(define (F x y z)
  (| (& x y) (& (& 0xffffffff (~ x)) z)))

(define (G x y z)
  (| (& x z) (& y (& 0xffffffff (~ z)))))

(define (H x y z)
  (^ x y z))

(define (I x y z)
  (^ y (| x (& 0xffffffff (~ z)))))

(define (rotate-left x n)
  (| (& 0xffffffff (<< x n)) (& 0xffffffff (>> x (- 32 n)))))

(define (FF a b c d x s ac)
  (set 'a (& 0xffffffff (+ a (F b c d) x ac)))
  (set 'a (rotate-left a s))
  (set 'a (& 0xffffffff (+ a b))))

(define (GG a b c d x s ac)
  (set 'a (& 0xffffffff (+ a (G b c d) x ac)))
  (set 'a (rotate-left a s))
  (set 'a (& 0xffffffff (+ a b))))

(define (HH a b c d x s ac)
  (set 'a (& 0xffffffff (+ a (H b c d) x ac)))
  (set 'a (rotate-left a s))
  (set 'a (& 0xffffffff (+ a b))))

(define (II a b c d x s ac)
  (set 'a (& 0xffffffff (+ a (I b c d) x ac)))
  (set 'a (rotate-left a s))
  (set 'a (& 0xffffffff (+ a b))))

(define (md5-init )
  (set 'md5-i '(0 0))
  (set 'md5-in (dup 0 64))
  (set 'md5-digest (dup 0 16))
  (set 'md5-buf '(0x67452301 0xefcdab89 0x98badcfe 0x10325476)))

(define (md5-update inbuf inlen)
  ;; compute number of bytes mod 64
  (set 'mdi (& (>> (md5-i 0) 3) 0x3f))

  ;; update number of bits
  (if (< (+ (md5-i 0)  (<< inlen 3)) (md5-i 0))
      (nth-set (md5-i 1) (+ 1 (md5-i 1))))

  (nth-set (md5-i 0) (+ (md5-i 0) (<< inlen 3)))
  (nth-set (md5-i 1) (+ (md5-i 1) (>> inlen 29)))

  (set 'inbuf-index 0)
  (while (> inlen 0)
	 ;; add new character to buffer, increment mdi
	 (nth-set (md5-in mdi) (inbuf inbuf-index))
	 (set 'mdi (+ mdi 1))
	 (set 'inbuf-index (+ inbuf-index 1))

	 ;; transform if necessary
	 (if (= mdi 0x40)
	     (begin
	       (set 'ii 0)
	       (set 'in (dup 0 16))
	       (for (i 0 15 1)
		    (nth-set (in i) (| (<< (char->int (md5-in (+ ii 3))) 24)
				       (<< (char->int (md5-in (+ ii 2))) 16)
				       (<< (char->int (md5-in (+ ii 1))) 8)
				       (char->int (md5-in ii))))
		    (set 'ii (+ ii 4)))
	       (transform  in)
	       (set 'mdi 0)))
	 (set 'inlen (- inlen 1))))

(define (char->int x)
  (if (integer? x) x (char x)))

(define (md5-final)
  (set 'in (dup 0 16))

  ;; save number of bits
  (nth-set (in 14) (md5-i 0))
  (nth-set (in 15) (md5-i 1))

  ;; compute number of bytse mod 64
  (set 'mdi (& (>> (md5-i 0) 3) 0x3f))

  ;; pad out to 56 mod 64
  (if (< mdi 56)
      (set 'padlen (- 56 mdi))
      (set 'padlen (- 120 mdi)))

  (set 'padding (dup 0 64))
  (nth-set (padding 0) 0x80)
  (md5-update padding padlen)

