Class: Morel::SortedWindow

Inherits:
Object
  • Object
show all
Defined in:
lib/morel/sorted_window.rb

Constant Summary collapse

@@code =

this code will be translated to javascript

lambda do |collection|
  lambda{ |k,v|
    unless window
      # list node for our linked list of key value pairs
      def Node k,v
        @next = nil
        @prev = nil
        @k    = k
        @v    = v
      end
       window = {
        last: nil,
        list: [],  # all the nodes sorted
         # search for a given key value pair
        find: lambda{ |k,v|
          # first search for the key
          beg = 0
          lst = @list[:length]-1
          mid = (beg+lst)>>1
          while true
            if k<@list[mid][:k]
              lst=mid
            else
              beg=mid
            end
            mid = (beg+lst)>>1
            break if mid==beg
          end
           # may not be exact match (multiple of same key value), searh in both directions for a exact match
          start = mid
          dir = 1
          while v != @list[mid][:v]
            mid += dir
            if mid == @list[:length]
              # end reached, flip direction and start over
              mid = start
              dir =- 1
            end
          end
           # found
          return mid
        },
         # add a new key value pair to the window (its linked list)
        add: lambda{ |k,v|
          if @list[:length]
            beg = 0
            lst = @list[:length]-1
            mid = (beg+lst)>>1
             # just add it to the end of our linked list
            n = Node.new(k,v)
            @last.next = n
            n.prev = @last
            @last = n
              # and insert it at the correct place in our sorted list
            if k>=@list[lst][:k]
              if @list[:length] == :max && k>@list[lst][:k]
                emit(n[:v][:_id],n[:v][:vol])
              end
              @list.push(n)
            else
              while true
                if k<@list[mid][:k]
                  lst=mid
                else
                  beg=mid
                end
                mid = (beg+lst)>>1
                break if mid==beg
              end
               if k<@list[mid][:k]
#                    if @list[:length] >= :max && mid==0
              #    # we got a new winner, so anounce it
              #    #print(tojson(this.list[mid].v));
#                      emit(@list[mid][:k],@list[mid][:v])
#emit(@list[mid][:v][:_id],@list[mid][:v][:vol])
#                    end
                @list.splice(mid,0,n)
              elsif k<@list[lst][:k]
                @list.splice(lst,0,n)
              else
                #print("!!!");
                #print(k);
                #print(this.list[mid].k);
                #print(this.list[end].k);
                while true
                end
              end
            end
             # dont let the window grow larger then its size
            if @list[:length] > :max
              # remove first
              @list.splice(this.find(@first[:k],@first[:v]),1)
              @first[:next].prev = nil
              @first = @first[:next]
            end
          else
            # the list is empty, just push it
            @last = Node.new(k,v)
            @first = @last
            @list.push(@last)
          end
        }
      }
    end
    window.add(v[:vol],v)
  }
end

Instance Method Summary collapse

Constructor Details

#initialize(params) ⇒ SortedWindow

Returns a new instance of SortedWindow.



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# File 'lib/morel/sorted_window.rb', line 132

def initialize params
  @collection = params[:collection]
  @size       = params[:size]
  @block      = params[:block]
end

Instance Method Details

#each_top ⇒ Object 



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# File 'lib/morel/sorted_window.rb', line 138

def each_top
  unless @map
    @map = Ruby2Js.new.process(@@code.to_code(@collection)).gsub(/window\(\)/,'window').gsub(/Node\(k, v\){/,'function Node(k, v){').gsub(/:max/,'max')
    @collection.db.add_stored_function('hello',@map)
    @map = "hello(this._id,this);"
  end
  reduce = "function(k,vals){ return 1; }"
  testing = @collection.collection.map_reduce(@map, reduce, :out => 'testing', :scope => { :window => nil, :max => @size }) #, :out => "testing", :query => { :user => user })
  testing.find.map{ |m| yield m; m }
end