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Added preliminaries of reading the speed zone information.

This commit is contained in:
Thomas Harte 2016-07-10 13:42:45 -04:00
parent 8ae78ba4e0
commit 4ae9f5ad5d

View File

@ -59,8 +59,7 @@ std::shared_ptr<Track> G64::get_track_at_position(unsigned int position)
if(position >= _number_of_tracks) return resulting_track;
// seek to this track's entry in the track table
long offset = (long)((position * 4) + 0xc);
fseek(_file, offset, SEEK_SET);
fseek(_file, (long)((position * 4) + 0xc), SEEK_SET);
// read the track offset
uint32_t track_offset;
@ -73,7 +72,7 @@ std::shared_ptr<Track> G64::get_track_at_position(unsigned int position)
if(!track_offset) return resulting_track;
// seek to the track start
fseek(_file, SEEK_SET, (int)track_offset);
fseek(_file, (int)track_offset, SEEK_SET);
// get the real track length
uint16_t track_length;
@ -84,9 +83,31 @@ std::shared_ptr<Track> G64::get_track_at_position(unsigned int position)
uint8_t track_contents[track_length];
fread(track_contents, 1, track_length, _file);
// check for speed-zone contents
// seek to this track's entry in the speed zone table
fseek(_file, (long)((position * 4) + 0x15c), SEEK_SET);
// TODO: package track_contents and speed_zones into a PCM track
// 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);
}
else
{
}
return resulting_track;
}