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Revision 361 - (hide annotations) (download)
Thu Jul 10 16:03:28 2008 UTC (6 years, 9 months ago) by ph10
File size: 158751 byte(s)
Fix off-end-of-buffer bug for patterns that match only at start of line.

1 nigel 3 ChangeLog for PCRE
2     ------------------
4 ph10 349 Version 8.0 02 Jul-08
5     ---------------------
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.
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.
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 == ...).
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.
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:
49     printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
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 351
59 ph10 357
60 ph10 347 Version 7.7 07-May-08
61 ph10 321 ---------------------
63     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
64 ph10 345 a string to a long long, pretend we don't even have a long long." This is
65 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
66 ph10 345
67 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
68     pre-7.6 versions, which defined a global no_arg variable instead of putting
69 ph10 332 it in the RE class. (See also #8 below.)
70 ph10 345
71     3. Remove a line of dead code, identified by coverity and reported by Nuno
72     Lopes.
74 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
75 ph10 321
76 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
77 ph10 345 of files, instead of just to the final components.
79 ph10 324 (2) If there was more than one level of directory, the subdirectories were
80     skipped unless they satisfied the include/exclude conditions. This is
81     inconsistent with GNU grep (and could even be seen as contrary to the
82     pcregrep specification - which I improved to make it absolutely clear).
83     The action now is always to scan all levels of directory, and just
84     apply the include/exclude patterns to regular files.
85 ph10 345
86 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
87 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
89 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
90 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
91 ph10 326 doesn't support NULs in patterns.
92 ph10 345
93     7. Added some missing "const"s to declarations of static tables in
94     pcre_compile.c and pcre_dfa_exec.c.
96 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
97 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
98 ph10 345 first patch. And a third patch - this was a messy problem.)
99 ph10 321
100 ph10 345 9. Applied Craig's patch to remove the use of push_back().
102 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
103     matching function regexec().
104 ph10 345
105     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
106     which, however, unlike Perl's \g{...}, are subroutine calls, not back
107 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
108     Oniguruma does).
109 ph10 345
110     12. Previously, a group with a zero repeat such as (...){0} was completely
111 ph10 335 omitted from the compiled regex. However, this means that if the group
112     was called as a subroutine from elsewhere in the pattern, things went wrong
113 ph10 345 (an internal error was given). Such groups are now left in the compiled
114     pattern, with a new opcode that causes them to be skipped at execution
115 ph10 335 time.
116 ph10 345
117 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
118     to the way PCRE behaves:
119 ph10 345
120 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
121 ph10 345
122     (b) A back reference to an unmatched subpattern matches an empty string
123 ph10 336 (Perl fails the current match path).
124 ph10 345
125 ph10 341 (c) A data ] in a character class must be notated as \] because if the
126 ph10 345 first data character in a class is ], it defines an empty class. (In
127 ph10 341 Perl it is not possible to have an empty class.) The empty class []
128     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
129     The negative empty class [^] matches any one character, independently
130     of the DOTALL setting.
131 ph10 345
132     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
133 ph10 340 non-existent subpattern following a character class starting with ']' and
134     containing () gave an internal compiling error instead of "reference to
135     non-existent subpattern". Fortunately, when the pattern did exist, the
136 ph10 345 compiled code was correct. (When scanning forwards to check for the
137 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
138 ph10 345 the class, so got the count wrong. When actually compiling, the reference
139 ph10 340 was subsequently set up correctly.)
140 ph10 345
141 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
142 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
143     other assertions are supported. I have made pcre_dfa_exec() support
144     (*FAIL).
146 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
147 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
148     cannot be changed at match time, I realized I could make a small
149     improvement to matching performance by compiling OP_ALLANY instead of
150     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
151     on the OP_ANY path.
153     17. Compiling pcretest on Windows with readline support failed without the
154 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
155 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
157 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
158 ph10 345 ncurses library to be included for pcretest when ReadLine support is
159     requested, but also to allow for it to be overridden. This patch came from
160     Daniel Bergström.
161 ph10 347
162 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
163 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
164     any errors with the current Unicode tables. Thanks to Peter Kankowski for
165     spotting this.
166 ph10 324
167 ph10 332
168 ph10 319 Version 7.6 28-Jan-08
169 ph10 300 ---------------------
171 ph10 302 1. A character class containing a very large number of characters with
172     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
173     overflow.
174 ph10 309
175     2. Patch to cut out the "long long" test in pcrecpp_unittest when
176     HAVE_LONG_LONG is not defined.
178 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
179 ph10 304 bring them up to date and include new features. This patch includes:
180 ph10 309
181 ph10 304 - Fixed PH's badly added libz and libbz2 support.
182     - Fixed a problem with static linking.
183 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
184 ph10 304 - Fixed dftables problem and added an option.
185     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
187     - Added readline support for pcretest.
188 ph10 309 - Added an listing of the option settings after cmake has run.
190 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
191     "pcre.dll" under mingw when using Configure/Make. I added stuff to
192     Makefile.am that cause it to include this special target, without
193     affecting anything else. Note that the same mingw target plus all
194     the other distribution libraries and programs are now supported
195     when configuring with CMake (see 6 below) instead of with
196     Configure/Make.
197 ph10 309
198 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
199     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
200 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
201     solves the problem, but it does no harm.
202 ph10 313
203 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
204 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
205 ph10 314 with CMake, and also correct the comment about stack recursion.
206 ph10 313
207 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
208 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
209     of a program that users should build themselves after PCRE is installed, so
210     building it automatically is not really right. What is more, it gave
211 ph10 312 trouble in some build environments.
212 ph10 300
213 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
214 ph10 308
215 ph10 319
216 ph10 298 Version 7.5 10-Jan-08
217 ph10 263 ---------------------
219     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
220     values in parens when parsing an RE using the C++ wrapper."
221 ph10 286
222 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
223     Characters greater than 255 were excluded from the class instead of being
224     included.
225 ph10 286
226     3. The same bug as (2) above applied to negated POSIX classes such as
227 ph10 265 [:^space:].
228 ph10 286
229 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
230     defined or documented. It seems to have been a typo for PCRE_STATIC, so
231 ph10 286 I have changed it.
233 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
234 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
235     first named subpattern whose name started with "a" (in other words, the
236 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
237     expected" is now given for (?&) (a zero-length name), and this patch also
238     makes it give the same error for \k'' (previously it complained that that
239     was a reference to a non-existent subpattern).
240 ph10 286
241 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
242 ph10 286 this is right because (?- can be followed by option settings as well as by
243 ph10 269 digits. I have, however, made the messages clearer.
244 ph10 286
245 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
246     than the number used in the conditional) now cause a compile-time error.
247     This is actually not compatible with Perl, which accepts such patterns, but
248     treats the conditional as always being FALSE (as PCRE used to), but it
249     seems to me that giving a diagnostic is better.
250 ph10 286
251 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
252 ph10 275 and messages.
253 ph10 286
254     9. Fix two occurrences of "backslash" in comments that should have been
255     "backspace".
257     10. Remove two redundant lines of code that can never be obeyed (their function
258     was moved elsewhere).
260     11. The program that makes PCRE's Unicode character property table had a bug
261     which caused it to generate incorrect table entries for sequences of
262 ph10 277 characters that have the same character type, but are in different scripts.
263 ph10 286 It amalgamated them into a single range, with the script of the first of
264 ph10 277 them. In other words, some characters were in the wrong script. There were
265     thirteen such cases, affecting characters in the following ranges:
266 ph10 286
267 ph10 277 U+002b0 - U+002c1
268     U+0060c - U+0060d
269 ph10 286 U+0061e - U+00612
270 ph10 277 U+0064b - U+0065e
271     U+0074d - U+0076d
272     U+01800 - U+01805
273     U+01d00 - U+01d77
274     U+01d9b - U+01dbf
275     U+0200b - U+0200f
276     U+030fc - U+030fe
277     U+03260 - U+0327f
278     U+0fb46 - U+0fbb1
279     U+10450 - U+1049d
280 ph10 286
281 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
282     compatible with GNU grep in that, if there was more than one match in a
283     line, it showed only the first of them. It now behaves in the same way as
284     GNU grep.
285 ph10 286
286     13. If the -o and -v options were combined for pcregrep, it printed a blank
287     line for every non-matching line. GNU grep prints nothing, and pcregrep now
288     does the same. The return code can be used to tell if there were any
289     non-matching lines.
291 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
293     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
294 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
295 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
296     and both kinds of lookbehind were skipped).
298 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
299 ph10 284 inclusion of <windows.h> to before rather than after the definition of
300     INVALID_FILE_ATTRIBUTES (patch from David Byron).
301 ph10 263
302 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
303 ph10 286 character property caused pcre_compile() to compile bad code, which led at
304     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
305     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
306     caused the error; without that there was no problem.
307 ph10 263
308 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
309 ph10 286
310 ph10 289 19. Added --enable-pcretest-libreadline.
311 ph10 286
312 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
313 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
314 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
315     later patch that removed the other one (the right fix) and added unit tests
316     that check the return values (which was not done before).
317 ph10 292
318 ph10 291 21. Several CMake things:
319 ph10 287
320 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
321 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
322 ph10 288
323 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
324     linked with the newly-built libraries, not previously installed ones.
325 ph10 291
327 ph10 298
328     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
329     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
330     UTF-8 newline character). The key issue is that the pattern starts .*;
331     this means that the match must be either at the beginning, or after a
332     newline. The bug was in the code for advancing after a failed match and
333     checking that the new position followed a newline. It was not taking
334 ph10 294 account of UTF-8 characters correctly.
335 ph10 298
336     23. PCRE was behaving differently from Perl in the way it recognized POSIX
337     character classes. PCRE was not treating the sequence [:...:] as a
338     character class unless the ... were all letters. Perl, however, seems to
339     allow any characters between [: and :], though of course it rejects as
340     unknown any "names" that contain non-letters, because all the known class
341     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
342     for example, whereas PCRE did not - it did not recognize a POSIX character
343     class. This seemed a bit dangerous, so the code has been changed to be
344     closer to Perl. The behaviour is not identical to Perl, because PCRE will
345     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
346     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
347     Perl does, and where it didn't before.
349 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
350     Windows environments %n is disabled by default.
351 ph10 292
353 ph10 260 Version 7.4 21-Sep-07
354 ph10 230 ---------------------
356     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
357 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
358     LF". That isn't really right - the whole point of the change was to try to
359     help when there was an actual mention of one of the two characters. So now
360     the change happens only if \r or \n (or a literal CR or LF) character is
361 ph10 230 encountered.
362 ph10 231
363     2. The 32-bit options word was also used for 6 internal flags, but the numbers
364     of both had grown to the point where there were only 3 bits left.
365     Fortunately, there was spare space in the data structure, and so I have
366     moved the internal flags into a new 16-bit field to free up more option
367 ph10 230 bits.
368 ph10 231
369     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
370     but did not set the internal JCHANGED flag - either of these is enough to
371     control the way the "get" function works - but the PCRE_INFO_JCHANGED
372     facility is supposed to tell if (?J) was ever used, so now (?J) at the
373 ph10 230 start sets both bits.
375 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
376     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
377 ph10 230
378 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
380     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
381 ph10 233 compatibility, even though it is no longer used.
382 ph10 243
383     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
384 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
385 ph10 259 windows.h file is present (where different names are used). [This was
386 ph10 257 reversed later after testing - see 16 below.]
387 ph10 243
388     8. Changed all #include <config.h> to #include "config.h". There were also
389 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
390 ph10 243
391 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
392 ph10 243 sequence off the lines that it output.
394     10. It was pointed out to me that arrays of string pointers cause lots of
395     relocations when a shared library is dynamically loaded. A technique of
396     using a single long string with a table of offsets can drastically reduce
397     these. I have refactored PCRE in four places to do this. The result is
398 ph10 240 dramatic:
399 ph10 243
400 ph10 240 Originally: 290
401     After changing UCP table: 187
402 ph10 243 After changing error message table: 43
403 ph10 240 After changing table of "verbs" 36
404     After changing table of Posix names 22
405 ph10 243
406 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
407 ph10 247
408 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
409 ph10 247 unicode-properties was also set.
411 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
412 ph10 231
413 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
414     checked only for CRLF.
415 ph10 233
416 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
418 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
419 ph10 253
420 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
421 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
422     entirely. This removes changes made in 7 above.
423 ph10 256
424 ph10 261 17. The CMake files have been updated, and there is now more information about
425     building with CMake in the NON-UNIX-USE document.
426 ph10 257
427 ph10 261
428 ph10 228 Version 7.3 28-Aug-07
429 ph10 157 ---------------------
431 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
432     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
433     brackets there is not right, since it causes compilers to look for an
434     installed pcre.h, not the version that is in the source that is being
435     compiled (which of course may be different). I have changed it back to:
436 ph10 197
437 ph10 189 #include "pcre.h"
438 ph10 197
439     I have a vague recollection that the change was concerned with compiling in
440     different directories, but in the new build system, that is taken care of
441     by the VPATH setting the Makefile.
443 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
444     when the subject happened to end in the byte 0x85 (e.g. if the last
445     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
446     characters but of course it shouldn't be taken as a newline when it is part
447     of another character. The bug was that, for an unlimited repeat of . in
448     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
449     characters when looking for a newline.
450 ph10 197
451     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
453     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
454     in debug output.
456 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
457     long printing in the pcrecpp unittest when running under MinGW.
458 ph10 189
459 ph10 197 6. ESC_K was left out of the EBCDIC table.
