partion2.c

基于dsp的软驱控制源程序

#include "gm82c765b.h"
#include "partion.h"
#include "global.h"
/************************************************************/
int ReadFileFromFloppy(int number_of_file)
{
	int i,logAddr,clustercount;
	unsigned int startcluster;	
	unsigned int temp;
	long filesize;
	char cluster[36];
	if(number_of_file>filecounts)
			return -1;	
	startcluster=(databuffer1[(number_of_file-1)*16+13]<<8)+(databuffer1[(number_of_file-1)*16+13]>>8);
	temp=(databuffer1[(number_of_file-1)*16+15]<<8)+(databuffer1[(number_of_file-1)*16+15]>>8);
	filesize=temp<<16;
	temp=(databuffer1[(number_of_file-1)*16+14]<<8)+(databuffer1[(number_of_file-1)*16+14]>>8);
	filesize+=temp;
	WriteFileInFlash(1,databuffer1+(number_of_file-1)*16,32);
	while(filesize>0)
	{	
	    clustercount=GetClusterChainOfFile(startcluster,cluster);
	    if(clustercount>=0)
	    {	    		 		
	 		for(i=0;i<clustercount;i+=4)
	 		{
	 			if(clustercount<i+4)
	 			{   
	 				filesize-=(clustercount-i)*512;
	 				if(filesize<=0)
	 				{
	 					filesize+=(clustercount-i)*512;
	 					logAddr=(startcluster-2)+GetDataLogicBlockAddr();
	 					if(!ReadDataFromFloppy(logAddr,databuffer,(int)filesize))
	 					{
	 						WriteFileInFlash(0,databuffer,(int)filesize);
	 						return 0;
	 					}
	 					else 
	 					{
	 						return -1;
	 					}	 						
	 				}
	 				logAddr=(startcluster-2)+GetDataLogicBlockAddr();
	 				if(!ReadDataFromFloppy(logAddr,databuffer,(clustercount-i)*512))
	 				{	
	 					WriteFileInFlash(0,databuffer,(clustercount-i)*512);
	 					startcluster=cluster[clustercount-1];
	 				}
	 				else
	 				{
	 					return -1;
	 				}	
	 				break;	        
	 			}
	 			logAddr=(startcluster-2)+GetDataLogicBlockAddr();
	    		if(!ReadDataFromFloppy(logAddr,databuffer,4*512))
	    		{
	    			WriteFileInFlash(0,databuffer,2048);
	    			filesize-=2048;
	    			startcluster=cluster[i+3];
	    		}
	    		else
	    		{
	    			return -1;
	    		}	
	    	}                                            /*for循环结束*/
	    	startcluster=cluster[clustercount-1];	    	    	
	    }                                                /*if(clustercount>=0循环结束*/
	    else
	    {
	    	return temp;
	    }
	} 
	return 0;	
}
/************************************************************/
int GetClusterChainOfFile(int startcluster,char *cluster)
{
    int clustercount=0;
    int maxcluster=0;
    int logAddr=0;
    int maxcount;
  	logAddr=(startcluster-2)+GetDataLogicBlockAddr();
    maxcount=36-logAddr%36;
    logAddr=GetFat1LogicBlockAddr();		
    while(1)
    {
    	maxcluster+=1024;
       	if((clustercount?cluster[clustercount-1]:startcluster)>maxcluster)
       	{
       		logAddr+=3;       		    		
       	}
       	else
    	{       		
        	if(!ReadDataFromFloppy(logAddr,databuffer,1536))
        	{           	
           	 	while(1)
            	{	
            		cluster[clustercount]=GetNextCluster(clustercount?cluster[clustercount-1]:startcluster,databuffer);         
            		if(cluster[clustercount]==0x0fff)
            		{  
            			++clustercount;
            			return clustercount; 
            		}
            		if(cluster[clustercount]>maxcluster)
       				{
       					++clustercount;
       					logAddr+=3;
       					break;
       				}
       				if(cluster[clustercount]==0)
       				{
       					return -2;
       				}
       				if((cluster[clustercount]-(clustercount?cluster[clustercount-1]:startcluster))!=1)
       				{
       					++clustercount;
       					return clustercount;
       				}
            		++clustercount;
            		if(clustercount==maxcount)
            		{
            			return clustercount;
            		}	
            	}
   		 	}
   		 	 else
        	{
        		return -1;
        	}
   		}
    }
}
/************************************************************/ 
int GetNextCluster(int currentcluster,char *data/*,int logicAddr*/)
{
    int offset=currentcluster%1024;
    int nextcluster=0;
    switch(offset%4)
    {
    	case 0:
    		nextcluster=((data[offset*3/4]&0xff00)>>8)+((data[offset*3/4]&0x000f)<<8);
    	    break;
    	case 1:
    		nextcluster=((data[offset*3/4]&0x00f0)>>4)+((data[offset*3/4+1]&0xff00)>>4);
    		break;
    	case 2:
    		nextcluster=(data[offset*3/4]&0x00ff)+(data[offset*3/4+1]&0x0f00);
    		break;
    	case 3:
    		nextcluster=((data[offset*3/4]&0xf000)>>12)+((data[offset*3/4]&0x00ff)<<4);
    		break;
    }
    return nextcluster;
    
}
/************************************************************/
int ListFileInRootDir()
{
	int i,j,k;
	CHS chsaddr;
	filecounts=0;
	for(i=GetRootDirLogicBlockAddr();i<GetDataLogicBlockAddr()-4;i+=4)
    {	
    	if(!ReadDataFromFloppy(i,databuffer,2048))
    	{
           	for(j=0;j<64;++j)
           	{           		
           		if(((databuffer[j*16]&0xff00)!=0xe500)&&(databuffer[j*16+13]!=0))
           		{           			
           		    for(k=0;k<16;++k)
           		    	databuffer1[filecounts*16+k]=databuffer[j*16+k];
           		    ++filecounts;
           		}	
           	}
    		
        }
        else
        {
         	return -1;
        }
        
    }    
    return filecounts;    
}