eris/str_diff.c

21 lines
704 B
C

#include "byte.h"
/* str_diff returns negative, 0, or positive, depending on whether the
* string a[0], a[1], ..., a[n]=='\0' is lexicographically smaller than,
* equal to, or greater than the string b[0], b[1], ..., b[m-1]=='\0'.
* When the strings are different, str_diff does not read bytes past the
* first difference. */
int str_diff(const char* a, const char* b) {
register const char* s=a;
register const char* t=b;
register int j;
j=0;
for (;;) {
if ((j=(*s-*t))) break; if (!*t) break; ++s; ++t;
if ((j=(*s-*t))) break; if (!*t) break; ++s; ++t;
if ((j=(*s-*t))) break; if (!*t) break; ++s; ++t;
if ((j=(*s-*t))) break; if (!*t) break; ++s; ++t;
}
return j;
}