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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 05-Mar-07  Version 7.4 10-Sep-07
5  ---------------------  ---------------------
6    
7   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one  1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
8      that is more "standard", making use of automake and other autotools. There      means that a class such as [\s] counted as "explicit reference to CR or
9        LF". That isn't really right - the whole point of the change was to try to
10        help when there was an actual mention of one of the two characters. So now
11        the change happens only if \r or \n (or a literal CR or LF) character is
12        encountered.
13    
14    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
15        of both had grown to the point where there were only 3 bits left.
16        Fortunately, there was spare space in the data structure, and so I have
17        moved the internal flags into a new 16-bit field to free up more option
18        bits.
19    
20    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
21        but did not set the internal JCHANGED flag - either of these is enough to
22        control the way the "get" function works - but the PCRE_INFO_JCHANGED
23        facility is supposed to tell if (?J) was ever used, so now (?J) at the
24        start sets both bits.
25    
26    4.  Added options (at build time, compile time, exec time) to change \R from
27        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
28    
29    5.  doc/pcresyntax.html was missing from the distribution.
30    
31    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
32        compatibility, even though it is no longer used.
33    
34    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
35        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
36        windows.h file is present (where different names are used).
37    
38    8.  Changed all #include <config.h> to #include "config.h". There were also
39        some further <pcre.h> cases that I changed to "pcre.h".
40    
41    9.  When pcregrep was used with the --colour option, it missed the line ending
42        sequence off the lines that it output.
43    
44    10. It was pointed out to me that arrays of string pointers cause lots of
45        relocations when a shared library is dynamically loaded. A technique of
46        using a single long string with a table of offsets can drastically reduce
47        these. I have refactored PCRE in four places to do this. The result is
48        dramatic:
49    
50          Originally:                          290
51          After changing UCP table:            187
52          After changing error message table:   43
53          After changing table of "verbs"       36
54          After changing table of Posix names   22
55    
56        Thanks to the folks working on Gregex for glib for this insight.
57    
58    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
59        unicode-properties was also set.
60    
61    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
62    
63    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
64        checked only for CRLF.
65    
66    
67    Version 7.3 28-Aug-07
68    ---------------------
69    
70     1. In the rejigging of the build system that eventually resulted in 7.1, the
71        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
72        brackets there is not right, since it causes compilers to look for an
73        installed pcre.h, not the version that is in the source that is being
74        compiled (which of course may be different). I have changed it back to:
75    
76          #include "pcre.h"
77    
78        I have a vague recollection that the change was concerned with compiling in
79        different directories, but in the new build system, that is taken care of
80        by the VPATH setting the Makefile.
81    
82     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
83        when the subject happened to end in the byte 0x85 (e.g. if the last
84        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
85        characters but of course it shouldn't be taken as a newline when it is part
86        of another character. The bug was that, for an unlimited repeat of . in
87        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
88        characters when looking for a newline.
89    
90     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
91    
92     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
93        in debug output.
94    
95     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
96        long printing in the pcrecpp unittest when running under MinGW.
97    
98     6. ESC_K was left out of the EBCDIC table.
99    
100     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
101        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
102        limit also applies to "virtual nesting" when a pattern is recursive, and in
103        this case 1000 isn't so big. I have been able to remove this limit at the
104        expense of backing off one optimization in certain circumstances. Normally,
105        when pcre_exec() would call its internal match() function recursively and
106        immediately return the result unconditionally, it uses a "tail recursion"
107        feature to save stack. However, when a subpattern that can match an empty
108        string has an unlimited repetition quantifier, it no longer makes this
109        optimization. That gives it a stack frame in which to save the data for
110        checking that an empty string has been matched. Previously this was taken
111        from the 1000-entry workspace that had been reserved. So now there is no
112        explicit limit, but more stack is used.
113    
114     8. Applied Daniel's patches to solve problems with the import/export magic
115        syntax that is required for Windows, and which was going wrong for the
116        pcreposix and pcrecpp parts of the library. These were overlooked when this
117        problem was solved for the main library.
