CRC

crc16_forSensAirS8.c

#include <stdio.h>
#include <stdlib.h>

#define u16 unsigned short
#define u8 unsigned char

static u16
crc16(u8 *p, int n)
{
  static const u16 wCRCTable[] = {
		0X0000, 0XC0C1, 0XC181, 0X0140, 0XC301, 0X03C0, 0X0280, 0XC241,
		0XC601, 0X06C0, 0X0780, 0XC741, 0X0500, 0XC5C1, 0XC481, 0X0440,
		0XCC01, 0X0CC0, 0X0D80, 0XCD41, 0X0F00, 0XCFC1, 0XCE81, 0X0E40,
		0X0A00, 0XCAC1, 0XCB81, 0X0B40, 0XC901, 0X09C0, 0X0880, 0XC841,
		0XD801, 0X18C0, 0X1980, 0XD941, 0X1B00, 0XDBC1, 0XDA81, 0X1A40,
		0X1E00, 0XDEC1, 0XDF81, 0X1F40, 0XDD01, 0X1DC0, 0X1C80, 0XDC41,
		0X1400, 0XD4C1, 0XD581, 0X1540, 0XD701, 0X17C0, 0X1680, 0XD641,
		0XD201, 0X12C0, 0X1380, 0XD341, 0X1100, 0XD1C1, 0XD081, 0X1040,
		0XF001, 0X30C0, 0X3180, 0XF141, 0X3300, 0XF3C1, 0XF281, 0X3240,
		0X3600, 0XF6C1, 0XF781, 0X3740, 0XF501, 0X35C0, 0X3480, 0XF441,
		0X3C00, 0XFCC1, 0XFD81, 0X3D40, 0XFF01, 0X3FC0, 0X3E80, 0XFE41,
		0XFA01, 0X3AC0, 0X3B80, 0XFB41, 0X3900, 0XF9C1, 0XF881, 0X3840,
		0X2800, 0XE8C1, 0XE981, 0X2940, 0XEB01, 0X2BC0, 0X2A80, 0XEA41,
		0XEE01, 0X2EC0, 0X2F80, 0XEF41, 0X2D00, 0XEDC1, 0XEC81, 0X2C40,
		0XE401, 0X24C0, 0X2580, 0XE541, 0X2700, 0XE7C1, 0XE681, 0X2640,
		0X2200, 0XE2C1, 0XE381, 0X2340, 0XE101, 0X21C0, 0X2080, 0XE041,
		0XA001, 0X60C0, 0X6180, 0XA141, 0X6300, 0XA3C1, 0XA281, 0X6240,
		0X6600, 0XA6C1, 0XA781, 0X6740, 0XA501, 0X65C0, 0X6480, 0XA441,
		0X6C00, 0XACC1, 0XAD81, 0X6D40, 0XAF01, 0X6FC0, 0X6E80, 0XAE41,
		0XAA01, 0X6AC0, 0X6B80, 0XAB41, 0X6900, 0XA9C1, 0XA881, 0X6840,
		0X7800, 0XB8C1, 0XB981, 0X7940, 0XBB01, 0X7BC0, 0X7A80, 0XBA41,
		0XBE01, 0X7EC0, 0X7F80, 0XBF41, 0X7D00, 0XBDC1, 0XBC81, 0X7C40,
		0XB401, 0X74C0, 0X7580, 0XB541, 0X7700, 0XB7C1, 0XB681, 0X7640,
		0X7200, 0XB2C1, 0XB381, 0X7340, 0XB101, 0X71C0, 0X7080, 0XB041,
		0X5000, 0X90C1, 0X9181, 0X5140, 0X9301, 0X53C0, 0X5280, 0X9241,
		0X9601, 0X56C0, 0X5780, 0X9741, 0X5500, 0X95C1, 0X9481, 0X5440,
		0X9C01, 0X5CC0, 0X5D80, 0X9D41, 0X5F00, 0X9FC1, 0X9E81, 0X5E40,
		0X5A00, 0X9AC1, 0X9B81, 0X5B40, 0X9901, 0X59C0, 0X5880, 0X9841,
		0X8801, 0X48C0, 0X4980, 0X8941, 0X4B00, 0X8BC1, 0X8A81, 0X4A40,
		0X4E00, 0X8EC1, 0X8F81, 0X4F40, 0X8D01, 0X4DC0, 0X4C80, 0X8C41,
		0X4400, 0X84C1, 0X8581, 0X4540, 0X8701, 0X47C0, 0X4680, 0X8641,
		0X8201, 0X42C0, 0X4380, 0X8341, 0X4100, 0X81C1, 0X8081, 0X4040 };
	u8 t;
	u16 w = 0xFFFF;

