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

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