simpleffs.c

一个简单的flash文件系统

	sprintf(c256DebugBuff,"create_file: insert %s int cache entry = %d\r\n",kname,entry);
	SysLog(LOG_DEBUG, c256DebugBuff, 0);
#endif
			strcpy(cachename[entry],kname);
			cacheuse[entry] = 1;
			cachepacket[entry] = packet;
			cachesector[entry] = workingsector;

			// need to mark the rest of the file as used
			if (length > PAYLOAD)
				length -= PAYLOAD;
			else
				length = 0;

			addr = sectortoaddress(workingsector);
			addr1 = (long)(INFOLENGTH + ((long)(packet-1) * PACKETLENGTH));
			addr = addr + addr1;
			oldpacket = packet;
			while (length) {

				if (length > PAYLOAD) {
					// link old packet in
					packet = get_unused_packet_from(workingsector);
					emb_program(addr+2,workingsector & 0xFF);
					emb_program(addr+3,packet & 0xFF);
					// set new as used
					if (packet > NUMPACKETS) {
						sprintf(c256DebugBuff, "ERROR: no unused packets in sector\r\n");
						SysLog(LOG_EMERG, c256DebugBuff, 0);
						system_error = ILLEGALPACKET;
						return ERR_SFFS_ILLEBAL_PACKET;
					}
					addr = sectortoaddress(workingsector) + (packet * INFOENTRY);
					emb_program(addr, USEDPACKET);	// marked as used
					emb_program(addr+1, 0xFF);	// marked as used
					length -= PAYLOAD;
					// set up for next run
					addr = sectortoaddress(workingsector);
					addr1 = (long)(INFOLENGTH + ((long)(packet-1) * PACKETLENGTH));
					addr = addr + addr1;
					oldpacket = packet;
				} else {
					// link old packet in
					packet = get_unused_packet_from(workingsector);
					emb_program(addr+2,workingsector & 0xFF);
					emb_program(addr+3,packet & 0xFF);
					packet = get_unused_packet_from(workingsector);
					if (packet > NUMPACKETS) 
					{
						sprintf(c256DebugBuff, "ERROR: no unused packets in sector\r\n");
						SysLog(LOG_EMERG, c256DebugBuff, 0);
						system_error = ILLEGALPACKET;
						return ERR_SFFS_ILLEBAL_PACKET;
					}
					addr = sectortoaddress(workingsector) + (packet * INFOENTRY);
					emb_program(addr, USEDPACKET);	// marked as used
					emb_program(addr+1, 0xFF);	// marked as used
					length = 0;
				}
			}
			break;
		case 'a':
			// this deletes an existing file
			packet = find_file(kname);
			if (packet != MAXSECTORS && delbfrwrite) {
				//delete_file(kname,packet);
				del_file(kname);
			}

#if DEBUG_CONSOL
	sprintf(c256DebugBuff, "Create append file length = %d\r\n",length);
	SysLog(LOG_DEBUG, c256DebugBuff, 0);
#endif
			wrapped = (workingsector-1) & (MAXSECTORS-1); //tips!!!
			addr = (((long)number_of_packets(RETFREE,workingsector) & 0xFF) * ((long)PAYLOAD & 0xFF)) & 0xFFFF;
			while (addr < length && 
				(workingsector != wrapped)) {
				//Search for the sector whose free space is enough
				workingsector++;
				workingsector %= MAXSECTORS;
				addr = (((long)number_of_packets(RETFREE,workingsector) & 0xFF) * ((long)PAYLOAD & 0xFF)) & 0xFFFF;
			}

