1 /* memcmp -- compare two memory regions. 2 This function is in the public domain. */ 3 4 /* 5 6 @deftypefn Supplemental int memcmp (const void *@var{x}, const void *@var{y}, @ 7 size_t @var{count}) 8 9 Compares the first @var{count} bytes of two areas of memory. Returns 10 zero if they are the same, a value less than zero if @var{x} is 11 lexically less than @var{y}, or a value greater than zero if @var{x} 12 is lexically greater than @var{y}. Note that lexical order is determined 13 as if comparing unsigned char arrays. 14 15 @end deftypefn 16 17 */ 18 19 #include <ansidecl.h> 20 #include <stddef.h> 21 22 int 23 memcmp (const PTR str1, const PTR str2, size_t count) 24 { 25 register const unsigned char *s1 = (const unsigned char*)str1; 26 register const unsigned char *s2 = (const unsigned char*)str2; 27 28 while (count-- > 0) 29 { 30 if (*s1++ != *s2++) 31 return s1[-1] < s2[-1] ? -1 : 1; 32 } 33 return 0; 34 } 35 36