460 ph10 189
461 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
462     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
463     limit also applies to "virtual nesting" when a pattern is recursive, and in
464     this case 1000 isn't so big. I have been able to remove this limit at the
465     expense of backing off one optimization in certain circumstances. Normally,
466     when pcre_exec() would call its internal match() function recursively and
467     immediately return the result unconditionally, it uses a "tail recursion"
468     feature to save stack. However, when a subpattern that can match an empty
469     string has an unlimited repetition quantifier, it no longer makes this
470     optimization. That gives it a stack frame in which to save the data for
471     checking that an empty string has been matched. Previously this was taken
472     from the 1000-entry workspace that had been reserved. So now there is no
473     explicit limit, but more stack is used.
474 ph10 189
475 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
476     syntax that is required for Windows, and which was going wrong for the
477     pcreposix and pcrecpp parts of the library. These were overlooked when this
478     problem was solved for the main library.
479 ph10 197
480 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
481     the size of patterns that contain repeated groups with explicit upper
482     limits. As the maximum quantifier is 65535, the maximum group length was
483     set at 30,000 so that the product of these two numbers did not overflow a
484     32-bit integer. However, it turns out that people want to use groups that
485     are longer than 30,000 bytes (though not repeat them that many times).
486     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
487     made it possible to implement the integer overflow checks in a much more
488     dynamic way, which I have now done. The artificial limitation on group
489     length has been removed - we now have only the limit on the total length of
490     the compiled pattern, which depends on the LINK_SIZE setting.
491 ph10 208
492     10. Fixed a bug in the documentation for get/copy named substring when
493     duplicate names are permitted. If none of the named substrings are set, the
494     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
495     empty string.
497     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
498     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
499     because the ] is interpreted as the first data character and the
500     terminating ] is not found. PCRE has been made compatible with Perl in this
501     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
502     cause memory overwriting.
504 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
505     string has been matched (to stop an infinite loop). It was not recognizing
506 ph10 208 a conditional subpattern that could match an empty string if that
507 ph10 206 subpattern was within another subpattern. For example, it looped when
508 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
509 ph10 206 condition was not nested. This bug has been fixed.
510 ph10 208
511 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
512     past the start of the subject in the presence of bytes with the top bit
513     set, for example "\x8aBCD".
514 ph10 211
515 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
516     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
517 ph10 200
518 ph10 211 14. Optimized (?!) to (*FAIL).
519 ph10 202
520 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
521     This restricts code points to be within the range 0 to 0x10FFFF, excluding
522     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
523     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
524     does: it's just the validity check that is more restrictive.
525 ph10 220
526     16. Inserted checks for integer overflows during escape sequence (backslash)
527     processing, and also fixed erroneous offset values for syntax errors during
528     backslash processing.
530 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
531 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
533 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
534     caused an overrun.
535 ph10 220
536     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
537     something other than just ASCII characters) inside a group that had an
538     unlimited repeat caused a loop at compile time (while checking to see
539     whether the group could match an empty string).
541 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
542     [\P{Any}] did so. (Error in the code for printing property names.)
543 ph10 210
544 ph10 220 21. An orphan \E inside a character class could cause a crash.
546     22. A repeated capturing bracket such as (A)? could cause a wild memory
547 ph10 218 reference during compilation.
548 ph10 220
549     23. There are several functions in pcre_compile() that scan along a compiled
550     expression for various reasons (e.g. to see if it's fixed length for look
551 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
552 ph10 220 present in the pattern. These operators have additional parameters compared
553     with \d, etc, and these were not being taken into account when moving along
554 ph10 218 the compiled data. Specifically:
555 ph10 220
556     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
557     length.
559     (b) An item such as \pL+ within a repeated group could cause crashes or
560 ph10 218 loops.
561 ph10 220
562 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
563 ph10 220 "reference to non-existent subpattern" error.
565 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
567 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
568 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
569 ph10 211
570 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
571 ph10 218
572 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
573 ph10 223 character were causing crashes (broken optimization).
574 ph10 227
575 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
576 ph10 227 \p or \P) caused a compile-time loop.
578 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
579     break. For example, the unstudied pattern [\r\n]A does not match the string
580     "\r\nA" because change 7.0/46 below moves the current point on by two
581     characters after failing to match at the start. However, the pattern \nA
582 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
583     the same is true. There doesn't seem any very clean way out of this, but
584     what I have chosen to do makes the common cases work: PCRE now takes note
585     of whether there can be an explicit match for \r or \n anywhere in the
586     pattern, and if so, 7.0/46 no longer applies. As part of this change,
587     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
588     pattern has explicit CR or LF references.
589 ph10 222
590 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
591 ph10 223
592 ph10 227
593 ph10 189 Version 7.2 19-Jun-07
594     ---------------------
596 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
597     which is apparently normally available under Windows.
598 ph10 159
599     2. Re-jig the pcregrep tests with different newline settings in an attempt
600     to make them independent of the local environment's newline setting.
601 ph10 157
602 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
603 ph10 165
604 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
605     was not 2, because the output contained actual offsets. The recent new
606 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
607     usable with all link sizes.
609 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
610     stack recursion. This gives a massive performance boost under BSD, but just
611 ph10 165 a small improvement under Linux. However, it saves one field in the frame
612 ph10 164 in all cases.
613 ph10 172
614 ph10 166 6. Added more features from the forthcoming Perl 5.10:
615 ph10 172
616 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
617     recursion call. It refers to the nth most recently opened parentheses.
618 ph10 172
619 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
620 ph10 172 to be opened parentheses.
622     (c) Conditions that refer to capturing parentheses can be specified
623 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
624 ph10 172
625 ph10 168 (d) \K resets the start of the current match so that everything before
626 ph10 172 is not part of it.
628 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
629 ph10 172
630 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
631 ph10 172 reference syntax.
632 ph10 182
633 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
634 ph10 182 alternative starts with the same number.
635 ph10 172
636 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
638 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
641     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
642     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
643 ph10 170 for detecting groups that can match an empty string.
644 ph10 159
645 ph10 172 9. A pattern with a very large number of alternatives (more than several
646     hundred) was running out of internal workspace during the pre-compile
647     phase, where pcre_compile() figures out how much memory will be needed. A
648     bit of new cunning has reduced the workspace needed for groups with
649     alternatives. The 1000-alternative test pattern now uses 12 bytes of
650     workspace instead of running out of the 4096 that are available.
651 ph10 182
652 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
653 ph10 172
654 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
655     The report of the bug said:
656 ph10 182
657 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
658     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
659 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
660 ph10 185
661 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
662 ph10 185 it matched the wrong number of bytes.
663 ph10 172
664 ph10 179
665 ph10 155 Version 7.1 24-Apr-07
666 ph10 98 ---------------------
668 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
669 ph10 122 that is more "standard", making use of automake and other Autotools. There
670 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
671     on this.
672 ph10 111
673     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
674     for recursive directory scanning broke on some systems because the files
675     are not scanned in any specific order and on different systems the order
676     was different. A call to "sort" has been inserted into RunGrepTest for the
677     approprate test as a short-term fix. In the longer term there may be an
678 ph10 100 alternative.
679 ph10 111
680 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
681 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
682     people do their own conversions for various reasons). The problems
683     concerned the use of low-level troff macros .br and .in. I have therefore
684     removed all such uses from the man pages (some were redundant, some could
685 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
686     HTML has been updated to handle .nf/.fi and to complain if it encounters
687     .br or .in.
688 ph10 111
689 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
690 ph10 123 arranged for config.h to be included in the distribution, with the name
691 ph10 111 config.h.generic, for the benefit of those who have to compile without
692     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
694     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
695     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
696 ph10 127 makevp.bat for the current PCRE, using the additional files
697 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
698 ph10 111
699     6. A Windows user reported a minor discrepancy with test 2, which turned out
700     to be caused by a trailing space on an input line that had got lost in his
701 ph10 102 copy. The trailing space was an accident, so I've just removed it.
702 ph10 111
703 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
704 ph10 111 that is needed.
706 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
707     as "const" (a) because they are and (b) because it helps the PHP
708     maintainers who have recently made a script to detect big data structures
709 ph10 111 in the php code that should be moved to the .rodata section. I remembered
710     to update Builducptable as well, so it won't revert if ucptable.h is ever
711 ph10 105 re-created.
712 ph10 111
713     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
714 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
715 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
716     support is not required. This saves 1.5-2K of code, which is important in
717 ph10 107 some applications.
718 ph10 111
719 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
720 ph10 111 so as not to refer to the tables, even though these functions will never be
721     called when UTF-8 support is disabled. Otherwise there are problems with a
722     shared library.
724 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
726     (a) It was defining its arguments as char * instead of void *.
728 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
729     a long time ago when I wrote it, but is no longer the case.
731 ph10 118 The emulated memove() is provided for those environments that have neither
732 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
733 ph10 118 is clearly not the case, as these two bugs were recently reported.
734 ph10 123
735 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
736 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
737     pages, and it removes trailing spaces from listed files. It also creates
738     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
739     case, it wraps all the #defines with #ifndefs. This script should be run
740 ph10 111 before "make dist".
741 ph10 123
742 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
743     with Unicode property support.
744 ph10 123
745     (a) For a maximizing quantifier, if the two different cases of the
746     character were of different lengths in their UTF-8 codings (there are
747     some cases like this - I found 11), and the matching function had to
748 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
749     were both the same length.
750 ph10 123
751     (b) When PCRE was configured to use the heap rather than the stack for
752     recursion during matching, it was not correctly preserving the data for
753     the other case of a UTF-8 character when checking ahead for a match
754     while processing a minimizing repeat. If the check also involved
755 ph10 115 matching a wide character, but failed, corruption could cause an
756     erroneous result when trying to check for a repeat of the original
757     character.
758 ph10 123
759 ph10 116 13. Some tidying changes to the testing mechanism:
760 ph10 98
761 ph10 116 (a) The RunTest script now detects the internal link size and whether there
762     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
763 ph10 123 values substituted by "configure". (The RunGrepTest script already did
764     this for UTF-8.) The configure.ac script no longer substitutes the
765     relevant variables.
767 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
768     with length and offset values. This means that the output is different
769     for different internal link sizes. Test 2 is skipped for link sizes
770     other than 2 because of this, bypassing the problem. Unfortunately,
771     there was also a test in test 3 (the locale tests) that used /B and
772 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
773     I have added a new /Z option to pcretest that replaces the length and
774     offset values with spaces. This is now used to make test 3 independent
775 ph10 122 of link size. (Test 2 will be tidied up later.)
776 ph10 123
777     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
778 ph10 122 segmentation fault instead of returning the appropriate error message.
779 ph10 134
780 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
781 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
782     This doesn't seem right; it now treats the CRLF combination as the line
783     ending, and so does not match in that case. It's only a pattern such as ^$
784     that would hit this one: something like ^ABC$ would have failed after \r
785     and then tried again after \r\n.
787 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
788 ph10 134 in an attempt to make files that differ only in their line terminators
789     compare equal. This works on Linux.
790 ph10 142
791 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
792     as it exited. This is now fixed, thanks to valgrind.
793 ph10 142
794 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
795 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
796     was because its rules for how to advance for /g after matching an empty
797 ph10 143 string at the end of a line did not allow for this case. They now check for
798     it specially.
799 ph10 150
800     20. pcretest is supposed to handle patterns and data of any length, by
801     extending its buffers when necessary. It was getting this wrong when the
802 ph10 147 buffer for a data line had to be extended.
803 ph10 150
804 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
805 ph10 150 CRLF as a newline sequence.
806 ph10 152
807 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
808 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
809     I have nevertheless tidied it up.
810 ph10 111
811 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
812 ph10 123
813 ph10 153 24. Added a man page for pcre-config.
814 ph10 152
815 ph10 153
816 nigel 93 Version 7.0 19-Dec-06
817     ---------------------
819     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
820     moving to gcc 4.1.1.
822     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
823     sys/time.h, which is documented as needed for this function. It doesn't
824     seem to matter on Linux, but it showed up on some releases of OS X.
826     3. It seems that there are systems where bytes whose values are greater than
827     127 match isprint() in the "C" locale. The "C" locale should be the
828     default when a C program starts up. In most systems, only ASCII printing
829     characters match isprint(). This difference caused the output from pcretest
830     to vary, making some of the tests fail. I have changed pcretest so that:
832     (a) When it is outputting text in the compiled version of a pattern, bytes
833     other than 32-126 are always shown as hex escapes.
835     (b) When it is outputting text that is a matched part of a subject string,
836     it does the same, unless a different locale has been set for the match
837     (using the /L modifier). In this case, it uses isprint() to decide.
839     4. Fixed a major bug that caused incorrect computation of the amount of memory
840     required for a compiled pattern when options that changed within the
841     pattern affected the logic of the preliminary scan that determines the
842     length. The relevant options are -x, and -i in UTF-8 mode. The result was
843     that the computed length was too small. The symptoms of this bug were
844     either the PCRE error "internal error: code overflow" from pcre_compile(),
845     or a glibc crash with a message such as "pcretest: free(): invalid next
846     size (fast)". Examples of patterns that provoked this bug (shown in
847     pcretest format) are:
849     /(?-x: )/x
850     /(?x)(?-x: \s*#\s*)/
851     /((?i)[\x{c0}])/8
852     /(?i:[\x{c0}])/8
854     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
855     is now done differently.
857     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
858     wrapper classes; (b) implement a new function in the C++ scanner that is
859     more efficient than the old way of doing things because it avoids levels of
860     recursion in the regex matching; (c) add a paragraph to the documentation
861     for the FullMatch() function.
