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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.6 21-Jan-08
5    ---------------------
7    1.  A character class containing a very large number of characters with
8        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
9        overflow.
11    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
12        HAVE_LONG_LONG is not defined.
14    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
15        bring them up to date and include new features. This patch includes:
17        - Fixed PH's badly added libz and libbz2 support.
18        - Fixed a problem with static linking.
19        - Added pcredemo. [But later removed - see 7 below.]
20        - Fixed dftables problem and added an option.
21        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
22            HAVE_LONG_LONG.
23        - Added readline support for pcretest.
24        - Added an listing of the option settings after cmake has run.
26    4.  A user submitted a patch to Makefile that makes it easy to create
27        "pcre.dll" under mingw when using Configure/Make. I added stuff to
28        Makefile.am that cause it to include this special target, without
29        affecting anything else. Note that the same mingw target plus all
30        the other distribution libraries and programs are now supported
31        when configuring with CMake (see 6 below) instead of with
32        Configure/Make.
34    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
35        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
36        exported in the Windows port". It has not yet been confirmed that the patch
37        solves the problem, but it does no harm.
39    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
40        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
41        with CMake, and also correct the comment about stack recursion.
43    7.  Remove the automatic building of pcredemo from the ./configure system and
44        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
45        of a program that users should build themselves after PCRE is installed, so
46        building it automatically is not really right. What is more, it gave
47        trouble in some build environments.
50    Version 7.5 10-Jan-08
51    ---------------------
53    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
54        values in parens when parsing an RE using the C++ wrapper."
56    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
57        Characters greater than 255 were excluded from the class instead of being
58        included.
60    3.  The same bug as (2) above applied to negated POSIX classes such as
61        [:^space:].
63    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
64        defined or documented. It seems to have been a typo for PCRE_STATIC, so
65        I have changed it.
67    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
68        first named subpattern) and a construct such as (?&a) would reference the
69        first named subpattern whose name started with "a" (in other words, the
70        length check was missing). Both these problems are fixed. "Subpattern name
71        expected" is now given for (?&) (a zero-length name), and this patch also
72        makes it give the same error for \k'' (previously it complained that that
73        was a reference to a non-existent subpattern).
75    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
76        this is right because (?- can be followed by option settings as well as by
77        digits. I have, however, made the messages clearer.
79    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
80        than the number used in the conditional) now cause a compile-time error.
81        This is actually not compatible with Perl, which accepts such patterns, but
82        treats the conditional as always being FALSE (as PCRE used to), but it
83        seems to me that giving a diagnostic is better.
85    8.  Change "alphameric" to the more common word "alphanumeric" in comments
86        and messages.
88    9.  Fix two occurrences of "backslash" in comments that should have been
89        "backspace".
91    10. Remove two redundant lines of code that can never be obeyed (their function
92        was moved elsewhere).
94    11. The program that makes PCRE's Unicode character property table had a bug
95        which caused it to generate incorrect table entries for sequences of
96        characters that have the same character type, but are in different scripts.
97        It amalgamated them into a single range, with the script of the first of
98        them. In other words, some characters were in the wrong script. There were
99        thirteen such cases, affecting characters in the following ranges:
101          U+002b0 - U+002c1
102          U+0060c - U+0060d
103          U+0061e - U+00612
104          U+0064b - U+0065e
105          U+0074d - U+0076d
106          U+01800 - U+01805
107          U+01d00 - U+01d77
108          U+01d9b - U+01dbf
109          U+0200b - U+0200f
110          U+030fc - U+030fe
111          U+03260 - U+0327f
112          U+0fb46 - U+0fbb1
113          U+10450 - U+1049d
115    12. The -o option (show only the matching part of a line) for pcregrep was not
116        compatible with GNU grep in that, if there was more than one match in a
117        line, it showed only the first of them. It now behaves in the same way as
118        GNU grep.
120    13. If the -o and -v options were combined for pcregrep, it printed a blank
121        line for every non-matching line. GNU grep prints nothing, and pcregrep now
122        does the same. The return code can be used to tell if there were any
123        non-matching lines.
