     class containing characters with values greater than 255, PCRE compilation
2024     went into a loop.
2025    
2026     12. A recursive reference to a subpattern that was within another subpattern
2027     that had a minimum quantifier of zero caused PCRE to crash. For example,
2028     (x(y(?2))z)? provoked this bug with a subject that got as far as the
2029     recursion. If the recursively-called subpattern itself had a zero repeat,
2030     that was OK.
2031    
2032     13. In pcretest, the buffer for reading a data line was set at 30K, but the
2033     buffer into which it was copied (for escape processing) was still set at
2034     1024, so long lines caused crashes.
2035    
2036     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2037     "internal error: code overflow...". This applied to any character class
2038     that was followed by a possessive quantifier.
2039    
2040     15. Modified the Makefile to add libpcre.la as a prerequisite for
2041     libpcreposix.la because I was told this is needed for a parallel build to
2042     work.
2043    
2044     16. If a pattern that contained .* following optional items at the start was
2045     studied, the wrong optimizing data was generated, leading to matching
2046     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2047     matching string must start with a or b or c. The correct conclusion for
2048     this pattern is that a match can start with any character.
2049    
2050    
2051 nigel 71 Version 4.4 13-Aug-03
2052     ---------------------
2053    
2054     1. In UTF-8 mode, a character class containing characters with values between
2055     127 and 255 was not handled correctly if the compiled pattern was studied.
2056     In fixing this, I have also improved the studying algorithm for such
2057     classes (slightly).
2058    
2059     2. Three internal functions had redundant arguments passed to them. Removal
2060     might give a very teeny performance improvement.
2061    
2062     3. Documentation bug: the value of the capture_top field in a callout is *one
2063     more than* the number of the hightest numbered captured substring.
2064    
2065     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2066     in incorrectly linking with a previously installed version. They now link
2067     explicitly with libpcre.la.
2068    
2069     5. configure.in no longer needs to recognize Cygwin specially.
2070    
2071     6. A problem in pcre.in for Windows platforms is fixed.
2072    
2073     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2074     pcretest, it used to include the size of the study block as part of its
2075     output. Unfortunately, the structure contains a field that has a different
2076     size on different hardware architectures. This meant that the tests that
2077     showed this size failed. As the block is currently always of a fixed size,
2078     this information isn't actually particularly useful in pcretest output, so
2079     I have just removed it.
2080    
2081     8. Three pre-processor statements accidentally did not start in column 1.
2082     Sadly, there are *still* compilers around that complain, even though
2083     standard C has not required this for well over a decade. Sigh.
2084    
2085     9. In pcretest, the code for checking callouts passed small integers in the
2086     callout_data field, which is a void * field. However, some picky compilers
2087     complained about the casts involved for this on 64-bit systems. Now
2088     pcretest passes the address of the small integer instead, which should get
2089     rid of the warnings.
2090    
2091     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2092     both compile and run time, and gives an error if an invalid UTF-8 sequence
2093     is found. There is a option for disabling this check in cases where the
2094     string is known to be correct and/or the maximum performance is wanted.
2095    
2096     11. In response to a bug report, I changed one line in Makefile.in from
2097    
2098     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2099     to
2100     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2101    
2102     to look similar to other lines, but I have no way of telling whether this
2103     is the right thing to do, as I do not use Windows. No doubt I'll get told
2104     if it's wrong...
2105    
2106    
2107 nigel 69 Version 4.3 21-May-03
2108     ---------------------
2109    
2110     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2111     Makefile.
2112    
2113     2. Some refactoring to improve the quality of the code:
2114    
2115     (i) The utf8_table... variables are now declared "const".
2116    
2117     (ii) The code for \cx, which used the "case flipping" table to upper case
2118     lower case letters, now just substracts 32. This is ASCII-specific,
2119     but the whole concept of \cx is ASCII-specific, so it seems
2120     reasonable.
2121    
2122     (iii) PCRE was using its character types table to recognize decimal and
2123     hexadecimal digits in the pattern. This is silly, because it handles
2124     only 0-9, a-f, and A-F, but the character types table is locale-
2125     specific, which means strange things might happen. A private
2126     table is now used for this - though it costs 256 bytes, a table is
2127     much faster than multiple explicit tests. Of course, the standard
2128     character types table is still used for matching digits in subject
2129     strings against \d.
2130    
2131     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2132     ending in _t are). So I've renamed it as ESC_tee.
2133    
2134     3. The first argument for regexec() in the POSIX wrapper should have been
2135     defined as "const".
2136    
2137     4. Changed pcretest to use malloc() for its buffers so that they can be
2138     Electric Fenced for debugging.
2139    
2140     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2141     to read one or more bytes before the start of the subject string. Often this
2142     had no effect on PCRE's behaviour, but in some circumstances it could
2143     provoke a segmentation fault.
2144    
2145     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2146     to try to read one or more bytes before the start of the subject string.
2147    
2148     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2149     UTF-8 support could misbehave in various ways if the subject string
2150     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2151     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2152     back over UTF-8 characters.)
2153    
2154    
2155 nigel 67 Version 4.2 14-Apr-03
2156     ---------------------
2157    
2158     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2159    
2160     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2161     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2162     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2163     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2164     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2165     and BUILD_EXEEXT
2166     Note: automatic setting of the BUILD variables is not yet working
2167     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2168     compile-time but not at link-time
2169     [LINK]: use for linking executables only
2170     make different versions for Windows and non-Windows
2171     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2172     libraries
2173     [LINK_FOR_BUILD]: new variable
2174     [OBJEXT]: use throughout
2175     [EXEEXT]: use throughout
2176     <winshared>: new target
2177     <wininstall>: new target
2178     <dftables.o>: use native compiler
2179     <dftables>: use native linker
2180     <install>: handle Windows platform correctly
2181     <clean>: ditto
2182     <check>: ditto
2183     copy DLL to top builddir before testing
2184    
2185     As part of these changes, -no-undefined was removed again. This was reported
2186     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2187     in any case.
