#include "xmodem.h"

/* 讀取單個(gè)數(shù)據(jù)包						 */
/* 返回0表示讀取數(shù)據(jù)包成功   */
/* 返回1表示數(shù)據(jù)包不完整 	 	 */
/* 返回2表示數(shù)據(jù)包檢驗(yàn)和出錯(cuò) */
static 
int RecFrame(struct Frame* oneFrame)
{
	int returnVal;	/* 返回的值 */
	int i;

	oneFrame->blkNum = sio_getc();
	oneFrame->blkNumRev = sio_getc();

	/* 檢驗(yàn)數(shù)據(jù)包完整性	 */
        
	if( oneFrame->blkNumRev + oneFrame->blkNum!=0xFF)
		returnVal = 1;
		
	else
	{
		/* 讀取數(shù)據(jù)區(qū) */
		for(i = 0; i < BLOCK_SIZE; ++i)
		{
			oneFrame->dataBlk[i] = sio_getc();
		}
		
		/* 檢驗(yàn)累加校驗(yàn)和 */
		oneFrame->checkSum = sio_getc();

    if(oneFrame->checkSum == CheckSum(oneFrame))
			returnVal = 0;
		else
			returnVal = 2;		
	}
	
	return (returnVal);	
}

/* Xmodem協(xié)議傳輸執(zhí)行函數(shù) */
void XmodemRun(char *ptr)
{	
  
  struct Frame dataFrame;
  
  sio_init( );
  do
	{
		taskDelay(60);
		if (!sio_ischar())
			sio_putc(NAK);
  } while(!sio_ischar());
  
    do
		{
			switch(sio_getc())
			{
				/* 控制字符為SOH，則接收該數(shù)據(jù)包 */
				case SOH:
					switch( RecFrame(&dataFrame) )
					{
						/* 數(shù)據(jù)包接收正常，發(fā)送ACK消息，將數(shù)據(jù)區(qū)的數(shù)據(jù)拷貝到內(nèi)存 */
						case 0:
							MemCpy(ptr, dataFrame.dataBlk, BLOCK_SIZE);
							ptr += BLOCK_SIZE;
							sio_putc(ACK);
							break;
							
						/* 數(shù)據(jù)包接收錯(cuò)誤，發(fā)送NAK消息 */
						case 1: case 2:
							sio_putc(NAK);
							break;	
					}		
					
					break;			

				case EOT:
					sio_putc(ACK);
					*(++ptr) = 0;		/* 給存儲(chǔ)區(qū)域的最后一個(gè)字節(jié)賦值0，終止sio_puts() */
          return;
          
        case CAN:
        	return;
					
				default:
					break;	
			}			
	} while(1);
}

/* 延時(shí)函數(shù) */
static
void DelayTime(int time)
{
	int i;
	for(i = 0; i < time; ++i)
		;
}

/* 將數(shù)據(jù)區(qū)的數(shù)據(jù)拷貝到內(nèi)存中 */
static
void MemCpy(char des[], char src[], int length)
{
	int i;
	for(i = 0; i < length; ++i)
	{
		des[i] = src[i];
	}
}

/* 計(jì)算校驗(yàn)和，返回校驗(yàn)和！！！！！！ */
static
unsigned char CheckSum(struct Frame *oneFrame)
{
	int i;
	unsigned char dataSum = 0x00;
	
	for(i = 0; i < BLOCK_SIZE; ++i)
	{
		dataSum += oneFrame->dataBlk[i];
	}
	
  return (dataSum & 0xff);
}

void getfile()
{
    char text[3000];
	int i;
	XmodemRun(text);
	for (i = strlen(text)-2; i> 0; i--)
		if (text[i] == 26)
			text[i] = 0;
	printf("%s\n",text);
	
	return;
}