   while (n--)
   {
      t = *p++ ^ w;
      w >>= 8;
      w ^= wCRCTable[t];
   }
   return w;
}

int
main()
{
  char *d, *t, text[1024], t2[3] = "  ";
  u8 *b, buf[1024];
  u16 crc;
  int i;

  while (fgets(text, 1024, stdin) != NULL) {
    for (t = text, b = buf; *t != '\n'; b++) {
      t2[0] = *t++;
      if (*t == '\n')
        break;
      t2[1] = *t++;
      *b = strtoul(t2, &d, 16);
    }
    for (i = 0; i < b - buf; i++)
      printf("%02x", buf[i]);
    crc = crc16(buf, b - buf);
    printf("%02x%02x", ((u8 *)&crc)[0], ((u8 *)&crc)[1]);
    printf("\n");
  }
}

crc8.c

// http://blog.goo.ne.jp/masaki_goo_2006/e/69f286d90e6140e6e8c021e43a11c815
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>     // CHAR_BIT

#define u8 unsigned char
#define u16 unsigned short

// 記号定数
// #define MSB_CRC8    (0x85)      // x8 + x7 + x2 + x0
//                           8 7654 3210
// example of the URL 8720   * 1000 0101 = 0x85
// CRC8               876420 * 1101 0101 = 0xd5
// CRC8-CCITT         87320  * 1000 1101 = 0x8d
// CRC8-SAEJ1850      ...
// CRC8-ATM           ...
// CRC8-Dallas/Maxim  8540   * 0011 0001 = 0x31 <- This is for SHT2x
#define MSB_CRC8  (0x31)

static unsigned char CRC8Table[ 256 ] = {
  0x00, 0x31, 0x62, 0x53, 0xC4, 0xF5, 0xA6, 0x97,
	0xB9, 0x88, 0xDB, 0xEA, 0x7D, 0x4C, 0x1F, 0x2E,
	0x43, 0x72, 0x21, 0x10, 0x87, 0xB6, 0xE5, 0xD4,
	0xFA, 0xCB, 0x98, 0xA9, 0x3E, 0x0F, 0x5C, 0x6D,
	0x86, 0xB7, 0xE4, 0xD5, 0x42, 0x73, 0x20, 0x11,
	0x3F, 0x0E, 0x5D, 0x6C, 0xFB, 0xCA, 0x99, 0xA8,
	0xC5, 0xF4, 0xA7, 0x96, 0x01, 0x30, 0x63, 0x52,
	0x7C, 0x4D, 0x1E, 0x2F, 0xB8, 0x89, 0xDA, 0xEB,
	
	0x3D, 0x0C, 0x5F, 0x6E, 0xF9, 0xC8, 0x9B, 0xAA,
	0x84, 0xB5, 0xE6, 0xD7, 0x40, 0x71, 0x22, 0x13,
	0x7E, 0x4F, 0x1C, 0x2D, 0xBA, 0x8B, 0xD8, 0xE9,
	0xC7, 0xF6, 0xA5, 0x94, 0x03, 0x32, 0x61, 0x50,
	0xBB, 0x8A, 0xD9, 0xE8, 0x7F, 0x4E, 0x1D, 0x2C,
	0x02, 0x33, 0x60, 0x51, 0xC6, 0xF7, 0xA4, 0x95,
	0xF8, 0xC9, 0x9A, 0xAB, 0x3C, 0x0D, 0x5E, 0x6F,
	0x41, 0x70, 0x23, 0x12, 0x85, 0xB4, 0xE7, 0xD6,
	
	0x7A, 0x4B, 0x18, 0x29, 0xBE, 0x8F, 0xDC, 0xED,
	0xC3, 0xF2, 0xA1, 0x90, 0x07, 0x36, 0x65, 0x54,
	0x39, 0x08, 0x5B, 0x6A, 0xFD, 0xCC, 0x9F, 0xAE,
	0x80, 0xB1, 0xE2, 0xD3, 0x44, 0x75, 0x26, 0x17,
	0xFC, 0xCD, 0x9E, 0xAF, 0x38, 0x09, 0x5A, 0x6B,
	0x45, 0x74, 0x27, 0x16, 0x81, 0xB0, 0xE3, 0xD2,
	0xBF, 0x8E, 0xDD, 0xEC, 0x7B, 0x4A, 0x19, 0x28,
	0x06, 0x37, 0x64, 0x55, 0xC2, 0xF3, 0xA0, 0x91,
	
