Class: AppleDos

Inherits:
FileSystem show all
Defined in:
lib/file_systems/AppleDos.rb

Overview

10-FF Up to 120 more track and sector pairs

Class Method Summary collapse

Methods inherited from FileSystem

all_file_systems, code_for_tests, compatability_score, is_valid_file_system_if, matching_score, non_matching_score

Methods included from SubclassTracking

extended

Class Method Details

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



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# File 'lib/file_systems/AppleDos.rb', line 173

def self.add_file(file_system_image,native_filetype_class,filename,file_contents,file_type=nil,aux_code=nil)
  #make sure the file type is supported on DOS 3.3!
  raise "#{native_filetype_class} not supported on Apple DOS 3.3 file system" if  native_filetype_class.file_system_file_types[self].nil?
  expected_file_type=native_filetype_class.file_system_file_types[self] 
  file_type=expected_file_type if file_type.nil?
  raise "inconsistent file_type (should be #{expected_file_type} but was #{file_type})" unless expected_file_type==file_type
  native_file=native_filetype_class.new(file_system_image,filename,file_contents,file_type,aux_code)
  raise "couldn't make #{native_filetype_class}" if native_file.nil?
  #if this file exists, delete it first
  file_system_image.delete_file(filename) unless file_system_image.files[filename].nil?
  catalog_slot=find_catalog_slot(file_system_image,nil)
  raise "CATALOG IS FULL!" if catalog_slot.nil?
  raise "invalid catalog slot " if catalog_slot[2].nil?
  free_sectors=free_sector_list(file_system_image)
  sectors_needed=1+(255+file_contents.length)/256
  raise "not enough free space - #{sectors_needed} sectors needed, #{free_sectors.length} available " unless sectors_needed<=free_sectors.length
  #TODO - allow files of more than 122 sectors
  raise "only files up to 122 sectors currently supported " if sectors_needed>122
  #TRACK/SECTOR LIST FORMAT (from Beneath Apple DOS p 4-6)
  # 00	Not used
  # 01	Track number of next T/S list of one is needed or zero if no more t/s list
  # 02 	Sector number of next T/S list (if one is present)
  # 03-04	Not used
  # 05-06	Sector offset in file of the first sector described by this list
  # 07-oB	Not used
  # 0C-0D	Track and sector of first data sector or zeros
  # 0E-0F	Track and sector of second data sector or zeros
  # 10-FF	Up to 120 more track and sector pairs
  track_sector_list="\0"*256
  track_sector_list_sector=free_sectors[0]
    (0..sectors_needed-2).each do |sector_in_file|
    sector_to_use=free_sectors[sector_in_file+1]
    track_sector_list[(sector_in_file*2)+0x0C]=sector_to_use[0]
    track_sector_list[(sector_in_file*2)+0X0D]=sector_to_use[1]
    sector_contents=file_contents[(sector_in_file*256),256] || ""
    self.set_sector(file_system_image,sector_to_use[0],sector_to_use[1],sector_contents)
  end
  #write the track/sector list
  self.set_sector(file_system_image,track_sector_list_sector[0],track_sector_list_sector[1],track_sector_list)

  #update the catalog file descriptive entry
  #FILE DESCRIPTIVE ENTRY (from Beneath Apple DOS p 4-6)
  # 00    Track of first track/sector list sector, if this is a deleted file this contains FF
  #	and the original track number is copied to the last byte of the file name (BYTE 20)
  #	If this byte contains a 00, the entry is assumed to never have been used and is
  #	available for use. (This means track 0 can never be used for data even if the DOS image
  #	is 'wiped' from the disk)
  #
  # 01    Sector of first track/sector list sector
  # 02    File type and flags:
  #	80+file type - file is locked
  #	00+file type - file is not locked
  #
  #	00 - TEXT file
  #	01 - INTEGER BASIC file
  #	02 - APPLESOFT BASIC file
  #	04 - BINARY file
  #	08 - S type file
  #	10 - RELOCATABLE object module file
  #	20 - a type file
  #	40 - b type file
  #
  # 03-20 File Name (30 characters)
  # 21-22 Length of file in sectors (LO/HI format)

  catalog_sector=file_system_image.get_sector(catalog_slot[0],catalog_slot[1])
  raise "invalid catalog track #{catalog_slot[0]},sector #{catalog_slot[1]}" if catalog_sector.nil?
  file_descriptive_entry="\0"*0x23
  file_descriptive_entry[0]=track_sector_list_sector[0]
  file_descriptive_entry[1]=track_sector_list_sector[1]
  file_descriptive_entry[2]=file_type
  file_descriptive_entry[3..0x20]=catalog_filename(filename)
  file_descriptive_entry[0x21]=(sectors_needed-1)%256
  file_descriptive_entry[0x22]=(sectors_needed-1)/256

  catalog_sector[catalog_slot[2],0x23]=file_descriptive_entry
  
  self.set_sector(file_system_image,catalog_slot[0],catalog_slot[1],catalog_sector)
  
  raise "catalog not updated correctly!" if find_catalog_slot(file_system_image,filename).nil?
  raise "error: file should now be in catalog" if files(file_system_image)[filename].nil?
  return native_file
end