  ;; append lenth in bits and transform
  (set 'ii 0)
  (for (i 0 13 1)
       (nth-set (in i) (| (<< (char->int (md5-in (+ ii 3))) 24)
			  (<< (char->int (md5-in (+ ii 2))) 16)
			  (<< (char->int (md5-in (+ ii 1))) 8) (char->int (md5-in ii))))
       (set 'ii (+ ii 4)))
  (transform in)

  ;; store buffer in digest
  (set 'ii 0)
  (for (i 0 3 1)
       (nth-set (md5-digest ii) (& (md5-buf i) 0xff))
       (nth-set (md5-digest (+ ii 1)) (& (>> (md5-buf i) 8) 0xff))
       (nth-set (md5-digest (+ ii 2)) (& (>> (md5-buf i) 16)  0xff))
       (nth-set (md5-digest (+ ii 3)) (& (>> (md5-buf i) 24)  0xff))
       (set 'ii (+ ii 4))))

(define (transform  in)
  (set 'a (md5-buf 0))
  (set 'b (md5-buf 1))
  (set 'c (md5-buf 2))
  (set 'd (md5-buf 3))

  ;; Round 1
  (set 'S11 7)
  (set 'S12 12)
  (set 'S13 17)
  (set 'S14 22)
  (set 'a (FF a b c d (in 0) S11 3614090360)) 
  (set 'd (FF d a b c (in 1) S12 3905402710)) 
  (set 'c (FF c d a b (in 2) S13  606105819)) 
  (set 'b (FF b c d a (in 3) S14 3250441966)) 
  (set 'a (FF a b c d (in 4) S11 4118548399)) 
  (set 'd (FF d a b c (in 5) S12 1200080426)) 
  (set 'c (FF c d a b (in 6) S13 2821735955)) 
  (set 'b (FF b c d a (in 7) S14 4249261313)) 
  (set 'a (FF a b c d (in 8) S11 1770035416)) 
  (set 'd (FF d a b c (in 9) S12 2336552879)) 
  (set 'c (FF c d a b (in 10) S13 4294925233))
  (set 'b (FF b c d a (in 11) S14 2304563134))
  (set 'a (FF a b c d (in 12) S11 1804603682))
  (set 'd (FF d a b c (in 13) S12 4254626195))
  (set 'c (FF c d a b (in 14) S13 2792965006))
  (set 'b (FF b c d a (in 15) S14 1236535329))

  ;; Round 2 
  (set 'S21 5)
  (set 'S22 9)
  (set 'S23 14)
  (set 'S24 20)
  (set 'a (GG a b c d (in 1) S21 4129170786)) 
  (set 'd (GG d a b c (in 6) S22 3225465664)) 
  (set 'c (GG c d a b (in 11) S23  643717713))
  (set 'b (GG b c d a (in 0) S24 3921069994)) 
  (set 'a (GG a b c d (in 5) S21 3593408605)) 
  (set 'd (GG d a b c (in 10) S22   38016083))
  (set 'c (GG c d a b (in 15) S23 3634488961))
  (set 'b (GG b c d a (in 4) S24 3889429448)) 
  (set 'a (GG a b c d (in 9) S21  568446438)) 
  (set 'd (GG d a b c (in 14) S22 3275163606))
  (set 'c (GG c d a b (in 3) S23 4107603335)) 
  (set 'b (GG b c d a (in 8) S24 1163531501)) 
  (set 'a (GG a b c d (in 13) S21 2850285829))
  (set 'd (GG d a b c (in 2) S22 4243563512)) 
  (set 'c (GG c d a b (in 7) S23 1735328473)) 
  (set 'b (GG b c d a (in 12) S24 2368359562))