118    
119     9. There were some crude static tests to avoid integer overflow when computing
120        the size of patterns that contain repeated groups with explicit upper
121        limits. As the maximum quantifier is 65535, the maximum group length was
122        set at 30,000 so that the product of these two numbers did not overflow a
123        32-bit integer. However, it turns out that people want to use groups that
124        are longer than 30,000 bytes (though not repeat them that many times).
125        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
126        made it possible to implement the integer overflow checks in a much more
127        dynamic way, which I have now done. The artificial limitation on group
128        length has been removed - we now have only the limit on the total length of
129        the compiled pattern, which depends on the LINK_SIZE setting.
130    
131    10. Fixed a bug in the documentation for get/copy named substring when
132        duplicate names are permitted. If none of the named substrings are set, the
133        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
134        empty string.
135    
136    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
137        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
138        because the ] is interpreted as the first data character and the
139        terminating ] is not found. PCRE has been made compatible with Perl in this
140        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
141        cause memory overwriting.
142    
143    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
144        string has been matched (to stop an infinite loop). It was not recognizing
145        a conditional subpattern that could match an empty string if that
146        subpattern was within another subpattern. For example, it looped when
147        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
148        condition was not nested. This bug has been fixed.
149    
150    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
151        past the start of the subject in the presence of bytes with the top bit
152        set, for example "\x8aBCD".
153    
154    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
155        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
156    
157    14. Optimized (?!) to (*FAIL).
158    
159    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
160        This restricts code points to be within the range 0 to 0x10FFFF, excluding
161        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
162        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
163        does: it's just the validity check that is more restrictive.
164    
165    16. Inserted checks for integer overflows during escape sequence (backslash)
166        processing, and also fixed erroneous offset values for syntax errors during
167        backslash processing.
168    
169    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
170        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
171    
172    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
173        caused an overrun.
174    
175    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
176        something other than just ASCII characters) inside a group that had an
177        unlimited repeat caused a loop at compile time (while checking to see
178        whether the group could match an empty string).
179    
180    20. Debugging a pattern containing \p or \P could cause a crash. For example,
181        [\P{Any}] did so. (Error in the code for printing property names.)
182    
183    21. An orphan \E inside a character class could cause a crash.
184    
185    22. A repeated capturing bracket such as (A)? could cause a wild memory
186        reference during compilation.
187    
188    23. There are several functions in pcre_compile() that scan along a compiled
189        expression for various reasons (e.g. to see if it's fixed length for look
190        behind). There were bugs in these functions when a repeated \p or \P was
191        present in the pattern. These operators have additional parameters compared
192        with \d, etc, and these were not being taken into account when moving along
193        the compiled data. Specifically:
194    
195        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
196            length.
197    
198        (b) An item such as \pL+ within a repeated group could cause crashes or
199            loops.
200    
201        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
202            "reference to non-existent subpattern" error.
203    
204        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
205    
206    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
207        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
208    
209    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
210    
211    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
212        character were causing crashes (broken optimization).
213    
214    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
215        \p or \P) caused a compile-time loop.
216    
217    28. More problems have arisen in unanchored patterns when CRLF is a valid line
218        break. For example, the unstudied pattern [\r\n]A does not match the string
219        "\r\nA" because change 7.0/46 below moves the current point on by two
220        characters after failing to match at the start. However, the pattern \nA
221        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
222        the same is true. There doesn't seem any very clean way out of this, but
223        what I have chosen to do makes the common cases work: PCRE now takes note
224        of whether there can be an explicit match for \r or \n anywhere in the
225        pattern, and if so, 7.0/46 no longer applies. As part of this change,
226        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
227        pattern has explicit CR or LF references.
228    
229    29. Added (*CR) etc for changing newline setting at start of pattern.
230    
231    
232    Version 7.2 19-Jun-07
233    ---------------------
234    
235     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
236        which is apparently normally available under Windows.
237    
238     2. Re-jig the pcregrep tests with different newline settings in an attempt
239        to make them independent of the local environment's newline setting.
240    
241     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
242    
243     4. Some of the "internals" tests were previously cut out when the link size
244        was not 2, because the output contained actual offsets. The recent new
245        "Z" feature of pcretest means that these can be cut out, making the tests
246        usable with all link sizes.
