Class: CPMDisk

Inherits:
DSK
  • Object
show all
Defined in:
lib/CPMDisk.rb

Constant Summary collapse

RECORD_SIZE = 
128
BLOCK_SIZE = 
1024
BLOCKS_PER_EXTENT = 
16
RECORDS_PER_BLOCK = 
BLOCK_SIZE/RECORD_SIZE
RECORDS_PER_EXTENT = 
RECORDS_PER_BLOCK*BLOCKS_PER_EXTENT
SECTORS_IN_BLOCK = 
[
  [0x00,0x06,0x0C,0x03],  #block 0
  [0x09,0x0F,0x0E,0x05],  #block 1
  [0x0B,0x02,0x08,0x07],  #block 2
  [0x0D,0x04,0x0A,0x01]  #block 3
]

Constants inherited from DSK

DSK::DSK_FILE_LENGTH, DSK::DSK_IMAGE_EXTENSIONS, DSK::FILE_SYSTEMS, DSK::INTERLEAVES, DSK::NIB_FILE_LENGTH, DSK::SECTOR_ORDERS

Instance Attribute Summary collapse

Attributes inherited from DSK

#file_bytes, #sector_order, #source_filename, #track_count

Instance Method Summary collapse

Methods inherited from DSK

#best_subclass, create_new, #disassemble_sector, #dump_sector, #files, #free_sector_list, #get_sector, #hex_dump, #is_cpm?, #is_dos33?, is_dsk_file?, #is_modified_dos?, #is_nadol?, #is_pascal?, #is_prodos?, read, #save_as, #set_boot_track, #set_sector

Constructor Details

#initialize(file_bytes, sector_order) ⇒ CPMDisk

Returns a new instance of CPMDisk.



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# File 'lib/CPMDisk.rb', line 55

def initialize(file_bytes,sector_order)    
	super(file_bytes,sector_order)
	self.read_catalog
end

Instance Attribute Details

#free_blocks ⇒ Object

Returns the value of attribute free_blocks.



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# File 'lib/CPMDisk.rb', line 15

def free_blocks
  @free_blocks
end

#free_directory_entries ⇒ Object

Returns the value of attribute free_directory_entries.



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# File 'lib/CPMDisk.rb', line 15

def free_directory_entries
  @free_directory_entries
end

Instance Method Details

#add_file(file) ⇒ Object 



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# File 'lib/CPMDisk.rb', line 86

def add_file(file)
  raise "only CPMFiles may be added to CPM format disks!" unless file.kind_of?(CPMFile)
  delete_file(file.full_filename) #so we can overwrite the file if it already exists  
  
  total_record_count=(file.contents.length/RECORD_SIZE.to_f).ceil
  total_blocks_needed=(total_record_count/RECORDS_PER_BLOCK.to_f).ceil    
  total_extents_needed=(total_blocks_needed/BLOCKS_PER_EXTENT.to_f).ceil
  
  raise "#{total_blocks_needed} free blocks required, only #{free_blocks.length} available" unless total_blocks_needed<=free_blocks.length
  raise "#{total_extents_needed} free directory entries required, only #{free_directory_entries.length} available" unless total_extents_needed<=free_directory_entries.length
  catalog=get_block(0)+get_block(1)
  padded_file_contents=file.contents+(0x1A.chr*BLOCK_SIZE)
  
  0.upto(total_extents_needed-1) do |extent_no|
    records_this_extent=(extent_no==(total_extents_needed-1) ? (total_record_count % RECORDS_PER_EXTENT):RECORDS_PER_EXTENT)
    blocks_this_extent=(records_this_extent/RECORDS_PER_BLOCK.to_f).ceil
    blocks_used=[0]*BLOCKS_PER_EXTENT
    first_record_this_extent=extent_no*RECORDS_PER_EXTENT
    contents_this_extent=padded_file_contents[(first_record_this_extent*RECORD_SIZE),blocks_this_extent*BLOCK_SIZE]
    