2188    
2189     3. Some tidies to get rid of compiler warnings:
2190    
2191     . In the match_data structure, match_limit was an unsigned long int, whereas
2192     match_call_count was an int. I've made them both unsigned long ints.
2193    
2194     . In pcretest the fact that a const uschar * doesn't automatically cast to
2195     a void * provoked a warning.
2196    
2197     . Turning on some more compiler warnings threw up some "shadow" variables
2198     and a few more missing casts.
2199    
2200     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2201     option, a class that contained a single character with a value between 128
2202     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2203    
2204     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2205     option, a class that contained several characters, but with at least one
2206     whose value was between 128 and 255 caused PCRE to crash.
2207    
2208    
2209 nigel 65 Version 4.1 12-Mar-03
2210     ---------------------
2211 nigel 63
2212 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2213     needed, and a string in dftables.c that was longer than standard compilers are
2214     required to support.
2215    
2216     2. Compiling with Sun's compiler found a few more places where the code could
2217     be tidied up in order to avoid warnings.
2218    
2219     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2220     first of these names is deprecated in the latest Autoconf in favour of the name
2221     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2222     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2223     analogy I have changed it to CFLAGS_FOR_BUILD.
2224    
2225     4. Added -no-undefined to the linking command in the Makefile, because this is
2226     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2227     linking step for the pcreposix library.
2228    
2229     5. PCRE was failing to diagnose the case of two named groups with the same
2230     name.
2231    
2232     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2233     literal character that is needed in the subject for a match, and scans along to
2234     ensure that it is present before embarking on the full matching process. This
2235     saves time in cases of nested unlimited repeats that are never going to match.
2236     Problem: the scan can take a lot of time if the subject is very long (e.g.
2237     megabytes), thus penalizing straightforward matches. It is now done only if the
2238     amount of subject to be scanned is less than 1000 bytes.
2239    
2240     7. A lesser problem with the same optimization is that it was recording the
2241     first character of an anchored pattern as "needed", thus provoking a search
2242     right along the subject, even when the first match of the pattern was going to
2243     fail. The "needed" character is now not set for anchored patterns, unless it
2244     follows something in the pattern that is of non-fixed length. Thus, it still
2245     fulfils its original purpose of finding quick non-matches in cases of nested
2246     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2247    
2248    
2249     Version 4.0 17-Feb-03
2250     ---------------------
2251    
2252 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2253     extended to the end of string, PCRE compiled incorrect data. This could lead to
2254     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2255    
2256     2. Moved to autoconf 2.53 and libtool 1.4.2.
2257    
2258     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2259     the special perltest8 script is no longer needed - all the tests can be run
2260     from a single perltest script.
2261    
2262     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2263     by \s. It has now been removed in PCRE. This means it isn't recognized as
2264     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2265     class [:space:] *does* include VT, thereby creating a mess.
2266    
2267     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2268     space and tab.
2269    
2270     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2271     its new features into the main test script, reducing the number of scripts.
2272    
2273     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2274     were backward compatible, and made the (?i) apply to the whole pattern, as if
2275     /i were given. Now it behaves more logically, and applies the option setting
2276     only to what follows. PCRE has been changed to follow suit. However, if it
2277     finds options settings right at the start of the pattern, it extracts them into
2278     the global options, as before. Thus, they show up in the info data.
2279    
2280     8. Added support for the \Q...\E escape sequence. Characters in between are
2281     treated as literals. This is slightly different from Perl in that $ and @ are
2282     also handled as literals inside the quotes. In Perl, they will cause variable
2283     interpolation. Note the following examples:
2284    
2285     Pattern PCRE matches Perl matches
2286    
2287     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2288     \Qabc\$xyz\E abc\$xyz abc\$xyz
2289     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2290    
2291     For compatibility with Perl, \Q...\E sequences are recognized inside character
2292     classes as well as outside them.
2293    
2294     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2295     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2296     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2297     signed/unsigned warnings.
2298    
2299     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2300     option for pcretest, so I've replaced it by a simple function that does just
2301     that job.
2302    
2303     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2304     "pcregrep -".
2305    
2306     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2307     Java package. This provides some syntactic sugar for simple cases of what my
2308     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2309     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2310     item, you can use this simplified notation. Note that only makes sense with
2311     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2312     greediness, whatever the setting of the PCRE_UNGREEDY option.
2313    
2314     13. A change of greediness default within a pattern was not taking effect at
2315     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2316     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2317     was abstracted outside.
2318    
2319     14. PCRE now supports the \G assertion. It is true when the current matching
2320     position is at the start point of the match. This differs from \A when the
2321     starting offset is non-zero. Used with the /g option of pcretest (or similar
2322     code), it works in the same way as it does for Perl's /g option. If all
2323     alternatives of a regex begin with \G, the expression is anchored to the start
2324     match position, and the "anchored" flag is set in the compiled expression.
2325    
2326     15. Some bugs concerning the handling of certain option changes within patterns
2327     have been fixed. These applied to options other than (?ims). For example,
2328     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2329     been the other way round. Some of this was related to change 7 above.
2330    
2331     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2332     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2333     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2334     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2335    
2336     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2337     mode. Unlike ".", it always matches newline, whatever the setting of
2338     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2339     assertions. Perl allows it, but it doesn't (in general) work because it can't
2340     calculate the length of the lookbehind. At least, that's the case for Perl
2341     5.8.0 - I've been told they are going to document that it doesn't work in
2342     future.
2343    
2344     18. Added an error diagnosis for escapes that PCRE does not support: these are
2345     \L, \l, \N, \P, \p, \U, \u, and \X.
2346    
2347     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2348     reading past the end of the pattern in cases such as /[abcd/.
2349    
2350     20. PCRE was getting more memory than necessary for patterns with classes that
2351     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2352    
2353     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2354     compiling PCRE for use with Virtual Pascal.
2355    
2356     22. Small fix to the Makefile to make it work properly if the build is done
2357     outside the source tree.
