update_crc_64( crc, c );
Parameters
| Parameter | Type | Description |
|---|---|---|
crc |
uint64_t |
The CRC value calculated from the byte stream upto but not including the current byte |
c |
unsigned char |
The next byte from the byte stream to be used in the CRC calculation |
Return Value
| Type | Description |
|---|---|
uint64_t |
The new CRC value of the byte stream including the current byte |
Description
The function update_crc_64() can be used to calculate the CRC value in a stream of bytes where it is not possible to first buffer the stream completely to calculate the CRC when all data is received. The parameters are the previous CRC value and the current byte which must be used to calculate the new CRC value.
In order for this function to work properly, the CRC value must be initialized before the first call to update_crc_64(). The most common initialization values are CRC_START_64_ECMA to perform the CRC-64 CRC calculation according to the ECMA-182 standard and CRC_START_64_WE for the CRC-64 variation of the ECMA calculation where a bit swap occurs a the end result.