125    14. Added --file-offsets and --line-offsets to pcregrep.
127    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
128        infinitely looping recursion. The bug was that positive lookaheads were not
129        being skipped when checking for a possible empty match (negative lookaheads
130        and both kinds of lookbehind were skipped).
132    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
133        inclusion of <windows.h> to before rather than after the definition of
134        INVALID_FILE_ATTRIBUTES (patch from David Byron).
136    17. Specifying a possessive quantifier with a specific limit for a Unicode
137        character property caused pcre_compile() to compile bad code, which led at
138        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
139        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
140        caused the error; without that there was no problem.
142    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
144    19. Added --enable-pcretest-libreadline.
146    20. In pcrecpp.cc, the variable 'count' was incremented twice in
147        RE::GlobalReplace(). As a result, the number of replacements returned was
148        double what it should be. I removed one of the increments, but Craig sent a
149        later patch that removed the other one (the right fix) and added unit tests
150        that check the return values (which was not done before).
152    21. Several CMake things:
154        (1) Arranged that, when cmake is used on Unix, the libraries end up with
155            the names libpcre and libpcreposix, not just pcre and pcreposix.
157        (2) The above change means that pcretest and pcregrep are now correctly
158            linked with the newly-built libraries, not previously installed ones.
162    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
163        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
164        UTF-8 newline character). The key issue is that the pattern starts .*;
165        this means that the match must be either at the beginning, or after a
166        newline. The bug was in the code for advancing after a failed match and
167        checking that the new position followed a newline. It was not taking
168        account of UTF-8 characters correctly.
170    23. PCRE was behaving differently from Perl in the way it recognized POSIX
171        character classes. PCRE was not treating the sequence [:...:] as a
172        character class unless the ... were all letters. Perl, however, seems to
173        allow any characters between [: and :], though of course it rejects as
174        unknown any "names" that contain non-letters, because all the known class
175        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
176        for example, whereas PCRE did not - it did not recognize a POSIX character
177        class. This seemed a bit dangerous, so the code has been changed to be
178        closer to Perl. The behaviour is not identical to Perl, because PCRE will
179        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
180        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
181        Perl does, and where it didn't before.
183    24. Rewrite so as to remove the single use of %n from pcregrep because in some
184        Windows environments %n is disabled by default.
187    Version 7.4 21-Sep-07
188    ---------------------
190    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
191        means that a class such as [\s] counted as "explicit reference to CR or
192        LF". That isn't really right - the whole point of the change was to try to
193        help when there was an actual mention of one of the two characters. So now
194        the change happens only if \r or \n (or a literal CR or LF) character is
195        encountered.
197    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
198        of both had grown to the point where there were only 3 bits left.
199        Fortunately, there was spare space in the data structure, and so I have
200        moved the internal flags into a new 16-bit field to free up more option
201        bits.
203    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
204        but did not set the internal JCHANGED flag - either of these is enough to
205        control the way the "get" function works - but the PCRE_INFO_JCHANGED
206        facility is supposed to tell if (?J) was ever used, so now (?J) at the
207        start sets both bits.
209    4.  Added options (at build time, compile time, exec time) to change \R from
210        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
212    5.  doc/pcresyntax.html was missing from the distribution.
214    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
215        compatibility, even though it is no longer used.
217    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
218        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
219        windows.h file is present (where different names are used). [This was
220        reversed later after testing - see 16 below.]
222    8.  Changed all #include <config.h> to #include "config.h". There were also
223        some further <pcre.h> cases that I changed to "pcre.h".
225    9.  When pcregrep was used with the --colour option, it missed the line ending
226        sequence off the lines that it output.
228    10. It was pointed out to me that arrays of string pointers cause lots of
229        relocations when a shared library is dynamically loaded. A technique of
230        using a single long string with a table of offsets can drastically reduce
231        these. I have refactored PCRE in four places to do this. The result is
232        dramatic:
234          Originally:                          290
235          After changing UCP table:            187
236          After changing error message table:   43
237          After changing table of "verbs"       36
238          After changing table of Posix names   22
240        Thanks to the folks working on Gregex for glib for this insight.
242    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
243        unicode-properties was also set.
