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Revision 230 - (hide annotations) (download)
Mon Sep 10 13:23:56 2007 UTC (7 years, 1 month ago) by ph10
File size: 139676 byte(s)
(1) Move internal flags out of the options field, to make room.
(2) \r and \n must be explicit to trigger the special CRLF handline exception.
(3) (?J) at the start now sets JCHANGED as well as DUPNAMES.

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

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