247    
248     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
249        stack recursion. This gives a massive performance boost under BSD, but just
250        a small improvement under Linux. However, it saves one field in the frame
251        in all cases.
252    
253     6. Added more features from the forthcoming Perl 5.10:
254    
255        (a) (?-n) (where n is a string of digits) is a relative subroutine or
256            recursion call. It refers to the nth most recently opened parentheses.
257    
258        (b) (?+n) is also a relative subroutine call; it refers to the nth next
259            to be opened parentheses.
260    
261        (c) Conditions that refer to capturing parentheses can be specified
262            relatively, for example, (?(-2)... or (?(+3)...
263    
264        (d) \K resets the start of the current match so that everything before
265            is not part of it.
266    
267        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
268    
269        (f) \g{name} is another synonym - part of Perl 5.10's unification of
270            reference syntax.
271    
272        (g) (?| introduces a group in which the numbering of parentheses in each
273            alternative starts with the same number.
274    
275        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
276    
277     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
278        PCRE_INFO_JCHANGED.
279    
280     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
281        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
282        for detecting groups that can match an empty string.
283    
284     9. A pattern with a very large number of alternatives (more than several
285        hundred) was running out of internal workspace during the pre-compile
286        phase, where pcre_compile() figures out how much memory will be needed. A
287        bit of new cunning has reduced the workspace needed for groups with
288        alternatives. The 1000-alternative test pattern now uses 12 bytes of
289        workspace instead of running out of the 4096 that are available.
290    
291    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
292    
293    11. Applied patch from Google to remove an optimization that didn't quite work.
294        The report of the bug said:
295    
296          pcrecpp::RE("a*").FullMatch("aaa") matches, while
297          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
298          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
299    
300    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
301        it matched the wrong number of bytes.
302    
303    
304    Version 7.1 24-Apr-07
305    ---------------------
306    
307     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
308        that is more "standard", making use of automake and other Autotools. There
309      is some re-arrangement of the files and adjustment of comments consequent      is some re-arrangement of the files and adjustment of comments consequent
310      on this.      on this.
311    
312   2. Part of the patch fixed a problem with the pcregrep tests. The test of -r   2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
313      for recursive directory scanning broke on some systems because the files      for recursive directory scanning broke on some systems because the files
314      are not scanned in any specific order and on different systems the order      are not scanned in any specific order and on different systems the order
315      was different. A call to "sort" has been inserted into RunGrepTest for the      was different. A call to "sort" has been inserted into RunGrepTest for the
316      approprate test as a short-term fix. In the longer term there may be an      approprate test as a short-term fix. In the longer term there may be an
317      alternative.      alternative.
318    
319   3. I had an email from Eric Raymond about problems translating some of PCRE's   3. I had an email from Eric Raymond about problems translating some of PCRE's
320      man pages to HTML (despite the fact that I distribute HTML pages, some      man pages to HTML (despite the fact that I distribute HTML pages, some
321      people do their own conversions for various reasons). The problems      people do their own conversions for various reasons). The problems
322      concerned the use of low-level troff macros .br and .in. I have therefore      concerned the use of low-level troff macros .br and .in. I have therefore
323      removed all such uses from the man pages (some were redundant, some could      removed all such uses from the man pages (some were redundant, some could
324      be replaced by .nf/.fi pairs). The maintain/132html script that I use to      be replaced by .nf/.fi pairs). The 132html script that I use to generate
325      generate HTML has been updated to handle .nf/.fi and to complain if it      HTML has been updated to handle .nf/.fi and to complain if it encounters
326      encounters .br or .in.      .br or .in.
327    
328   4. Updated comments in configure.ac that get placed in config.h.in and also   4. Updated comments in configure.ac that get placed in config.h.in and also
329      arranged for config.h to be included in the distribution, for the benefit      arranged for config.h to be included in the distribution, with the name
330      of those who have to compile without Autotools (compare pcre.h).      config.h.generic, for the benefit of those who have to compile without
331        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
332    
333     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
334        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
335        makevp.bat for the current PCRE, using the additional files
336        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
337    
338     6. A Windows user reported a minor discrepancy with test 2, which turned out
339        to be caused by a trailing space on an input line that had got lost in his
340        copy. The trailing space was an accident, so I've just removed it.