245    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
247    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
248        checked only for CRLF.
250    14. Added casts to pcretest.c to avoid compiler warnings.
252    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
254    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
255        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
256        entirely. This removes changes made in 7 above.
258    17. The CMake files have been updated, and there is now more information about
259        building with CMake in the NON-UNIX-USE document.
262    Version 7.3 28-Aug-07
263    ---------------------
265     1. In the rejigging of the build system that eventually resulted in 7.1, the
266        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
267        brackets there is not right, since it causes compilers to look for an
268        installed pcre.h, not the version that is in the source that is being
269        compiled (which of course may be different). I have changed it back to:
271          #include "pcre.h"
273        I have a vague recollection that the change was concerned with compiling in
274        different directories, but in the new build system, that is taken care of
275        by the VPATH setting the Makefile.
277     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
278        when the subject happened to end in the byte 0x85 (e.g. if the last
279        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
280        characters but of course it shouldn't be taken as a newline when it is part
281        of another character. The bug was that, for an unlimited repeat of . in
282        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
283        characters when looking for a newline.
285     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
287     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
288        in debug output.
290     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
291        long printing in the pcrecpp unittest when running under MinGW.
293     6. ESC_K was left out of the EBCDIC table.
295     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
296        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
297        limit also applies to "virtual nesting" when a pattern is recursive, and in
298        this case 1000 isn't so big. I have been able to remove this limit at the
299        expense of backing off one optimization in certain circumstances. Normally,
300        when pcre_exec() would call its internal match() function recursively and
301        immediately return the result unconditionally, it uses a "tail recursion"
302        feature to save stack. However, when a subpattern that can match an empty
303        string has an unlimited repetition quantifier, it no longer makes this
304        optimization. That gives it a stack frame in which to save the data for
305        checking that an empty string has been matched. Previously this was taken
306        from the 1000-entry workspace that had been reserved. So now there is no
307        explicit limit, but more stack is used.
309     8. Applied Daniel's patches to solve problems with the import/export magic
310        syntax that is required for Windows, and which was going wrong for the
311        pcreposix and pcrecpp parts of the library. These were overlooked when this
312        problem was solved for the main library.
314     9. There were some crude static tests to avoid integer overflow when computing
315        the size of patterns that contain repeated groups with explicit upper
316        limits. As the maximum quantifier is 65535, the maximum group length was
317        set at 30,000 so that the product of these two numbers did not overflow a
318        32-bit integer. However, it turns out that people want to use groups that
319        are longer than 30,000 bytes (though not repeat them that many times).
320        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
321        made it possible to implement the integer overflow checks in a much more
322        dynamic way, which I have now done. The artificial limitation on group
323        length has been removed - we now have only the limit on the total length of
324        the compiled pattern, which depends on the LINK_SIZE setting.
326    10. Fixed a bug in the documentation for get/copy named substring when
327        duplicate names are permitted. If none of the named substrings are set, the
328        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
329        empty string.
331    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
332        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
333        because the ] is interpreted as the first data character and the
334        terminating ] is not found. PCRE has been made compatible with Perl in this
335        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
336        cause memory overwriting.
338    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
339        string has been matched (to stop an infinite loop). It was not recognizing
340        a conditional subpattern that could match an empty string if that
341        subpattern was within another subpattern. For example, it looped when
342        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
343        condition was not nested. This bug has been fixed.
345    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
346        past the start of the subject in the presence of bytes with the top bit
347        set, for example "\x8aBCD".
349    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
350        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
352    14. Optimized (?!) to (*FAIL).
354    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
355        This restricts code points to be within the range 0 to 0x10FFFF, excluding
356        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
357        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
358        does: it's just the validity check that is more restrictive.
360    16. Inserted checks for integer overflows during escape sequence (backslash)
361        processing, and also fixed erroneous offset values for syntax errors during
362        backslash processing.