  ;; Round 3 
  (set 'S31 4)
  (set 'S32 11)
  (set 'S33 16)
  (set 'S34 23)
  (set 'a (HH a b c d (in 5) S31 4294588738)) 
  (set 'd (HH d a b c (in 8) S32 2272392833)) 
  (set 'c (HH c d a b (in 11) S33 1839030562))
  (set 'b (HH b c d a (in 14) S34 4259657740))
  (set 'a (HH a b c d (in 1) S31 2763975236)) 
  (set 'd (HH d a b c (in 4) S32 1272893353)) 
  (set 'c (HH c d a b (in 7) S33 4139469664)) 
  (set 'b (HH b c d a (in 10) S34 3200236656))
  (set 'a (HH a b c d (in 13) S31  681279174))
  (set 'd (HH d a b c (in 0) S32 3936430074)) 
  (set 'c (HH c d a b (in 3) S33 3572445317)) 
  (set 'b (HH b c d a (in 6) S34   76029189)) 
  (set 'a (HH a b c d (in 9) S31 3654602809)) 
  (set 'd (HH d a b c (in 12) S32 3873151461))
  (set 'c (HH c d a b (in 15) S33  530742520))
  (set 'b (HH b c d a (in 2) S34 3299628645)) 

  ;; Round 4 
  (set 'S41 6)
  (set 'S42 10)
  (set 'S43 15)
  (set 'S44 21)
  (set 'a (II a b c d (in 0) S41 4096336452)) 
  (set 'd (II d a b c (in 7) S42 1126891415)) 
  (set 'c (II c d a b (in 14) S43 2878612391))
  (set 'b (II b c d a (in 5) S44 4237533241)) 
  (set 'a (II a b c d (in 12) S41 1700485571))
  (set 'd (II d a b c (in 3) S42 2399980690)) 
  (set 'c (II c d a b (in 10) S43 4293915773))
  (set 'b (II b c d a (in 1) S44 2240044497)) 
  (set 'a (II a b c d (in 8) S41 1873313359)) 
  (set 'd (II d a b c (in 15) S42 4264355552))
  (set 'c (II c d a b (in 6) S43 2734768916)) 
  (set 'b (II b c d a (in 13) S44 1309151649))
  (set 'a (II a b c d (in 4) S41 4149444226)) 
  (set 'd (II d a b c (in 11) S42 3174756917))
  (set 'c (II c d a b (in 2) S43  718787259)) 
  (set 'b (II b c d a (in 9) S44 3951481745)) 

  (nth-set (md5-buf 0) (+ a (md5-buf 0)))
  (nth-set (md5-buf 1) (+ b (md5-buf 1)))
  (nth-set (md5-buf 2) (+ c (md5-buf 2)))
  (nth-set (md5-buf 3) (+ d (md5-buf 3))))

(define (md5-string str)
  (md5-init)
  (md5-update str (length str))
  (md5-final)
  (set 'result "")
  (for (i 0 15 1)
       (set 'result (append result (format "%02x" (md5-digest i)))))
  result)

class Array
  def to_h(key_definition)
    result_hash = Hash.new()
    
    counter = 0
    key_definition.each do |definition|
      if not self[counter] == nil then
        result_hash[definition] = self[counter].strip
      else
        # Insert the key definition with a empty value.
        # Because we probably still want the hash to contain the key.
        result_hash[definition] = ""
      end
      # For some reason counter.next didn't work here....
      counter = counter + 1
    end
    
    return result_hash
  end
end

key_definitions = Array['foo', 'bar', 'foobar', 'extra']
some_values     = Array['bla', 99, 'blabla']

some_values.to_h(key_definitions)   # => {'foo' => 'bla', 'bar' => 99, 'foobar' => 'blabla', 'extra' => ''}

def some_method(opts={})
  my_foo =  opts[:foo] || 'mydefaultfoo'
end

class Hash
  def with_defaults(defaults)
    self.merge(defaults) { |key, old, new| old.nil? ? new : old } 
  end

  def with_defaults!(defaults)
    self.merge!(defaults) { |key, old, new| old.nil? ? new : old }
  end
end

