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/****************************************************************************
* fs/nxffs/nxffs_util.c
*
* Copyright (C) 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* References: Linux/Documentation/filesystems/romfs.txt
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <string.h>
#include "nxffs.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Public Types
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxffs_rdle16
*
* Description:
* Get a (possibly unaligned) 16-bit little endian value.
*
* Input Parameters:
* val - A pointer to the first byte of the little endian value.
*
* Returned Value:
* A uint16_t representing the whole 16-bit integer value
*
****************************************************************************/
uint16_t nxffs_rdle16(FAR const uint8_t *val)
{
return (uint16_t)val[1] << 8 | (uint16_t)val[0];
}
/****************************************************************************
* Name: nxffs_wrle16
*
* Description:
* Put a (possibly unaligned) 16-bit little endian value.
*
* Input Parameters:
* dest - A pointer to the first byte to save the little endian value.
* val - The 16-bit value to be saved.
*
* Returned Value:
* None
*
****************************************************************************/
void nxffs_wrle16(uint8_t *dest, uint16_t val)
{
dest[0] = val & 0xff; /* Little endian means LS byte first in byte stream */
dest[1] = val >> 8;
}
/****************************************************************************
* Name: nxffs_rdle32
*
* Description:
* Get a (possibly unaligned) 32-bit little endian value.
*
* Input Parameters:
* val - A pointer to the first byte of the little endian value.
*
* Returned Value:
* A uint32_t representing the whole 32-bit integer value
*
****************************************************************************/
uint32_t nxffs_rdle32(FAR const uint8_t *val)
{
/* Little endian means LS halfword first in byte stream */
return (uint32_t)nxffs_rdle16(&val[2]) << 16 | (uint32_t)nxffs_rdle16(val);
}
/****************************************************************************
* Name: nxffs_wrle32
*
* Description:
* Put a (possibly unaligned) 32-bit little endian value.
*
* Input Parameters:
* dest - A pointer to the first byte to save the little endian value.
* val - The 32-bit value to be saved.
*
* Returned Value:
* None
*
****************************************************************************/
void nxffs_wrle32(uint8_t *dest, uint32_t val)
{
/* Little endian means LS halfword first in byte stream */
nxffs_wrle16(dest, (uint16_t)(val & 0xffff));
nxffs_wrle16(dest+2, (uint16_t)(val >> 16));
}
/****************************************************************************
* Name: nxffs_erased
*
* Description:
* Check if a block of memory is in the erased state.
*
* Input Parameters:
* buffer - Address of the start of the memory to check.
* buflen - The number of bytes to check.
*
* Returned Values:
* The number of erased bytes found at the beginning of the memory region.
*
****************************************************************************/
size_t nxffs_erased(FAR const uint8_t *buffer, size_t buflen)
{
size_t nerased = 0;
for (; nerased < buflen; nerased++)
{
if (*buffer != CONFIG_NXFFS_ERASEDSTATE)
{
break;
}
buffer++;
}
return nerased;
}
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