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Wed Jan 23 18:05:06 2008 UTC (7 years, 3 months ago) by ph10
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Tidies for 7.6-RC2.

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


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