# Splits a file (eg. abc.ext) to a number of smaller files (eg. abc.ext.piece1, abc.ext.piece2 etc)
# Does not do any error handling
# Expects file to be split to exist in the current directory!
# Usage: ruby file_splitter.rb <filename.ext> <num_of_pieces>
# Example: ruby file_splitter.rb myfile.txt 10

class FileSplitter
	def initialize(filename, num_of_splits)
		@filename = filename
		@file = File.new(filename, "rb")
		@num_of_splits = num_of_splits
		
		# when we are splitting a file into a given number of pieces, the last piece could be bigger than the others
		@each_size, @extra = File.size(filename).divmod(@num_of_splits)
	end
	
	def split
		(1..@num_of_splits).each do |n|
			File.open(@filename + ".piece#{n}", "wb") do |f|
				f << @file.read(@each_size) 
				if n == @num_of_splits and not @extra.nil?
					f << @file.read(@extra)
				end
			end
		end
	end
end

if ARGV.size != 2
	puts "Usage: ruby file_splitter.rb <filename.ext> <num_of_pieces>"
	puts "Example: ruby file_splitter.rb myfile.txt 10"
else
	FileSplitter.new(ARGV[0], ARGV[1].to_i).split
end