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/*
* This file is part of the openfat project.
*
* Copyright (C) 2011 Department of Physics, University of Otago
* Written by Gareth McMullin <gareth@blacksphere.co.nz>
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*/
/* Macros for structure access. Host system may be little or big endian,
* and may not be capable of misaligned access. Always use these for
* access to the on-disk FAT structures.
*/
#ifndef __LEACCESS_H
#define __LEACCESS_H
#include <stdint.h>
static inline uint16_t __get_le16(const uint16_t *p)
{
return *(uint8_t *)p + (*((uint8_t *)p + 1) << 8);
}
static inline void __put_le16(uint16_t *p, uint16_t v)
{
*(uint8_t *)p = v & 0xff;
*((uint8_t *)p + 1) = v >> 8;
}
static inline uint32_t __get_le32(const uint32_t *p)
{
return __get_le16((uint16_t *)p) +
(uint32_t)(__get_le16((const uint16_t *)p + 1) << 16);
}
static inline void __put_le32(uint32_t *p, uint32_t v)
{
__put_le16((uint16_t *)p, v & 0xffff);
__put_le16((uint16_t *)p + 1, v >> 16);
}
#ifdef __TEST__
#include <stdio.h>
#include <assert.h>
int main(void)
{
const char testdata[] = "\x01\x23\x45\x67";
printf("%08X\n", __get_le32((uint32_t *)testdata));
assert(__get_le32((uint32_t *)testdata) == 0x67452301);
return 0;
}
#endif
#endif
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