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Smart Photoionization Detector Module PIDS3
User Manual
PIDS3 - User Manual (en) - 1.03.docx
Analytical Control Instruments GmbH, Volmerstraße 9A, 12489 Berlin, Germany, www.aci-berlin.com Page 33 of 58
11.1.1 Checksum calculation
The checksum is calculated over the bytes in message section.
Code example (C#):
public static uint Crc32 ( byte [] buffer, uint offset, uint count )
{
const uint polynomial = 0xEDB88320;
uint crc = uint .MaxValue;
for ( uint index = offset; index < count; index++ )
{
crc ^= buffer[index];
for ( uint bit = 0; bit < 8; bit++)
{
crc = (crc >> 1) ^ (crc & 1) * polynomial;
}
}
return ~crc;
}
Code example (C or C++):
uint32_t Crc32 ( const void * buffer, uint32_t offset, uint32_t count )
{
const uint32_t polynomial = 0xEDB88320;
uint32_t crc = 0xFFFFFFFF;
uint8_t* src = &((uint8_t*) buffer)[offset];
while ( count-- )
{
crc ^= *src++;
for ( uint32_t bit = 0; bit < 8; bit++ )
{
crc = ( crc >> 1 ) ^ ( crc & 1 ) * polynomial;
}
}
return ~crc;
}