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Revision 368 - (hide annotations) (download)
Sun Aug 24 16:25:20 2008 UTC (6 years ago) by ph10
File size: 159458 byte(s)
Make it clearer that ovector values are byte offsets, not character counts.

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

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