memcmp.c
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:2k
- /* Copyright (C) 2000 MySQL AB
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- /* memcmp(lhs, rhs, len)
- compares the two memory areas lhs[0..len-1] ?? rhs[0..len-1]. It
- returns an integer less than, equal to, or greater than 0 according
- as lhs[-] is lexicographically less than, equal to, or greater than
- rhs[-]. Note that this is not at all the same as bcmp, which tells
- you *where* the difference is but not what.
- Note: suppose we have int x, y; then memcmp(&x, &y, sizeof x) need
- not bear any relation to x-y. This is because byte order is machine
- dependent, and also, some machines have integer representations that
- are shorter than a machine word and two equal integers might have
- different values in the spare bits. On a ones complement machine,
- -0 == 0, but the bit patterns are different.
- */
- #include "strings.h"
- #if !defined(HAVE_MEMCPY)
- int memcmp(lhs, rhs, len)
- register char *lhs, *rhs;
- register int len;
- {
- while (--len >= 0)
- if (*lhs++ != *rhs++) return (uchar) lhs[-1] - (uchar) rhs[-1];
- return 0;
- }
- #endif