/*
 
 */

#include "crc.h"


//=====================================================CRC-16====================校验方式======================================================

// CRC_LIB库  https://github.com/lammertb/libcrc/tree/v2.0

/* USER CODE BEGIN 0 */

// CRC 低位字节值表
//获取CRC16校验值(CRC-CCITT (0xFFFF))
// puchMsg:要校验的数组
// usDataLen:校验的长度
//返回值:CRC16码
// CRC8校验
// ptr:要校验的数组
// len:数组长度
//返回值:CRC8码
uint8_t Get_Crc8(uint8_t *ptr, uint16_t len)
{
    uint8_t crc;
    uint8_t i;
    crc = 0;
    while (len--)
    {
        crc ^= *ptr++;
        for (i = 0; i < 8; i++)
        {
            if (crc & 0x01)
                crc = (crc >> 1) ^ 0x8C;
            else
                crc >>= 1;
        }
    }
    return crc;
}

/*
天信盒子校验
*/
unsigned char CRC8(const unsigned char *dest, unsigned short int len)
{
    unsigned char crc = 0;
    unsigned char tempI;
    unsigned char sum;
    while (len--)
    {
        unsigned char extract = *dest++;
        for (tempI = 8; tempI; tempI--)
        {
            sum = (crc ^ extract) & 0x01;
            crc >>= 1;
            if (sum)
            {
                crc ^= 0x8c;
            }
            extract >>= 1;
        }
    }
    return crc;
}

//求和校验 所有字节之和为0
uint16_t Checksum_Sum(uint8_t *buf, uint16_t len)
{
    uint8_t check = 0;
    while (len--)
    {
        check += *buf++;
    }
    check = 256 - check % 256;
    return (check)&0x00ff;
}



uint16_t ip_chksum(uint16_t initcksum, uint8_t *ptr, int len)
{
    unsigned int cksum;
    int idx;
    int odd;

    cksum = (unsigned int) initcksum;

    odd = len & 1;
    len -= odd;

    for (idx = 0; idx < len; idx += 2) {
        cksum += ((unsigned long) ptr[idx] << 8) + ((unsigned long) ptr[idx+1]);
    }

    if (odd) {      /* buffer is odd length */
        cksum += ((unsigned long) ptr[idx] << 8);
    }

    /*
     * Fold in the carries
     */

    while (cksum >> 16) {
        cksum = (cksum & 0xFFFF) + (cksum >> 16);
    }

    return cksum;
}

uint16_t tcp_chksum(uint16_t initcksum, uint8_t *tcphead, int tcplen , uint32_t *srcaddr, uint32_t *destaddr)
{
//    uint8_t pseudoheader[12];
    uint16_t calccksum = 0;

//    memcpy(&pseudoheader[0],srcaddr,IP_ADDR_LEN);
//    memcpy(&pseudoheader[4],destaddr,IP_ADDR_LEN);
//    pseudoheader[8] = 0; /* 填充零 */
//    pseudoheader[9] = IPPROTO_TCP;
//    pseudoheader[10] = (tcplen >> 8) & 0xFF;
//    pseudoheader[11] = (tcplen & 0xFF);

//    calccksum = ip_chksum(0,pseudoheader,sizeof(pseudoheader));
    calccksum = ip_chksum(calccksum,tcphead,tcplen);
    calccksum = ~calccksum;
    return calccksum;
}

//TCP的头部校验，求校验和 所有字节之和为0
uint16_t tcpChecksum(uint8_t *buf, uint16_t len)
{
//    uint16_t *headerPtr;
//    uint16_t check_sum;
//    int32_t n,sum;
//    
//    sum = 0;
//    headerPtr = (uint16_t *)buf;
//    for(n = 0; n < len/2; n++)
//    {
//        sum += *headerPtr++;
//    }
//    check_sum = ((sum>>16) &0xFFFF) + (sum&0xFFFF);
//    check_sum = ~check_sum;

//    return check_sum;
    
    uint16_t calccksum;
    
    calccksum = ip_chksum(0,buf,len);
    calccksum = ~calccksum;
    return calccksum;
}






//直接计算法计算CRC16
unsigned int cal_crc16(unsigned char buffer[], unsigned char len)
{
    unsigned char i = 0, j = 0;
    unsigned int crc_register = 0;

    //总字节数
    while (len-- != 0)
    {
        //一个字节8位，故循环8次
        for (i = 0x80; i != 0; i = i >> 1)
        {
            //如果最高位为1，则进行异或运算
            if ((crc_register & 0x80000) != 0)
            {
                //最高位为1，左移移出
                crc_register <<= 1;
                //与多项式进行异或运算
                crc_register ^= 0x1021;
            }
            else
            {
                //最高位为0，则直接左移移出
                crc_register <<= 1;
            }

            //加上本位的CRC码（不太明白？）
            if ((buffer[j] & i) != 0)
            {
                crc_register ^= 0x1021;
            }
        }
        //指向下一个字节
        j++;
    }

    //返回CRC-16检验码
    return (crc_register);
}

uint16_t cbus_crc(uint8_t pbuf[]) //校验算法与MavLink校验相似，长度不同，无额外字节
{
    uint8_t length = pbuf[1];
    uint16_t sum = 0xFFFF;
    uint8_t i, stoplen;
    uint8_t tmp;

    stoplen = length + 3;

    i = 1;
    while (i < stoplen)
    {
        tmp = pbuf[i] ^ (uint8_t)(sum & 0xff);
        tmp ^= (tmp << 4);
        sum = (sum >> 8) ^ (tmp << 8) ^ (tmp << 3) ^ (tmp >> 4);
        i++;
    }

    return sum;
}


const unsigned int table[256] = {
    0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
    0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
    0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
    0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
    0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
    0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
    0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
    0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
    0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
    0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
    0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
    0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
    0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
    0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
    0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
    0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
    0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
    0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
    0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
    0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
    0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
    0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
    0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
    0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
    0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
    0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
    0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
    0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
    0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
    0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
    0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
    0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
};

unsigned int crc_fullymax(unsigned char *q, int len)
{
    unsigned int value_ = 0xa635;

    while (len--)
    {
        value_ = table [(value_ >> 8 ^ *q++) & 0xff] ^ (value_ << 8);
    }
    
    return value_;
}






uint8_t poweramp_CRC8(uint8_t *ptr, uint8_t len, uint8_t key)
{
    uint8_t i;
    uint8_t crc=0;
    while(len--!=0)
    {
        for(i=0x80; i!=0; i/=2)
        {
            if((crc & 0x80) != 0)
            {
                crc *= 2;
                crc ^= key;
            }
            else
                crc *= 2;
            
            if((*ptr & i)!=0)
                crc ^= key;
        }
        ptr++;
    }
    return(crc);
}



uint8_t YRSocCalcXor(uint8_t *buf, uint8_t len)
{
    uint8_t  i = 0;
    uint8_t *p = 0;
    char checksum = 0;
    p = buf;
    checksum = *p;
    p++;

    for(i=1; i<len; i++)
    {
        checksum ^= *p;
        p++;
    }
    return checksum;
}



