strrstr

[Reuben Thomas <rrt at sc3d dot org>]

Hi,

I note that glibc has no strrstr implementation, and I can't after a bit of 
searching find anything saying that there's no desire to have this 
widely-used and implemented function.

I have written an original implementation which I use in GNU Zile, and which 
has therefore already had its copyright assigned to the FSF. It was written 
for correctness and simplicity, and has been in production use in Zile for 
some years, although at present it has no test suite. Here it is:

#include <stddef.h>
#include <string.h>

char *strrstr (const char *s, const char *t);

char *
strrstr (const char *s, const char *t)
{
  size_t i, j, tlen = strlen (t);

  for (i = strlen (s); i >= tlen; i--)
    {
      for (j = 0; j < tlen && s[i - tlen + j] == t[j]; j++)
	;
      if (j == tlen)
	return (char *) (s + i - tlen);
    }

  return NULL;
}

Would it be any use for glibc? glibc's one of the most widely-deployed C 
libraries that still lacks this function.

--
http://rrt.sc3d.org/ | resident, a.  unable to leave (Bierce)