src/string/wcsstr.c doesn't work

src/string/wcsstr.c doesn't work

[Yves Bastide]

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Hi,

twoway_wcsstr doesn't (always) work with periodic needles. With the
attached example

haystack = L"playing play play play always";
needle = L"play play play";

mem0 = 9, ms = 3; thus, after a left-half mismatch on "playing", mem is 9 and
    for (k = ms + 1; k>mem && n[k - 1] == h[k - 1]; k--);
terminates immediately.

yves

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#include <wchar.h>
#include <assert.h>

int main(int argc, char* argv[])
{
        wchar_t const *haystack = L"playing play play play always";
        wchar_t const *needle = L"play play play";

        wchar_t * p = wcsstr(haystack, needle);

        assert(p);
        return 0;
}

Re: src/string/wcsstr.c doesn't work

[Rich Felker]

On Fri, Apr 18, 2014 at 06:41:46PM +0200, Yves Bastide wrote:
> Hi,
> 
> twoway_wcsstr doesn't (always) work with periodic needles. With the
> attached example
> 
> haystack = L"playing play play play always";
> needle = L"play play play";
> 
> mem0 = 9, ms = 3; thus, after a left-half mismatch on "playing", mem is 9 and
>     for (k = ms + 1; k>mem && n[k - 1] == h[k - 1]; k--);
> terminates immediately.

Thanks! Immediate termination of this loop is correct, but the
subsequent conditional should have been treating it as success rather
than failure. Fix committed.

Rich