863     6. The escape sequence \n was being treated as whatever was defined as
864     "newline". Not only was this contrary to the documentation, which states
865     that \n is character 10 (hex 0A), but it also went horribly wrong when
866     "newline" was defined as CRLF. This has been fixed.
868     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
869     was being set to -1 for the "end of line" case (supposedly a value that no
870     character can have). Though this value is never used (the check for end of
871     line is "zero bytes in current character"), it caused compiler complaints.
872     I've changed it to 0xffffffff.
874     8. In pcre_version.c, the version string was being built by a sequence of
875     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
876     string (as it is for production releases) called a macro with an empty
877     argument. The C standard says the result of this is undefined. The gcc
878     compiler treats it as an empty string (which was what was wanted) but it is
879     reported that Visual C gives an error. The source has been hacked around to
880     avoid this problem.
882     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
883     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
884     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
885     of them did).
887     10. Originally, pcretest opened its input and output without "b"; then I was
888     told that "b" was needed in some environments, so it was added for release
889     5.0 to both the input and output. (It makes no difference on Unix-like
890     systems.) Later I was told that it is wrong for the input on Windows. I've
891     now abstracted the modes into two macros, to make it easier to fiddle with
892     them, and removed "b" from the input mode under Windows.
894     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
896     12. Added -help and --help to pcretest as an official way of being reminded
897     of the options.
899     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
900     and pcrecpp.cc because they annoy compilers at high warning levels.
902     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
904     15. Fixed an occurrence of == in configure.ac that should have been = (shell
905     scripts are not C programs :-) and which was not noticed because it works
906     on Linux.
908     16. pcretest is supposed to handle any length of pattern and data line (as one
909     line or as a continued sequence of lines) by extending its input buffer if
910     necessary. This feature was broken for very long pattern lines, leading to
911     a string of junk being passed to pcre_compile() if the pattern was longer
912     than about 50K.
914     17. I have done a major re-factoring of the way pcre_compile() computes the
915     amount of memory needed for a compiled pattern. Previously, there was code
916     that made a preliminary scan of the pattern in order to do this. That was
917     OK when PCRE was new, but as the facilities have expanded, it has become
918     harder and harder to keep it in step with the real compile phase, and there
919     have been a number of bugs (see for example, 4 above). I have now found a
920     cunning way of running the real compile function in a "fake" mode that
921     enables it to compute how much memory it would need, while actually only
922     ever using a few hundred bytes of working memory and without too many
923     tests of the mode. This should make future maintenance and development
924     easier. A side effect of this work is that the limit of 200 on the nesting
925     depth of parentheses has been removed (though this was never a serious
926     limitation, I suspect). However, there is a downside: pcre_compile() now
927     runs more slowly than before (30% or more, depending on the pattern). I
928     hope this isn't a big issue. There is no effect on runtime performance.
930     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
931     newline (only possible for the last line of a file) and it was a
932     pattern that set a locale (followed by /Lsomething), pcretest crashed.
934     19. Added additional timing features to pcretest. (1) The -tm option now times
935     matching only, not compiling. (2) Both -t and -tm can be followed, as a
936     separate command line item, by a number that specifies the number of
937     repeats to use when timing. The default is 50000; this gives better
938     precision, but takes uncomfortably long for very large patterns.
940     20. Extended pcre_study() to be more clever in cases where a branch of a
941     subpattern has no definite first character. For example, (a*|b*)[cd] would
942     previously give no result from pcre_study(). Now it recognizes that the
943     first character must be a, b, c, or d.
945     21. There was an incorrect error "recursive call could loop indefinitely" if
946     a subpattern (or the entire pattern) that was being tested for matching an
947     empty string contained only one non-empty item after a nested subpattern.
948     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
949     incorrectly, because the \d was being skipped in the check.
951     22. The pcretest program now has a new pattern option /B and a command line
952     option -b, which is equivalent to adding /B to every pattern. This causes
953     it to show the compiled bytecode, without the additional information that
954     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
955     is the same as /B/I).
957     23. A new optimization is now able automatically to treat some sequences such
958     as a*b as a*+b. More specifically, if something simple (such as a character
959     or a simple class like \d) has an unlimited quantifier, and is followed by
960     something that cannot possibly match the quantified thing, the quantifier
961     is automatically "possessified".
963     24. A recursive reference to a subpattern whose number was greater than 39
964     went wrong under certain circumstances in UTF-8 mode. This bug could also
965     have affected the operation of pcre_study().
967     25. Realized that a little bit of performance could be had by replacing
968     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
970     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
972     27. Possessive quantifiers such as a++ were previously implemented by turning
973     them into atomic groups such as ($>a+). Now they have their own opcodes,
974     which improves performance. This includes the automatically created ones
975     from 23 above.
977     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
978     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
979     the first matched character to be a colon. This applied both to named and
980     numbered groups.
982     29. The ucpinternal.h header file was missing its idempotency #ifdef.
984     30. I was sent a "project" file called libpcre.a.dev which I understand makes
985     building PCRE on Windows easier, so I have included it in the distribution.
987     31. There is now a check in pcretest against a ridiculously large number being
988     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
989     loop, the loop is abandoned.
991     32. Forward references to subpatterns in conditions such as (?(2)...) where
992     subpattern 2 is defined later cause pcre_compile() to search forwards in
993     the pattern for the relevant set of parentheses. This search went wrong
994     when there were unescaped parentheses in a character class, parentheses
995     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
997     33. "Subroutine" calls and backreferences were previously restricted to
998     referencing subpatterns earlier in the regex. This restriction has now
999     been removed.
1001     34. Added a number of extra features that are going to be in Perl 5.10. On the
1002     whole, these are just syntactic alternatives for features that PCRE had
1003     previously implemented using the Python syntax or my own invention. The
1004     other formats are all retained for compatibility.
1006     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1007     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1008     also .NET compatible.
1010     (b) A recursion or subroutine call to a named group can now be defined as
1011     (?&name) as well as (?P>name).
1013     (c) A backreference to a named group can now be defined as \k<name> or
1014     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1015     5.10, are also .NET compatible.
1017     (d) A conditional reference to a named group can now use the syntax
1018     (?(<name>) or (?('name') as well as (?(name).
1020     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1021     groups (named and numbered) that are never evaluated inline, but can be
1022     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1023     is always false. There may be only one alternative in such a group.
1025     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1026     as the simple (?(R). The condition is true only if the most recent
1027     recursion is that of the given number or name. It does not search out
1028     through the entire recursion stack.
1030     (g) The escape \gN or \g{N} has been added, where N is a positive or
1031     negative number, specifying an absolute or relative reference.
1033     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1034     some "unreachable code" warnings.
1036     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1037     things, this adds five new scripts.
1039     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1040     There were also incompatibilities regarding the handling of \Q..\E inside
1041     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1042     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1044     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1045     matches an empty string, and forcibly breaks the loop. There were bugs in
1046     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1047     against aaaa the result was just "a" rather than "aaaa", for example. Two
1048     separate and independent bugs (that affected different cases) have been
1049     fixed.
1051     39. Refactored the code to abolish the use of different opcodes for small
1052     capturing bracket numbers. This is a tidy that I avoided doing when I
1053     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1054     The new approach is not only tidier, it makes it possible to reduce the
1055     memory needed to fix the previous bug (38).
1057     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1058     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1059     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1060     mode.
1062     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1063     report.
1065     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1066     copy construction and assignment in the C++ wrapper.
1068     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1069     couple of bugs that could have given wrong results in the "--newline=crlf"
1070     case.
1072     44. Added a number of casts and did some reorganization of signed/unsigned int
1073     variables following suggestions from Dair Grant. Also renamed the variable
1074     "this" as "item" because it is a C++ keyword.
1076     45. Arranged for dftables to add
1078     #include "pcre_internal.h"
1080     to pcre_chartables.c because without it, gcc 4.x may remove the array
1081     definition from the final binary if PCRE is built into a static library and
1082     dead code stripping is activated.
1084     46. For an unanchored pattern, if a match attempt fails at the start of a
1085     newline sequence, and the newline setting is CRLF or ANY, and the next two
1086     characters are CRLF, advance by two characters instead of one.
1089 nigel 91 Version 6.7 04-Jul-06
1090     ---------------------
1092     1. In order to handle tests when input lines are enormously long, pcretest has
1093     been re-factored so that it automatically extends its buffers when
1094     necessary. The code is crude, but this _is_ just a test program. The
1095     default size has been increased from 32K to 50K.
1097     2. The code in pcre_study() was using the value of the re argument before
1098     testing it for NULL. (Of course, in any sensible call of the function, it
1099     won't be NULL.)
1101     3. The memmove() emulation function in pcre_internal.h, which is used on
1102     systems that lack both memmove() and bcopy() - that is, hardly ever -
1103     was missing a "static" storage class specifier.
1105     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1106     containing an extended class (one that cannot be represented by a bitmap
1107     because it contains high-valued characters or Unicode property items, e.g.
1108     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1109     pattern, but PCRE should not loop if you do not (it no longer does).
1110     [Detail: two cases were found: (a) a repeated subpattern containing an
1111     extended class; (b) a recursive reference to a subpattern that followed a
1112     previous extended class. It wasn't skipping over the extended class
1113     correctly when UTF-8 mode was not set.]
1115     5. A negated single-character class was not being recognized as fixed-length
1116     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1117     compile error "lookbehind assertion is not fixed length".
1119     6. The RunPerlTest auxiliary script was showing an unexpected difference
1120     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1121     write a Perl script that can interpret lines of an input file either as
1122     byte characters or as UTF-8, which is what "perltest" was being required to
1123     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1124     can't do is switch easily at run time between having the "use utf8;" pragma
1125     or not. In the end, I fudged it by using the RunPerlTest script to insert
1126     "use utf8;" explicitly for the UTF-8 tests.
1128     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1129     the end of the subject string, contrary to the documentation and to what
1130     Perl does. This was true of both matching functions. Now it matches only at
1131     the start of the subject and immediately after *internal* newlines.
1133     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1134     a pointer to an int instead of a pointer to an unsigned long int. This
1135     caused problems on 64-bit systems.
1137     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1138     instance of the 'standard' template library not being so standard".
1140     10. There was no check on the number of named subpatterns nor the maximum
1141     length of a subpattern name. The product of these values is used to compute
1142     the size of the memory block for a compiled pattern. By supplying a very
1143     long subpattern name and a large number of named subpatterns, the size
1144     computation could be caused to overflow. This is now prevented by limiting
1145     the length of names to 32 characters, and the number of named subpatterns
1146     to 10,000.
1148     11. Subpatterns that are repeated with specific counts have to be replicated in
1149     the compiled pattern. The size of memory for this was computed from the
1150     length of the subpattern and the repeat count. The latter is limited to
1151     65535, but there was no limit on the former, meaning that integer overflow
1152     could in principle occur. The compiled length of a repeated subpattern is
1153     now limited to 30,000 bytes in order to prevent this.
1155     12. Added the optional facility to have named substrings with the same name.
1157     13. Added the ability to use a named substring as a condition, using the
1158     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1159     are numbers (not recommended). Forward references are permitted.
1161     14. Added forward references in named backreferences (if you see what I mean).
1163     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1164     pattern could run off the end of the subject. For example, the pattern
1165     "(?s)(.{1,5})"8 did this with the subject "ab".
1167     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1168     PCRE_CASELESS was set when matching characters that were quantified with ?
1169     or *.
1171     17. A character class other than a single negated character that had a minimum
1172     but no maximum quantifier - for example [ab]{6,} - was not handled
1173     correctly by pce_dfa_exec(). It would match only one character.
1175     18. A valid (though odd) pattern that looked like a POSIX character
1176     class but used an invalid character after [ (for example [[,abc,]]) caused
1177     pcre_compile() to give the error "Failed: internal error: code overflow" or
1178     in some cases to crash with a glibc free() error. This could even happen if
1179     the pattern terminated after [[ but there just happened to be a sequence of
1180     letters, a binary zero, and a closing ] in the memory that followed.
1182     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1183     over the years. Originally (before any Unicode support), just the bottom 8
1184     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1185     output from "man perlunicode" includes this:
1187     The regular expression compiler produces polymorphic opcodes. That
1188     is, the pattern adapts to the data and automatically switches to
1189     the Unicode character scheme when presented with Unicode data--or
1190     instead uses a traditional byte scheme when presented with byte
1191     data.
1193     Sadly, a wide octal escape does not cause a switch, and in a string with
1194     no other multibyte characters, these octal escapes are treated as before.
1195     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1196     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1197     Unicode string.
1199     I have not perpetrated such confusion in PCRE. Up till now, it took just
1200     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1201     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1202     translate to the appropriate multibyte character.
1204     29. Applied some refactoring to reduce the number of warnings from Microsoft
1205     and Borland compilers. This has included removing the fudge introduced
1206     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1207     a warning about an unused variable.
1209     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1210     characters since release 4.0, because Perl (from release 5.004) does not.
1211     [Or at least, is documented not to: some releases seem to be in conflict
1212     with the documentation.] However, when a pattern was studied with
1213     pcre_study() and all its branches started with \s, PCRE still included VT
1214     as a possible starting character. Of course, this did no harm; it just
1215     caused an unnecessary match attempt.
1217     22. Removed a now-redundant internal flag bit that recorded the fact that case
1218     dependency changed within the pattern. This was once needed for "required
1219     byte" processing, but is no longer used. This recovers a now-scarce options
1220     bit. Also moved the least significant internal flag bit to the most-
1221     significant bit of the word, which was not previously used (hangover from
1222     the days when it was an int rather than a uint) to free up another bit for
1223     the future.
