fat32finddirentry.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 FAT32FindDIREntry(CHAR *DirName);

BYTE FAT32FindDIREntry(CHAR *DirName)
{
	xdata BYTE i,j,k,m,n;
	xdata DWORD chain;
	xdata CHAR temp[27];

	chain=FAT32.CurrentDirectory;
	FAT32.ClusSecCnt=0;
	while(chain!=0x0fffffff)
	{
		FAT32ReadCluster(&chain);
		for (i=0;i<16;i++)
		{
			if (sDIR[i].Name[0]==0xe5||sDIR[i].Name[0]==0x00) continue;			//空目录项跳过
			if ((sDIR[i].Attr&FAT32_ATTR_LONG_NAME_MASK)==FAT32_ATTR_LONG_NAME)
			//长文件名
			{
				j=lDIR[i].Ord - FAT32_LAST_LONG_ENTRY;
				LongFileName[0]=0;n=0;
				for(;j>0;j--)
				{
					FAT32GetPartLongName(lDIR+i,temp);
					m=strlen((char *)temp);
					k=m+n;
					for(;n>0;n--)
						LongFileName[m+n]=LongFileName[n];
					LongFileName[m+n]=LongFileName[n];
					m--;
					for(;m>0;m--)
						LongFileName[m]=temp[m];
					LongFileName[m]=temp[m];
					n=k;
					i++;
					if (i==16)
					{
						FAT32ReadCluster(&chain);
						i=0;
					}
				}
				if (strcmp((const char *)DirName,(const char *)LongFileName)==0) return(i);
			}
			else
			{
			//短文件名
				if (sDIR[i].Attr&FAT32_ATTR_VOLUME_ID) continue;		//如果是卷标则跳过
				for(j=0;j<11;j++)
					temp[j]=sDIR[i].Name[j];
				temp[j]=0;
				if (strcmp((const char *)DirName,(const char *)temp)==0) return(i);
			}
		}
	}
	return(i);
}