nanodeath/threadz

require 'thread'

module Threadz
    # Related to, or at least named after, Java's AtomicInteger.
    # Provides a thread-safe integer counter thing.
    # The code used in this file, while slightly verbose, is to optimize
    # performance.  Avoiding additional method calls and blocks is preferred.
    class AtomicInteger # :nodoc:
        def initialize(value)
            @value = value
            @mutex = Mutex.new
        end
        
        def value
            @value
        end
        
        def increment(amount=1)
            # We could use Mutex#synchronize here, but compared to modifying an
            # integer, creating a block is crazy expensive
            @mutex.lock
            @value += amount
            @mutex.unlock
        end

        def decrement(amount=1)
            # We could refactor and just call set here, but it's faster just to write
            # the extra two lines.
            @mutex.lock
            @value -= amount
            @mutex.unlock
        end

        def set(value)
            @mutex.lock
            @value = value
            @mutex.unlock
        end
    end
end