2358    
2359     23. Added a new extension: a condition to go with recursion. If a conditional
2360     subpattern starts with (?(R) the "true" branch is used if recursion has
2361     happened, whereas the "false" branch is used only at the top level.
2362    
2363     24. When there was a very long string of literal characters (over 255 bytes
2364     without UTF support, over 250 bytes with UTF support), the computation of how
2365     much memory was required could be incorrect, leading to segfaults or other
2366     strange effects.
2367    
2368     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2369     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2370     there was a subsequent back reference to those brackets. This meant that, for
2371     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2372     possible to check for precisely this case. All we can do is abandon the
2373     optimization if .* occurs inside capturing brackets when there are any back
2374     references whatsoever. (See below for a better fix that came later.)
2375    
2376     26. The handling of the optimization for finding the first character of a
2377     non-anchored pattern, and for finding a character that is required later in the
2378     match were failing in some cases. This didn't break the matching; it just
2379     failed to optimize when it could. The way this is done has been re-implemented.
2380    
2381     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2382    
2383     28. Added a new feature that provides some of the functionality that Perl
2384     provides with (?{...}). The facility is termed a "callout". The way it is done
2385     in PCRE is for the caller to provide an optional function, by setting
2386     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2387     global variable. By default it is unset, which disables all calling out. To get
2388     the function called, the regex must include (?C) at appropriate points. This
2389     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2390     This provides a means of identifying different callout points. When PCRE
2391     reaches such a point in the regex, if pcre_callout has been set, the external
2392     function is called. It is provided with data in a structure called
2393     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2394     matching continues; if it returns a non-zero value, the match at the current
2395     point fails. However, backtracking will occur if possible. [This was changed
2396     later and other features added - see item 49 below.]
2397    
2398     29. pcretest is upgraded to test the callout functionality. It provides a
2399     callout function that displays information. By default, it shows the start of
2400     the match and the current position in the text. There are some new data escapes
2401     to vary what happens:
2402    
2403     \C+ in addition, show current contents of captured substrings
2404     \C- do not supply a callout function
2405     \C!n return 1 when callout number n is reached
2406     \C!n!m return 1 when callout number n is reached for the mth time
2407    
2408     30. If pcregrep was called with the -l option and just a single file name, it
2409     output "<stdin>" if a match was found, instead of the file name.
2410    
2411     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2412     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2413     pcre_exec(). This saves a malloc/free per call. The default value of
2414     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2415     when configuring.
2416    
2417     32. The default maximum size of a compiled pattern is 64K. There have been a
2418     few cases of people hitting this limit. The code now uses macros to handle the
2419     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2420     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2421     configuring. Tests 2 and 5 work only with 2-byte links because they output
2422     debugging information about compiled patterns.
2423    
2424     33. Internal code re-arrangements:
2425    
2426     (a) Moved the debugging function for printing out a compiled regex into
2427     its own source file (printint.c) and used #include to pull it into
2428     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2429     separate copies.
2430    
2431     (b) Defined the list of op-code names for debugging as a macro in
2432     internal.h so that it is next to the definition of the opcodes.
2433    
2434     (c) Defined a table of op-code lengths for simpler skipping along compiled
2435     code. This is again a macro in internal.h so that it is next to the
2436     definition of the opcodes.
2437    
2438     34. Added support for recursive calls to individual subpatterns, along the
2439     lines of Robin Houston's patch (but implemented somewhat differently).
2440    
2441     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2442     allow it to read and process whole directories in Win32. This code was
2443     contributed by Lionel Fourquaux; it has not been tested by me.
2444    
2445     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2446     used to name a group. Names consist of alphanumerics and underscores, and must
2447     be unique. Back references use the syntax (?P=name) and recursive calls use
2448     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2449     numbers. The function pcre_fullinfo() can be used after compilation to extract
2450     a name/number map. There are three relevant calls:
2451    
2452     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2453     PCRE_INFO_NAMECOUNT yields the number of entries
2454     PCRE_INFO_NAMETABLE yields a pointer to the map.
2455    
2456     The map is a vector of fixed-size entries. The size of each entry depends on
2457     the length of the longest name used. The first two bytes of each entry are the
2458     group number, most significant byte first. There follows the corresponding
2459     name, zero terminated. The names are in alphabetical order.
2460    
2461     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2462     case instead of 255. Making it the same both with and without UTF-8 support
2463     means that the same test output works with both.
2464    
2465     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2466     calling malloc() with a zero argument.
2467    
2468     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2469     optimization. I've improved things by keeping a bitmap of backreferences with
2470     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2471     fact referenced, the optimization can be applied. It is unlikely that a
2472     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2473     the match to follow \n) will appear inside brackets with a number greater than
2474     31, but if it does, any back reference > 31 suppresses the optimization.
2475    
2476     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2477     of disabling numbered capturing parentheses. Any opening parenthesis that is
2478     not followed by ? behaves as if it were followed by ?: but named parentheses
2479     can still be used for capturing (and they will acquire numbers in the usual
2480     way).
2481    
2482     41. Redesigned the return codes from the match() function into yes/no/error so
2483     that errors can be passed back from deep inside the nested calls. A malloc
2484     failure while inside a recursive subpattern call now causes the
2485     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2486    
2487     42. It is now possible to set a limit on the number of times the match()
2488     function is called in a call to pcre_exec(). This facility makes it possible to
2489     limit the amount of recursion and backtracking, though not in a directly
2490     obvious way, because the match() function is used in a number of different
2491     circumstances. The count starts from zero for each position in the subject
2492     string (for non-anchored patterns). The default limit is, for compatibility, a
2493     large number, namely 10 000 000. You can change this in two ways:
2494    
2495     (a) When configuring PCRE before making, you can use --with-match-limit=n
2496     to set a default value for the compiled library.
2497    
2498     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2499     a different value is set. See 45 below.
2500    
2501     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2502    
2503     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2504     of things that can be changed at compile time. The first argument specifies
2505     what is wanted and the second points to where the information is to be placed.
