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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 */
/** */
/** Directory */
/** */
/**************************************************************************/
/**************************************************************************/
#define FX_SOURCE_CODE
/* Include necessary system files. */
#include "fx_api.h"
#include "fx_system.h"
#include "fx_directory.h"
#include "fx_utility.h"
#ifdef FX_ENABLE_EXFAT
#include "fx_directory_exFAT.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _fx_utility_exFAT_allocate_new_cluster PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function allocates new cluster media for a free */
/* directory entry. */
/* */
/* INPUT */
/* */
/* media_ptr Media control block pointer */
/* directory_ptr Pointer to directory to */
/* search in */
/* last_cluster Last cluster of entry */
/* cluster Allocated cluster */
/* */
/* OUTPUT */
/* */
/* return status */
/* */
/* CALLS */
/* */
/* _fx_directory_exFAT_entry_read Read exFAT entries */
/* _fx_utility_exFAT_bitmap_flush Flush exFAT allocation bitmap */
/* _fx_utility_exFAT_bitmap_free_cluster_find */
/* Find free cluster */
/* _fx_utility_exFAT_cluster_state_get Get cluster state */
/* _fx_utility_FAT_entry_read Read FAT entry */
/* _fx_utility_FAT_entry_write Write FAT entry */
/* */
/* CALLED BY */
/* */
/* _fx_directory_exFAT_free_search */
/* */
/* 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_allocate_new_cluster(FX_MEDIA *media_ptr, FX_DIR_ENTRY *directory_ptr,
ULONG *last_cluster, ULONG *cluster)
{
UINT status = FX_SUCCESS;
ULONG cluster_count;
ULONG bytes_per_cluster;
ULONG i;
ULONG FAT_value = 0;
UCHAR cluster_state = FX_EXFAT_BITMAP_CLUSTER_OCCUPIED;
/* Clear the last cluster number. */
*last_cluster = 0;
/* Check if we have any already allocated clusters. */
if (!directory_ptr || (directory_ptr -> fx_dir_entry_available_file_size > 0))
{
/* Calculate bytes per cluster. */
bytes_per_cluster = ((ULONG)media_ptr -> fx_media_bytes_per_sector) *
((ULONG)media_ptr -> fx_media_sectors_per_cluster);
/* Check if FAT table is not used. */
if (directory_ptr && (directory_ptr -> fx_dir_entry_dont_use_fat & 1))
{
/* Calculate the cluster count associated with the directory. */
cluster_count = (ULONG)((directory_ptr -> fx_dir_entry_available_file_size + bytes_per_cluster - 1) /
bytes_per_cluster);
/* Calculate the next cluster and the last cluster. */
*cluster = directory_ptr -> fx_dir_entry_cluster + cluster_count;
*last_cluster = *cluster - 1;
/* Make sure the next cluster number don't exceed the total cluster number. */
if (*cluster < media_ptr -> fx_media_total_clusters + FX_FAT_ENTRY_START)
{
/* Get cluster state. */
status = _fx_utility_exFAT_cluster_state_get(media_ptr, *cluster, &cluster_state);
if (status != FX_SUCCESS)
{
/* Return the bad status. */
return(status);
}
}
/* Is the next cluster free? */
if (cluster_state == FX_EXFAT_BITMAP_CLUSTER_FREE)
{
/* Yes, so we still don't need to use FAT. */
return(FX_SUCCESS);
}
/* Now we should use FAT. Clear the bit 0. */
directory_ptr -> fx_dir_entry_dont_use_fat &= (CHAR)0xfe;
/* Loop to build FAT chain. */
for (i = directory_ptr -> fx_dir_entry_cluster; i < *last_cluster; ++i)
{
/* Write the FAT entry. */
status = _fx_utility_FAT_entry_write(media_ptr, i, i + 1);
if (status != FX_SUCCESS)
{
/* Return the bad status. */
return(status);
}
}
/* Write last cluster entry. */
status = _fx_utility_FAT_entry_write(media_ptr, *last_cluster, FX_LAST_CLUSTER_exFAT);
if (status != FX_SUCCESS)
{
/* Return the bad status. */
return(status);
}
}
else
{
/* Find last cluster by walk through the FAT chain. */
/* See if we are in sub directory or the root directory. And set the start cluster. */
if (directory_ptr)
{
*cluster = directory_ptr -> fx_dir_entry_cluster;
}
else
{
*cluster = media_ptr -> fx_media_root_cluster_32;
}
/* Initialize loop variables. */
*last_cluster = 0;
i = 0;
/* Follow the link of FAT entries. */
while ((*cluster >= FX_FAT_ENTRY_START) && (*cluster < FX_RESERVED_1_exFAT))
{
/* Read the current cluster entry from the FAT. */
status = _fx_utility_FAT_entry_read(media_ptr, *cluster, &FAT_value);
i++;
/* Check the return value. */
if (status != FX_SUCCESS)
{
/* Return the error status. */
return(status);
}
/* Determine if the FAT read was invalid. */
if ((*cluster == FAT_value) || (i > media_ptr -> fx_media_total_clusters))
{
/* Return the bad status. */
return(FX_FAT_READ_ERROR);
}
/* Save the last valid cluster. */
*last_cluster = *cluster;
/* Setup for the next cluster. */
*cluster = FAT_value;
}
}
}
/* Find free cluster from exFAT media. */
status = _fx_utility_exFAT_bitmap_free_cluster_find(media_ptr,
media_ptr -> fx_media_cluster_search_start,
cluster);
return(status);
}
#endif /* FX_ENABLE_EXFAT */
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