websocket 传输数据帧打包 (client端)

/*
Vertion: 0.2.1
date:    2015.8.11
content: gcc 编译通过
*/

//websocket 传输数据帧打包  client端
//参数：src 为输入字符串  
//      len为输入字串src长度   
//      mask为4个字节掩码值
//      des 为输出掩码后字节数组。
//      sum 为输出des实际长度 (len+6: len<=125
//                             len+8: 125<len<=65535
//                             len+10: len>65535
//                             0: 组帧失败)
void maskpak(unsigned char src[],
         unsigned int len,
         unsigned char mask[],
         unsigned char des[],
         unsigned int *sum)
{
    unsigned char FIN    =0X80;
    unsigned char RSV1   =0X00;
    unsigned char RSV2   =0X00;
    unsigned char RSV3   =0X00;
    unsigned char OPCODE =0X01; //文本帧
    unsigned char MASK   =0X80; //掩码标识
    unsigned char PLEN   =0X00;

    int index=0;
    int i; 
 
        des[index++]= FIN +RSV1 +RSV2 +RSV3 +OPCODE;

    if(len<=125)
    {
        PLEN =len;
    }else if(len<=0XFFFF)
    {
        PLEN =126;
    }else
    {
        PLEN =127;
    }
    des[index++]= MASK +PLEN;
    
    //网络字节序标准为: 大端方式(即高字节在前低字节在后)
    if(PLEN<=125)
    {
        *sum= len+6;
    }
    else if(126==PLEN)
    {
        unsigned short temp;
        temp =len;
        des[index++] =(unsigned char)(temp>>8);
        des[index++] =(unsigned char)temp;
        *sum= len+8;
    }else if(127==PLEN)
    {
        unsigned int temp;
        temp =len;
        des[index++] =(unsigned char)(temp>>24);
        des[index++] =(unsigned char)(temp>>16);
        des[index++] =(unsigned char)(temp>>8);
        des[index++] =(unsigned char)temp;
        *sum=len+10;
    }else
    {
        *sum= 0;
        return;
    }
    
    for(i=0;i<4;i++)
    {
        des[index++] =mask[i];
    }
    
    for(i=0;i<len;i++)
    {
        des[index++] =src[i]^mask[i%4];
    }
}

// 测试代码
int main(int argc,char *argv)
{
    unsigned char src[200];
    unsigned char mask[4]= {0X00,0X00,0X00,0X00};
    unsigned char des[200+8];
    unsigned int len = 200;
    unsigned int sum;

    int i;

    for (i=0;i<200;i++)
    {
        src[i] = i;
    }
    maskpak(src,len,mask,des,&sum);

    printf("SUM=%d  
",sum);
    for(i=0;i<sum;i++)
    {
        printf("%.2X ",(unsigned char)(des[i]));
    }

    return 0;
}