michael@0: # Uses a binary search algorithm to locate a value in the specified array.
michael@0: window.binary_search = (items, value) ->
michael@0: 
michael@0:   start = 0
michael@0:   stop  = items.length - 1
michael@0:   pivot = Math.floor (start + stop) / 2
michael@0: 
michael@0:   while items[pivot] isnt value and start < stop
michael@0: 
michael@0:     # Adjust the search area.
michael@0:     stop  = pivot - 1 if value < items[pivot]
michael@0:     start = pivot + 1 if value > items[pivot]
michael@0: 
michael@0:     # Recalculate the pivot.
michael@0:     pivot = Math.floor (stop + start) / 2
michael@0: 
michael@0:   # Make sure we've found the correct value.
michael@0:   if items[pivot] is value then pivot else -1