2506     The current list of available information is:
2507    
2508     PCRE_CONFIG_UTF8
2509    
2510     The output is an integer that is set to one if UTF-8 support is available;
2511     otherwise it is set to zero.
2512    
2513     PCRE_CONFIG_NEWLINE
2514    
2515     The output is an integer that it set to the value of the code that is used for
2516     newline. It is either LF (10) or CR (13).
2517    
2518     PCRE_CONFIG_LINK_SIZE
2519    
2520     The output is an integer that contains the number of bytes used for internal
2521     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2522    
2523     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2524    
2525     The output is an integer that contains the threshold above which the POSIX
2526     interface uses malloc() for output vectors. See item 31 above.
2527    
2528     PCRE_CONFIG_MATCH_LIMIT
2529    
2530     The output is an unsigned integer that contains the default limit of the number
2531     of match() calls in a pcre_exec() execution. See 42 above.
2532    
2533     44. pcretest has been upgraded by the addition of the -C option. This causes it
2534     to extract all the available output from the new pcre_config() function, and to
2535     output it. The program then exits immediately.
2536    
2537     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2538     order to support additional features. One way would have been to define
2539     pcre_exec2() (for example) with extra arguments, but this would not have been
2540     extensible, and would also have required all calls to the original function to
2541     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2542     is used for passing in "extra" data from pcre_study().
2543    
2544     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2545     contains the following fields:
2546    
2547     flags a bitmap indicating which of the following fields are set
2548     study_data opaque data from pcre_study()
2549     match_limit a way of specifying a limit on match() calls for a specific
2550     call to pcre_exec()
2551     callout_data data for callouts (see 49 below)
2552    
2553     The flag bits are also defined in pcre.h, and are
2554    
2555     PCRE_EXTRA_STUDY_DATA
2556     PCRE_EXTRA_MATCH_LIMIT
2557     PCRE_EXTRA_CALLOUT_DATA
2558    
2559     The pcre_study() function now returns one of these new pcre_extra blocks, with
2560     the actual study data pointed to by the study_data field, and the
2561     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2562     before. That is, this change is entirely upwards-compatible and requires no
2563     change to existing code.
2564    
2565     If you want to pass in additional data to pcre_exec(), you can either place it
2566     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2567     block.
2568    
2569     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2570     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2571     times with different match limits, until it finds the minimum value needed for
2572     pcre_exec() to complete. The value is then output. This can be instructive; for
2573     most simple matches the number is quite small, but for pathological cases it
2574     gets very large very quickly.
2575    
2576     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2577     returns the size of the data block pointed to by the study_data field in a
2578     pcre_extra block, that is, the value that was passed as the argument to
2579     pcre_malloc() when PCRE was getting memory in which to place the information
2580     created by pcre_study(). The fourth argument should point to a size_t variable.
2581     pcretest has been extended so that this information is shown after a successful
2582     pcre_study() call when information about the compiled regex is being displayed.
2583    
2584     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2585     because what follows is always an absolute path. (Later: it turns out that this
2586     is more than cosmetic for MinGW, because it doesn't like empty path
2587     components.)
2588    
2589     49. Some changes have been made to the callout feature (see 28 above):
2590    
2591     (i) A callout function now has three choices for what it returns:
2592    
2593     0 => success, carry on matching
2594     > 0 => failure at this point, but backtrack if possible
2595     < 0 => serious error, return this value from pcre_exec()
2596    
2597     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2598     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2599     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2600     use by callout functions. It will never be used by PCRE itself.
2601    
2602     (ii) The pcre_extra structure (see 45 above) has a void * field called
2603     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2604     pcre_callout_block structure has a field of the same name. The contents of
2605     the field passed in the pcre_extra structure are passed to the callout
2606     function in the corresponding field in the callout block. This makes it
2607     easier to use the same callout-containing regex from multiple threads. For
2608     testing, the pcretest program has a new data escape
2609    
2610     \C*n pass the number n (may be negative) as callout_data
2611    
2612     If the callout function in pcretest receives a non-zero value as
2613     callout_data, it returns that value.
2614    
2615     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2616     there were some redundant $(CFLAGS) in commands that are now specified as
2617     $(LINK), which already includes $(CFLAGS).
2618    
2619     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2620     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2621     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2622     one-byte characters throughout. Note that case-insensitive matching applies
2623     only to characters whose values are less than 256. PCRE doesn't support the
2624     notion of cases for higher-valued characters.
2625    
2626     (i) A character class whose characters are all within 0-255 is handled as
2627     a bit map, and the map is inverted for negative classes. Previously, a
2628     character > 255 always failed to match such a class; however it should
2629     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2630    
2631     (ii) A negated character class with a single character < 255 is coded as
2632     "not this character" (OP_NOT). This wasn't working properly when the test
2633     character was multibyte, either singly or repeated.
2634    
2635     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2636     mode, for example: \x{100}{2,3}.
2637    
2638     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2639     singly or repeated) now correctly test multibyte characters. However,
2640     PCRE doesn't recognize any characters with values greater than 255 as
2641     digits, spaces, or word characters. Such characters always match \D, \S,
2642     and \W, and never match \d, \s, or \w.
2643    
2644     (v) Classes may now contain characters and character ranges with values
2645     greater than 255. For example: [ab\x{100}-\x{400}].
2646    
2647     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2648     PCRE in UTF-8 mode.
2649    
2650     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2651     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2652     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2653     value.)
2654    
2655     53. The single man page has become too large. I have therefore split it up into
2656     a number of separate man pages. These also give rise to individual HTML pages;
2657     these are now put in a separate directory, and there is an index.html page that
2658     lists them all. Some hyperlinking between the pages has been installed.
2659    
2660     54. Added convenience functions for handling named capturing parentheses.
2661    
2662     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2663     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2664     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2665     are faulted.
2666    
2667     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2668     calling configure. These values are used when compiling the dftables.c program
2669     which is run to generate the source of the default character tables. They
2670     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2671     you will need to set these values.