			if ((workingsector == wrapped) && (addr < length)) {

#if DEBUG_CONSOL
	sprintf(c256DebugBuff, "consolidate: befor consolidate workingsector=%d,\r\n",workingsector);
	SysLog(LOG_DEBUG, c256DebugBuff, 0);
#endif
				workingsector=my_consolidate(); 				
				if(workingsector == -1)
					return -1;
				//my_consolidate(); //I won't update the working setor.
#if DEBUG_CONSOL
	sprintf(c256DebugBuff, "consolidate: after consolidate workingsector=%d,\r\n",workingsector);
	SysLog(LOG_DEBUG, c256DebugBuff, 0);
#endif
				wrapped = (workingsector-1) & (MAXSECTORS-1);
				addr = (((long)number_of_packets(RETFREE,workingsector) & 0xFF) * ((long)PAYLOAD & 0xFF)) & 0xFFFF;
				while (addr < length && 
					(workingsector != wrapped)) {
					workingsector++;
					workingsector %= MAXSECTORS;
					addr = (((long)number_of_packets(RETFREE,workingsector) & 0xFF) * ((long)PAYLOAD & 0xFF)) & 0xFFFF;
				}
			} else {
				// get number of erased sectors
				sector = 0;
				for (i=0; i<MAXSECTORS; i++) {
					if (sectorerased[i]) {
						sector++;
					}
				}

				// if need to consolidate sectors do it.
				if (sector < 3) {
					doconsolidate = 1; //??? I think uncomment the following part is better.
				/*
					workingsector = consolidate();
					wrapped = (workingsector-1) & (MAXSECTORS-1);
					addr = (((long)number_of_packets(RETFREE,workingsector) & 0xFF) * ((long)PAYLOAD & 0xFF)) & 0xFFFF;
					while (addr < length && 
						(workingsector != wrapped)) {
						workingsector++;
						workingsector %= MAXSECTORS;
						addr = (((long)number_of_packets(RETFREE,workingsector) & 0xFF) * ((long)PAYLOAD & 0xFF)) & 0xFFFF;
					}
				*/
				}
			}
			sectorerased[workingsector] = 0;

#if DEBUG_CREATE
	sprintf(c256DebugBuff, "create_file: workingsector = %d\r\n",workingsector);
	SysLog(LOG_DEBUG, c256DebugBuff, 0);
#endif
			// find first unused packet and wr
			packet = get_unused_packet_from(workingsector);
#if DEBUG_CREATE
	sprintf(c256DebugBuff, "create_file: packet = %d\r\n",packet);
	SysLog(LOG_DEBUG, c256DebugBuff, 0);
#endif
			if (packet > NUMPACKETS) 
			{
				sprintf(c256DebugBuff, "Illegal packet\r\n");
				SysLog(LOG_EMERG, c256DebugBuff, 0);
				system_error = ERR_SFFS_ILLEBAL_PACKET;
				return ERR_SFFS_ILLEBAL_PACKET;
			}

			addr = sectortoaddress(workingsector) + (packet * INFOENTRY);
			// write file name
			for (i=0; i<INFOENTRY; i++)
				emb_program(addr+i, kname[i]);

			// put name into cache
			// go find an empty entry in the cache
			cacheentry = 0;
			done = 0;
			while (cacheentry < MAXCACHE && !done) {
				if (!cacheuse[cacheentry]) {
					done = 1;
				} else {
					cacheentry++;
				}
			}

			// if didn't find an empty entry in the cache take the least used
			if (cacheentry == MAXCACHE) {
				cacheentry = 0;
				smallest = 255;
				entry = 0;
				while (cacheentry < MAXCACHE) {
					entry = cacheuse[cacheentry] < smallest ? cacheentry : entry;
					smallest = cacheuse[cacheentry] < smallest ? cacheuse[cacheentry] : smallest;
					cacheentry++;
				}
			} else {
				entry = cacheentry;
			}

#if DEBUG_CREATE
	sprintf(c256DebugBuff, "create_file: insert %s int cache entry = %d\r\n",kname,entry);
	SysLog(LOG_DEBUG, c256DebugBuff, 0);
#endif
			strcpy(cachename[entry],kname);
			cacheuse[entry] = 1;
			cachepacket[entry] = packet;
			cachesector[entry] = workingsector;

