Class: AppleCPM

Inherits:
FileSystem show all
Defined in:
lib/file_systems/AppleCPM.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
]

Class Method Summary collapse

Methods inherited from FileSystem

all_file_systems, code_for_tests, compatability_score, is_valid_file_system_if, non_matching_score

Methods included from SubclassTracking

extended

Class Method Details

.add_file(file_system_image, native_filetype_class, full_filename, file_contents, file_type = nil, aux_code = nil) ⇒ Object 



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# File 'lib/file_systems/AppleCPM.rb', line 129

def self.add_file(file_system_image,native_filetype_class,full_filename,file_contents,file_type=nil,aux_code=nil)
  raise "#{native_filetype_class} not supported on Apple CPM file system" if  native_filetype_class.file_system_file_types[self].nil?
  partial_filename,file_type=CPMFile.split_filename(full_filename)
  full_filename ="#{partial_filename}.#{file_type}"
#    puts "#{full_filename},#{partial_filename},#{file_type}"
  delete_file(file_system_image,full_filename) unless file_system_image.files[full_filename].nil? #so we can overwrite the file if it already exists  
  free_blocks,free_directory_entries=find_free_space(file_system_image)
  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
#    puts "#{total_extents_needed} extents needed"
  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(file_system_image,0)+get_block(file_system_image,1)
  padded_file_contents=file_contents+(0x1A.chr*BLOCK_SIZE)
  
  total_extents_needed.times 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]
    
    blocks_this_extent.times do |block_no|
        this_block=free_blocks[block_no+(extent_no*BLOCKS_PER_EXTENT)]
        set_block(file_system_image,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,partial_filename,file_type,extent_no,0,0,records_this_extent,blocks_used].flatten.pack("CA8A3C4C16")
    catalog[dir_entry_start,0x20]=dir_entry
#      puts "dir entry # #{dir_entry_no}"
  end
  
  set_block(file_system_image,0,catalog[0,BLOCK_SIZE])
  set_block(file_system_image,1,catalog[BLOCK_SIZE,BLOCK_SIZE])
  
  native_file=files(file_system_image)[full_filename]
  raise "error: file should now be in catalog\n #{file_system_image.catalog}" if native_file.nil?
  return native_file
end

.delete_file(file_system_image, full_filename) ⇒ Object 



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# File 'lib/file_systems/AppleCPM.rb', line 172

def self.delete_file(file_system_image,full_filename)
  catalog=get_block(file_system_image,0)+get_block(file_system_image,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(file_system_image,0,catalog[0,BLOCK_SIZE])
  set_block(file_system_image,1,catalog[BLOCK_SIZE,BLOCK_SIZE])
end

.files(file_system_image) ⇒ 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/file_systems/AppleCPM.rb', line 81

def self.files(file_system_image)
  files=FileContainer.new
  catalog=get_block(file_system_image,0)+get_block(file_system_image,1)
  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 (dir_entry[0]<0x10) then
      file_name=dir_entry[0x01..0x08].gsub(' ','')
      file_ext=dir_entry[0x09..0x0B].gsub(' ','')
      full_filename="#{file_name}.#{file_ext}"
      files<<NativeFileType.best_fit(file_system_image,full_filename,'',file_ext)
      if files[full_filename].nil? then
        files<<file 
      end
      s=""
      0x10.upto(0x1f) do |i|
        block=dir_entry[i]
        s+=get_block(file_system_image,block) unless block==0
      end        
      records_allocated=dir_entry[0x0F]
      files[full_filename].contents+=s[0,(records_allocated*128)]
    end
  end    
  files
end

.find_free_space(file_system_image) ⇒ Object 



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# File 'lib/file_systems/AppleCPM.rb', line 107

def self.find_free_space(file_system_image)
  free_blocks=[]
  free_directory_entries=[]
  #first two blocks are where the catalog lives
  (2..((file_system_image.track_count-3)*4)-1).each {|block| free_blocks<<block}
  catalog=get_block(file_system_image,0)+get_block(file_system_image,1)
  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 (dir_entry[0]<0x10) then
      0x10.upto(0x1f) do |i|
        block=dir_entry[i]
        free_blocks.delete(block)
      end        
    else
      free_directory_entries<<dir_entry_no      
    end
  end    
  [free_blocks,free_directory_entries]
end

.get_block(file_system_image, block_no) ⇒ Object 



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# File 'lib/file_systems/AppleCPM.rb', line 32

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

.host_system ⇒ Object 



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# File 'lib/file_systems/AppleCPM.rb', line 11

def self.host_system
  Apple2
end

.matching_score ⇒ Object 



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# File 'lib/file_systems/AppleCPM.rb', line 15

def self.matching_score
  20
end

.set_block(file_system_image, block_no, contents) ⇒ Object 



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# File 'lib/file_systems/AppleCPM.rb', line 39

def self.set_block(file_system_image,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]
    file_system_image.set_sector(track_no,sector_no,contents[(i*256),256])
  end  
end