2672    
2673     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2674    
2675    
2676     Version 3.9 02-Jan-02
2677 nigel 61 ---------------------
2678    
2679     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2680    
2681     2. If --disable-static was given, the building process failed when trying to
2682     build pcretest and pcregrep. (For some reason it was using libtool to compile
2683     them, which is not right, as they aren't part of the library.)
2684    
2685    
2686 nigel 59 Version 3.8 18-Dec-01
2687     ---------------------
2688    
2689     1. The experimental UTF-8 code was completely screwed up. It was packing the
2690     bytes in the wrong order. How dumb can you get?
2691    
2692    
2693 nigel 57 Version 3.7 29-Oct-01
2694     ---------------------
2695    
2696     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2697     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2698     this didn't happen under Solaris 8, where I normally test things.
2699    
2700 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2701     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2702     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2703     this fix an hour or so after the initial 3.7 release.)
2704 nigel 57
2705 nigel 59
2706 nigel 55 Version 3.6 23-Oct-01
2707     ---------------------
2708    
2709     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2710     offsets passed as NULL with zero offset count.
2711    
2712     2. The config.guess and config.sub files had not been updated when I moved to
2713     the latest autoconf.
2714    
2715    
2716 nigel 53 Version 3.5 15-Aug-01
2717     ---------------------
2718 nigel 5
2719 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2720     had been forgotten.
2721    
2722     2. By using declared but undefined structures, we can avoid using "void"
2723     definitions in pcre.h while keeping the internal definitions of the structures
2724     private.
2725    
2726     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2727     user point of view, this means that both static and shared libraries are built
2728     by default, but this can be individually controlled. More of the work of
2729     handling this static/shared cases is now inside libtool instead of PCRE's make
2730     file.
2731    
2732     4. The pcretest utility is now installed along with pcregrep because it is
2733     useful for users (to test regexs) and by doing this, it automatically gets
2734     relinked by libtool. The documentation has been turned into a man page, so
2735     there are now .1, .txt, and .html versions in /doc.
2736    
2737     5. Upgrades to pcregrep:
2738     (i) Added long-form option names like gnu grep.
2739     (ii) Added --help to list all options with an explanatory phrase.
2740     (iii) Added -r, --recursive to recurse into sub-directories.
2741     (iv) Added -f, --file to read patterns from a file.
2742    
2743     6. pcre_exec() was referring to its "code" argument before testing that
2744     argument for NULL (and giving an error if it was NULL).
2745    
2746     7. Upgraded Makefile.in to allow for compiling in a different directory from
2747     the source directory.
2748    
2749     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2750     options bits, the pointer it was passed was to an int instead of to an unsigned
2751     long int. This mattered only on 64-bit systems.
2752    
2753     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2754     generated) instead of pcre.in, which it its source. Also made the same change
2755     in several of the .c files.
2756    
2757     10. A new release of gcc defines printf() as a macro, which broke pcretest
2758     because it had an ifdef in the middle of a string argument for printf(). Fixed
2759     by using separate calls to printf().
2760    
2761     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2762     script, to force use of CR or LF instead of \n in the source. On non-Unix
2763     systems, the value can be set in config.h.
2764    
2765     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2766     absolute limit. Changed the text of the error message to make this clear, and
2767     likewise updated the man page.
2768    
2769     13. The limit of 99 on the number of capturing subpatterns has been removed.
2770     The new limit is 65535, which I hope will not be a "real" limit.
2771    
2772    
2773 nigel 51 Version 3.4 22-Aug-00
2774     ---------------------
2775    
2776     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2777    
2778     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2779    
2780    
2781 nigel 49 Version 3.3 01-Aug-00
2782     ---------------------
2783    
2784     1. If an octal character was given, but the value was greater than \377, it
2785     was not getting masked to the least significant bits, as documented. This could
2786     lead to crashes in some systems.
2787    
2788     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2789     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2790    
2791     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2792     These just pass their arguments on to (pcre_free)(), but they are provided
2793     because some uses of PCRE bind it to non-C systems that can call its functions,
2794     but cannot call free() or pcre_free() directly.
2795    
2796     4. Add "make test" as a synonym for "make check". Corrected some comments in
2797     the Makefile.
2798    
2799     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2800     Makefile.
2801    
2802     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2803     command called pgrep for grepping around the active processes.
2804    
2805     7. Added the beginnings of support for UTF-8 character strings.
2806    
2807     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2808     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2809     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2810     out for the ar command.)
2811    
2812    
2813 nigel 47 Version 3.2 12-May-00
2814     ---------------------
2815    
2816     This is purely a bug fixing release.
2817    
2818     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2819     of ZA. This was just one example of several cases that could provoke this bug,
2820     which was introduced by change 9 of version 2.00. The code for breaking
2821     infinite loops after an iteration that matches an empty string was't working
2822     correctly.
2823    
2824     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2825     when matched against abbab (for example). After matching an empty string, it
2826     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2827     caused it to match further down the string than it should.
2828    
2829     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2830     was there because it doesn't seem to be needed, and it causes trouble on some
2831     systems, as it is not a Standard C header. It has been removed.
2832    
2833     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2834     were reported on the Macintosh. The changes were from
2835    
2836     while ((c = *(++ptr)) != 0 && c != '\n');
2837     to
2838     while ((c = *(++ptr)) != 0 && c != '\n') ;
2839    
2840     Totally extraordinary, but if that's what it takes...
2841    
2842     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2843     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2844     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2845     assumes the way PCRE uses memmove() (always moving upwards).
2846    
2847     6. PCRE is being used in one environment where strchr() is not available. There
2848     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2849     faster code anyway.
2850    
2851    
2852 nigel 45 Version 3.1 09-Feb-00
2853     ---------------------
2854    
2855     The only change in this release is the fixing of some bugs in Makefile.in for
2856     the "install" target:
2857    
2858     (1) It was failing to install pcreposix.h.