.catalog_filename(filename) ⇒ Object

render a filename in form suitable for inclusion in a DOS catalog



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# File 'lib/file_systems/AppleDos.rb', line 258

def self.catalog_filename(filename)
    s=""
    for i in 0..29
      c=(filename[i])
      if c.nil? then
        c=0xA0        
        else 
        c=(c|0x80)
      end
      s+=c.chr
    end
    s
end

.delete_file(file_system_image, filename) ⇒ Object 



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# File 'lib/file_systems/AppleDos.rb', line 349

def self.delete_file(file_system_image,filename)
  this_files_catalog_slot=find_catalog_slot(file_system_image,filename)    
  #if file not in catalog, do nothing
  return if this_files_catalog_slot.nil? 
  file_descriptive_entry=file_system_image.get_sector(this_files_catalog_slot[0],this_files_catalog_slot[1])[this_files_catalog_slot[2],0x23]
  
  #mark sector as free in sector usage list
  sector_usage_bitmap_sector=file_system_image.get_sector(vtoc_track_no,vtoc_sector_no)
  sectors_to_mark_available=get_track_sector_list(file_system_image,file_descriptive_entry[0x00],file_descriptive_entry[0x01])
  sectors_to_mark_available<<[file_descriptive_entry[0x01],file_descriptive_entry[0x00]]
  
  sectors_to_mark_available.each do |ts|
    offset_of_byte_containing_this_sector=0x38+(ts[0]*4)
    if ts[1]<8 then 
      offset_of_byte_containing_this_sector+=1
    end
    byte_containing_this_sector=sector_usage_bitmap_sector[offset_of_byte_containing_this_sector]   
    byte_containing_this_sector=byte_containing_this_sector|(2**(ts[1]%8))
    sector_usage_bitmap_sector[offset_of_byte_containing_this_sector]=byte_containing_this_sector
  end
  file_system_image.set_sector(vtoc_track_no,vtoc_sector_no,sector_usage_bitmap_sector)
  
  #mark slot as available in catalog
  catalog_sector=file_system_image.get_sector(this_files_catalog_slot[0],this_files_catalog_slot[1])
  catalog_sector[this_files_catalog_slot[2]+0x20]=catalog_sector[this_files_catalog_slot[2]] #save the current "first track no" in last byte of filename
  catalog_sector[this_files_catalog_slot[2]]=0xFF
  file_system_image.set_sector(this_files_catalog_slot[0],this_files_catalog_slot[1],catalog_sector)
end

.files(file_system_image) ⇒ Object 



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# File 'lib/file_systems/AppleDos.rb', line 114

def self.files(file_system_image)
  files=FileContainer.new
  vtoc_sector=file_system_image.get_sector(vtoc_track_no,vtoc_sector_no)
  catalog_sector=file_system_image.get_sector(vtoc_sector[01],vtoc_sector[02])
  done=false
  visited_sectors={}
  while !done
    break if catalog_sector.nil?
    (0..6).each {|file_number|
      file_descriptive_entry_start=11+file_number*35
      file_descriptive_entry=catalog_sector[file_descriptive_entry_start,36]					
      break if (file_descriptive_entry[0]==0xFF) # skip deleted files
      filename=""
      file_descriptive_entry[3..32].to_s.each_byte{|b| filename+=(b.%128).chr}
      filename.gsub!(/ *$/,"") #strip off trailing spaces
      filename.tr!("\x00-\x1f","\x40-\x5f") #convert non-printable chars to corresponding uppercase letter
      locked=(file_descriptive_entry[2]>=0x80)
      sector_count=file_descriptive_entry[0x21]+file_descriptive_entry[0x22]*256
  
      file_type_code=file_descriptive_entry[2]%0x80
#      puts "filename #{filename} sector count #{sector_count}"
      contents=""
      ts_list_track_no=file_descriptive_entry[0]
      ts_list_sector_no=file_descriptive_entry[1]
      while (ts_list_track_no>0) && (ts_list_track_no<=0X22) && (ts_list_sector_no<=0x0f)
        ts_list_sector=file_system_image.get_sector(ts_list_track_no,ts_list_sector_no)
        ts_list_track_no=ts_list_sector[1]
        ts_list_sector_no=ts_list_sector[2]

        0x0C.step(0xff,2) {|i|						
          data_track_no=ts_list_sector[i]
          data_sector_no=ts_list_sector[i+1]
          if (data_track_no>0) && (data_track_no<=0X22) && (data_sector_no<=0x0f) then
            contents+=file_system_image.get_sector(data_track_no,data_sector_no)
          end
        }
        if contents.length>0 then
          files<<NativeFileType.best_fit(file_system_image,filename,contents,file_type_code)
        end
      end
    }
    next_track=catalog_sector[1]		
    next_sector=catalog_sector[2]%0x10
    if (next_track==0) &&( next_sector==0) then
      done=true
    else 
      #check we haven't got into an endless loop
      s="#{next_track}/#{next_sector}"
  #    puts s
      if (!visited_sectors[s].nil?) then
        done=true
      end
      visited_sectors[s]=true
      catalog_sector=file_system_image.get_sector(next_track,next_sector)
    end
  end
  files
end

