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

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