progressbar.rb

# Ruby/ProgressBar - a text progress bar library
#
# Copyright (C) 2001 Satoru Takabayashi <satoru@namazu.org>
#     All rights reserved.
#     This is free software with ABSOLUTELY NO WARRANTY.
#
# You can redistribute it and/or modify it under the terms
# of Ruby's licence.
#

class ProgressBar
  VERSION = "0.3"

  def initialize title, total, out = STDERR
    @title = title
    @total = total
    @out = out
    @current = 0
    @previous = 0
    @is_finished = false
    @start_time = Time.now
    @bar = '###########################'
    show_progress
  end

  def format_time t
    t = t.to_i
    sec = t % 60
    min  = (t / 60) % 60
    hour = t / 3600
    sprintf('%02d:%02d:%02d', hour, min, sec);
  end

  # ETA stands for Estimated Time of Arrival.
  def eta
    if @current == 0
      'ETA:  --:--:--'
    else
      elapsed = Time.now - @start_time
      eta = elapsed * @total / @current - elapsed;
      sprintf("ETA:  %s", format_time(eta))
    end
  end

  def elapsed
    elapsed = Time.now - @start_time
    sprintf("Time: %s", format_time(elapsed))
  end
  
  def time
    @is_finished ? elapsed : eta
  end

  def eol
    @is_finished ? "\n" : "\r"
  end

  def bar percentage
    len = percentage * @bar.length / 100
    sprintf('[%.*s%*s]', len, @bar, @bar.length - len, '')
  end

  def show percentage
    @out.printf('%-14s %3d%% %s %s%s',
		@title[0,13] + ':',
		percentage,
		bar(percentage),
		time,
		eol)
  end

  def show_progress
    if @total.zero?
      cur_percentage = 100
      prev_percentage = 0
    else
      cur_percentage  = (@current  * 100 / @total).to_i
      prev_percentage = (@previous * 100 / @total).to_i
    end

    if cur_percentage > prev_percentage || @is_finished
      show(cur_percentage)
    end
  end

  public
  def finish
    @current = @total
    @is_finished = true
    show_progress
  end

  def set count
    if count < 0 || count > @total
      raise "invalid count: #{count} (total: #{total})"
    end
    @current = count
    show_progress
    @previous = @current
  end

  def inc step = 1
    @current += step
    @current = @total if @current > @total
    show_progress
    @previous = @current
  end
end