    0.upto(blocks_this_extent-1) do |block_no|
        this_block=free_blocks[block_no+(extent_no*BLOCKS_PER_EXTENT)]
        set_block(this_block,contents_this_extent[block_no*BLOCK_SIZE,BLOCK_SIZE])
        blocks_used[block_no]=this_block
    end
    dir_entry_no=free_directory_entries[extent_no]
    dir_entry_start=dir_entry_no*0x20
    dir_entry=[0,file.filename,file.file_type,extent_no,0,0,records_this_extent,blocks_used].flatten.pack("CA8A3C4C16")
    catalog[dir_entry_start..dir_entry_start+0x1F]=dir_entry
  end
  
  set_block(0,catalog[0,BLOCK_SIZE])
  set_block(1,catalog[BLOCK_SIZE,BLOCK_SIZE])
  self.read_catalog

end

#delete_file(full_filename) ⇒ Object 



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# File 'lib/CPMDisk.rb', line 69

def delete_file(full_filename)
  catalog=get_block(0)+get_block(1)
  (partial_filename,file_ext)=CPMFile.split_filename(full_filename)
  0.upto(63) do |dir_entry_no|
    dir_entry_start=dir_entry_no*0x20
    dir_entry=catalog[dir_entry_start..dir_entry_start+0x1F]              
    if (partial_filename==dir_entry[0x01..0x08].gsub(' ','')) && (file_ext==dir_entry[0x09..0x0B].gsub(' ',''))      
      #we found a matching filename, so set the 'user number' field to a 'blank' entry
      catalog[dir_entry_start]=0xE5
    end
  end
  
  set_block(0,catalog[0,BLOCK_SIZE])
  set_block(1,catalog[BLOCK_SIZE,BLOCK_SIZE])
  self.read_catalog
end

#dump_catalog ⇒ Object 



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# File 'lib/CPMDisk.rb', line 45

def dump_catalog
	s=""
	files.keys.sort.each { |file_name|		
		file=files[file_name]	
		s<< sprintf("% 12s % 6d \n",file.full_filename,file.contents.length)
	}
	s
end

#file_system ⇒ Object 



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# File 'lib/CPMDisk.rb', line 60

def file_system
	:cpm
end

#get_block(block_no) ⇒ Object 



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# File 'lib/CPMDisk.rb', line 29

def get_block(block_no)
  track_no= ((block_no/4)+3)%track_count
  s=""
  SECTORS_IN_BLOCK[block_no%4].each {|sector_no|s+=get_sector(track_no,sector_no)}
  s
end

#make_file(filename, contents, file_options = {}) ⇒ Object 



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# File 'lib/CPMDisk.rb', line 64

def make_file(filename,contents,file_options={})
  return CPMFile.new(filename,contents)
end

#read_catalog ⇒ Object

CPM DIR looks like this: $00 User number, or E5h if it’s a free entry $01..0B Filename + extension: 8+3 characters $0C..0D Extent number of this entry $0E ??? $0F Number of 128-byte records allocated in this extant $10..1F Allocation map for this directory entry



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# File 'lib/CPMDisk.rb', line 132

def read_catalog
   @free_blocks=[]
   @free_directory_entries=[]
   @files={}
   #first two blocks are where the catalog lives
   (2..((track_count-3)*4)-1).each {|block| @free_blocks<<block}
   catalog=get_block(0)+get_block(1)
   #require 'DumpUtilities'
   #puts DumpUtilities.hex_dump(catalog)
   0.upto(63) do |dir_entry_no|
     #puts dir_entry_no
     dir_entry_start=dir_entry_no*0x20
     dir_entry=catalog[dir_entry_start..dir_entry_start+0x1F]      
     if (dir_entry[0]<0x10) then
       file_name=dir_entry[0x01..0x08].gsub(' ','')
       file_ext=dir_entry[0x09..0x0B].gsub(' ','')
               
       if (file_ext=="BAS") then
         file=MBASICFile.new("#{file_name}.#{file_ext}",'')
       else
         file=CPMFile.new("#{file_name}.#{file_ext}",'')
       end
       if @files[file.full_filename].nil? then
         @files[file.full_filename]=file 
       end
       s=""
       0x10.upto(0x1f) do |i|
         block=dir_entry[i]
         @free_blocks.delete(block)
         s+=get_block(block) unless block==0
       end        
       records_allocated=dir_entry[0x0F]
       @files[file.full_filename].contents+=s[0,(records_allocated*128)]
     else
       @free_directory_entries<<dir_entry_no
     end
   end
end

#set_block(block_no, contents) ⇒ Object 



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# File 'lib/CPMDisk.rb', line 36

def set_block(block_no,contents)
  raise "invalid block #{block_no} - length was #{contents.length}" unless contents.length==BLOCK_SIZE
  track_no=(block_no/4)+3
  0.upto(3) do |i|
    sector_no=SECTORS_IN_BLOCK[block_no%4][i]
    set_sector(track_no,sector_no,contents[(i*256),256])
  end  
end