341    
342     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
343        that is needed.
344    
345     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
346        as "const" (a) because they are and (b) because it helps the PHP
347        maintainers who have recently made a script to detect big data structures
348        in the php code that should be moved to the .rodata section. I remembered
349        to update Builducptable as well, so it won't revert if ucptable.h is ever
350        re-created.
351    
352     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
353        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
354        order to be able to cut out the UTF-8 tables in the latter when UTF-8
355        support is not required. This saves 1.5-2K of code, which is important in
356        some applications.
357    
358        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
359        so as not to refer to the tables, even though these functions will never be
360        called when UTF-8 support is disabled. Otherwise there are problems with a
361        shared library.
362    
363    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
364    
365        (a) It was defining its arguments as char * instead of void *.
366    
367        (b) It was assuming that all moves were upwards in memory; this was true
368            a long time ago when I wrote it, but is no longer the case.
369    
370        The emulated memove() is provided for those environments that have neither
371        memmove() nor bcopy(). I didn't think anyone used it these days, but that
372        is clearly not the case, as these two bugs were recently reported.
373    
374    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
375        and Detrail to create the HTML documentation, the .txt form of the man
376        pages, and it removes trailing spaces from listed files. It also creates
377        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
378        case, it wraps all the #defines with #ifndefs. This script should be run
379        before "make dist".
380    
381    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
382        with Unicode property support.
383    
384        (a) For a maximizing quantifier, if the two different cases of the
385            character were of different lengths in their UTF-8 codings (there are
386            some cases like this - I found 11), and the matching function had to
387            back up over a mixture of the two cases, it incorrectly assumed they
388            were both the same length.
389    
390        (b) When PCRE was configured to use the heap rather than the stack for
391            recursion during matching, it was not correctly preserving the data for
392            the other case of a UTF-8 character when checking ahead for a match
393            while processing a minimizing repeat. If the check also involved
394            matching a wide character, but failed, corruption could cause an
395            erroneous result when trying to check for a repeat of the original
396            character.
397    
398    13. Some tidying changes to the testing mechanism:
399    
400        (a) The RunTest script now detects the internal link size and whether there
401            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
402            values substituted by "configure". (The RunGrepTest script already did
403            this for UTF-8.) The configure.ac script no longer substitutes the
404            relevant variables.
405    
406        (b) The debugging options /B and /D in pcretest show the compiled bytecode
407            with length and offset values. This means that the output is different
408            for different internal link sizes. Test 2 is skipped for link sizes
409            other than 2 because of this, bypassing the problem. Unfortunately,
410            there was also a test in test 3 (the locale tests) that used /B and
411            failed for link sizes other than 2. Rather than cut the whole test out,
412            I have added a new /Z option to pcretest that replaces the length and
413            offset values with spaces. This is now used to make test 3 independent
414            of link size. (Test 2 will be tidied up later.)
415    
416    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
417        segmentation fault instead of returning the appropriate error message.
418    
419    15. In multiline mode when the newline sequence was set to "any", the pattern
420        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
421        This doesn't seem right; it now treats the CRLF combination as the line
422        ending, and so does not match in that case. It's only a pattern such as ^$
423        that would hit this one: something like ^ABC$ would have failed after \r
424        and then tried again after \r\n.
425    
426    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
427        in an attempt to make files that differ only in their line terminators
428        compare equal. This works on Linux.
429    
430    17. Under certain error circumstances pcregrep might try to free random memory
431        as it exited. This is now fixed, thanks to valgrind.
432    
433    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
434        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
435        was because its rules for how to advance for /g after matching an empty
436        string at the end of a line did not allow for this case. They now check for
437        it specially.
438    
439    20. pcretest is supposed to handle patterns and data of any length, by
440        extending its buffers when necessary. It was getting this wrong when the
441        buffer for a data line had to be extended.
442    
443    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
444        CRLF as a newline sequence.
445    
446    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
447        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
448        I have nevertheless tidied it up.
449    
450    23. Added some casts to kill warnings from HP-UX ia64 compiler.
451    
452    24. Added a man page for pcre-config.
453    
454    
455  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
456  ---------------------  ---------------------

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