1225     23. Added support for CRLF line endings as well as CR and LF. As well as the
1226     default being selectable at build time, it can now be changed at runtime
1227     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1228     specify that it is scanning data with non-default line endings.
1230     24. Changed the definition of CXXLINK to make it agree with the definition of
1231     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1233     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1234     recursions. This makes a big different to stack usage for some patterns.
1236     26. If a subpattern containing a named recursion or subroutine reference such
1237     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1238     the space required for the compiled pattern went wrong and gave too small a
1239     value. Depending on the environment, this could lead to "Failed: internal
1240     error: code overflow at offset 49" or "glibc detected double free or
1241     corruption" errors.
1243     27. Applied patches from Google (a) to support the new newline modes and (b) to
1244     advance over multibyte UTF-8 characters in GlobalReplace.
1246     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1247     difference for some implementation of PCRE in some Windows version.
1249     29. Added some extra testing facilities to pcretest:
1251     \q<number> in a data line sets the "match limit" value
1252     \Q<number> in a data line sets the "match recursion limt" value
1253     -S <number> sets the stack size, where <number> is in megabytes
1255     The -S option isn't available for Windows.
1258 nigel 89 Version 6.6 06-Feb-06
1259     ---------------------
1261     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1262     in pcreposix.h. I have copied the definition from pcre.h.
1264     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1265     because pcre.h is no longer a built file.
1267     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1268     not normally included in the compiled code.
1271 nigel 87 Version 6.5 01-Feb-06
1272     ---------------------
1274     1. When using the partial match feature with pcre_dfa_exec(), it was not
1275     anchoring the second and subsequent partial matches at the new starting
1276     point. This could lead to incorrect results. For example, with the pattern
1277     /1234/, partially matching against "123" and then "a4" gave a match.
1279     2. Changes to pcregrep:
1281     (a) All non-match returns from pcre_exec() were being treated as failures
1282     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1283     error message is output. Some extra information is given for the
1285     probably the only errors that are likely to be caused by users (by
1286     specifying a regex that has nested indefinite repeats, for instance).
1287     If there are more than 20 of these errors, pcregrep is abandoned.
1289     (b) A binary zero was treated as data while matching, but terminated the
1290     output line if it was written out. This has been fixed: binary zeroes
1291     are now no different to any other data bytes.
1293     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1294     used to set a locale for matching. The --locale=xxxx long option has
1295     been added (no short equivalent) to specify a locale explicitly on the
1296     pcregrep command, overriding the environment variables.
1298     (d) When -B was used with -n, some line numbers in the output were one less
1299     than they should have been.
1301     (e) Added the -o (--only-matching) option.
1303     (f) If -A or -C was used with -c (count only), some lines of context were
1304     accidentally printed for the final match.
1306     (g) Added the -H (--with-filename) option.
1308     (h) The combination of options -rh failed to suppress file names for files
1309     that were found from directory arguments.
1311     (i) Added the -D (--devices) and -d (--directories) options.
1313     (j) Added the -F (--fixed-strings) option.
1315     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1317     (l) Added the --colo(u)r option.
1319     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1320     is not present by default.
1322     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1323     items such as (?R) or (?1), when the recursion could match a number of
1324     alternatives. If it matched one of the alternatives, but subsequently,
1325     outside the recursion, there was a failure, the code tried to back up into
1326     the recursion. However, because of the way PCRE is implemented, this is not
1327     possible, and the result was an incorrect result from the match.
1329     In order to prevent this happening, the specification of recursion has
1330     been changed so that all such subpatterns are automatically treated as
1331     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1333     4. I had overlooked the fact that, in some locales, there are characters for
1334     which isalpha() is true but neither isupper() nor islower() are true. In
1335     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1336     and ordfeminine) are like this. This affected the treatment of \w and \W
1337     when they appeared in character classes, but not when they appeared outside
1338     a character class. The bit map for "word" characters is now created
1339     separately from the results of isalnum() instead of just taking it from the
1340     upper, lower, and digit maps. (Plus the underscore character, of course.)
1342     5. The above bug also affected the handling of POSIX character classes such as
1343     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1344     permanent tables. Instead, the bit maps for such a class were previously
1345     created as the appropriate unions of the upper, lower, and digit bitmaps.
1346     Now they are created by subtraction from the [[:word:]] class, which has
1347     its own bitmap.
1349     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1350     It is created by subtracting the vertical space characters (\x09, \x0a,
1351     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1352     subtraction was done in the overall bitmap for a character class, meaning
1353     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1354     be recognized. This bug has been fixed.
1356     7. Patches from the folks at Google:
1358     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1359     real life, but is still worth protecting against".
1361     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1362     regular expressions".
1364     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1365     have it.
1367     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1368     "configure" and the latter not, in order to fix a problem somebody had
1369     with compiling the Arg class on HP-UX.
1371     (e) Improve the error-handling of the C++ wrapper a little bit.
1373     (f) New tests for checking recursion limiting.
1375     8. The pcre_memmove() function, which is used only if the environment does not
1376     have a standard memmove() function (and is therefore rarely compiled),
1377     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1378     returning a result (though PCRE never actually uses the result).
1380     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1381     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1382     returned instead of calling malloc() with an overflowing number that would
1383     most likely cause subsequent chaos.
1385     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1387     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1388     with this option is matched, the nmatch and pmatch options of regexec() are
1389     ignored.
1391     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1392     provided in case anyone wants to the the POSIX interface with UTF-8
1393     strings.
1395     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1396     C++ linking (needed for some HP-UX environments).
1398     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1399     (unused parameter) and in the pcre_printint() function (omitted "default"
1400     switch label when the default is to do nothing).
1402     15. Added some code to make it possible, when PCRE is compiled as a C++
1403     library, to replace subject pointers for pcre_exec() with a smart pointer
1404     class, thus making it possible to process discontinuous strings.
1406     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1407     much the same function. They were added by different people who were trying
1408     to make PCRE easy to compile on non-Unix systems. It has been suggested
1409     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1410     for compiling on Windows systems. I have therefore replaced it with
1411     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1412     defaults to "extern" for C or "extern C" for C++, which works fine on
1413     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1414     SCOPE with something explicit in config.h. In addition:
1416     (a) pcreposix.h still had just "extern" instead of either of these macros;
1417     I have replaced it with PCRE_DATA_SCOPE.
1419     (b) Functions such as _pcre_xclass(), which are internal to the library,
1420     but external in the C sense, all had PCRE_EXPORT in their definitions.
1421     This is apparently wrong for the Windows case, so I have removed it.
1422     (It makes no difference on Unix-like systems.)
1424     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1425     of recursive calls to match(). This is different to MATCH_LIMIT because
1426     that limits the total number of calls to match(), not all of which increase
1427     the depth of recursion. Limiting the recursion depth limits the amount of
1428     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1429     when PCRE is compiled, and changed at run time. A patch from Google adds
1430     this functionality to the C++ interface.
1432     18. Changes to the handling of Unicode character properties:
1434     (a) Updated the table to Unicode 4.1.0.
1436     (b) Recognize characters that are not in the table as "Cn" (undefined).
1438     (c) I revised the way the table is implemented to a much improved format
1439     which includes recognition of ranges. It now supports the ranges that
1440     are defined in UnicodeData.txt, and it also amalgamates other
1441     characters into ranges. This has reduced the number of entries in the
1442     table from around 16,000 to around 3,000, thus reducing its size
1443     considerably. I realized I did not need to use a tree structure after
1444     all - a binary chop search is just as efficient. Having reduced the
1445     number of entries, I extended their size from 6 bytes to 8 bytes to
1446     allow for more data.
1448     (d) Added support for Unicode script names via properties such as \p{Han}.
1450     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1451     matching that character.
1453     20. When matching a repeated Unicode property with a minimum greater than zero,
1454     (for example \pL{2,}), PCRE could look past the end of the subject if it
1455     reached it while seeking the minimum number of characters. This could
1456     happen only if some of the characters were more than one byte long, because
1457     there is a check for at least the minimum number of bytes.
1459     21. Refactored the implementation of \p and \P so as to be more general, to
1460     allow for more different types of property in future. This has changed the
1461     compiled form incompatibly. Anybody with saved compiled patterns that use
1462     \p or \P will have to recompile them.
1464     22. Added "Any" and "L&" to the supported property types.
1466     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1467     but give a compile time error if the value is greater than 0xff.
1469     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1470     accidentally not being installed or uninstalled.
1472     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1473     made were to insert the current release number. This seemed silly, because
1474     it made things harder for people building PCRE on systems that don't run
1475     "configure". I have turned pcre.h into a distributed file, no longer built
1476     by "configure", with the version identification directly included. There is
1477     no longer a pcre.h.in file.
1479     However, this change necessitated a change to the pcre-config script as
1480     well. It is built from pcre-config.in, and one of the substitutions was the
1481     release number. I have updated configure.ac so that ./configure now finds
1482     the release number by grepping pcre.h.
1484     26. Added the ability to run the tests under valgrind.
1487 nigel 85 Version 6.4 05-Sep-05
1488     ---------------------
1490     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1491     "--" to be printed when multiple files were scanned, even when none of the
1492     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1493     consider it to be a bug, and have restored the previous behaviour.
1495     2. A couple of code tidies to get rid of compiler warnings.
1497     3. The pcretest program used to cheat by referring to symbols in the library
1498     whose names begin with _pcre_. These are internal symbols that are not
1499     really supposed to be visible externally, and in some environments it is
1500     possible to suppress them. The cheating is now confined to including
1501     certain files from the library's source, which is a bit cleaner.
1503     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1504     file's purpose clearer.
1506     5. Reorganized pcre_ucp_findchar().
1509 nigel 83 Version 6.3 15-Aug-05
1510     ---------------------
1512     1. The file libpcre.pc.in did not have general read permission in the tarball.
1514     2. There were some problems when building without C++ support:
1516     (a) If C++ support was not built, "make install" and "make test" still
1517     tried to test it.
1519     (b) There were problems when the value of CXX was explicitly set. Some
1520     changes have been made to try to fix these, and ...
1522     (c) --disable-cpp can now be used to explicitly disable C++ support.
1524     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1525     backslash in a target when C++ was disabled. This confuses some
1526     versions of "make", apparently. Using an intermediate variable solves
1527     this. (Same for CPP_LOBJ.)
1529     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1530     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1531     necessary on certain architectures.
1533     4. Added a setting of -export-symbols-regex to the link command to remove
1534     those symbols that are exported in the C sense, but actually are local
1535     within the library, and not documented. Their names all begin with
1536     "_pcre_". This is not a perfect job, because (a) we have to except some
1537     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1538     available (and never for static libraries). I have made a note to try to
1539     find a way round (a) in the future.
1542 nigel 81 Version 6.2 01-Aug-05
1543     ---------------------
1545     1. There was no test for integer overflow of quantifier values. A construction
1546     such as {1111111111111111} would give undefined results. What is worse, if
1547     a minimum quantifier for a parenthesized subpattern overflowed and became
1548     negative, the calculation of the memory size went wrong. This could have
1549     led to memory overwriting.
1551     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1553     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1554     operating environments where this matters.
1556     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1557     PCRE options from within the C++ wrapper.
1559     5. Named capturing subpatterns were not being correctly counted when a pattern
1560     was compiled. This caused two problems: (a) If there were more than 100
1561     such subpatterns, the calculation of the memory needed for the whole
1562     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1563     back references of the form \12, where the number was greater than 9, were
1564     not recognized as back references, even though there were sufficient
1565     previous subpatterns.
1567     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1568     versions of gcc, e.g. 2.95.4.
1571 nigel 79 Version 6.1 21-Jun-05
1572     ---------------------
1574     1. There was one reference to the variable "posix" in pcretest.c that was not
1575     surrounded by "#if !defined NOPOSIX".
1577     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1578     the cross-check on the old pcre_info() function, for the benefit of the
1579     cut-down version of PCRE that is currently imported into Exim.
1581     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1582     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1583     patterns that start (?i) but I don't think that matters. The use of (?i) is
1584     just an example; this all applies to the other options as well.
1586     4. Since libtool seems to echo the compile commands it is issuing, the output
1587     from "make" can be reduced a bit by putting "@" in front of each libtool
1588     compile command.
1590     5. Patch from the folks at Google for configure.in to be a bit more thorough
1591     in checking for a suitable C++ installation before trying to compile the
1592     C++ stuff. This should fix a reported problem when a compiler was present,
1593     but no suitable headers.
1595     6. The man pages all had just "PCRE" as their title. I have changed them to
1596     be the relevant file name. I have also arranged that these names are
1597     retained in the file doc/pcre.txt, which is a concatenation in text format
1598     of all the man pages except the little individual ones for each function.
1600     7. The NON-UNIX-USE file had not been updated for the different set of source
1601     files that come with release 6. I also added a few comments about the C++
1602     wrapper.
1605 nigel 77 Version 6.0 07-Jun-05
1606     ---------------------
1608     1. Some minor internal re-organization to help with my DFA experiments.
1610     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1611     didn't matter for the library itself when fully configured, but did matter
1612     when compiling without UCP support, or within Exim, where the ucp files are
1613     not imported.
1615     3. Refactoring of the library code to split up the various functions into
1616     different source modules. The addition of the new DFA matching code (see
1617     below) to a single monolithic source would have made it really too
1618     unwieldy, quite apart from causing all the code to be include in a
1619     statically linked application, when only some functions are used. This is
1620     relevant even without the DFA addition now that patterns can be compiled in
1621     one application and matched in another.
