Ventoy/vtoycli/fat_io_lib/release/fat_cache.c
2021-11-12 19:56:05 +08:00

92 lines
3.5 KiB
C

//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// FAT16/32 File IO Library
// V2.6
// Ultra-Embedded.com
// Copyright 2003 - 2012
//
// Email: admin@ultra-embedded.com
//
// License: GPL
// If you would like a version with a more permissive license for use in
// closed source commercial applications please contact me for details.
//-----------------------------------------------------------------------------
//
// This file is part of FAT File IO Library.
//
// FAT File IO Library is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// FAT File IO Library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with FAT File IO Library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
#include <string.h>
#include "fat_cache.h"
// Per file cluster chain caching used to improve performance.
// This does not have to be enabled for architectures with low
// memory space.
//-----------------------------------------------------------------------------
// fatfs_cache_init:
//-----------------------------------------------------------------------------
int fatfs_cache_init(struct fatfs *fs, FL_FILE *file)
{
#ifdef FAT_CLUSTER_CACHE_ENTRIES
int i;
for (i=0;i<FAT_CLUSTER_CACHE_ENTRIES;i++)
{
file->cluster_cache_idx[i] = 0xFFFFFFFF; // Not used
file->cluster_cache_data[i] = 0;
}
#endif
return 1;
}
//-----------------------------------------------------------------------------
// fatfs_cache_get_next_cluster:
//-----------------------------------------------------------------------------
int fatfs_cache_get_next_cluster(struct fatfs *fs, FL_FILE *file, uint32 clusterIdx, uint32 *pNextCluster)
{
#ifdef FAT_CLUSTER_CACHE_ENTRIES
uint32 slot = clusterIdx % FAT_CLUSTER_CACHE_ENTRIES;
if (file->cluster_cache_idx[slot] == clusterIdx)
{
*pNextCluster = file->cluster_cache_data[slot];
return 1;
}
#endif
return 0;
}
//-----------------------------------------------------------------------------
// fatfs_cache_set_next_cluster:
//-----------------------------------------------------------------------------
int fatfs_cache_set_next_cluster(struct fatfs *fs, FL_FILE *file, uint32 clusterIdx, uint32 nextCluster)
{
#ifdef FAT_CLUSTER_CACHE_ENTRIES
uint32 slot = clusterIdx % FAT_CLUSTER_CACHE_ENTRIES;
if (file->cluster_cache_idx[slot] == clusterIdx)
file->cluster_cache_data[slot] = nextCluster;
else
{
file->cluster_cache_idx[slot] = clusterIdx;
file->cluster_cache_data[slot] = nextCluster;
}
#endif
return 1;
}