fat32_access.c

一个FAT32文件系统的源代码,可用于嵌入式系统,并能够直接在linux下直接验证.

//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
//					    FAT32 File IO Library Linux Test Version
//									  V1.0L
// 	  								Rob Riglar
//								Copyright 2003,2004 
//
//   					  Email: [e-mail]
//
//			   Compiled and tested on Redhat 'Shrike' with GNU gcc
//-----------------------------------------------------------------------------
//
// This file is part of FAT32 File IO Library.
//
// FAT32 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.
//
// FAT32 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 FAT32 File IO Library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "../IDE/IDE_Access.h"
#include "FAT32_Access.h"
#include "FAT32_Base.h"
//-----------------------------------------------------------------------------
// FAT32_LoadFAT: Load FAT32 Parameters
//-----------------------------------------------------------------------------
void FAT32_LoadFAT(void)
{
 	 printf("\r\nLoading Partition 1");
	 FAT32_FindFAT32Details();
	 printf("\r\nFAT Parameters Loaded Successfully");
}

//-----------------------------------------------------------------------------
// FAT32_SectorReader: From the provided startcluster and sector offset, load using 
//		   IDE_BufferSector the required sector into memory.
//-----------------------------------------------------------------------------
int FAT32_SectorReader(UI32 Startcluster, UI32 offset)
{
 	  UI32 SectortoRead = 0;
	  UI32 ClustertoRead = 0;
	  UI32 ClusterChain = 0;
	  UI32 i;
	  
	  // Set start of cluster chain to initial value
	  ClusterChain = Startcluster;

	  // Find parameters
	  ClustertoRead = offset / FAT32.SectorsPerCluster;	  
	  SectortoRead = offset - (ClustertoRead*FAT32.SectorsPerCluster);

	  // Follow chain to find cluster to read
	  for (i=0; i<ClustertoRead; i++)
	  	  ClusterChain = FAT32_FindNextCluster(ClusterChain);

	  // If end of cluster chain then return 1
	  if (ClusterChain==0xFFFFFFFF) return 1;

	  // Else read sector and return 0
	  IDE_BufferSector(FAT32_LBAofCluster(ClusterChain)+SectortoRead);
	  
	  return 0;
}

//-----------------------------------------------------------------------------
// ShowFATDetails
//-----------------------------------------------------------------------------
void ShowFATDetails(void)
{
printf("\r\nCurrent Disc FAT details\r\n------------------------\r\nRoot Dir First Cluster = ");   
printf("0x%x",FAT32.RootDir_First_Cluster);
printf("\r\nFAT Begin LBA = ");
printf("0x%x",FAT32.fat_begin_lba);
printf("\r\nCluster Begin LBA = ");
printf("0x%x",FAT32.cluster_begin_lba);
printf("\r\nSectors Per Cluster = ");
printf("%d",FAT32.SectorsPerCluster);
printf("\r\n\r\nFormula for conversion from Cluster num to LBA is;");
printf("\r\nLBA = (cluster_begin_lba + ((Cluster_Number-2)*SectorsPerCluster)))\r\n");
printf("\r\nMax LBA address on this drive is 0x%lx",IDE_Internal.maxLBA-1);
}