2859    
2860     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2861    
2862    
2863 nigel 43 Version 3.0 01-Feb-00
2864     ---------------------
2865 nigel 41
2866     1. Add support for the /+ modifier to perltest (to output $` like it does in
2867     pcretest).
2868    
2869     2. Add support for the /g modifier to perltest.
2870    
2871     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2872     matches null strings.
2873    
2874     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2875     pattern. Perl treats empty patterns specially - it reuses the most recent
2876     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2877     effect.
2878    
2879     5. The POSIX interface was broken in that it was just handing over the POSIX
2880     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2881     required a bigger vector, with some working space on the end. This means that
2882     the POSIX wrapper now has to get and free some memory, and copy the results.
2883    
2884 nigel 43 6. Added some simple autoconf support, placing the test data and the
2885     documentation in separate directories, re-organizing some of the
2886     information files, and making it build pcre-config (a GNU standard). Also added
2887     libtool support for building PCRE as a shared library, which is now the
2888     default.
2889 nigel 41
2890 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2891     09 are not valid octal constants. Single digits will be used for minor values
2892     less than 10.
2893    
2894     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2895     existing programs that set these in the POSIX interface can use PCRE without
2896     modification.
2897    
2898     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2899     return all that pcre_info() returns, plus additional data. The pcre_info()
2900     function is retained for compatibility, but is considered to be obsolete.
2901    
2902     10. Added experimental recursion feature (?R) to handle one common case that
2903     Perl 5.6 will be able to do with (?p{...}).
2904    
2905     11. Added support for POSIX character classes like [:alpha:], which Perl is
2906     adopting.
2907    
2908    
2909 nigel 39 Version 2.08 31-Aug-99
2910     ----------------------
2911    
2912     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2913     trying to match at the startoffset position, but instead was moving forward to
2914     the next newline as if a previous match had failed.
2915    
2916     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2917     and could get into a loop if a null string was matched other than at the start
2918     of the subject.
2919    
2920     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2921     be distinguished at compile time, and for completeness also added PCRE_DATE.
2922    
2923     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2924     in GnuWin32 environments.
2925    
2926    
2927 nigel 37 Version 2.07 29-Jul-99
2928     ----------------------
2929    
2930     1. The documentation is now supplied in plain text form and HTML as well as in
2931     the form of man page sources.
2932    
2933     2. C++ compilers don't like assigning (void *) values to other pointer types.
2934     In particular this affects malloc(). Although there is no problem in Standard
2935     C, I've put in casts to keep C++ compilers happy.
2936    
2937     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2938     should be (const char *).
2939    
2940     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2941     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2942     However, I haven't made this a standard facility. The documentation doesn't
2943     mention it, and the Makefile doesn't support it.
2944    
2945     5. The Makefile now contains an "install" target, with editable destinations at
2946     the top of the file. The pcretest program is not installed.
2947    
2948     6. pgrep -V now gives the PCRE version number and date.
2949    
2950     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2951     causing the entire string to be ignored, instead of just the last character.
2952    
2953     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2954     non-matching string, it can take a very, very long time, even for strings of
2955     quite modest length, because of the nested recursion. PCRE now does better in
2956     some of these cases. It does this by remembering the last required literal
2957     character in the pattern, and pre-searching the subject to ensure it is present
2958     before running the real match. In other words, it applies a heuristic to detect
2959     some types of certain failure quickly, and in the above example, if presented
2960     with a string that has no trailing " it gives "no match" very quickly.
2961    
2962     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2963     other alternatives are tried instead.
2964    
2965    
2966 nigel 35 Version 2.06 09-Jun-99
2967     ----------------------
2968    
2969     1. Change pcretest's output for amount of store used to show just the code
2970     space, because the remainder (the data block) varies in size between 32-bit and
2971     64-bit systems.
2972    
2973     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2974     start matching at. This allows lookbehinds to work when searching for multiple
2975     occurrences in a string.
2976    
2977     3. Added additional options to pcretest for testing multiple occurrences:
2978    
2979     /+ outputs the rest of the string that follows a match
2980     /g loops for multiple occurrences, using the new startoffset argument
2981     /G loops for multiple occurrences by passing an incremented pointer
2982    
2983     4. PCRE wasn't doing the "first character" optimization for patterns starting
2984     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2985     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2986     the letter 'x'. On long subject strings, this gives a significant speed-up.
2987    
2988    
2989 nigel 33 Version 2.05 21-Apr-99
2990     ----------------------
2991    
2992     1. Changed the type of magic_number from int to long int so that it works
2993     properly on 16-bit systems.
2994    
2995     2. Fixed a bug which caused patterns starting with .* not to work correctly
2996     when the subject string contained newline characters. PCRE was assuming
2997     anchoring for such patterns in all cases, which is not correct because .* will
2998     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2999     DOTALL is set at top level; otherwise it knows that patterns starting with .*
3000     must be retried after every newline in the subject.
3001    
3002    
3003 nigel 31 Version 2.04 18-Feb-99
3004     ----------------------
3005    
3006     1. For parenthesized subpatterns with repeats whose minimum was zero, the
3007     computation of the store needed to hold the pattern was incorrect (too large).
3008     If such patterns were nested a few deep, this could multiply and become a real
3009     problem.
3010    
3011     2. Added /M option to pcretest to show the memory requirement of a specific
3012     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3013    
3014     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3015     compiled in such a way that the backtracking after subsequent failure was
3016     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3017     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3018    
3019    
3020 nigel 29 Version 2.03 02-Feb-99
3021     ----------------------
3022    
3023     1. Fixed typo and small mistake in man page.
3024    
3025 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
3026     LICENCE file containing the conditions.
3027 nigel 29
3028     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3029     Perl, that is the internal \ allows the delimiter to be included in the
3030     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3031     the final delimiter, add \ to the end of the pattern (to test the error).
3032    
3033     4. Added the convenience functions for extracting substrings after a successful
3034     match. Updated pcretest to make it able to test these functions.
