www.pudn.com > fat32.c51.rar > FATREADFILE.C

#ifndef _FAT32_DEFINE 
 #include "FAT32.c" 
#endif 
 
WORD FAT32ReadFile(BYTE fp); 
 
WORD FAT32ReadFile(BYTE fp) 
{ 
	register WORD tmp; 
 
	if (FCB[fp].ByteCnt==FCB[fp].Size) return(0); 
	else 
	{ 
		FCB[fp].ByteCnt+=IDE.BytesPerSec; 
		if (FCB[fp].ByteCnt<=FCB[fp].Size) tmp=IDE.BytesPerSec; 
		else 
		{ 
			FCB[fp].ByteCnt-=IDE.BytesPerSec; 
			tmp=FCB[fp].Size-FCB[fp].ByteCnt; 
			FCB[fp].ByteCnt=FCB[fp].Size; 
		} 
 
		if (FCB[fp].ClusSecCnt==FAT32.SecPerClus)			//读下一簇 
		{ 
			FCB[fp].LastCluster=FAT32NextCluster(FCB[fp].LastCluster); 
			if (FCB[fp].LastCluster==0x0fffffff) return(0); 
			IDEReadSector(ClusterToSector(FCB[fp].LastCluster)); 
			FCB[fp].ClusSecCnt=1; 
		} 
		else if (FCB[fp].ClusSecCnt==0)					//读第一簇 
		{ 
			IDEReadSector(ClusterToSector(FCB[fp].LastCluster)); 
			FCB[fp].ClusSecCnt++; 
		} 
		else										//读当前簇下一扇区 
		{ 
			IDEReadSector(ClusterToSector(FCB[fp].LastCluster)+FCB[fp].ClusSecCnt); 
			FCB[fp].ClusSecCnt++; 
		} 
	} 
	return(tmp); 
}