1 #include "byte.h"
2
3 /* str_diff returns negative, 0, or positive, depending on whether the
4 * string a[0], a[1], ..., a[n]=='\0' is lexicographically smaller than,
5 * equal to, or greater than the string b[0], b[1], ..., b[m-1]=='\0'.
6 * When the strings are different, str_diff does not read bytes past the
7 * first difference. */
str_diffn(const char * a,const char * b,size_t limit)8 int str_diffn(const char* a, const char* b, size_t limit) {
9 register const unsigned char* s=(const unsigned char*)a;
10 register const unsigned char* t=(const unsigned char*)b;
11 register const unsigned char* u=t+limit;
12 register int j;
13 j=0;
14 for (;;) {
15 if (t>=u || (j=(*s-*t)) || !*t) break;
16 ++s; ++t;
17 if (t>=u || (j=(*s-*t)) || !*t) break;
18 ++s; ++t;
19 if (t>=u || (j=(*s-*t)) || !*t) break;
20 ++s; ++t;
21 if (t>=u || (j=(*s-*t)) || !*t) break;
22 ++s; ++t;
23 }
24 return j;
25 }
26