			// need to mark the rest of the file as used
			if (length > PAYLOAD)
				length -= PAYLOAD;
			else
				length = 0;

			addr = sectortoaddress(workingsector);
			addr1 = (long)(INFOLENGTH + ((long)(packet-1) * PACKETLENGTH));
			addr = addr + addr1;
			oldpacket = packet;
			while (length) {

				if (length > PAYLOAD) {
					// link old packet in
					packet = get_unused_packet_from(workingsector);
					emb_program(addr+2,workingsector & 0xFF);
					emb_program(addr+3,packet & 0xFF);
					// set new as used
					if (packet > NUMPACKETS) {
						sprintf(c256DebugBuff, "ERROR: no unused packets in sector\r\n");
						SysLog(LOG_EMERG, c256DebugBuff, 0);
						system_error = ILLEGALPACKET;
						return ERR_SFFS_ILLEBAL_PACKET;
					}
					addr = sectortoaddress(workingsector) + (packet * INFOENTRY);
					emb_program(addr, USEDPACKET);	// marked as used
					emb_program(addr+1, 0xFF);	// marked as used
					length -= PAYLOAD;
					// set up for next run
					addr = sectortoaddress(workingsector);
					addr1 = (long)(INFOLENGTH + ((long)(packet-1) * PACKETLENGTH));
					addr = addr + addr1;
					oldpacket = packet;
				} else {
					// link old packet in
					packet = get_unused_packet_from(workingsector);
					emb_program(addr+2,workingsector & 0xFF);
					emb_program(addr+3,packet & 0xFF);
					packet = get_unused_packet_from(workingsector);
					if (packet > NUMPACKETS) 
					{
						sprintf(c256DebugBuff, "ERROR: no unused packets in sector\r\n");
						SysLog(LOG_EMERG, c256DebugBuff, 0);
						system_error = ILLEGALPACKET;
						return ERR_SFFS_ILLEBAL_PACKET;
					}
					addr = sectortoaddress(workingsector) + (packet * INFOENTRY);
					emb_program(addr, USEDPACKET);	// marked as used
					emb_program(addr+1, 0xFF);	// marked as used
					length = 0;
				}
			}
			break;
		default:
			return ERR_PARAM;
	}
#if DEBUG_CREATE
	printf("Create %s success!\r\n",filename);
#endif	
	return OK;
}

int createfile4java(char *filename, int offset, char attribute,unsigned int length) 
{
	return create_file(filename+offset, attribute, length);
}


/*
 * filename: valid file name
 * string:	 C string, must have \0
 * This API is not good, it should be changed to 
 * char* filename, char* pBuff, int bufflength
 * It could only append the space which had already reserved for the file
 * return how many bytes is written.
 *		  -1 means failed
 */
int append_to_file(char *filename, char *string) 
{
	int j;
	int sector;
	int packet;
	long addr;
	long addr1;
	int dataptr;
	unsigned char data;
	unsigned char olddata;
	int packetlen;
	int done;
	int link;
	int eof;

	if(!fdiskReady){
		SysLog(LOG_DEBUG, "flash disk not ready!", 0);
		return -1;
	}
	sector = find_file(filename);
	if (sector == MAXSECTORS) 
	{
		return -1;
	}

	packet = find_packet(filename,sector);
	addr = sectortoaddress(sector);
	addr1 = (long)(INFOLENGTH + ((long)(packet-1) * PACKETLENGTH));
	addr = addr + addr1;

	packetlen = PAYLOAD;
	dataptr = 6;
	done = 0;
	data = 0;
	eof = 0;

	//locate the end of the file
	while (!done && !eof) {
		olddata = data;
		data = read_flash(addr+(long)dataptr);
		if (data == 0xFF) {
			done = 1;
		} else {
			packetlen--;
			dataptr++;
		}
		if (!packetlen) {
			packetlen = PAYLOAD;
			dataptr = 6;
			link = read_flash(addr+2) * PACKETLENGTH + read_flash(addr+3);
			if (link == 0xFFFF) {
				eof = 1;
			} else {
				packet = link & 0xFF;
				addr = sectortoaddress(sector);
				addr1 = (long)(INFOLENGTH + ((long)(packet-1) * PACKETLENGTH));
				addr = addr + addr1;
			}
		}
	}

	//I am at the end of the file
	j = 0;
	if ((dataptr & 1) && (string[j]) && !eof) {
		emb_program(addr+(long)dataptr-1,olddata);
		emb_program(addr+(long)dataptr++, string[j]);
		packetlen--;
		j++;
	}