1623     The downside of splitting up is that there have to be some external
1624     functions and data tables that are used internally in different modules of
1625     the library but which are not part of the API. These have all had their
1626     names changed to start with "_pcre_" so that they are unlikely to clash
1627     with other external names.
1629     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1630     a different (DFA) algorithm. Although it is slower than the original
1631     function, it does have some advantages for certain types of matching
1632     problem.
1634     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1635     including restarting after a partial match.
1637     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1638     defined when compiling for Windows was sent to me. I have put it into the
1639     code, though I have no means of testing or verifying it.
1641     7. Added the pcre_refcount() auxiliary function.
1643     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1644     match before or at the first newline in the subject string. In pcretest,
1645     the /f option on a pattern can be used to set this.
1647     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1648     would behave wrongly. This has been present in PCRE since release 4.0.
1650     10. A number of changes to the pcregrep command:
1652     (a) Refactored how -x works; insert ^(...)$ instead of setting
1653     PCRE_ANCHORED and checking the length, in preparation for adding
1654     something similar for -w.
1656     (b) Added the -w (match as a word) option.
1658     (c) Refactored the way lines are read and buffered so as to have more
1659     than one at a time available.
1661     (d) Implemented a pcregrep test script.
1663     (e) Added the -M (multiline match) option. This allows patterns to match
1664     over several lines of the subject. The buffering ensures that at least
1665     8K, or the rest of the document (whichever is the shorter) is available
1666     for matching (and similarly the previous 8K for lookbehind assertions).
1668     (f) Changed the --help output so that it now says
1670     -w, --word-regex(p)
1672     instead of two lines, one with "regex" and the other with "regexp"
1673     because that confused at least one person since the short forms are the
1674     same. (This required a bit of code, as the output is generated
1675     automatically from a table. It wasn't just a text change.)
1677     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1678     option but starts with a hyphen. Could be a pattern or a path name
1679     starting with a hyphen, for instance.
1681     (h) "-" can be given as a file name to represent stdin.
1683     (i) When file names are being printed, "(standard input)" is used for
1684     the standard input, for compatibility with GNU grep. Previously
1685     "<stdin>" was used.
1687     (j) The option --label=xxx can be used to supply a name to be used for
1688     stdin when file names are being printed. There is no short form.
1690     (k) Re-factored the options decoding logic because we are going to add
1691     two more options that take data. Such options can now be given in four
1692     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1694     (l) Added the -A, -B, and -C options for requesting that lines of context
1695     around matches be printed.
1697     (m) Added the -L option to print the names of files that do not contain
1698     any matching lines, that is, the complement of -l.
1700     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1701     continue to scan other files.
1703     (o) The -s option was incorrectly implemented. For compatibility with other
1704     greps, it now suppresses the error message for a non-existent or non-
1705     accessible file (but not the return code). There is a new option called
1706     -q that suppresses the output of matching lines, which was what -s was
1707     previously doing.
1709     (p) Added --include and --exclude options to specify files for inclusion
1710     and exclusion when recursing.
1712     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1713     Hopefully, it now does.
1715     12. Missing cast in pcre_study().
1717     13. Added an "uninstall" target to the makefile.
1719     14. Replaced "extern" in the function prototypes in Makefile.in with
1720     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1721     world, but is set differently for Windows.
1723     15. Added a second compiling function called pcre_compile2(). The only
1724     difference is that it has an extra argument, which is a pointer to an
1725     integer error code. When there is a compile-time failure, this is set
1726     non-zero, in addition to the error test pointer being set to point to an
1727     error message. The new argument may be NULL if no error number is required
1728     (but then you may as well call pcre_compile(), which is now just a
1729     wrapper). This facility is provided because some applications need a
1730     numeric error indication, but it has also enabled me to tidy up the way
1731     compile-time errors are handled in the POSIX wrapper.
1733     16. Added VPATH=.libs to the makefile; this should help when building with one
1734     prefix path and installing with another. (Or so I'm told by someone who
1735     knows more about this stuff than I do.)
1737     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1738     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1739     match everything, including newlines. This is not POSIX-compatible, but
1740     somebody wanted the feature. From pcretest it can be activated by using
1741     both the P and the s flags.
1743     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1745     19. libpcre.pc was being incorrectly installed as executable.
1747     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1748     it now also looks for '\r' so that it will work unmodified on Windows.
1750     21. Added Google's contributed C++ wrapper to the distribution.
1752     22. Added some untidy missing memory free() calls in pcretest, to keep
1753     Electric Fence happy when testing.
1757 nigel 75 Version 5.0 13-Sep-04
1758     ---------------------
1760     1. Internal change: literal characters are no longer packed up into items
1761     containing multiple characters in a single byte-string. Each character
1762     is now matched using a separate opcode. However, there may be more than one
1763     byte in the character in UTF-8 mode.
1765     2. The pcre_callout_block structure has two new fields: pattern_position and
1766     next_item_length. These contain the offset in the pattern to the next match
1767     item, and its length, respectively.
1769     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1770     insertion of callouts before each pattern item. Added the /C option to
1771     pcretest to make use of this.
1773     4. On the advice of a Windows user, the lines
1775     #if defined(_WIN32) || defined(WIN32)
1776     _setmode( _fileno( stdout ), 0x8000 );
1777     #endif /* defined(_WIN32) || defined(WIN32) */
1779     have been added to the source of pcretest. This apparently does useful
1780     magic in relation to line terminators.
1782     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1783     for the benefit of those environments where the "b" makes a difference.
1785     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1786     to know about it. I have put a hack into configure.in that adds in code
1787     to set GCC=yes if CC=icc. This seems to end up at a point in the
1788     generated configure script that is early enough to affect the setting of
1789     compiler options, which is what is needed, but I have no means of testing
1790     whether it really works. (The user who reported this had patched the
1791     generated configure script, which of course I cannot do.)
1793     LATER: After change 22 below (new libtool files), the configure script
1794     seems to know about icc (and also ecc). Therefore, I have commented out
1795     this hack in configure.in.
1797     7. Added support for pkg-config (2 patches were sent in).
1799     8. Negated POSIX character classes that used a combination of internal tables
1800     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1801     [[:^ascii]]. Typically, they would match almost any characters. The other
1802     POSIX classes were not broken in this way.
1804     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1805     to find the match, as PCRE was deluded into thinking that the match had to
1806     start at the start point or following a newline. The same bug applied to
1807     patterns with negative forward assertions or any backward assertions
1808     preceding ".*" at the start, unless the pattern required a fixed first
1809     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1811     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1812     starting at the last subject character, bytes beyond the end of the subject
1813     string were read.
1815     11. Renamed the variable "class" as "classbits" to make life easier for C++
1816     users. (Previously there was a macro definition, but it apparently wasn't
1817     enough.)
1819     12. Added the new field "tables" to the extra data so that tables can be passed
1820     in at exec time, or the internal tables can be re-selected. This allows
1821     a compiled regex to be saved and re-used at a later time by a different
1822     program that might have everything at different addresses.
1824     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1825     -R library as well as a -L library.
1827     14. The debugging options of pcretest (-d on the command line or D on a
1828     pattern) showed incorrect output for anything following an extended class
1829     that contained multibyte characters and which was followed by a quantifier.
1831     15. Added optional support for general category Unicode character properties
1832     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1833     support. It adds about 90K to the size of the library. The meanings of the
1834     inbuilt class escapes such as \d and \s have NOT been changed.
1836     16. Updated pcredemo.c to include calls to free() to release the memory for the
1837     compiled pattern.
1839     17. The generated file chartables.c was being created in the source directory
1840     instead of in the building directory. This caused the build to fail if the
1841     source directory was different from the building directory, and was
1842     read-only.
1844     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1845     file. No doubt somebody will tell me if they don't make sense... Also added
1846     Dan Mooney's comments about building on OpenVMS.
1848     19. Added support for partial matching via the PCRE_PARTIAL option for
1849     pcre_exec() and the \P data escape in pcretest.
1851     20. Extended pcretest with 3 new pattern features:
1853     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1854     write the compiled pattern to the file whose name is "rest-of-line".
1855     This is a straight binary dump of the data, with the saved pointer to
1856     the character tables forced to be NULL. The study data, if any, is
1857     written too. After writing, pcretest reads a new pattern.
1859     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1860     compiled pattern from the given file. There must not be any
1861     occurrences of "<" in the file name (pretty unlikely); if there are,
1862     pcretest will instead treat the initial "<" as a pattern delimiter.
1863     After reading in the pattern, pcretest goes on to read data lines as
1864     usual.
1866     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1867     and 16-bit fields in a compiled pattern, to simulate a pattern that
1868     was compiled on a host of opposite endianness.
1870     21. The pcre-exec() function can now cope with patterns that were compiled on
1871     hosts of opposite endianness, with this restriction:
1873     As for any compiled expression that is saved and used later, the tables
1874     pointer field cannot be preserved; the extra_data field in the arguments
1875     to pcre_exec() should be used to pass in a tables address if a value
1876     other than the default internal tables were used at compile time.
1878     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1879     now diagnosed as an error. Previously, most of the time, a negative number
1880     would have been treated as zero, but if in addition "ovector" was passed as
1881     NULL, a crash could occur.
1883     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1884     new versions from the libtool 1.5 distribution (the last one is a copy of
1885     a file called libtool.m4). This seems to have fixed the need to patch
1886     "configure" to support Darwin 1.3 (which I used to do). However, I still
1887     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1888     workstation).
1890     24. Changed the PCRE licence to be the more standard "BSD" licence.
1893 nigel 73 Version 4.5 01-Dec-03
1894     ---------------------
1896     1. There has been some re-arrangement of the code for the match() function so
1897     that it can be compiled in a version that does not call itself recursively.
1898     Instead, it keeps those local variables that need separate instances for
1899     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1900     needs to "recurse". Keeping track of where control must go is done by means
1901     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1902     hide most of the details from the main code, and operates only if
1903     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1904     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1905     operating.
1907     To make it easier for callers to provide specially tailored get/free
1908     functions for this usage, two new functions, pcre_stack_malloc, and
1909     pcre_stack_free, are used. They are always called in strict stacking order,
1910     and the size of block requested is always the same.
1912     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1913     PCRE has been compiled to use the stack or the heap for recursion. The
1914     -C option of pcretest uses this to show which version is compiled.
1916     A new data escape \S, is added to pcretest; it causes the amounts of store
1917     obtained and freed by both kinds of malloc/free at match time to be added
1918     to the output.
1920     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1921     what's available on my current Linux desktop machine.
1923     3. When matching a UTF-8 string, the test for a valid string at the start has
1924     been extended. If start_offset is not zero, PCRE now checks that it points
1925     to a byte that is the start of a UTF-8 character. If not, it returns
1926     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1927     this is necessary because there may be backward assertions in the pattern.
1928     When matching the same subject several times, it may save resources to use
1929     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1931     4. The code for checking the validity of UTF-8 strings has been tightened so
1932     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1933     containing "overlong sequences".
1935     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1936     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1937     should have been "&", but it just so happened that all the cases this let
1938     through by mistake were picked up later in the function.
1940     6. I had used a variable called "isblank" - this is a C99 function, causing
1941     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1943     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1944     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1945     so the version is shown; (c) stop "make test" echoing "./RunTest".
1947     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1949     9. The prototype for memmove() for systems that don't have it was using
1950     size_t, but the inclusion of the header that defines size_t was later. I've
1951     moved the #includes for the C headers earlier to avoid this.
1953     10. Added some adjustments to the code to make it easier to compiler on certain
1954     special systems:
1956     (a) Some "const" qualifiers were missing.
1957     (b) Added the macro EXPORT before all exported functions; by default this
1958     is defined to be empty.
1959     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1960     that it reads its output file name as an argument instead of writing
1961     to the standard output and assuming this can be redirected.
1963     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1964     class containing characters with values greater than 255, PCRE compilation
1965     went into a loop.
1967     12. A recursive reference to a subpattern that was within another subpattern
1968     that had a minimum quantifier of zero caused PCRE to crash. For example,
1969     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1970     recursion. If the recursively-called subpattern itself had a zero repeat,
1971     that was OK.
1973     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1974     buffer into which it was copied (for escape processing) was still set at
1975     1024, so long lines caused crashes.
1977     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1978     "internal error: code overflow...". This applied to any character class
1979     that was followed by a possessive quantifier.
1981     15. Modified the Makefile to add libpcre.la as a prerequisite for
1982     libpcreposix.la because I was told this is needed for a parallel build to
1983     work.
1985     16. If a pattern that contained .* following optional items at the start was
1986     studied, the wrong optimizing data was generated, leading to matching
1987     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1988     matching string must start with a or b or c. The correct conclusion for
1989     this pattern is that a match can start with any character.
1992 nigel 71 Version 4.4 13-Aug-03
1993     ---------------------
1995     1. In UTF-8 mode, a character class containing characters with values between
1996     127 and 255 was not handled correctly if the compiled pattern was studied.
1997     In fixing this, I have also improved the studying algorithm for such
1998     classes (slightly).
2000     2. Three internal functions had redundant arguments passed to them. Removal
2001     might give a very teeny performance improvement.
2003     3. Documentation bug: the value of the capture_top field in a callout is *one
2004     more than* the number of the hightest numbered captured substring.
2006     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2007     in incorrectly linking with a previously installed version. They now link
2008     explicitly with libpcre.la.
2010     5. configure.in no longer needs to recognize Cygwin specially.
2012     6. A problem in pcre.in for Windows platforms is fixed.
