$:.unshift(File.dirname(__FILE__)) unless
	$:.include?(File.dirname(__FILE__)) || $:.include?(File.expand_path(File.dirname(__FILE__)))

$:.unshift(File.dirname(__FILE__+"\\..")) unless
	$:.include?(File.dirname(__FILE__+"\\..")) || $:.include?(File.expand_path(File.dirname(__FILE__+"\\..")))

require 'ImageFormat'

class D81< ImageFormat
	
#
# For manipulating D81 files, as used by many C64 emulators.
#
# References: 
#     http://www.unusedino.de/ec64/technical/formats/d81.html
#

D81_BYTES_PER_SECTOR=0x100
D81_SECTORS_PER_TRACK=40
def self.possible_extensions
    ['.d81']
end  

def self.host_system
    C64
end  

def sectors_in_track(track_no)
 D81_SECTORS_PER_TRACK
end

#for a given byte stream, how many tracks could be interpreted by this image format?
def track_count
    file_bytes.length/(D81_SECTORS_PER_TRACK*256)
end

def end_track
  return   track_count
end

#what track does the directory start on?
def dir_track_no
  40
end

#what sector does the directory start on?
def dir_sector_no
  3
end
def get_sector(track_no,sector_no)    
    return nil  unless track_no.between?(1,end_track)
		return nil unless sector_no.between?(0,D81_SECTORS_PER_TRACK-1)   
    track_start=D81_BYTES_PER_SECTOR*(D81_SECTORS_PER_TRACK*(track_no-1))
    sector_start=track_start+(D81_BYTES_PER_SECTOR*sector_no)
#    puts "T %0d, S %0d, TRACK OFFSET=$%x, SECTOR OFFSET=$%x" % [track_no,sector_no,track_start,sector_start]
		file_bytes[sector_start,D81_BYTES_PER_SECTOR]
end

def set_sector(track_no,sector_no,sector_contents)
    raise "d81 currently read only"
    raise "invalid track number #{track_no}" unless track_no.between?(1,end_track)
    raise "invalid sector number #{sector_no}" unless sector_no.between?(0,D81_SECTORS_PER_TRACK-1)
    padded_sector_contents=(sector_contents+("\000"*D81_BYTES_PER_SECTOR))[0,D81_BYTES_PER_SECTOR]
    track_start=D81_BYTES_PER_SECTOR*(D81_SECTORS_PER_TRACK*(track_no-1))
    sector_start=track_start+(D81_BYTES_PER_SECTOR*sector_no)
		file_bytes[sector_start,D81_BYTES_PER_SECTOR]=padded_sector_contents
end

end
# == Author
# Jonno Downes (jonno@jamtronix.com)
#
# == Copyright
# Copyright (c) 2008,2009 Jonno Downes (jonno@jamtronix.com)
#
#Permission is hereby granted, free of charge, to any person obtaining
#a copy of this software and associated documentation files (the
#"Software"), to deal in the Software without restriction, including
#without limitation the rights to use, copy, modify, merge, publish,
#distribute, sublicense, and/or sell copies of the Software, and to
#permit persons to whom the Software is furnished to do so, subject to
#the following conditions:

# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.