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Revision 321 - (hide annotations) (download)
Wed Mar 5 17:10:45 2008 UTC (6 years, 4 months ago) by ph10
File size: 151017 byte(s)
Craig's patch to sort out a long long problem: "If we can't convert 
a string to a long long, pretend we don't even have a long long."

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

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