1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
|
#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_diffn(const char* a, const char* b, size_t limit) {
register const unsigned char* s=(const unsigned char*)a;
register const unsigned char* t=(const unsigned char*)b;
register const unsigned char* u=t+limit;
register int j;
j=0;
for (;;) {
if (t>=u) break; if ((j=(*s-*t))) break; if (!*t) break; ++s; ++t;
if (t>=u) break; if ((j=(*s-*t))) break; if (!*t) break; ++s; ++t;
if (t>=u) break; if ((j=(*s-*t))) break; if (!*t) break; ++s; ++t;
if (t>=u) break; if ((j=(*s-*t))) break; if (!*t) break; ++s; ++t;
}
return j;
}
|