2014     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2015     pcretest, it used to include the size of the study block as part of its
2016     output. Unfortunately, the structure contains a field that has a different
2017     size on different hardware architectures. This meant that the tests that
2018     showed this size failed. As the block is currently always of a fixed size,
2019     this information isn't actually particularly useful in pcretest output, so
2020     I have just removed it.
2022     8. Three pre-processor statements accidentally did not start in column 1.
2023     Sadly, there are *still* compilers around that complain, even though
2024     standard C has not required this for well over a decade. Sigh.
2026     9. In pcretest, the code for checking callouts passed small integers in the
2027     callout_data field, which is a void * field. However, some picky compilers
2028     complained about the casts involved for this on 64-bit systems. Now
2029     pcretest passes the address of the small integer instead, which should get
2030     rid of the warnings.
2032     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2033     both compile and run time, and gives an error if an invalid UTF-8 sequence
2034     is found. There is a option for disabling this check in cases where the
2035     string is known to be correct and/or the maximum performance is wanted.
2037     11. In response to a bug report, I changed one line in Makefile.in from
2039     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2040     to
2041     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2043     to look similar to other lines, but I have no way of telling whether this
2044     is the right thing to do, as I do not use Windows. No doubt I'll get told
2045     if it's wrong...
2048 nigel 69 Version 4.3 21-May-03
2049     ---------------------
2051     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2052     Makefile.
2054     2. Some refactoring to improve the quality of the code:
2056     (i) The utf8_table... variables are now declared "const".
2058     (ii) The code for \cx, which used the "case flipping" table to upper case
2059     lower case letters, now just substracts 32. This is ASCII-specific,
2060     but the whole concept of \cx is ASCII-specific, so it seems
2061     reasonable.
2063     (iii) PCRE was using its character types table to recognize decimal and
2064     hexadecimal digits in the pattern. This is silly, because it handles
2065     only 0-9, a-f, and A-F, but the character types table is locale-
2066     specific, which means strange things might happen. A private
2067     table is now used for this - though it costs 256 bytes, a table is
2068     much faster than multiple explicit tests. Of course, the standard
2069     character types table is still used for matching digits in subject
2070     strings against \d.
2072     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2073     ending in _t are). So I've renamed it as ESC_tee.
2075     3. The first argument for regexec() in the POSIX wrapper should have been
2076     defined as "const".
2078     4. Changed pcretest to use malloc() for its buffers so that they can be
2079     Electric Fenced for debugging.
2081     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2082     to read one or more bytes before the start of the subject string. Often this
2083     had no effect on PCRE's behaviour, but in some circumstances it could
2084     provoke a segmentation fault.
2086     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2087     to try to read one or more bytes before the start of the subject string.
2089     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2090     UTF-8 support could misbehave in various ways if the subject string
2091     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2092     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2093     back over UTF-8 characters.)
2096 nigel 67 Version 4.2 14-Apr-03
2097     ---------------------
2099     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2101     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2102     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2103     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2104     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2105     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2106     and BUILD_EXEEXT
2107     Note: automatic setting of the BUILD variables is not yet working
2108     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2109     compile-time but not at link-time
2110     [LINK]: use for linking executables only
2111     make different versions for Windows and non-Windows
2112     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2113     libraries
2114     [LINK_FOR_BUILD]: new variable
2115     [OBJEXT]: use throughout
2116     [EXEEXT]: use throughout
2117     <winshared>: new target
2118     <wininstall>: new target
2119     <dftables.o>: use native compiler
2120     <dftables>: use native linker
2121     <install>: handle Windows platform correctly
2122     <clean>: ditto
2123     <check>: ditto
2124     copy DLL to top builddir before testing
2126     As part of these changes, -no-undefined was removed again. This was reported
2127     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2128     in any case.
2130     3. Some tidies to get rid of compiler warnings:
2132     . In the match_data structure, match_limit was an unsigned long int, whereas
2133     match_call_count was an int. I've made them both unsigned long ints.
2135     . In pcretest the fact that a const uschar * doesn't automatically cast to
2136     a void * provoked a warning.
2138     . Turning on some more compiler warnings threw up some "shadow" variables
2139     and a few more missing casts.
2141     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2142     option, a class that contained a single character with a value between 128
2143     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2145     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2146     option, a class that contained several characters, but with at least one
2147     whose value was between 128 and 255 caused PCRE to crash.
2150 nigel 65 Version 4.1 12-Mar-03
2151     ---------------------
2152 nigel 63
2153 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2154     needed, and a string in dftables.c that was longer than standard compilers are
2155     required to support.
2157     2. Compiling with Sun's compiler found a few more places where the code could
2158     be tidied up in order to avoid warnings.
2160     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2161     first of these names is deprecated in the latest Autoconf in favour of the name
2162     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2163     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2164     analogy I have changed it to CFLAGS_FOR_BUILD.
2166     4. Added -no-undefined to the linking command in the Makefile, because this is
2167     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2168     linking step for the pcreposix library.
2170     5. PCRE was failing to diagnose the case of two named groups with the same
2171     name.
2173     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2174     literal character that is needed in the subject for a match, and scans along to
2175     ensure that it is present before embarking on the full matching process. This
2176     saves time in cases of nested unlimited repeats that are never going to match.
2177     Problem: the scan can take a lot of time if the subject is very long (e.g.
2178     megabytes), thus penalizing straightforward matches. It is now done only if the
2179     amount of subject to be scanned is less than 1000 bytes.
2181     7. A lesser problem with the same optimization is that it was recording the
2182     first character of an anchored pattern as "needed", thus provoking a search
2183     right along the subject, even when the first match of the pattern was going to
2184     fail. The "needed" character is now not set for anchored patterns, unless it
2185     follows something in the pattern that is of non-fixed length. Thus, it still
2186     fulfils its original purpose of finding quick non-matches in cases of nested
2187     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2190     Version 4.0 17-Feb-03
2191     ---------------------
2193 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2194     extended to the end of string, PCRE compiled incorrect data. This could lead to
2195     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2197     2. Moved to autoconf 2.53 and libtool 1.4.2.
2199     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2200     the special perltest8 script is no longer needed - all the tests can be run
2201     from a single perltest script.
2203     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2204     by \s. It has now been removed in PCRE. This means it isn't recognized as
2205     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2206     class [:space:] *does* include VT, thereby creating a mess.
2208     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2209     space and tab.
2211     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2212     its new features into the main test script, reducing the number of scripts.
2214     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2215     were backward compatible, and made the (?i) apply to the whole pattern, as if
2216     /i were given. Now it behaves more logically, and applies the option setting
2217     only to what follows. PCRE has been changed to follow suit. However, if it
2218     finds options settings right at the start of the pattern, it extracts them into
2219     the global options, as before. Thus, they show up in the info data.
2221     8. Added support for the \Q...\E escape sequence. Characters in between are
2222     treated as literals. This is slightly different from Perl in that $ and @ are
2223     also handled as literals inside the quotes. In Perl, they will cause variable
2224     interpolation. Note the following examples:
2226     Pattern PCRE matches Perl matches
2228     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2229     \Qabc\$xyz\E abc\$xyz abc\$xyz
2230     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2232     For compatibility with Perl, \Q...\E sequences are recognized inside character
2233     classes as well as outside them.
2235     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2236     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2237     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2238     signed/unsigned warnings.
2240     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2241     option for pcretest, so I've replaced it by a simple function that does just
2242     that job.
2244     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2245     "pcregrep -".
2247     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2248     Java package. This provides some syntactic sugar for simple cases of what my
2249     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2250     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2251     item, you can use this simplified notation. Note that only makes sense with
2252     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2253     greediness, whatever the setting of the PCRE_UNGREEDY option.
2255     13. A change of greediness default within a pattern was not taking effect at
2256     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2257     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2258     was abstracted outside.
2260     14. PCRE now supports the \G assertion. It is true when the current matching
2261     position is at the start point of the match. This differs from \A when the
2262     starting offset is non-zero. Used with the /g option of pcretest (or similar
2263     code), it works in the same way as it does for Perl's /g option. If all
2264     alternatives of a regex begin with \G, the expression is anchored to the start
2265     match position, and the "anchored" flag is set in the compiled expression.
2267     15. Some bugs concerning the handling of certain option changes within patterns
2268     have been fixed. These applied to options other than (?ims). For example,
2269     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2270     been the other way round. Some of this was related to change 7 above.
2272     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2273     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2274     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2275     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2277     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2278     mode. Unlike ".", it always matches newline, whatever the setting of
2279     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2280     assertions. Perl allows it, but it doesn't (in general) work because it can't
2281     calculate the length of the lookbehind. At least, that's the case for Perl
2282     5.8.0 - I've been told they are going to document that it doesn't work in
2283     future.
2285     18. Added an error diagnosis for escapes that PCRE does not support: these are
2286     \L, \l, \N, \P, \p, \U, \u, and \X.
2288     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2289     reading past the end of the pattern in cases such as /[abcd/.
2291     20. PCRE was getting more memory than necessary for patterns with classes that
2292     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2294     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2295     compiling PCRE for use with Virtual Pascal.
2297     22. Small fix to the Makefile to make it work properly if the build is done
2298     outside the source tree.
2300     23. Added a new extension: a condition to go with recursion. If a conditional
2301     subpattern starts with (?(R) the "true" branch is used if recursion has
2302     happened, whereas the "false" branch is used only at the top level.
2304     24. When there was a very long string of literal characters (over 255 bytes
2305     without UTF support, over 250 bytes with UTF support), the computation of how
2306     much memory was required could be incorrect, leading to segfaults or other
2307     strange effects.
2309     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2310     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2311     there was a subsequent back reference to those brackets. This meant that, for
2312     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2313     possible to check for precisely this case. All we can do is abandon the
2314     optimization if .* occurs inside capturing brackets when there are any back
2315     references whatsoever. (See below for a better fix that came later.)
2317     26. The handling of the optimization for finding the first character of a
2318     non-anchored pattern, and for finding a character that is required later in the
2319     match were failing in some cases. This didn't break the matching; it just
2320     failed to optimize when it could. The way this is done has been re-implemented.
2322     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2324     28. Added a new feature that provides some of the functionality that Perl
2325     provides with (?{...}). The facility is termed a "callout". The way it is done
2326     in PCRE is for the caller to provide an optional function, by setting
2327     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2328     global variable. By default it is unset, which disables all calling out. To get
2329     the function called, the regex must include (?C) at appropriate points. This
2330     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2331     This provides a means of identifying different callout points. When PCRE
2332     reaches such a point in the regex, if pcre_callout has been set, the external
2333     function is called. It is provided with data in a structure called
2334     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2335     matching continues; if it returns a non-zero value, the match at the current
2336     point fails. However, backtracking will occur if possible. [This was changed
2337     later and other features added - see item 49 below.]
2339     29. pcretest is upgraded to test the callout functionality. It provides a
2340     callout function that displays information. By default, it shows the start of
2341     the match and the current position in the text. There are some new data escapes
2342     to vary what happens:
2344     \C+ in addition, show current contents of captured substrings
2345     \C- do not supply a callout function
2346     \C!n return 1 when callout number n is reached
2347     \C!n!m return 1 when callout number n is reached for the mth time
2349     30. If pcregrep was called with the -l option and just a single file name, it
2350     output "<stdin>" if a match was found, instead of the file name.
2352     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2353     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2354     pcre_exec(). This saves a malloc/free per call. The default value of
2355     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2356     when configuring.
2358     32. The default maximum size of a compiled pattern is 64K. There have been a
2359     few cases of people hitting this limit. The code now uses macros to handle the
2360     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2361     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2362     configuring. Tests 2 and 5 work only with 2-byte links because they output
2363     debugging information about compiled patterns.
2365     33. Internal code re-arrangements:
2367     (a) Moved the debugging function for printing out a compiled regex into
2368     its own source file (printint.c) and used #include to pull it into
2369     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2370     separate copies.
2372     (b) Defined the list of op-code names for debugging as a macro in
2373     internal.h so that it is next to the definition of the opcodes.
2375     (c) Defined a table of op-code lengths for simpler skipping along compiled
2376     code. This is again a macro in internal.h so that it is next to the
2377     definition of the opcodes.
2379     34. Added support for recursive calls to individual subpatterns, along the
2380     lines of Robin Houston's patch (but implemented somewhat differently).
2382     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2383     allow it to read and process whole directories in Win32. This code was
2384     contributed by Lionel Fourquaux; it has not been tested by me.
2386     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2387     used to name a group. Names consist of alphanumerics and underscores, and must
2388     be unique. Back references use the syntax (?P=name) and recursive calls use
2389     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2390     numbers. The function pcre_fullinfo() can be used after compilation to extract
2391     a name/number map. There are three relevant calls:
2393     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2394     PCRE_INFO_NAMECOUNT yields the number of entries
2395     PCRE_INFO_NAMETABLE yields a pointer to the map.
2397     The map is a vector of fixed-size entries. The size of each entry depends on
2398     the length of the longest name used. The first two bytes of each entry are the
2399     group number, most significant byte first. There follows the corresponding
2400     name, zero terminated. The names are in alphabetical order.
2402     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2403     case instead of 255. Making it the same both with and without UTF-8 support
2404     means that the same test output works with both.
2406     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2407     calling malloc() with a zero argument.
2409     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2410     optimization. I've improved things by keeping a bitmap of backreferences with
2411     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2412     fact referenced, the optimization can be applied. It is unlikely that a
2413     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2414     the match to follow \n) will appear inside brackets with a number greater than
2415     31, but if it does, any back reference > 31 suppresses the optimization.
