diff_sigdump.rb

#!/usr/bin/env ruby

require "terminal-table"

slim_path = ARGV[0]
fat_path  = ARGV[1]

def parse_objects(path)
  ok = false
  counts = {}
  File.read(path).split("\n").each do |line|
    if line.include?("All objects:")
      ok = true
      next
    end
    if line.include?("bytes")
      ok = false
      next
    end
    unless ok
      next
    end
    count, klass = line.strip.split(": ")
    count.gsub!(",", "")
    counts[klass] = count.to_i
  end
  counts
end

slim_counts = parse_objects(slim_path)
fat_counts  = parse_objects(fat_path)

result = {}
(slim_counts.keys + fat_counts.keys).uniq.each do |klass|
  slim_count = slim_counts[klass] || 0
  fat_count  = fat_counts[klass]  || 0
  diff_count = fat_count - slim_count
  next if diff_count == 0
  result[klass] = { diff: diff_count, slim: slim_count, fat: fat_count }
end

len = 120
klasses = result.keys.sort_by { |klass| result[klass][:diff] }.reverse
table = Terminal::Table.new do |t|
  t.add_row %w(Class Diff Slim Fat)
  t.add_separator
  klasses.each do |klass|
    data = result[klass]
    title = klass
    title = title[0, len] + "..." if title.length > len
    t.add_row [title, data[:diff], data[:slim], data[:fat]]
  end
end

puts table