Method: FileUtil.split

Defined in:
lib/ec2/amitools/fileutil.rb

.split(filename, part_name_prefix, cb_size, dst_dir) ⇒ Object

Split the specified file into chunks of the specified size. yields the <file,chunk,chunk size> to a block which writes the actual chunks The chunks are output to the local directory. Typical invocation looks like: FileUtil.split(‘file’,5){|sf,cf,cs| ChunkWriter.write_chunk(sf,cf,cs)}

((|filename|)) The file to split. ((|part_name_prefix|)) The prefix for the parts filenames. ((|cb_size|)) The chunk size in bytes. ((|dst_dir|)) The destination to create the file parts in.

Returns a list of the created filenames.



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# File 'lib/ec2/amitools/fileutil.rb', line 91

def FileUtil.split(filename, part_name_prefix, cb_size, dst_dir)
  begin
    # Check file exists and is accessible.
    begin
      file = File.new(filename, File::RDONLY)
    rescue SystemCallError => e
      raise FileError.new(filename, "could not open file to split", e)
    end
    
    # Create the part file upfront to catch any creation/access errors
    # before writing out data.
    nr_parts = (Float(File.size(filename)) / Float(cb_size)).ceil
    part_names = []
    nr_parts.times do |i|
      begin
        nr_parts_digits = nr_parts.to_s.length
        part_name_suffix = PART_SUFFIX + i.to_s.rjust(nr_parts_digits).gsub(' ', '0')
        part_names[i] = part_name = part_name_prefix + part_name_suffix
        FileUtils.touch File.join(dst_dir, part_name)
      rescue SystemCallError => e
        raise FileError.new(filename, "could not create part file", e)
      end
    end
    
    # Write parts to files.
    part_names.each do |part_file_name|
      File.open(File.join(dst_dir, part_file_name), 'w+') do |pf|
        write_chunk(file, pf, cb_size)
      end
    end

    part_names
  ensure
    file.close if not file.nil?
  end
end