2016-07-10 14:17:53 +00:00
|
|
|
//
|
|
|
|
// G64.cpp
|
|
|
|
// Clock Signal
|
|
|
|
//
|
|
|
|
// Created by Thomas Harte on 10/07/2016.
|
|
|
|
// Copyright © 2016 Thomas Harte. All rights reserved.
|
|
|
|
//
|
|
|
|
|
|
|
|
#include "G64.hpp"
|
|
|
|
|
|
|
|
using namespace Storage;
|
|
|
|
|
|
|
|
G64::G64(const char *file_name)
|
|
|
|
{
|
|
|
|
_file = fopen(file_name, "rb");
|
|
|
|
|
|
|
|
if(!_file)
|
|
|
|
throw ErrorNotGCR;
|
|
|
|
|
|
|
|
// read and check the file signature
|
|
|
|
char signature[8];
|
2016-07-10 17:32:59 +00:00
|
|
|
if(fread(signature, 1, 8, _file) != 8)
|
2016-07-10 14:17:53 +00:00
|
|
|
throw ErrorNotGCR;
|
|
|
|
|
|
|
|
if(memcmp(signature, "GCR-1541", 8))
|
|
|
|
throw ErrorNotGCR;
|
|
|
|
|
|
|
|
// check the version number
|
|
|
|
int version = fgetc(_file);
|
|
|
|
if(version != 0)
|
|
|
|
{
|
|
|
|
throw ErrorUnknownVersion;
|
|
|
|
}
|
|
|
|
|
|
|
|
// get the number of tracks and track size
|
|
|
|
_number_of_tracks = (uint8_t)fgetc(_file);
|
|
|
|
_maximum_track_size = (uint16_t)fgetc(_file);
|
|
|
|
_maximum_track_size |= (uint16_t)fgetc(_file) << 8;
|
|
|
|
}
|
|
|
|
|
|
|
|
G64::~G64()
|
|
|
|
{
|
|
|
|
if(_file) fclose(_file);
|
|
|
|
}
|
|
|
|
|
|
|
|
unsigned int G64::get_head_position_count()
|
|
|
|
{
|
|
|
|
// give at least 84 tracks, to yield the normal geometry but,
|
|
|
|
// if there are more, shove them in
|
|
|
|
return _number_of_tracks > 84 ? _number_of_tracks : 84;
|
|
|
|
}
|
|
|
|
|
|
|
|
std::shared_ptr<Track> G64::get_track_at_position(unsigned int position)
|
|
|
|
{
|
|
|
|
std::shared_ptr<Track> resulting_track;
|
|
|
|
|
|
|
|
// if there's definitely no track here, return the empty track
|
|
|
|
// (TODO: should be supplying one with an index hole?)
|
|
|
|
if(position >= _number_of_tracks) return resulting_track;
|
|
|
|
|
|
|
|
// seek to this track's entry in the track table
|
2016-07-10 17:42:45 +00:00
|
|
|
fseek(_file, (long)((position * 4) + 0xc), SEEK_SET);
|
2016-07-10 14:17:53 +00:00
|
|
|
|
|
|
|
// read the track offset
|
|
|
|
uint32_t track_offset;
|
|
|
|
track_offset = (uint32_t)fgetc(_file);
|
|
|
|
track_offset |= (uint32_t)fgetc(_file) << 8;
|
|
|
|
track_offset |= (uint32_t)fgetc(_file) << 16;
|
|
|
|
track_offset |= (uint32_t)fgetc(_file) << 24;
|
|
|
|
|
|
|
|
// if the track offset is zero, this track doesn't exist, so...
