#--
# Copyright (c) 2009, John Mettraux, jmettraux@gmail.com
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
# Made in Japan.
#++


module Rufus
module Tokyo

  #
  # A mixin for Cabinet and Map, gathers all the hash-like methods
  #
  module HashMethods

    include Enumerable

    attr_accessor :default_proc

    # The [] methods
    #
    # (assumes there's an underlying get(k) method)
    #
    def [] (k)

      val = get(k)

      return val unless val.nil?
      return nil unless @default_proc

      @default_proc.call(self, k)
    end

    # Returns an array of all the values
    #
    def values

      collect { |k, v| v }
    end

    # Our classical 'each'
    #
    def each
      # 
      # drop to Edo's C API calls to avoid two-step iteration
      # (keys() then each())
      # 
      if defined?(@db) and %w[iterinit iternext].all? { |m| @db.respond_to?(m) }
        @db.iterinit
        while k = @db.iternext
          yield(k, self[k])
        end
      # 
      # drop to Tokyo's FFI calls to avoid two-step iteration
      # (keys() then each())
      # 
      elsif self.class.name != "Rufus::Tokyo::Table" and # use String for Edo
            defined?(@db)                            and
            respond_to?(:lib)                        and
            %w[abs_iterinit abs_iternext].all? { |m| lib.respond_to?(m) }
        begin
          lib.abs_iterinit(@db)
          int = FFI::MemoryPointer.new(:int)
          loop do
            key_pointer = lib.abs_iternext(@db, int)
            break if key_pointer.address.zero?
            k = key_pointer.get_bytes(0, int.get_int(0))
            yield(k, self[k])
          end
        ensure
          int.free if int
        end
      # we couldn't do it fast, so go ahead with slow-but-accurate
      else
        keys.each { |k| yield(k, self[k]) }
      end
    end

    # Turns this instance into a Ruby hash
    #
    def to_h

      self.inject({}) { |h, (k, v)| h[k] = v; h }
    end

    # Turns this instance into an array of [ key, value ]
    #
    def to_a

      #self.collect { |e| e }
        # not OK with ruby 1.9.1

      self.inject([]) { |a, (k, v)| a << [ k, v ]; a }
    end

    # Returns a new Ruby hash which is a merge of this Map and the given hash
    #
    def merge (h)

      self.to_h.merge(h)
    end

    # Merges the entries in the given hash into this map
    #
    def merge! (h)

      h.each { |k, v| self[k] = v }

      self
    end

    # Returns the default value, the value that would be returned by h[k] if
    # k did not exist among h keys.
    #
    def default (key=nil)

      return nil unless @default_proc

      @default_proc.call(self, key) rescue nil
    end

    # Sets the default value for the Hash.
    #
    # Warning : use #default_proc= if you want to change the default_proc
    # directly.
    #
    def default= (val)

      @default_proc = val.nil? ? nil : lambda { |h, k| val }
    end
  end

end
end