CRC32 crc;

// Read a stream of bytes.
while (bytesRemain)
{
    // Read a byte from arbitrary source.
    uint8_t byte = readAByteFromAStream();

    // Add the byte to the checksum.
    crc.update(byte);
}

// Calculate the checksum.
uint32_t checksum = crc.finalize();

// To reuse the same instance, call.
crc.reset();

uint8_t byteBuffer[32] = { 0x00, 0x01, 0x02, 0x03,
                           0x04, 0x05, 0x06, 0x07,
                           0x08, 0x09, 0x0A, 0x0B,
                           0x0C, 0x0D, 0x0E, 0x0F,
                           0x10, 0x11, 0x12, 0x13,
                           0x14, 0x15, 0x16, 0x17,
                           0x18, 0x19, 0x1A, 0x1B,
                           0x1C, 0x1D, 0x1E, 0x1F };

// Calculate the checksum of an entire buffer at once.
uint32_t checksum = CRC32::calculate(byteBuffer, 32);