checksum.c
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:1k
- /* 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 */
- #include <my_global.h>
- #include "my_sys.h"
- /*
- Calculate a long checksum for a memoryblock.
- SYNOPSIS
- my_checksum()
- crc start value for crc
- pos pointer to memory block
- length length of the block
- */
- ha_checksum my_checksum(ha_checksum crc, const byte *pos, uint length)
- {
- #ifdef NOT_USED
- const byte *end=pos+length;
- for ( ; pos != end ; pos++)
- crc=((crc << 8) + *((uchar*) pos)) + (crc >> (8*sizeof(ha_checksum)-8));
- return crc;
- #else
- return (ha_checksum)crc32((uint)crc, (const uchar *)pos, length);
- #endif
- }