	0x47, 0x76, 0x25, 0x14, 0x83, 0xB2, 0xE1, 0xD0,
	0xFE, 0xCF, 0x9C, 0xAD, 0x3A, 0x0B, 0x58, 0x69,
	0x04, 0x35, 0x66, 0x57, 0xC0, 0xF1, 0xA2, 0x93,
	0xBD, 0x8C, 0xDF, 0xEE, 0x79, 0x48, 0x1B, 0x2A,
	0xC1, 0xF0, 0xA3, 0x92, 0x05, 0x34, 0x67, 0x56,
	0x78, 0x49, 0x1A, 0x2B, 0xBC, 0x8D, 0xDE, 0xEF,
	0x82, 0xB3, 0xE0, 0xD1, 0x46, 0x77, 0x24, 0x15,
	0x3B, 0x0A, 0x59, 0x68, 0xFF, 0xCE, 0x9D, 0xAC,
};

// CRC8の計算(生成多項式:0x85,左送り)
static unsigned char crc8_1( const void *buff, size_t size )
{
    unsigned char *p = (unsigned char *)buff;
    unsigned char crc8;
    int i;
    
    for ( crc8 = 0x00 ; size != 0 ; size-- ){
        crc8 ^= *p++;
        
        for (i = 0 ; i < CHAR_BIT ; i++ ){
            if ( crc8 & 0x80 ){
                crc8 <<= 1; crc8 ^= MSB_CRC8;
            }
            else{
                crc8 <<= 1;
            }
        }
    }
    return crc8;
}

u8
crc8_2(u8 *d, int n)
{
  int i;
  u8 bit, crc;

  for (i = 0; i < n; i++) {
    crc ^= d[i];
    for (bit = 8; bit > 0; bit--) {
      if (crc & 0x80)
        crc = (crc<<1)^0x131;
      else
        crc = (crc<<1);
    }
  }
  return crc;
}

// CRC8テーブルから計算
static unsigned char crc8_3( const void *buff, size_t size )
{
    unsigned char *data = (unsigned char *)buff;
    unsigned char  crc8 = 0x00;
    
    while ( size != 0 ){
        crc8 = CRC8Table[ crc8 ^ *data ];
        data++;
        size--;
    }
    return crc8;
}


int
main()
{
  char *d, *t, text[1024], t2[3] = "  ";
  u8 *b, buf[1024];
  u8 c1, c2, c3;
  int i;

  while (fgets(text, 1024, stdin) != NULL) {
    for (t = text, b = buf; *t != '\n'; b++) {
      t2[0] = *t++;
      if (*t == '\n')
        break;
      t2[1] = *t++;
      *b = strtoul(t2, &d, 16);
    }
    for (i = 0; i < b - buf; i++)
      printf("%02x", buf[i]);
    c1 = crc8_1(buf, b - buf);
    c2 = crc8_2(buf, b - buf);
    c3 = crc8_3(buf, b - buf);
    printf(", %02x, %02x, %02x", c1, c2, c3);
    printf("\n");
  }
}

make_crc8_table.c

#include <stdio.h>
#include <limits.h>     // CHAR_BIT

// 記号定数
#define MSB_CRC8    (0x31)      // x8 + x5 + x4 + x0

// CRC8テーブルの初期化
static void InitCRC8Table( unsigned char table[256] )
{
    unsigned char value;
    int i, n;
    
    for (n = 0 ; n < 256 ; n++ ){
        value = (unsigned char)(n << (8 - CHAR_BIT));   // value = n;
        
        for ( i = 0 ; i < CHAR_BIT ; i++ ){
            if ( value & 0x80 ){
                value <<= 1; value ^= MSB_CRC8;
            }
            else{
                value <<= 1;
            }
        }
        table[ n ] = value;
    }
}

// CRC8テーブルの表示
static void ListCRC8Table( unsigned char table[256] )
{
    unsigned char *p = table;
    int i, j, k;
    
    printf( "static unsigned char CRC8Table[ 256 ] = {\n" );
    for ( k = 3 ; k >= 0 ; k-- ){
        for ( j = 0 ; j < 8 ; j++ ){
            for ( i = 0 ; i < 8 ; i++ ){
                printf( (i == 0) ? "\t" : " " );
                printf( "0x%02X,", *p++ );
            }
            printf( "\n" );
        }
        if ( k != 0 ) printf( "\t\n" );
    }
    printf( "};\n" );
}

// メイン関数
int main( void )
{
    unsigned char table[ 256 ];
    
    InitCRC8Table( table );
    ListCRC8Table( table );
    return 0;
}