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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** FileX Component */
/** */
/** Utility */
/** */
/**************************************************************************/
/**************************************************************************/
#define FX_SOURCE_CODE
/* Include necessary system files. */
#include "fx_api.h"
#ifdef FX_ENABLE_EXFAT
#include "fx_system.h"
#include "fx_media.h"
#include "fx_utility.h"
#include "fx_directory_exFAT.h"
#ifdef FX_ENABLE_FAULT_TOLERANT
#include "fx_fault_tolerant.h"
#endif /* FX_ENABLE_FAULT_TOLERANT */
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _fx_utility_exFAT_cluster_state_get PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function gets the cluster state of exFAT volume. */
/* */
/* INPUT */
/* */
/* media_ptr Media control block pointer */
/* cluster Cluster number */
/* cluster_state UCHAR pointer to store state */
/* */
/* OUTPUT */
/* */
/* return status */
/* */
/* CALLS */
/* */
/* _fx_utility_exFAT_bitmap_cache_prepare */
/* Read bitmap to cache */
/* _fx_fault_tolerant_read_FAT Read FAT entry from log file */
/* */
/* CALLED BY */
/* */
/* FileX System Functions */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 William E. Lamie Initial Version 6.0 */
/* 09-30-2020 William E. Lamie Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
UINT _fx_utility_exFAT_cluster_state_get(FX_MEDIA *media_ptr, ULONG cluster, UCHAR *cluster_state)
{
UINT status;
UINT bitmap_offset;
UCHAR cluster_shift;
UCHAR eight_clusters_block;
#ifdef FX_ENABLE_FAULT_TOLERANT
ULONG value;
if (media_ptr -> fx_media_fault_tolerant_enabled &&
(media_ptr -> fx_media_fault_tolerant_state & FX_FAULT_TOLERANT_STATE_STARTED))
{
/* Redirect this request to the log file.
During file or directory operations with Fault Tolerant
protection, intermediate operations are written to the fault
tolerant log file. Therefore, FAT-entry read should search for
fault tolerant log before the request can be passed to normal FAT
entry read routine.
*/
status = _fx_fault_tolerant_read_FAT(media_ptr, cluster, &value, FX_FAULT_TOLERANT_BITMAP_LOG_TYPE);
/* Return on success. */
if (status != FX_READ_CONTINUE)
{
*cluster_state = (UCHAR)value;
return(status);
}
}
#endif /* FX_ENABLE_FAULT_TOLERANT */
/* Prepare bitmap cache. */
status = _fx_utility_exFAT_bitmap_cache_prepare(media_ptr, cluster);
/* Was it successful? */
if (status == FX_SUCCESS)
{
/* Calculate the bitmap offset. */
bitmap_offset = (UINT)(cluster - media_ptr -> fx_media_exfat_bitmap_cache_start_cluster) >> BITS_PER_BYTE_SHIFT;
/* Pickup the 8 cluster block. */
eight_clusters_block = *(media_ptr -> fx_media_exfat_bitmap_cache + bitmap_offset);
/* Check all 8 bits for 0x00 (all clusters in the block are free). */
if (eight_clusters_block == 0x00)
{
/* Cluster is free, return state. */
*cluster_state = FX_EXFAT_BITMAP_CLUSTER_FREE;
}
/* Check all 8 bits for 0xFF (all 8 clusters are occupied). */
else if (0xFF == eight_clusters_block)
{
/* Cluster is not free, return state. */
*cluster_state = FX_EXFAT_BITMAP_CLUSTER_OCCUPIED;
}
else
{
/* Check bit respondent for cluster state. */
cluster_shift = (UCHAR)((cluster - FX_FAT_ENTRY_START) % BITS_PER_BYTE);
*cluster_state = (eight_clusters_block >> cluster_shift) & 0x1;
}
}
/* Return status. */
return(status);
}
#endif /* FX_ENABLE_EXFAT */
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