150 lines
4.4 KiB
C
150 lines
4.4 KiB
C
/****************************************************************************
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* fs/nxffs/nxffs_util.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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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* 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 Value:
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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(FAR 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_wrle16
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*
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* Description:
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* Put a (possibly unaligned) 16-bit little endian value.
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*
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* Input Parameters:
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* dest - A pointer to the first byte to save the little endian value.
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* val - The 16-bit value to be saved.
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void nxffs_wrle16(uint8_t *dest, uint16_t val)
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{
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dest[0] = val & 0xff; /* Little endian means LS byte first in byte stream */
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dest[1] = val >> 8;
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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 Value:
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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(FAR 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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/****************************************************************************
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* Name: nxffs_wrle32
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*
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* Description:
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* Put a (possibly unaligned) 32-bit little endian value.
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*
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* Input Parameters:
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* dest - A pointer to the first byte to save the little endian value.
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* val - The 32-bit value to be saved.
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void nxffs_wrle32(uint8_t *dest, uint32_t val)
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{
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/* Little endian means LS halfword first in byte stream */
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nxffs_wrle16(dest, (uint16_t)(val & 0xffff));
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nxffs_wrle16(dest + 2, (uint16_t)(val >> 16));
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}
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/****************************************************************************
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* Name: nxffs_erased
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*
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* Description:
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* Check if a block of memory is in the erased state.
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*
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* Input Parameters:
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* buffer - Address of the start of the memory to check.
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* buflen - The number of bytes to check.
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*
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* Returned Value:
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* The number of erased bytes found at the beginning of the memory region.
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*
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****************************************************************************/
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size_t nxffs_erased(FAR const uint8_t *buffer, size_t buflen)
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{
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size_t nerased = 0;
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for (; nerased < buflen; nerased++)
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{
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if (*buffer != CONFIG_NXFFS_ERASEDSTATE)
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{
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break;
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}
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buffer++;
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}
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return nerased;
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}
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