.find_catalog_slot(file_system_image, filename) ⇒ Object

iterate through the CATALOG to find either the named file or (if nil is passed in) an empty slot



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# File 'lib/file_systems/AppleDos.rb', line 295

def self.find_catalog_slot(file_system_image,filename)
  vtoc_sector=file_system_image.get_sector(vtoc_track_no,vtoc_sector_no)
  catalog_filename=catalog_filename(filename.upcase) unless filename.nil?
  catalog_track_no=vtoc_sector[01]
  catalog_sector_no=vtoc_sector[02]
  
  while (catalog_track_no+catalog_sector_no>0) do
    catalog=file_system_image.get_sector(catalog_track_no,catalog_sector_no)    
    (0..7).each do |slot_no|
      slot_start=slot_no*0x23+0x0B
      if filename.nil? && (catalog[slot_start]==0x00)|| (catalog[slot_start]==0xFF) then        
        return [catalog_track_no,catalog_sector_no,slot_start]
      end
      if (!filename.nil?) && (catalog[slot_start+0x03..slot_start+0x20]==catalog_filename) then
        return [catalog_track_no,catalog_sector_no,slot_start]
      end
    end
    catalog_track_no=catalog[01]
    catalog_sector_no=catalog[02]    
  end
  nil
end

.free_sector_list(file_system_image) ⇒ Object

iterate through the sector usage bitmap, return a list of [track,sector] for sectors marked available



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# File 'lib/file_systems/AppleDos.rb', line 273

def self.free_sector_list(file_system_image)
  end_of_sector_usage_bitmap=(file_system_image.track_count*4+0x38)-1
  sector_usage_bitmap=file_system_image.get_sector(vtoc_track_no,vtoc_sector_no)[0x38..end_of_sector_usage_bitmap]
  free_sectors=[]
  #skip track 0 - even if sectors there are unused, we can't include them in a catalog or track/sector list
    (1..file_system_image.track_count-1).each do |track|
      track_bitmap_lo=sector_usage_bitmap[track*4+1]
      track_bitmap_hi=sector_usage_bitmap[track*4]
      (0..7).each do |sector|
        if ((track_bitmap_lo & (2**(sector)))!=0) then
          free_sectors<<[track,sector,0]
        end
        if ((track_bitmap_hi & (2**(sector)))!=0) then
          free_sectors<<[track,sector+8,0]
        end        
      end
    end
    free_sectors.sort
end

.get_track_sector_list(file_system_image, ts_list_track_no, ts_list_sector_no) ⇒ Object

given a track and sector, treat it as a track/sector list and return an array containing track/sector pairs



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# File 'lib/file_systems/AppleDos.rb', line 336

def self.get_track_sector_list(file_system_image,ts_list_track_no,ts_list_sector_no)
  ts_list_sector=file_system_image.get_sector(ts_list_track_no,ts_list_sector_no)
  ts_list=[]
  for entry_number in 0..121
    data_track_no=ts_list_sector[entry_number*2+0x0C]
    data_sector_no=ts_list_sector[entry_number*2+0x0D]
    if( (data_track_no!=0 || data_sector_no!=0)  && data_track_no<file_system_image.track_count && data_sector_no<=0x0f) then
      ts_list<<[data_track_no,data_sector_no]
    end
  end
  ts_list
end

.host_system ⇒ Object 



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# File 'lib/file_systems/AppleDos.rb', line 88

def self.host_system
  Apple2
end

.set_sector(file_system_image, track, sector, contents) ⇒ Object 



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# File 'lib/file_systems/AppleDos.rb', line 318

def self.set_sector(file_system_image,track,sector,contents)
  file_system_image.set_sector(track,sector,contents)  
  
  #now mark sector as used in sector usage list  
  if ((track!=vtoc_track_no) || (sector!=vtoc_sector_no)) then #don't bother marking the VTOC sectors used
    sector_usage_bitmap_sector=file_system_image.get_sector(vtoc_track_no,vtoc_sector_no)  
    offset_of_byte_containing_this_sector=0x38+(track*4)
    if sector<8 then 
        offset_of_byte_containing_this_sector+=1
    end
    byte_containing_this_sector=sector_usage_bitmap_sector[offset_of_byte_containing_this_sector]
    byte_containing_this_sector=byte_containing_this_sector&(0xff-(2**(sector%8)))
    sector_usage_bitmap_sector[offset_of_byte_containing_this_sector]=byte_containing_this_sector
    file_system_image.set_sector(vtoc_track_no,vtoc_sector_no,sector_usage_bitmap_sector)
  end
end

.vtoc_sector_no ⇒ Object 



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# File 'lib/file_systems/AppleDos.rb', line 110

def self.vtoc_sector_no
  0
end

.vtoc_track_no ⇒ Object 



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# File 'lib/file_systems/AppleDos.rb', line 106

def self.vtoc_track_no
  0x11
end