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Transition FileX to Eclipse Fundation

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TiejunZhou
2024-01-02 07:35:14 +00:00
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common/src/fx_media_check_lost_cluster_check.c
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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 */
/** */
/** Media */
/** */
/**************************************************************************/
/**************************************************************************/
#define FX_SOURCE_CODE
/* Include necessary system files. */
#include "fx_api.h"
#include "fx_media.h"
#include "fx_utility.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _fx_media_check_lost_cluster_check PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function examines all clusters to see if there are any unused */
/* clusters that are also unavailable. If specified, this routine will */
/* also mark the cluster as available. */
/* */
/* INPUT */
/* */
/* media_ptr Pointer to a previously */
/* opened media */
/* logical_fat Pointer to the logical FAT */
/* bit map */
/* total_clusters Total number of clusters */
/* error_correction_option Option for correcting lost */
/* cluster errors */
/* */
/* OUTPUT */
/* */
/* error Error code */
/* */
/* CALLS */
/* */
/* _fx_utility_FAT_entry_read Read a FAT entry */
/* _fx_utility_FAT_entry_write Write a FAT entry */
/* */
/* CALLED BY */
/* */
/* _fx_check_media Check media function */
/* */
/* 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 */
/* */
/**************************************************************************/
ULONG _fx_media_check_lost_cluster_check(FX_MEDIA *media_ptr, UCHAR *logical_fat, ULONG total_clusters, ULONG error_correction_option)
{
ULONG cluster, next_cluster = 0;
ULONG fat_last;
ULONG error;
UINT status;
/* Calculate the FAT reserved and last sector values. */
if (media_ptr -> fx_media_32_bit_FAT)
{
fat_last = FX_LAST_CLUSTER_1_32;
}
else
{
fat_last = FX_LAST_CLUSTER_1;
}
/* Initialize the error. */
error = 0;
/* Loop through all the clusters to see if any clusters NOT in the logical sector FAT have
a non zero value. */
for (cluster = FX_FAT_ENTRY_START; cluster < total_clusters; cluster++)
{
/* Determine if this cluster is in the logical FAT. */
if (logical_fat[cluster >> 3] & (1 << (cluster & 7)))
{
/* Yes, the cluster is in use by a file or sub-directory. Just continue the loop. */
continue;
}
/* Otherwise, the cluster is not in use. */
/* Read the contents of what should be a free cluster. */
status = _fx_utility_FAT_entry_read(media_ptr, cluster, &next_cluster);
/* Check for a good status. */
if (status)
{
/* Set the error code. */
error = error | FX_IO_ERROR;
/* Return error code. */
return(error);
}
/* Determine if the contents of the cluster is valid. */
if (((next_cluster > (ULONG)FX_FREE_CLUSTER) && (next_cluster < media_ptr -> fx_media_fat_reserved)) ||
(next_cluster >= fat_last))
{
/* Lost cluster is present. */
/* Set the error code status. */
error = FX_LOST_CLUSTER_ERROR;
/* Determine if the lost cluster should be recovered. */
if (error_correction_option & FX_LOST_CLUSTER_ERROR)
{
/* Make the cluster available again. */
status = _fx_utility_FAT_entry_write(media_ptr, cluster, FX_FREE_CLUSTER);
/* Check for a good status. */
if (status)
{
/* Increment the available clusters. */
media_ptr -> fx_media_available_clusters++;
/* Set the error code. */
error = error | FX_IO_ERROR;
/* Return error code. */
return(error);
}
}
}
}
/* Return error code. */
return(error);
}