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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"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _fx_utility_exFAT_bitmap_free_cluster_find PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function searches for a free cluster. */
/* */
/* INPUT */
/* */
/* media_ptr Media control block pointer */
/* search_start_cluster Cluster number to begin search*/
/* free_cluster ULONG pointer to store cluster*/
/* */
/* OUTPUT */
/* */
/* return status */
/* */
/* CALLS */
/* */
/* _fx_utility_exFAT_cluster_state_get Get cluster state */
/* */
/* 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_bitmap_free_cluster_find(FX_MEDIA *media_ptr, ULONG search_start_cluster, ULONG *free_cluster)
{
UINT status;
UCHAR cluster_state;
ULONG cluster = search_start_cluster;
/* Search for a free cluster. */
while (cluster < media_ptr -> fx_media_total_clusters + FX_FAT_ENTRY_START)
{
/* Get the cluster state. */
status = _fx_utility_exFAT_cluster_state_get(media_ptr, cluster, &cluster_state);
/* Check the status of the state get. */
if (status != FX_SUCCESS)
{
/* Media error or out of total clusters number - stop searching. */
return(status);
}
/* Is this cluster free? */
if (cluster_state == FX_EXFAT_BITMAP_CLUSTER_FREE)
{
/* Yes, finished the search. */
/* Return the cluster. */
*free_cluster = cluster;
/* Return success. */
return(FX_SUCCESS);
}
/* Move to next cluster. */
cluster++;
}
/* See if there is anything to search in the beginning. */
if (search_start_cluster > FX_FAT_ENTRY_START)
{
/* Start at the beginning. */
cluster = FX_FAT_ENTRY_START;
/* Loop to search clusters. */
while (cluster < search_start_cluster)
{
/* Get the cluster state. */
status = _fx_utility_exFAT_cluster_state_get(media_ptr, cluster, &cluster_state);
if (status != FX_SUCCESS)
{
/* Media error or out of total clusters number - stop searching. */
return(status);
}
/* Is this cluster free? */
if (cluster_state == FX_EXFAT_BITMAP_CLUSTER_FREE)
{
/* Yes, finished the search. */
/* Return the cluster. */
*free_cluster = cluster;
/* Return success. */
return(FX_SUCCESS);
}
/* Move to the next cluster. */
cluster++;
}
}
/* No more free clusters, return error. */
return(FX_NO_MORE_SPACE);
}
#endif /* FX_ENABLE_EXFAT */
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