64 lines
1.3 KiB
C++
64 lines
1.3 KiB
C++
/*
|
|
* DiskCopy42.cpp
|
|
* profuse
|
|
*
|
|
* Created by Kelvin Sherlock on 1/4/09.
|
|
*
|
|
*/
|
|
|
|
#include "DiskCopy42.h"
|
|
#include "common.h"
|
|
#include <string.h>
|
|
|
|
|
|
uint32_t DiskCopy42::CheckSum(uint8_t *buffer, unsigned length)
|
|
{
|
|
uint32_t checksum = 0;
|
|
if (length & 0x01) return -1;
|
|
|
|
/*
|
|
* checksum starts at 0
|
|
* foreach big-endian 16-bit word w:
|
|
* checksum += w
|
|
* checksum = checksum rotate right 1 (bit 0 --> bit 31)
|
|
*/
|
|
|
|
for(unsigned i = 0; i < length; i += 2)
|
|
{
|
|
checksum += (buffer[i] << 8);
|
|
checksum += buffer[i + 1];
|
|
checksum = (checksum >> 1) | (checksum << 31);
|
|
//if (checksum & 0x01) checksum = (checksum >> 1) | 0x80000000;
|
|
//else checksum >>= 1;
|
|
}
|
|
return checksum;
|
|
|
|
}
|
|
|
|
bool DiskCopy42::Load(const uint8_t *buffer)
|
|
{
|
|
unsigned i;
|
|
|
|
i = buffer[0];
|
|
if (i >= 64) return false;
|
|
|
|
memcpy(disk_name, &buffer[1], i);
|
|
disk_name[i] = 0;
|
|
|
|
|
|
data_size = load32_be(&buffer[64]);
|
|
tag_size = load32_be(&buffer[68]);
|
|
|
|
data_checksum = load32_be(&buffer[72]);
|
|
tag_checksum = load32_be(&buffer[76]);
|
|
|
|
disk_format = buffer[80];
|
|
format_byte = buffer[81];
|
|
private_word = load16_be(&buffer[82]);
|
|
|
|
if (private_word != 0x100) return false;
|
|
|
|
return true;
|
|
}
|
|
|