学步园

通过ASCII码对GSM PDU 7bit短信编码

int8_t Gsm_Encode7bitFromAscii(char* pDest,uint16_t dSize, uint16_t* pLen,const char* pSrc,uint16_t sSize) 
{ 
  uint16_t nSrc;         
	uint16_t nDst;        
  uint16_t nChar;    
	uint8_t nLeft;
	uint16_t nSrcLength=sSize; 
	
	nSrc = 0;     
	nDst = 0;     
	while(nSrc<nSrcLength)     
	{   
		
		nChar = nSrc & 7;           
		if(nChar == 0)         
		{ 
		  nLeft = *pSrc;         
		}         
		else         
		{ 
      *pDest = (*pSrc << (8-nChar)) | nLeft;              
			nLeft = *pSrc >> nChar; 
      pDest++;             
		  nDst++;         
		}         
    pSrc++; 
	  nSrc++;     
	}     
  return nDst; 
}     

GSM PDU 7bit短信解码：

/*
*函数功能：GSM PDU 7bit短信解码
*输入参数：pDest：存放ASCII码的目的地址指针，
           dSize：存放ASCII码的目的地址大小
           pSrc： PUD 7BIT 原地址
           sSize：原地址大小
*返回参数：0：转换成功，-1：转换失败
*函数说明：
*/
int8_t Gsm_Decode7bitToASCII(char* pDest,uint16_t dSize, uint16_t* pLen,const char* pSrc,uint16_t sSize) 
{ 
   uint16_t nSrc,nDst;        
   uint16_t nByte;      
   uint8_t nLeft;  
   uint16_t nSrcLength;
   uint8_t ui8Array[3];
   uint8_t ui8Addr = 0;
	
	/*检测数据有效性*/
	if((pDest == NULL)||(dSize == 0)||(pSrc == NULL)||(sSize == 0)||(pLen == NULL))
		return -1;
	
	/*如果目的地址空间不足，则直接返回错误*/
	if(dSize < (sSize*8/7+1)*2)
		return -1;
	
	nSrc = 0;     
	nDst = 0;     
        nByte = 0;     
	nLeft = 0;   
       nSrcLength=sSize;  
	
        while(nSrc<nSrcLength)     
	{ 
          ui8Array[ui8Addr] = (((unsigned char)(*pSrc) << nByte) | nLeft) & 0x7f;       
          nLeft = (unsigned char)(*pSrc)>> (7-nByte);     
          ui8Addr++;         
	  nDst++;     
          nByte++;     
             if(nByte == 7)         
		{ 
			if(ui8Addr==2)
			{
				ui8Addr = 0;
				*pDest++ = AsciiToHex(ui8Array[0],ui8Array[1]);
			}
			else if(ui8Addr>2)
			{
				return -1;
			}
			
      ui8Array[ui8Addr] = nLeft;     
      ui8Addr++;             
			nDst++;     
      nByte = 0;             
		  nLeft = 0;         
		}
		if(ui8Addr==2)
		{
			ui8Addr = 0;
			*pDest++ = AsciiToHex(ui8Array[0],ui8Array[1]);
		}
		else if(ui8Addr>2)
		{
			return -1;
		}		
         pSrc++;         
	  nSrc++;     
	}     
  *pLen = nDst; 
  return 0; 
}