diff options
Diffstat (limited to 'clib/src/checksum.c')
-rw-r--r-- | clib/src/checksum.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/clib/src/checksum.c b/clib/src/checksum.c new file mode 100644 index 0000000..fea96b4 --- /dev/null +++ b/clib/src/checksum.c @@ -0,0 +1,43 @@ +/* + * Copyright (c) International Business Machines Corp., 2014 + * + * 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 + */ + +#include <stdio.h> +#include <stdint.h> + +#include "assert.h" +#include "checksum.h" + +uint32_t memcpy_checksum(void *__restrict __dst, const void *__restrict __src, + size_t __n) +{ + uint8_t sum[4] = { 0, }; + + /* assert(((uintptr_t)__src & 3) == 0); */ + + size_t i; + + if (__dst == NULL) + for (i = 0; i < __n; i++) + sum[i & 3] ^= ((uint8_t *) __src)[i]; + else + for (i = 0; i < __n; i++) + sum[i & 3] ^= ((uint8_t *) __src)[i], + ((uint8_t *) __dst)[i] = ((uint8_t *) __src)[i]; + + return (sum[0] << 24) | (sum[1] << 16) | (sum[2] << 8) | sum[3]; +} |