昔でっちあげたもの - ファイル分割

file_splitter.rb

#!/usr/bin/ruby -w
#
#  Copyright 2010 (C)  Kenichi Kamiya

class Integer
	def number_of_digits
		n = 1
		while abs > 10 ** i
			n += 1
		end
		n
	end
end

class File
  class << self
    def foreach_bytesize(path, bytesize)
      return enum_for __callee__, path, bytesize unless block_given?
      
      open path, 'rb' do |input|
        until input.eof?
          yield input.read bytesize
        end
      end
    end
  end
end

class DataSize
  BINARY_PREFIXES = %w(byte kiro mega giga tera).freeze
  RATIO = 1024
  
  def initialize(size, unit='byte')
    raise ArgumentError unless BINARY_PREFIXES.include? unit
    
    @byte = size * (RATIO ** BINARY_PREFIXES.index(unit))
  end
  
  BINARY_PREFIXES.each_with_index do |prefix, idx|
    define_method prefix do
      @byte * (Rational(1, RATIO) ** idx)
    end
  end
end

require 'pathname'
require 'io/nosey'

extend IO::Nosey

PATH = ask 'Source file ?', %r!\A([^/:*?"<>|]+)$! do |_, m|
  path = Pathname.new m[1]

  if path.readable?
    path
  else
    invalid "This script cannont read '#{path}'."
  end
end

puts "Path: #{PATH}", "Size: #{DataSize.new(PATH.size).mega.to_f.to_s[0..4]}MB"

UNIT = choose("Choose a unit.", *DataSize::BINARY_PREFIXES)
SIZE = ask('Size on the unit ?', /\A([1-9]\d*)\z/) {|s, m|m[1].to_i}
DATA_SIZE = DataSize.new SIZE, UNIT

SPLITED_PATHS = []

File.foreach_bytesize(PATH, DATA_SIZE.byte).with_index do |data, idx|
  path = "#{PATH}.#{idx + 1}"
  SPLITED_PATHS << path
  
  open path, 'wb' do |output|
    output << data
  end
end

open "#{PATH}.bat", 'w' do |bat|
  bat.puts %Q!copy /BV-Y #{SPLITED_PATHS.map{|path|"\"#{path}\""}.join '+'} "#{PATH}"!
end