73308cef13
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3537 42af7a65-404d-4744-a932-0658087f49c3
108 lines
4.1 KiB
C
108 lines
4.1 KiB
C
/****************************************************************************
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* fs/nxffs/nxffs_util.c
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*
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* Copyright (C) 2011 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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*
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* References: Linux/Documentation/filesystems/romfs.txt
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <string.h>
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#include "nxffs.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/****************************************************************************
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* Public Variables
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxffs_rdle16
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*
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* Description:
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* Get a (possibly unaligned) 16-bit little endian value.
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*
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* Input Parameters:
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* val - A pointer to the first byte of the little endian value.
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*
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* Returned Values:
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* A uint16_t representing the whole 16-bit integer value
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*
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****************************************************************************/
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uint16_t nxffs_rdle16(const uint8_t *val)
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{
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return (uint16_t)val[1] << 8 | (uint16_t)val[0];
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}
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/****************************************************************************
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* Name: nxffs_rdle32
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*
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* Description:
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* Get a (possibly unaligned) 32-bit little endian value.
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*
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* Input Parameters:
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* val - A pointer to the first byte of the little endian value.
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*
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* Returned Values:
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* A uint32_t representing the whole 32-bit integer value
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*
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****************************************************************************/
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uint32_t nxffs_rdle32(const uint8_t *val)
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{
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/* Little endian means LS halfword first in byte stream */
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return (uint32_t)nxffs_rdle16(&val[2]) << 16 | (uint32_t)nxffs_rdle16(val);
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}
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