fat32_access.c

FAT32代码

//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
//					        FAT32 File IO Library
//								    V2.0
// 	  							 Rob Riglar
//						    Copyright 2003 - 2007
//
//   					  Email: [e-mail]
//
//-----------------------------------------------------------------------------
//
// 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 "FAT32_Definitions.h"
#include "FAT32_Base.h"
#include "FAT32_Table.h"
#include "FAT32_Access.h"
#include "FAT32_Write.h"
#include "FAT32_Filestring.h"
#include "FAT32_Misc.h"

//-----------------------------------------------------------------------------
// FAT32_InitFAT: Load FAT32 Parameters
//-----------------------------------------------------------------------------
BOOL FAT32_InitFAT(void)
{
	FATFS_Internal.SectorCurrentlyLoaded = 0xFFFFFFFF;
	FATFS_Internal.NextFreeCluster = 0xFFFFFFFF;
	return FAT32_Init();
}
//-----------------------------------------------------------------------------
// FAT32_SectorReader: From the provided startcluster and sector offset
// Returns True if success, returns False if not (including if read out of range)
//-----------------------------------------------------------------------------
BOOL FAT32_SectorReader(UINT32 Startcluster, UINT32 offset)
{
	UINT32 SectortoRead = 0;
	UINT32 ClustertoRead = 0;
	UINT32 ClusterChain = 0;
	UINT32 i;
	UINT32 lba;

	// 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 false
	if (ClusterChain==0xFFFFFFFF) 
		return FALSE;

	// Calculate sector address
	lba = FAT32_LBAofCluster(ClusterChain)+SectortoRead;

	// Else read sector if not already loaded
	if (lba!=FATFS_Internal.SectorCurrentlyLoaded)
	{
		FATFS_Internal.SectorCurrentlyLoaded = lba;
		return FAT_ReadSector(FATFS_Internal.SectorCurrentlyLoaded, FATFS_Internal.currentsector);
	}
	else
		return TRUE;
}

//-----------------------------------------------------------------------------
// FAT32_SectorWriter: Write to the provided startcluster and sector offset
// Returns True if success, returns False if not 
//-----------------------------------------------------------------------------
#ifdef INCLUDE_WRITE_SUPPORT
BOOL FAT32_SectorWriter(UINT32 Startcluster, UINT32 offset)
{
 	UINT32 SectortoWrite = 0;
	UINT32 ClustertoWrite = 0;
	UINT32 ClusterChain = 0;
	UINT32 LastClusterChain = 0xFFFFFFFF;
	UINT32 i;
	
	// Set start of cluster chain to initial value
	ClusterChain = Startcluster;

	// Find parameters
	ClustertoWrite = offset / FAT32.SectorsPerCluster;	  
	SectortoWrite = offset - (ClustertoWrite*FAT32.SectorsPerCluster);

	// Follow chain to find cluster to read
	for (i=0; i<ClustertoWrite; i++)
	{
		// Find next link in the chain
		LastClusterChain = ClusterChain;
	  	ClusterChain = FAT32_FindNextCluster(ClusterChain);

		// Dont keep following a dead end
		if (ClusterChain==0xFFFFFFFF)
			break;
	}

	// If end of cluster chain 
	if (ClusterChain==0xFFFFFFFF) 
	{
		// Add another cluster to the last good cluster chain
		if (!FAT32_AddFreeSpaceToChain(&LastClusterChain))
			return FALSE;

		ClusterChain = LastClusterChain;
	}

	// Calculate write address
	FATFS_Internal.SectorCurrentlyLoaded = FAT32_LBAofCluster(ClusterChain)+SectortoWrite;

	// Write to disk
	return FAT_WriteSector(FATFS_Internal.SectorCurrentlyLoaded, FATFS_Internal.currentsector);
}
#endif
//-----------------------------------------------------------------------------
// FAT32_ShowFATDetails: Show the details about the filesystem
//-----------------------------------------------------------------------------
void FAT32_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");
}
//-----------------------------------------------------------------------------
// FAT32_GetRootCluster: Get the root dir cluster
//-----------------------------------------------------------------------------
UINT32 FAT32_GetRootCluster()
{
	return FAT32.RootDir_First_Cluster;
}
//-------------------------------------------------------------
// FAT32_GetFileEntry: Find the file entry for a filename
//-------------------------------------------------------------
UINT32 FAT32_GetFileEntry(UINT32 Cluster, char *nametofind, FAT32_ShortEntry *sfEntry)
{
	BYTE item=0;
	UINT16 recordoffset = 0;
	BYTE i=0;
	int x=0;
	char LongFilename[MAX_LONG_FILENAME];
	char ShortFilename[13];
	FAT32_ShortEntry *directoryEntry;

	FATMisc_ClearLFN(TRUE);

	// Main cluster following loop
	while (TRUE)
	{
		// Read sector
		if (FAT32_SectorReader(Cluster, x++)) // If sector read was successfull
		{
			// Analyse Sector
			for (item=0; item<=15;item++)
			{
				// Create the multiplier for sector access
				recordoffset = (32*item);

				// Overlay directory entry over buffer
				directoryEntry = (FAT32_ShortEntry*)(FATFS_Internal.currentsector+recordoffset);

				// Long File Name Text Found
				if (FATMisc_If_LFN_TextOnly(directoryEntry) ) 
					FATMisc_CacheLFN(FATFS_Internal.currentsector+recordoffset);

				// If Invalid record found delete any long file name information collated
				else if (FATMisc_If_LFN_Invalid(directoryEntry) ) 
					FATMisc_ClearLFN(FALSE);

				// Normal SFN Entry and Long text exists 
				else if (FATMisc_If_LFN_Exists(directoryEntry) ) 
				{
					FATMisc_GetLFNCache((BYTE*)LongFilename);

					// Compare names to see if they match
					if (FileString_Compare(LongFilename, nametofind)) 
					{
						memcpy(sfEntry,directoryEntry,sizeof(FAT32_ShortEntry));
						return TRUE;
					}

		 			FATMisc_ClearLFN(FALSE);
				}

				// Normal Entry, only 8.3 Text		 
				else if (FATMisc_If_noLFN_SFN_Only(directoryEntry) )
				{
					memset(ShortFilename, 0, sizeof(ShortFilename));

					// Copy name to string
					for (i=0; i<8; i++) 
						ShortFilename[i] = directoryEntry->Name[i];

					// If not . or .. entry
					if (ShortFilename[0]!='.')
                        ShortFilename[8] = '.';
					else
						ShortFilename[8] = ' ';

					// Extension
					for (i=8; i<11; i++) 
						ShortFilename[i+1] = directoryEntry->Name[i];
		  			
					// Compare names to see if they match
					if (FileString_Compare(ShortFilename, nametofind)) 
					{
						memcpy(sfEntry,directoryEntry,sizeof(FAT32_ShortEntry));
						return TRUE;
					}

					FATMisc_ClearLFN(FALSE);
				}
			} // End of if
		} 
		else
			break;
	} // End of while loop

	return FALSE;
}
//-------------------------------------------------------------
// FAT32_SFNexists: Check if a short filename exists.
// NOTE: shortname is XXXXXXXXYYY not XXXXXXXX.YYY
//-------------------------------------------------------------
#ifdef INCLUDE_WRITE_SUPPORT
BOOL FAT32_SFNexists(UINT32 Cluster, char *shortname)
{
	BYTE item=0;
	UINT16 recordoffset = 0;