fat32openfile.c

基于c51的SD驱动程序,在FAT32文件系统中.

#ifndef _FAT32_DEFINE
 #include "FAT32.c"
#endif

BYTE FAT32OpenFile(CHAR *filename);

BYTE FAT32OpenFile(CHAR *filename)
{
	register BYTE i,j;
	
	i=0;
	while(i<FAT32_MAX_FCB&&FCB[i].FirstCluster) i++;

	if (i==FAT32_MAX_FCB) return(FAT32_ERR_FILE_OPEN_ERROR);			//文件控制块已满
	else
	{
		j=FAT32FindDIREntry(filename);
		if (j<16)
		{
			strcpy((char *)FCB[i].FileName,(char *)filename);
			FCB[i].Size=MEMSwap32(sDIR[j].FileSize);
			((WORD *)&FCB[i].FirstCluster)[0]=MEMSwap16(sDIR[j].FstClusHI);
			((WORD *)&FCB[i].FirstCluster)[1]=MEMSwap16(sDIR[j].FstClusLO);
			FCB[i].LastCluster=FCB[i].FirstCluster; 
			FCB[i].ClusSecCnt=0;
			FCB[i].ByteCnt=0;
			return(i);
		}
		else return(FAT32_ERR_FILE_OPEN_ERROR);
	}
}