|
|
|
|
if(!track_offset) return resulting_track;
|
|
|
|
|
|
|
|
// seek to the track start
|
2016-07-10 17:42:45 +00:00
|
|
|
fseek(_file, (int)track_offset, SEEK_SET);
|
2016-07-10 14:17:53 +00:00
|
|
|
|
|
|
|
// get the real track length
|
|
|
|
uint16_t track_length;
|
|
|
|
track_length = (uint16_t)fgetc(_file);
|
|
|
|
track_length |= (uint16_t)fgetc(_file) << 8;
|
|
|
|
|
|
|
|
// grab the byte contents of this track
|
2016-07-10 20:10:05 +00:00
|
|
|
std::unique_ptr<uint8_t> track_contents(new uint8_t[track_length]);
|
|
|
|
fread(track_contents.get(), 1, track_length, _file);
|
2016-07-10 14:17:53 +00:00
|
|
|
|
2016-07-10 17:42:45 +00:00
|
|
|
// seek to this track's entry in the speed zone table
|
|
|
|
fseek(_file, (long)((position * 4) + 0x15c), SEEK_SET);
|
2016-07-10 14:17:53 +00:00
|
|
|
|
2016-07-10 17:42:45 +00:00
|
|
|
// read the speed zone offsrt
|
|
|
|
uint32_t speed_zone_offset;
|
|
|
|
speed_zone_offset = (uint32_t)fgetc(_file);
|
|
|
|
speed_zone_offset |= (uint32_t)fgetc(_file) << 8;
|
|
|
|
speed_zone_offset |= (uint32_t)fgetc(_file) << 16;
|
|
|
|
speed_zone_offset |= (uint32_t)fgetc(_file) << 24;
|
|
|
|
|
|
|
|
// if the speed zone is not constant, create a track based on the whole table; otherwise create one that's constant
|
|
|
|
if(speed_zone_offset > 3)
|
|
|
|
{
|
|
|
|
// seek to start of speed zone
|
|
|
|
fseek(_file, (int)speed_zone_offset, SEEK_SET);
|
|
|
|
|
|
|
|
uint16_t speed_zone_length = (track_length + 3) >> 2;
|
|
|
|
|
|
|
|
// read the speed zone bytes
|
|
|
|
uint8_t speed_zone_contents[speed_zone_length];
|
|
|
|
fread(speed_zone_contents, 1, speed_zone_length, _file);
|
2016-07-10 20:10:05 +00:00
|
|
|
|
|
|
|
// TODO: divide into individual PCMSegments (per byte, if necessary), shove into a PCMTrack
|
2016-07-10 17:42:45 +00:00
|
|
|
}
|
|
|
|
else
|
|
|
|
{
|
2016-07-10 20:10:05 +00:00
|
|
|
PCMSegment segment;
|
|
|
|
segment.duration.length = track_length * 8;
|
|
|
|
segment.duration.clock_rate = track_length * 8;
|
|
|
|
segment.data = std::move(track_contents);
|
|
|
|
|
|
|
|
resulting_track.reset(new PCMTrack(std::move(segment)));
|
2016-07-10 17:42:45 +00:00
|
|
|
}
|
2016-07-10 14:17:53 +00:00
|
|
|
|
|
|
|
return resulting_track;
|
|
|
|
}
|
2016-07-10 20:10:05 +00:00
|
|
|
|
|
|
|
#pragma mark - PCMTrack
|
|
|
|
|
|
|
|
unsigned int greatest_common_divisor(unsigned int a, unsigned int b)
|
|
|
|
{
|
|
|
|
if(a < b)
|
|
|
|
{
|
|
|
|
unsigned int swap = b;
|
|
|
|
b = a;
|
|
|
|
a = swap;
|
|
|
|
}
|
|
|
|
|
|
|
|
while(1) {
|
|
|
|
if(!a) return b;
|
|
|
|
if(!b) return a;
|
|
|
|
|
|
|
|
unsigned int remainder = a%b;
|
|
|
|
a = b;
|
|
|
|
b = remainder;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
unsigned int least_common_multiple(unsigned int a, unsigned int b)
|
|
|
|
{
|
|
|
|
unsigned int gcd = greatest_common_divisor(a, b);
|
|
|
|
return (a*b) / gcd;
|
|
|
|
}
|
|
|
|
|
|
|
|
PCMTrack::PCMTrack(std::vector<PCMSegment> segments)
|
|
|
|
{
|
|
|
|
_segments = std::move(segments);
|
|
|
|
fix_length();
|
|
|
|
}
|
|
|
|
|
|
|
|
PCMTrack::PCMTrack(PCMSegment segment)
|
|
|
|
{
|
|
|
|
_segments.push_back(std::move(segment));
|
|
|
|
fix_length();
|
|
|
|
}
|
|
|
|
|
|
|
|
PCMTrack::Event PCMTrack::get_next_event()
|
|
|
|
{
|
|
|
|
PCMTrack::Event new_event;
|
|
|
|
return new_event;
|
|
|
|
}
|
|
|
|
|
|
|
|
void PCMTrack::fix_length()
|
|
|
|
{
|
|
|
|
// find the least common multiple of all segment clock rates
|
|
|
|
_track_clock_rate = _segments[0].duration.clock_rate;
|
|
|
|
for(size_t c = 1; c < _segments.size(); c++)
|
|
|
|
{
|
|
|
|
_track_clock_rate = least_common_multiple(_track_clock_rate, _segments[c].duration.clock_rate);
|
|
|
|
}
|
|
|
|
|
|
|
|
// therby determine the total length, storing it to next_event as the divisor
|
|
|
|
_next_event.length.clock_rate = 0;
|
|
|
|
for(size_t c = 0; c < _segments.size(); c++)
|
|
|
|
{
|
|
|
|
unsigned int multiplier = _track_clock_rate / _segments[c].duration.clock_rate;
|
|
|
|
_next_event.length.clock_rate += _segments[c].duration.length * multiplier;
|
|
|
|
}
|
|
|
|
|
|
|
|
_segment_pointer = _bit_pointer = 0;
|
|
|
|
}
|