	//we are at the even address now
	while (string[j] && !eof) 
	{
		if (packetlen) {
			emb_program(addr+(long)dataptr++, string[j]);
			if (string[j+1] == 0) {
				if (!((addr+((long)dataptr-1)) & 1)) {
					emb_program(addr+(long)dataptr,0xFF);
				}
			}
			j++;
			packetlen--;
		} else {
			packetlen = PAYLOAD;
			dataptr = 6;
			link = read_flash(addr+2) * PACKETLENGTH + read_flash(addr+3);
			if (link == 0xFFFF) {
				eof = 1;
			} else {
				packet = link & 0xFF;
				addr = sectortoaddress(sector);
				addr1 = (long)(INFOLENGTH + ((long)(packet-1) * PACKETLENGTH));
				addr = addr + addr1;
			}
		}
	}
	
	if (string[j]) {
		system_error = 1;
	}

	return j;
}


int appendfile4java(char* filename, int nameoffset, char* string, int stringoffset, int datalength)
{
	return append_to_file(filename+nameoffset, string+stringoffset);   
}

/*
 * return -1: not exists
 *		   1: exists
 */
int file_exists(char *filename) 
{
	if (find_file(filename) == MAXSECTORS) 
	{
		return -1;
	}

	return 1;
}

int file_exists4java(char *filename, int offset) 
{
	return file_exists(filename+offset);
}


/*
 * Have not been test yet
 */
int read_app_file(char *filename, char *data, int start, int length) 
{
	long addr;
	long addr1;
	int link;
	int done;
	int tsector;
	int dataptr;
	int packetlen;
	int packetptr;
	int packet;

	if(!fdiskReady){
		SysLog(LOG_DEBUG, "flash disk not ready!", 0);
		return -1;
	}
	tsector = find_file(filename);
	if (tsector == MAXSECTORS) {
		return -1;
	}

	packet = find_packet(filename,tsector);
	if (packet > NUMPACKETS) {
		return -1;
	}

	addr = sectortoaddress(tsector);
	addr1 = (long)(INFOLENGTH + ((long)(packet-1) * PACKETLENGTH));
	addr = addr + addr1;

	done = 0;
	dataptr = 0;
	packetptr = 6;
	packetlen = PAYLOAD;
	while (dataptr < start && !done) {
		link = read_flash(addr+packetptr);
		if (link == 0xFF) {
			done = 1;
		} else {
			packetlen--;
			dataptr++;
			packetptr++;
		}
		if (!packetlen) {
			packetlen = PAYLOAD;
			packetptr = 6;
			link = read_flash(addr+2) * PACKETLENGTH + read_flash(addr+3);
			if (link == 0xFFFF) {
				done = 1;
			} else {
				packet = link;
				addr = sectortoaddress(tsector);
				addr1 = (long)(INFOLENGTH + ((long)(packet-1) * PACKETLENGTH));
				addr = addr + addr1;
			}
		}
	}

	dataptr = 0;
	packetptr = 6;
	while (dataptr < length && !done) {
		link =	read_flash(addr+(long)packetptr);
		if ((link & 0xFF) == 0xFF) {
			done = 1;
		} else {
			data[dataptr++] = link;
			packetptr++;
			packetlen--;
		}
		if (!packetlen) {
			packetlen = PAYLOAD;
			packetptr = 6;
			link = read_flash(addr+2) * PACKETLENGTH + read_flash(addr+3);
			if (link == 0xFFFF) {
				done = 1;
			} else {
				packet = link;
				addr = sectortoaddress(tsector);
				addr1 = (long)(INFOLENGTH + ((long)(packet-1) * PACKETLENGTH));
				addr = addr + addr1;
			}
		}
	}
	return dataptr;
}

/*
 * get currnet free space
 */
int get_avaible_space(void)
{
	int i;
	int space;
	
//	if(!fdiskReady){
//		SysLog(LOG_DEBUG, "flash disk not ready!", 0);
//		return -1;
//	}

	space=0;
	
	for(i=0;i<MAXSECTORS;i++)
	{
		space+=number_of_packets(RETFREE, i)*250;
		//space+=number_of_packets(RETDELETED, i)*250;
	}
	return space;
}

int del_file4java(char *filename