364    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
365        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
367    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
368        caused an overrun.
370    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
371        something other than just ASCII characters) inside a group that had an
372        unlimited repeat caused a loop at compile time (while checking to see
373        whether the group could match an empty string).
375    20. Debugging a pattern containing \p or \P could cause a crash. For example,
376        [\P{Any}] did so. (Error in the code for printing property names.)
378    21. An orphan \E inside a character class could cause a crash.
380    22. A repeated capturing bracket such as (A)? could cause a wild memory
381        reference during compilation.
383    23. There are several functions in pcre_compile() that scan along a compiled
384        expression for various reasons (e.g. to see if it's fixed length for look
385        behind). There were bugs in these functions when a repeated \p or \P was
386        present in the pattern. These operators have additional parameters compared
387        with \d, etc, and these were not being taken into account when moving along
388        the compiled data. Specifically:
390        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
391            length.
393        (b) An item such as \pL+ within a repeated group could cause crashes or
394            loops.
396        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
397            "reference to non-existent subpattern" error.
399        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
401    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
402        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
404    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
406    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
407        character were causing crashes (broken optimization).
409    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
410        \p or \P) caused a compile-time loop.
412    28. More problems have arisen in unanchored patterns when CRLF is a valid line
413        break. For example, the unstudied pattern [\r\n]A does not match the string
414        "\r\nA" because change 7.0/46 below moves the current point on by two
415        characters after failing to match at the start. However, the pattern \nA
416        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
417        the same is true. There doesn't seem any very clean way out of this, but
418        what I have chosen to do makes the common cases work: PCRE now takes note
419        of whether there can be an explicit match for \r or \n anywhere in the
420        pattern, and if so, 7.0/46 no longer applies. As part of this change,
421        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
422        pattern has explicit CR or LF references.
424    29. Added (*CR) etc for changing newline setting at start of pattern.
427    Version 7.2 19-Jun-07
428    ---------------------
430     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
431        which is apparently normally available under Windows.
433     2. Re-jig the pcregrep tests with different newline settings in an attempt
434        to make them independent of the local environment's newline setting.
436     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
438     4. Some of the "internals" tests were previously cut out when the link size
439        was not 2, because the output contained actual offsets. The recent new
440        "Z" feature of pcretest means that these can be cut out, making the tests
441        usable with all link sizes.
443     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
444        stack recursion. This gives a massive performance boost under BSD, but just
445        a small improvement under Linux. However, it saves one field in the frame
446        in all cases.
448     6. Added more features from the forthcoming Perl 5.10:
450        (a) (?-n) (where n is a string of digits) is a relative subroutine or
451            recursion call. It refers to the nth most recently opened parentheses.
453        (b) (?+n) is also a relative subroutine call; it refers to the nth next
454            to be opened parentheses.
456        (c) Conditions that refer to capturing parentheses can be specified
457            relatively, for example, (?(-2)... or (?(+3)...
459        (d) \K resets the start of the current match so that everything before
460            is not part of it.
462        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
464        (f) \g{name} is another synonym - part of Perl 5.10's unification of
465            reference syntax.
467        (g) (?| introduces a group in which the numbering of parentheses in each
468            alternative starts with the same number.
470        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
472     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
475     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
476        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
477        for detecting groups that can match an empty string.
479     9. A pattern with a very large number of alternatives (more than several
480        hundred) was running out of internal workspace during the pre-compile
481        phase, where pcre_compile() figures out how much memory will be needed. A
482        bit of new cunning has reduced the workspace needed for groups with
483        alternatives. The 1000-alternative test pattern now uses 12 bytes of
484        workspace instead of running out of the 4096 that are available.
486    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
488    11. Applied patch from Google to remove an optimization that didn't quite work.
489        The report of the bug said:
491          pcrecpp::RE("a*").FullMatch("aaa") matches, while
492          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
493          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
495    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
496        it matched the wrong number of bytes.
499  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
500  ---------------------  ---------------------

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