3035    
3036    
3037 nigel 27 Version 2.02 14-Jan-99
3038     ----------------------
3039    
3040     1. Initialized the working variables associated with each extraction so that
3041     their saving and restoring doesn't refer to uninitialized store.
3042    
3043     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3044     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3045     fix the problem.
3046    
3047     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3048     calls, and wasn't printing the correct value for compiling calls. Increased the
3049     default value of LOOPREPEAT, and the number of significant figures in the
3050     times.
3051    
3052     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3053    
3054     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3055     a building problem on Windows NT with a FAT file system.
3056    
3057    
3058 nigel 25 Version 2.01 21-Oct-98
3059     ----------------------
3060    
3061     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3062     to character tables built by pcre_maketables() in the current locale. If NULL
3063     is passed, the default tables are used.
3064    
3065    
3066 nigel 23 Version 2.00 24-Sep-98
3067 nigel 21 ----------------------
3068    
3069 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3070     it any more.
3071    
3072     2. Allow quantification of (?>) groups, and make it work correctly.
3073    
3074     3. The first character computation wasn't working for (?>) groups.
3075    
3076     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3077     end of the subject) and add 5.005's \z, which really does match only at the
3078     very end of the subject.
3079    
3080     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3081    
3082     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3083     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3084     localized options. All options to pcre_study() were also removed.
3085    
3086     7. Add other new features from 5.005:
3087    
3088     $(?<= positive lookbehind
3089     $(?<! negative lookbehind
3090     (?imsx-imsx) added the unsetting capability
3091     such a setting is global if at outer level; local otherwise
3092     (?imsx-imsx:) non-capturing groups with option setting
3093     (?(cond)re|re) conditional pattern matching
3094    
3095     A backreference to itself in a repeated group matches the previous
3096     captured string.
3097    
3098     8. General tidying up of studying (both automatic and via "study")
3099     consequential on the addition of new assertions.
3100    
3101     9. As in 5.005, unlimited repeated groups that could match an empty substring
3102     are no longer faulted at compile time. Instead, the loop is forcibly broken at
3103     runtime if any iteration does actually match an empty substring.
3104    
3105     10. Include the RunTest script in the distribution.
3106    
3107     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3108     discrepancies, some of which were old and were also with respect to 5.004. They
3109     have now been fixed.
3110    
3111    
3112     Version 1.09 28-Apr-98
3113     ----------------------
3114    
3115 nigel 21 1. A negated single character class followed by a quantifier with a minimum
3116     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
3117     program crashes, or just wrong answers. This did not apply to negated classes
3118     containing more than one character, or to minima other than one.
3119    
3120    
3121 nigel 19 Version 1.08 27-Mar-98
3122     ----------------------
3123    
3124     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3125    
3126     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3127     latter must appear before anything that relies on it in the pattern.
3128    
3129    
3130 nigel 17 Version 1.07 16-Feb-98
3131     ----------------------
3132    
3133     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3134     repeat of a potentially empty string).
3135    
3136    
3137 nigel 15 Version 1.06 23-Jan-98
3138     ----------------------
3139    
3140     1. Added Markus Oberhumer's little patches for C++.
3141    
3142     2. Literal strings longer than 255 characters were broken.
3143    
3144    
3145 nigel 13 Version 1.05 23-Dec-97
3146     ----------------------
3147    
3148     1. Negated character classes containing more than one character were failing if
3149     PCRE_CASELESS was set at run time.
3150    
3151    
3152 nigel 11 Version 1.04 19-Dec-97
3153     ----------------------
3154    
3155     1. Corrected the man page, where some "const" qualifiers had been omitted.
3156    
3157     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3158     input syntax.
3159    
3160     3. Fixed memory leak which occurred when a regex with back references was
3161     matched with an offsets vector that wasn't big enough. The temporary memory
3162     that is used in this case wasn't being freed if the match failed.
3163    
3164     4. Tidied pcretest to ensure it frees memory that it gets.
3165    
3166     5. Temporary memory was being obtained in the case where the passed offsets
3167     vector was exactly big enough.
3168    
3169     6. Corrected definition of offsetof() from change 5 below.
3170    
3171     7. I had screwed up change 6 below and broken the rules for the use of
3172     setjmp(). Now fixed.
3173    
3174    
3175 nigel 9 Version 1.03 18-Dec-97
3176     ----------------------
3177    
3178     1. A erroneous regex with a missing opening parenthesis was correctly
3179     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3180     on some systems.
3181    
3182     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3183     it was reported that one broken compiler failed on the former because "code" is
3184     also an independent variable.
3185    
3186     3. The erroneous regex a[]b caused an array overrun reference.
3187    
3188     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3189     fail on data ending with that character. (It was going on too far, and checking
3190     the next character, typically a binary zero.) This was specific to the
3191     optimized code for single-character negative classes.
3192    
3193     5. Added a contributed patch from the TIN world which does the following:
3194    
3195     + Add an undef for memmove, in case the the system defines a macro for it.
3196    
3197     + Add a definition of offsetof(), in case there isn't one. (I don't know
3198     the reason behind this - offsetof() is part of the ANSI standard - but
3199     it does no harm).
3200    
3201     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3202     most of the places where whitespace preceded '#'. I have given up and
3203     allowed the remaining 2 cases to be at the margin.
3204    
3205     + Rename some variables in pcre to eliminate shadowing. This seems very
3206     pedantic, but does no harm, of course.
3207    
3208     6. Moved the call to setjmp() into its own function, to get rid of warnings
3209     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3210    
3211     7. Constructs such as \d{8,} were compiling into the equivalent of
3212 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3213 nigel 9 outcome, but in this particular case used more store than had been allocated,
3214     which caused the bug to be discovered because it threw up an internal error.
3215    
3216     8. The debugging code in both pcre and pcretest for outputting the compiled
3217     form of a regex was going wrong in the case of back references followed by
3218     curly-bracketed repeats.
3219    
3220    
3221 nigel 7 Version 1.02 12-Dec-97
3222     ----------------------
3223    
3224     1. Typos in pcre.3 and comments in the source fixed.
