/**
* \file crc.c
* Functions and types for CRC checks.
*
* Generated on Thu Oct 30 15:54:49 2008,
* by pycrc v0.6.6, http://www.tty1.net/pycrc/
* using the configuration:
* Width = 8
* Poly = 0x07
* XorIn = 0x00
* ReflectIn = False
* XorOut = 0x00
* ReflectOut = False
* Algorithm = table-driven
*****************************************************************************/
#include "crc.h"
/**
* Static table used for the table_driven implementation.
*****************************************************************************/
uc8 crc8_table[16] =
{
0x00, 0x07, 0x0e, 0x09, 0x1c, 0x1b, 0x12, 0x15, 0x38, 0x3f, 0x36, 0x31, 0x24, 0x23, 0x2a, 0x2d
};
uc16 crc16_table[16] =
{
0x0000, 0xcc01, 0xd801, 0x1400, 0xf001, 0x3c00, 0x2800, 0xe401,
0xa001, 0x6c00, 0x7800, 0xb401, 0x5000, 0x9c01, 0x8801, 0x4400
};
/**
* Update the crc value with new data.
*
* \param crc The current crc value.
* \param data Pointer to a buffer of \a data_len bytes.
* \param data_len Number of bytes in the \a data buffer.
* \return The updated crc value.
*****************************************************************************/
u8 crc8_update (u8 crc, u8 *data, u8 data_len)
{
u8 tbl_idx;
while (data_len)
{
tbl_idx = (crc >> 4) ^ (*data >> 4);
crc = crc8_table[tbl_idx & 0x0f] ^ (crc tbl_idx = (crc >> 4) ^ (*data >> 0);
crc = crc8_table[tbl_idx & 0x0f] ^ (crc
data++;
data_len--;
}
return crc & 0xff;
}
u16 crc16_update (u16 crc, u8 *data, u8 data_len)
{
u8 tbl_idx;
while (data_len--)
{
tbl_idx = crc ^ (*data >> (0 * 4) );
crc = crc16_table[tbl_idx & 0x0f] ^ (crc >> 4);
tbl_idx = crc ^ (*data >> (1 * 4) );
crc = crc16_table[tbl_idx & 0x0f] ^ (crc >> 4);
data++;
}
return crc & 0xffff;
}
