| 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}, size_t @var{count}) |
| 7 | |
| 8 | Compares the first @var{count} bytes of two areas of memory. Returns |
| 9 | zero if they are the same, a value less than zero if @var{x} is |
| 10 | lexically less than @var{y}, or a value greater than zero if @var{x} |
| 11 | is lexically greater than @var{y}. Note that lexical order is determined |
| 12 | as if comparing unsigned char arrays. |
| 13 | |
| 14 | @end deftypefn |
| 15 | |
| 16 | */ |
| 17 | |
| 18 | #include <ansidecl.h> |
| 19 | #ifdef __STDC__ |
| 20 | #include <stddef.h> |
| 21 | #else |
| 22 | #define size_t unsigned long |
| 23 | #endif |
| 24 | |
| 25 | int |
| 26 | DEFUN(memcmp, (str1, str2, count), |
| 27 | const PTR str1 AND const PTR str2 AND size_t count) |
| 28 | { |
| 29 | register const unsigned char *s1 = (const unsigned char*)str1; |
| 30 | register const unsigned char *s2 = (const unsigned char*)str2; |
| 31 | |
| 32 | while (count-- > 0) |
| 33 | { |
| 34 | if (*s1++ != *s2++) |
| 35 | return s1[-1] < s2[-1] ? -1 : 1; |
| 36 | } |
| 37 | return 0; |
| 38 | } |
| 39 | |