2417     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2418     of disabling numbered capturing parentheses. Any opening parenthesis that is
2419     not followed by ? behaves as if it were followed by ?: but named parentheses
2420     can still be used for capturing (and they will acquire numbers in the usual
2421     way).
2423     41. Redesigned the return codes from the match() function into yes/no/error so
2424     that errors can be passed back from deep inside the nested calls. A malloc
2425     failure while inside a recursive subpattern call now causes the
2426     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2428     42. It is now possible to set a limit on the number of times the match()
2429     function is called in a call to pcre_exec(). This facility makes it possible to
2430     limit the amount of recursion and backtracking, though not in a directly
2431     obvious way, because the match() function is used in a number of different
2432     circumstances. The count starts from zero for each position in the subject
2433     string (for non-anchored patterns). The default limit is, for compatibility, a
2434     large number, namely 10 000 000. You can change this in two ways:
2436     (a) When configuring PCRE before making, you can use --with-match-limit=n
2437     to set a default value for the compiled library.
2439     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2440     a different value is set. See 45 below.
2442     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2444     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2445     of things that can be changed at compile time. The first argument specifies
2446     what is wanted and the second points to where the information is to be placed.
2447     The current list of available information is:
2451     The output is an integer that is set to one if UTF-8 support is available;
2452     otherwise it is set to zero.
2456     The output is an integer that it set to the value of the code that is used for
2457     newline. It is either LF (10) or CR (13).
2461     The output is an integer that contains the number of bytes used for internal
2462     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2466     The output is an integer that contains the threshold above which the POSIX
2467     interface uses malloc() for output vectors. See item 31 above.
2471     The output is an unsigned integer that contains the default limit of the number
2472     of match() calls in a pcre_exec() execution. See 42 above.
2474     44. pcretest has been upgraded by the addition of the -C option. This causes it
2475     to extract all the available output from the new pcre_config() function, and to
2476     output it. The program then exits immediately.
2478     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2479     order to support additional features. One way would have been to define
2480     pcre_exec2() (for example) with extra arguments, but this would not have been
2481     extensible, and would also have required all calls to the original function to
2482     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2483     is used for passing in "extra" data from pcre_study().
2485     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2486     contains the following fields:
2488     flags a bitmap indicating which of the following fields are set
2489     study_data opaque data from pcre_study()
2490     match_limit a way of specifying a limit on match() calls for a specific
2491     call to pcre_exec()
2492     callout_data data for callouts (see 49 below)
2494     The flag bits are also defined in pcre.h, and are
2500     The pcre_study() function now returns one of these new pcre_extra blocks, with
2501     the actual study data pointed to by the study_data field, and the
2502     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2503     before. That is, this change is entirely upwards-compatible and requires no
2504     change to existing code.
2506     If you want to pass in additional data to pcre_exec(), you can either place it
2507     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2508     block.
2510     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2511     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2512     times with different match limits, until it finds the minimum value needed for
2513     pcre_exec() to complete. The value is then output. This can be instructive; for
2514     most simple matches the number is quite small, but for pathological cases it
2515     gets very large very quickly.
2517     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2518     returns the size of the data block pointed to by the study_data field in a
2519     pcre_extra block, that is, the value that was passed as the argument to
2520     pcre_malloc() when PCRE was getting memory in which to place the information
2521     created by pcre_study(). The fourth argument should point to a size_t variable.
2522     pcretest has been extended so that this information is shown after a successful
2523     pcre_study() call when information about the compiled regex is being displayed.
2525     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2526     because what follows is always an absolute path. (Later: it turns out that this
2527     is more than cosmetic for MinGW, because it doesn't like empty path
2528     components.)
2530     49. Some changes have been made to the callout feature (see 28 above):
2532     (i) A callout function now has three choices for what it returns:
2534     0 => success, carry on matching
2535     > 0 => failure at this point, but backtrack if possible
2536     < 0 => serious error, return this value from pcre_exec()
2538     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2539     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2540     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2541     use by callout functions. It will never be used by PCRE itself.
2543     (ii) The pcre_extra structure (see 45 above) has a void * field called
2544     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2545     pcre_callout_block structure has a field of the same name. The contents of
2546     the field passed in the pcre_extra structure are passed to the callout
2547     function in the corresponding field in the callout block. This makes it
2548     easier to use the same callout-containing regex from multiple threads. For
2549     testing, the pcretest program has a new data escape
2551     \C*n pass the number n (may be negative) as callout_data
2553     If the callout function in pcretest receives a non-zero value as
2554     callout_data, it returns that value.
2556     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2557     there were some redundant $(CFLAGS) in commands that are now specified as
2558     $(LINK), which already includes $(CFLAGS).
2560     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2561     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2562     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2563     one-byte characters throughout. Note that case-insensitive matching applies
2564     only to characters whose values are less than 256. PCRE doesn't support the
2565     notion of cases for higher-valued characters.
2567     (i) A character class whose characters are all within 0-255 is handled as
2568     a bit map, and the map is inverted for negative classes. Previously, a
2569     character > 255 always failed to match such a class; however it should
2570     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2572     (ii) A negated character class with a single character < 255 is coded as
2573     "not this character" (OP_NOT). This wasn't working properly when the test
2574     character was multibyte, either singly or repeated.
2576     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2577     mode, for example: \x{100}{2,3}.
2579     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2580     singly or repeated) now correctly test multibyte characters. However,
2581     PCRE doesn't recognize any characters with values greater than 255 as
2582     digits, spaces, or word characters. Such characters always match \D, \S,
2583     and \W, and never match \d, \s, or \w.
2585     (v) Classes may now contain characters and character ranges with values
2586     greater than 255. For example: [ab\x{100}-\x{400}].
2588     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2589     PCRE in UTF-8 mode.
2591     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2592     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2593     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2594     value.)
2596     53. The single man page has become too large. I have therefore split it up into
2597     a number of separate man pages. These also give rise to individual HTML pages;
2598     these are now put in a separate directory, and there is an index.html page that
2599     lists them all. Some hyperlinking between the pages has been installed.
2601     54. Added convenience functions for handling named capturing parentheses.
2603     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2604     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2605     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2606     are faulted.
2608     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2609     calling configure. These values are used when compiling the dftables.c program
2610     which is run to generate the source of the default character tables. They
2611     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2612     you will need to set these values.
2614     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2617     Version 3.9 02-Jan-02
2618 nigel 61 ---------------------
2620     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2622     2. If --disable-static was given, the building process failed when trying to
2623     build pcretest and pcregrep. (For some reason it was using libtool to compile
2624     them, which is not right, as they aren't part of the library.)
2627 nigel 59 Version 3.8 18-Dec-01
2628     ---------------------
2630     1. The experimental UTF-8 code was completely screwed up. It was packing the
2631     bytes in the wrong order. How dumb can you get?
2634 nigel 57 Version 3.7 29-Oct-01
2635     ---------------------
2637     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2638     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2639     this didn't happen under Solaris 8, where I normally test things.
2641 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2642     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2643     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2644     this fix an hour or so after the initial 3.7 release.)
2645 nigel 57
2646 nigel 59
2647 nigel 55 Version 3.6 23-Oct-01
2648     ---------------------
2650     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2651     offsets passed as NULL with zero offset count.
2653     2. The config.guess and config.sub files had not been updated when I moved to
2654     the latest autoconf.
2657 nigel 53 Version 3.5 15-Aug-01
2658     ---------------------
2659 nigel 5
2660 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2661     had been forgotten.
2663     2. By using declared but undefined structures, we can avoid using "void"
2664     definitions in pcre.h while keeping the internal definitions of the structures
2665     private.
2667     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2668     user point of view, this means that both static and shared libraries are built
2669     by default, but this can be individually controlled. More of the work of
2670     handling this static/shared cases is now inside libtool instead of PCRE's make
2671     file.
2673     4. The pcretest utility is now installed along with pcregrep because it is
2674     useful for users (to test regexs) and by doing this, it automatically gets
2675     relinked by libtool. The documentation has been turned into a man page, so
2676     there are now .1, .txt, and .html versions in /doc.
2678     5. Upgrades to pcregrep:
2679     (i) Added long-form option names like gnu grep.
2680     (ii) Added --help to list all options with an explanatory phrase.
2681     (iii) Added -r, --recursive to recurse into sub-directories.
2682     (iv) Added -f, --file to read patterns from a file.
2684     6. pcre_exec() was referring to its "code" argument before testing that
2685     argument for NULL (and giving an error if it was NULL).
2687     7. Upgraded Makefile.in to allow for compiling in a different directory from
2688     the source directory.
2690     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2691     options bits, the pointer it was passed was to an int instead of to an unsigned
2692     long int. This mattered only on 64-bit systems.
2694     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2695     generated) instead of pcre.in, which it its source. Also made the same change
2696     in several of the .c files.
2698     10. A new release of gcc defines printf() as a macro, which broke pcretest
2699     because it had an ifdef in the middle of a string argument for printf(). Fixed
2700     by using separate calls to printf().
2702     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2703     script, to force use of CR or LF instead of \n in the source. On non-Unix
2704     systems, the value can be set in config.h.
2706     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2707     absolute limit. Changed the text of the error message to make this clear, and
2708     likewise updated the man page.
2710     13. The limit of 99 on the number of capturing subpatterns has been removed.
2711     The new limit is 65535, which I hope will not be a "real" limit.
2714 nigel 51 Version 3.4 22-Aug-00
2715     ---------------------
2717     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2719     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2722 nigel 49 Version 3.3 01-Aug-00
2723     ---------------------
2725     1. If an octal character was given, but the value was greater than \377, it
2726     was not getting masked to the least significant bits, as documented. This could
2727     lead to crashes in some systems.
2729     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2730     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2732     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2733     These just pass their arguments on to (pcre_free)(), but they are provided
2734     because some uses of PCRE bind it to non-C systems that can call its functions,
2735     but cannot call free() or pcre_free() directly.
2737     4. Add "make test" as a synonym for "make check". Corrected some comments in
2738     the Makefile.
2740     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2741     Makefile.
2743     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2744     command called pgrep for grepping around the active processes.
2746     7. Added the beginnings of support for UTF-8 character strings.
2748     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2749     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2750     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2751     out for the ar command.)
2754 nigel 47 Version 3.2 12-May-00
2755     ---------------------
2757     This is purely a bug fixing release.
2759     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2760     of ZA. This was just one example of several cases that could provoke this bug,
2761     which was introduced by change 9 of version 2.00. The code for breaking
2762     infinite loops after an iteration that matches an empty string was't working
2763     correctly.
2765     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2766     when matched against abbab (for example). After matching an empty string, it
2767     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2768     caused it to match further down the string than it should.
2770     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2771     was there because it doesn't seem to be needed, and it causes trouble on some
2772     systems, as it is not a Standard C header. It has been removed.
2774     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2775     were reported on the Macintosh. The changes were from
2777     while ((c = *(++ptr)) != 0 && c != '\n');
2778     to
2779     while ((c = *(++ptr)) != 0 && c != '\n') ;
2781     Totally extraordinary, but if that's what it takes...
2783     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2784     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2785     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2786     assumes the way PCRE uses memmove() (always moving upwards).
2788     6. PCRE is being used in one environment where strchr() is not available. There
2789     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2790     faster code anyway.
2793 nigel 45 Version 3.1 09-Feb-00
2794     ---------------------
2796     The only change in this release is the fixing of some bugs in Makefile.in for
2797     the "install" target:
2799     (1) It was failing to install pcreposix.h.
2801     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2804 nigel 43 Version 3.0 01-Feb-00
2805     ---------------------
2806 nigel 41
2807     1. Add support for the /+ modifier to perltest (to output $` like it does in
2808     pcretest).
2810     2. Add support for the /g modifier to perltest.
2812     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2813     matches null strings.
2815     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2816     pattern. Perl treats empty patterns specially - it reuses the most recent
2817     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2818     effect.
2820     5. The POSIX interface was broken in that it was just handing over the POSIX
2821     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2822     required a bigger vector, with some working space on the end. This means that
2823     the POSIX wrapper now has to get and free some memory, and copy the results.
2825 nigel 43 6. Added some simple autoconf support, placing the test data and the
2826     documentation in separate directories, re-organizing some of the
2827     information files, and making it build pcre-config (a GNU standard). Also added
2828     libtool support for building PCRE as a shared library, which is now the
2829     default.
2830 nigel 41
2831 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2832     09 are not valid octal constants. Single digits will be used for minor values
2833     less than 10.
2835     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2836     existing programs that set these in the POSIX interface can use PCRE without
2837     modification.
2839     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2840     return all that pcre_info() returns, plus additional data. The pcre_info()
2841     function is retained for compatibility, but is considered to be obsolete.
2843     10. Added experimental recursion feature (?R) to handle one common case that
2844     Perl 5.6 will be able to do with (?p{...}).
2846     11. Added support for POSIX character classes like [:alpha:], which Perl is
2847     adopting.
2850 nigel 39 Version 2.08 31-Aug-99
2851     ----------------------
2853     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2854     trying to match at the startoffset position, but instead was moving forward to
2855     the next newline as if a previous match had failed.
2857     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2858     and could get into a loop if a null string was matched other than at the start
2859     of the subject.
2861     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2862     be distinguished at compile time, and for completeness also added PCRE_DATE.
2864     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2865     in GnuWin32 environments.
2868 nigel 37 Version 2.07 29-Jul-99
2869     ----------------------
2871     1. The documentation is now supplied in plain text form and HTML as well as in
2872     the form of man page sources.
2874     2. C++ compilers don't like assigning (void *) values to other pointer types.