3225    
3226     2. Applied a contributed patch to get rid of places where it used to remove
3227     'const' from variables, and fixed some signed/unsigned and uninitialized
3228     variable warnings.
3229    
3230     3. Added the "runtest" target to Makefile.
3231    
3232     4. Set default compiler flag to -O2 rather than just -O.
3233    
3234    
3235 nigel 5 Version 1.01 19-Nov-97
3236     ----------------------
3237    
3238     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3239     like /([ab]*)*/, that is, for classes with more than one character in them.
3240    
3241     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3242     as /((?>a*))*/ (a PCRE_EXTRA facility).
3243    
3244    
3245     Version 1.00 18-Nov-97
3246     ----------------------
3247    
3248     1. Added compile-time macros to support systems such as SunOS4 which don't have
3249     memmove() or strerror() but have other things that can be used instead.
3250    
3251     2. Arranged that "make clean" removes the executables.
3252    
3253    
3254 nigel 3 Version 0.99 27-Oct-97
3255     ----------------------
3256    
3257     1. Fixed bug in code for optimizing classes with only one character. It was
3258     initializing a 32-byte map regardless, which could cause it to run off the end
3259     of the memory it had got.
3260    
3261     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3262    
3263    
3264     Version 0.98 22-Oct-97
3265     ----------------------
3266    
3267     1. Fixed bug in code for handling temporary memory usage when there are more
3268     back references than supplied space in the ovector. This could cause segfaults.
3269    
3270    
3271     Version 0.97 21-Oct-97
3272     ----------------------
3273    
3274     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3275    
3276     2. Optimized negated single characters not to use a bit map.
3277    
3278     3. Brought error texts together as macro definitions; clarified some of them;
3279     fixed one that was wrong - it said "range out of order" when it meant "invalid
3280     escape sequence".
3281    
3282     4. Changed some char * arguments to const char *.
3283    
3284     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3285    
3286     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3287     pcretest.
3288    
3289    
3290     Version 0.96 16-Oct-97
3291     ----------------------
3292    
3293     1. Added a simple "pgrep" utility to the distribution.
3294    
3295     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3296     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3297     where "ddd" means "one or more decimal digits".
3298    
3299     3. Fixed serious bug. If a pattern had a back reference, but the call to
3300     pcre_exec() didn't supply a large enough ovector to record the related
3301     identifying subpattern, the match always failed. PCRE now remembers the number
3302     of the largest back reference, and gets some temporary memory in which to save
3303     the offsets during matching if necessary, in order to ensure that
3304     backreferences always work.
3305    
3306     4. Increased the compatibility with Perl in a number of ways:
3307    
3308     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3309     to request this handling. The option can be set at compile or exec time.
3310    
3311     (b) $ matches before a terminating newline by default; an option
3312     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3313     mode). The option can be set at compile or exec time.
3314    
3315     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3316     the same as Perl's. If the decimal number it represents is less than 10
3317     or there aren't that many previous left capturing parentheses, an octal
3318     escape is read. Inside a character class, it's always an octal escape,
3319     even if it is a single digit.
3320    
3321     (d) An escaped but undefined alphabetic character is taken as a literal,
3322     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3323     escapes.
3324    
3325     (e) {0} is now permitted. (The previous item is removed from the compiled
3326     pattern).
3327    
3328     5. Changed all the names of code files so that the basic parts are no longer
3329     than 10 characters, and abolished the teeny "globals.c" file.
3330    
3331     6. Changed the handling of character classes; they are now done with a 32-byte
3332     bit map always.
3333    
3334     7. Added the -d and /D options to pcretest to make it possible to look at the
3335     internals of compilation without having to recompile pcre.
3336    
3337    
3338     Version 0.95 23-Sep-97
3339     ----------------------
3340    
3341     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3342     \x20 at the start of a run of normal characters. These were being treated as
3343     real characters, instead of the source characters being re-checked.
3344    
3345    
3346     Version 0.94 18-Sep-97
3347     ----------------------
3348    
3349     1. The functions are now thread-safe, with the caveat that the global variables
3350     containing pointers to malloc() and free() or alternative functions are the
3351     same for all threads.
3352    
3353     2. Get pcre_study() to generate a bitmap of initial characters for non-
3354     anchored patterns when this is possible, and use it if passed to pcre_exec().
3355    
3356    
3357     Version 0.93 15-Sep-97
3358     ----------------------
3359    
3360     1. /(b)|(:+)/ was computing an incorrect first character.
3361    
3362     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3363     but not actually doing anything yet.
3364    
3365     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3366     as Perl does (e.g. [-az] or [az-]).
3367    
3368     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3369     all possible positions.
3370    
3371     5. Split up into different modules to avoid including unneeded functions in a
3372     compiled binary. However, compile and exec are still in one module. The "study"
3373     function is split off.
3374    
3375     6. The character tables are now in a separate module whose source is generated
3376     by an auxiliary program - but can then be edited by hand if required. There are
3377     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3378     toupper() in the code.
3379    
3380     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3381     make them global. Abolish the function for setting them, as the caller can now
3382     set them directly.
3383    
3384    
3385     Version 0.92 11-Sep-97
3386     ----------------------
3387    
3388     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3389     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3390    
3391     2. Caseless matching was not working in character classes if the characters in
3392     the pattern were in upper case.
3393    
3394     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3395    
3396     4. Make PCRE_ANCHORED public and accept as a compile option.
3397    
3398     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3399     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3400     pass them.
3401    
3402     6. Give an error if bad option bits passed at compile or run time.
3403    
3404     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3405     pcretest to cause it to pass that flag.
3406    
3407     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3408     options, and the first character, if set.
3409    
3410     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3411    
3412    
3413     Version 0.91 10-Sep-97
3414     ----------------------
3415    
3416     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3417     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3418    
3419     2. PCRE was looping on encountering an indefinitely repeated back reference to
3420     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3421     Perl does - treats the match as successful.
3422    
3423     ****

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