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Revision 219 - (hide annotations) (download)
Thu Aug 16 11:46:40 2007 UTC (7 years ago) by ph10
File size: 137343 byte(s)
Fixed bug with repeated \S or \W in UTF-8 mode.

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

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