2875     In particular this affects malloc(). Although there is no problem in Standard
2876     C, I've put in casts to keep C++ compilers happy.
2878     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2879     should be (const char *).
2881     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2882     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2883     However, I haven't made this a standard facility. The documentation doesn't
2884     mention it, and the Makefile doesn't support it.
2886     5. The Makefile now contains an "install" target, with editable destinations at
2887     the top of the file. The pcretest program is not installed.
2889     6. pgrep -V now gives the PCRE version number and date.
2891     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2892     causing the entire string to be ignored, instead of just the last character.
2894     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2895     non-matching string, it can take a very, very long time, even for strings of
2896     quite modest length, because of the nested recursion. PCRE now does better in
2897     some of these cases. It does this by remembering the last required literal
2898     character in the pattern, and pre-searching the subject to ensure it is present
2899     before running the real match. In other words, it applies a heuristic to detect
2900     some types of certain failure quickly, and in the above example, if presented
2901     with a string that has no trailing " it gives "no match" very quickly.
2903     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2904     other alternatives are tried instead.
2907 nigel 35 Version 2.06 09-Jun-99
2908     ----------------------
2910     1. Change pcretest's output for amount of store used to show just the code
2911     space, because the remainder (the data block) varies in size between 32-bit and
2912     64-bit systems.
2914     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2915     start matching at. This allows lookbehinds to work when searching for multiple
2916     occurrences in a string.
2918     3. Added additional options to pcretest for testing multiple occurrences:
2920     /+ outputs the rest of the string that follows a match
2921     /g loops for multiple occurrences, using the new startoffset argument
2922     /G loops for multiple occurrences by passing an incremented pointer
2924     4. PCRE wasn't doing the "first character" optimization for patterns starting
2925     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2926     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2927     the letter 'x'. On long subject strings, this gives a significant speed-up.
2930 nigel 33 Version 2.05 21-Apr-99
2931     ----------------------
2933     1. Changed the type of magic_number from int to long int so that it works
2934     properly on 16-bit systems.
2936     2. Fixed a bug which caused patterns starting with .* not to work correctly
2937     when the subject string contained newline characters. PCRE was assuming
2938     anchoring for such patterns in all cases, which is not correct because .* will
2939     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2940     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2941     must be retried after every newline in the subject.
2944 nigel 31 Version 2.04 18-Feb-99
2945     ----------------------
2947     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2948     computation of the store needed to hold the pattern was incorrect (too large).
2949     If such patterns were nested a few deep, this could multiply and become a real
2950     problem.
2952     2. Added /M option to pcretest to show the memory requirement of a specific
2953     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2955     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2956     compiled in such a way that the backtracking after subsequent failure was
2957     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2958     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2961 nigel 29 Version 2.03 02-Feb-99
2962     ----------------------
2964     1. Fixed typo and small mistake in man page.
2966 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2967     LICENCE file containing the conditions.
2968 nigel 29
2969     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2970     Perl, that is the internal \ allows the delimiter to be included in the
2971     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2972     the final delimiter, add \ to the end of the pattern (to test the error).
2974     4. Added the convenience functions for extracting substrings after a successful
2975     match. Updated pcretest to make it able to test these functions.
2978 nigel 27 Version 2.02 14-Jan-99
2979     ----------------------
2981     1. Initialized the working variables associated with each extraction so that
2982     their saving and restoring doesn't refer to uninitialized store.
2984     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2985     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2986     fix the problem.
2988     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2989     calls, and wasn't printing the correct value for compiling calls. Increased the
2990     default value of LOOPREPEAT, and the number of significant figures in the
2991     times.
2993     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2995     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2996     a building problem on Windows NT with a FAT file system.
2999 nigel 25 Version 2.01 21-Oct-98
3000     ----------------------
3002     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3003     to character tables built by pcre_maketables() in the current locale. If NULL
3004     is passed, the default tables are used.
3007 nigel 23 Version 2.00 24-Sep-98
3008 nigel 21 ----------------------
3010 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3011     it any more.
3013     2. Allow quantification of (?>) groups, and make it work correctly.
3015     3. The first character computation wasn't working for (?>) groups.
3017     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3018     end of the subject) and add 5.005's \z, which really does match only at the
3019     very end of the subject.
3021     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3023     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3024     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3025     localized options. All options to pcre_study() were also removed.
3027     7. Add other new features from 5.005:
3029     $(?<= positive lookbehind
3030     $(?<! negative lookbehind
3031     (?imsx-imsx) added the unsetting capability
3032     such a setting is global if at outer level; local otherwise
3033     (?imsx-imsx:) non-capturing groups with option setting
3034     (?(cond)re|re) conditional pattern matching
3036     A backreference to itself in a repeated group matches the previous
3037     captured string.
3039     8. General tidying up of studying (both automatic and via "study")
3040     consequential on the addition of new assertions.
3042     9. As in 5.005, unlimited repeated groups that could match an empty substring
3043     are no longer faulted at compile time. Instead, the loop is forcibly broken at
3044     runtime if any iteration does actually match an empty substring.
3046     10. Include the RunTest script in the distribution.
3048     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3049     discrepancies, some of which were old and were also with respect to 5.004. They
3050     have now been fixed.
3053     Version 1.09 28-Apr-98
3054     ----------------------
3056 nigel 21 1. A negated single character class followed by a quantifier with a minimum
3057     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
3058     program crashes, or just wrong answers. This did not apply to negated classes
3059     containing more than one character, or to minima other than one.
3062 nigel 19 Version 1.08 27-Mar-98
3063     ----------------------
3065     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3067     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3068     latter must appear before anything that relies on it in the pattern.
3071 nigel 17 Version 1.07 16-Feb-98
3072     ----------------------
3074     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3075     repeat of a potentially empty string).
3078 nigel 15 Version 1.06 23-Jan-98
3079     ----------------------
3081     1. Added Markus Oberhumer's little patches for C++.
3083     2. Literal strings longer than 255 characters were broken.
3086 nigel 13 Version 1.05 23-Dec-97
3087     ----------------------
3089     1. Negated character classes containing more than one character were failing if
3090     PCRE_CASELESS was set at run time.
3093 nigel 11 Version 1.04 19-Dec-97
3094     ----------------------
3096     1. Corrected the man page, where some "const" qualifiers had been omitted.
3098     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3099     input syntax.
3101     3. Fixed memory leak which occurred when a regex with back references was
3102     matched with an offsets vector that wasn't big enough. The temporary memory
3103     that is used in this case wasn't being freed if the match failed.
3105     4. Tidied pcretest to ensure it frees memory that it gets.
3107     5. Temporary memory was being obtained in the case where the passed offsets
3108     vector was exactly big enough.
3110     6. Corrected definition of offsetof() from change 5 below.
3112     7. I had screwed up change 6 below and broken the rules for the use of
3113     setjmp(). Now fixed.
3116 nigel 9 Version 1.03 18-Dec-97
3117     ----------------------
3119     1. A erroneous regex with a missing opening parenthesis was correctly
3120     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3121     on some systems.
3123     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3124     it was reported that one broken compiler failed on the former because "code" is
3125     also an independent variable.
3127     3. The erroneous regex a[]b caused an array overrun reference.
3129     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3130     fail on data ending with that character. (It was going on too far, and checking
3131     the next character, typically a binary zero.) This was specific to the
3132     optimized code for single-character negative classes.
3134     5. Added a contributed patch from the TIN world which does the following:
3136     + Add an undef for memmove, in case the the system defines a macro for it.
3138     + Add a definition of offsetof(), in case there isn't one. (I don't know
3139     the reason behind this - offsetof() is part of the ANSI standard - but
3140     it does no harm).
3142     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3143     most of the places where whitespace preceded '#'. I have given up and
3144     allowed the remaining 2 cases to be at the margin.
3146     + Rename some variables in pcre to eliminate shadowing. This seems very
3147     pedantic, but does no harm, of course.
3149     6. Moved the call to setjmp() into its own function, to get rid of warnings
3150     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3152     7. Constructs such as \d{8,} were compiling into the equivalent of
3153 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3154 nigel 9 outcome, but in this particular case used more store than had been allocated,
3155     which caused the bug to be discovered because it threw up an internal error.
3157     8. The debugging code in both pcre and pcretest for outputting the compiled
3158     form of a regex was going wrong in the case of back references followed by
3159     curly-bracketed repeats.
3162 nigel 7 Version 1.02 12-Dec-97
3163     ----------------------
3165     1. Typos in pcre.3 and comments in the source fixed.
3167     2. Applied a contributed patch to get rid of places where it used to remove
3168     'const' from variables, and fixed some signed/unsigned and uninitialized
3169     variable warnings.
3171     3. Added the "runtest" target to Makefile.
3173     4. Set default compiler flag to -O2 rather than just -O.
3176 nigel 5 Version 1.01 19-Nov-97
3177     ----------------------
3179     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3180     like /([ab]*)*/, that is, for classes with more than one character in them.
3182     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3183     as /((?>a*))*/ (a PCRE_EXTRA facility).
3186     Version 1.00 18-Nov-97
3187     ----------------------
3189     1. Added compile-time macros to support systems such as SunOS4 which don't have
3190     memmove() or strerror() but have other things that can be used instead.
3192     2. Arranged that "make clean" removes the executables.
3195 nigel 3 Version 0.99 27-Oct-97
3196     ----------------------
3198     1. Fixed bug in code for optimizing classes with only one character. It was
3199     initializing a 32-byte map regardless, which could cause it to run off the end
3200     of the memory it had got.
3202     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3205     Version 0.98 22-Oct-97
3206     ----------------------
3208     1. Fixed bug in code for handling temporary memory usage when there are more
3209     back references than supplied space in the ovector. This could cause segfaults.
3212     Version 0.97 21-Oct-97
3213     ----------------------
3215     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3217     2. Optimized negated single characters not to use a bit map.
3219     3. Brought error texts together as macro definitions; clarified some of them;
3220     fixed one that was wrong - it said "range out of order" when it meant "invalid
3221     escape sequence".
3223     4. Changed some char * arguments to const char *.
3225     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3227     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3228     pcretest.
3231     Version 0.96 16-Oct-97
3232     ----------------------
3234     1. Added a simple "pgrep" utility to the distribution.
3236     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3237     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3238     where "ddd" means "one or more decimal digits".
3240     3. Fixed serious bug. If a pattern had a back reference, but the call to
3241     pcre_exec() didn't supply a large enough ovector to record the related
3242     identifying subpattern, the match always failed. PCRE now remembers the number
3243     of the largest back reference, and gets some temporary memory in which to save
3244     the offsets during matching if necessary, in order to ensure that
3245     backreferences always work.
3247     4. Increased the compatibility with Perl in a number of ways:
3249     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3250     to request this handling. The option can be set at compile or exec time.
3252     (b) $ matches before a terminating newline by default; an option
3253     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3254     mode). The option can be set at compile or exec time.
3256     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3257     the same as Perl's. If the decimal number it represents is less than 10
3258     or there aren't that many previous left capturing parentheses, an octal
3259     escape is read. Inside a character class, it's always an octal escape,
3260     even if it is a single digit.
3262     (d) An escaped but undefined alphabetic character is taken as a literal,
3263     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3264     escapes.
3266     (e) {0} is now permitted. (The previous item is removed from the compiled
3267     pattern).
3269     5. Changed all the names of code files so that the basic parts are no longer
3270     than 10 characters, and abolished the teeny "globals.c" file.
3272     6. Changed the handling of character classes; they are now done with a 32-byte
3273     bit map always.
3275     7. Added the -d and /D options to pcretest to make it possible to look at the
3276     internals of compilation without having to recompile pcre.
3279     Version 0.95 23-Sep-97
3280     ----------------------
3282     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3283     \x20 at the start of a run of normal characters. These were being treated as
3284     real characters, instead of the source characters being re-checked.
3287     Version 0.94 18-Sep-97
3288     ----------------------
3290     1. The functions are now thread-safe, with the caveat that the global variables
3291     containing pointers to malloc() and free() or alternative functions are the
3292     same for all threads.
3294     2. Get pcre_study() to generate a bitmap of initial characters for non-
3295     anchored patterns when this is possible, and use it if passed to pcre_exec().
3298     Version 0.93 15-Sep-97
3299     ----------------------
3301     1. /(b)|(:+)/ was computing an incorrect first character.
3303     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3304     but not actually doing anything yet.
3306     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3307     as Perl does (e.g. [-az] or [az-]).
3309     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3310     all possible positions.
3312     5. Split up into different modules to avoid including unneeded functions in a
3313     compiled binary. However, compile and exec are still in one module. The "study"
3314     function is split off.
3316     6. The character tables are now in a separate module whose source is generated
3317     by an auxiliary program - but can then be edited by hand if required. There are
3318     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3319     toupper() in the code.
3321     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3322     make them global. Abolish the function for setting them, as the caller can now
3323     set them directly.
3326     Version 0.92 11-Sep-97
3327     ----------------------
3329     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3330     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3332     2. Caseless matching was not working in character classes if the characters in
3333     the pattern were in upper case.
3335     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3337     4. Make PCRE_ANCHORED public and accept as a compile option.
3339     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3340     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3341     pass them.
3343     6. Give an error if bad option bits passed at compile or run time.
3345     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3346     pcretest to cause it to pass that flag.
3348     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3349     options, and the first character, if set.
3351     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3354     Version 0.91 10-Sep-97
3355     ----------------------
3357     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3358     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3360     2. PCRE was looping on encountering an indefinitely repeated back reference to
3361     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3362     Perl does - treats the match as successful.
3364     ****


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