>> params_for_with(:clean_range => 'clean_range', :raw_range => 'raw_range', :total_count => 'total_count')
=> 'total_count=' + total_count + '&' + 'clean_range=' + clean_range + '&' + 'raw_range=' + raw_range

def params_for_with(options = {})
    options.collect { |param_name, js_fragment| "'#{param_name}='+#{js_fragment}" }.join("+'&'+")
    # or this one
    #options.stringify_keys.collect { |param_name, js_fragment| '"' << param_name << '="+' << js_fragment }.join('+"&"+')
end

class Array
  def to_h
    Hash[*self]
  end
end

['action', 'go', 'id', 6].to_h   # => { 'action' => 'go', 'id' => 6 }

class Hash

  # lets through the keys in the argument
  # >> {:one => 1, :two => 2, :three => 3}.pass(:one)
  # => {:one=>1}
  def pass(*keys)
    tmp = self.clone
    tmp.delete_if {|k,v| ! keys.include?(k) }
    tmp
  end

  # blocks the keys in the arguments
  # >> {:one => 1, :two => 2, :three => 3}.block(:one)
  # => {:two=>2, :three=>3}
  def block(*keys)
    tmp = self.clone
    tmp.delete_if {|k,v| keys.include?(k) }
    tmp
  end

end

def some_action
    # some script kiddie also passed in :bee, which we don't want tampered with _here_.
    @model = Model.create(params.pass(:foo, :bar))
  end

hash_var = array_var..inject({}) {|h, elem| h[elem[0]]=elem[1]; h}

class Hash

   def extract_keys

      keys = []

      each_pair do |k1, v1|

         if v1.is_a?(Hash)

            v1.each_pair { |k2, v2|
               if !v2.is_a?(Hash) then keys << [k1, k2]; next end
            v2.each_pair { |k3, v3|
               if !v3.is_a?(Hash) then keys << [k1, k2, k3]; next end
            v3.each_pair { |k4, v4|
               if !v4.is_a?(Hash) then keys << [k1, k2, k3, k4]; next end
            v4.each_pair { |k5, v5|
               if !v5.is_a?(Hash) then keys << [k1, k2, k3, k4, k5]; next end
            v5.each_pair { |k6, v6|
               if !v6.is_a?(Hash) then keys << [k1, k2, k3, k4, k5, k6]; next end
               # add more v[n].each_pair ... loops to process more hash dimensions
            } } } } }      # "}" * 5

         else
            keys << [k1]
         end

      end
      
      keys

   end


   def all_values
      extract_keys.map do |subar|
         key = ""
         subar.size.times { |i| key << "[subar[#{i}]]" }
         hash_str = "self" << key << " rescue nil"   # example: "self[subar[0]][subar[1]][subar[2]][subar[3]] rescue nil"
         hash_value = eval(hash_str) 
      end
   end


#-------------------------


   # Find every path and it's value in a Hash, http://snippets.dzone.com/posts/show/3565
   # Author: Florian Aßmann

   def each_path
      raise ArgumentError unless block_given?
      self.class.each_path(self) { |path, object| yield(path, object) }
   end

   protected
   #def self.each_path(object, path = '', &block)
   def self.each_path(object, path = [], &block)   # alternative
      if object.is_a?(Hash)
         object.each do |key, value|
            #self.each_path(value, "#{ path }#{ key }/", &block)
            self.each_path(value, [path , key].flatten, &block)   # alternative
         end
      else 
         yield(path, object)
      end
   end 

end


h = {"a"=>"b", "c"=>"d", 1=>{2=>{"e"=>"f", 3=>{4=>"value"}}}} 

puts h[1][2].class          # Hash
puts h[1][2]["e"].class     # String

extracted_keys = h.extract_keys
puts extracted_keys.inspect         # [["a"], [1, 2, "e"], [1, 2, 3, 4], ["c"]]

puts h[1][2].has_key?("e")                 # true
puts extracted_keys.include?([1, 2, "e"])  # true


h = {700=>{4=>"value"}, "a"=>"b", 3=>{4=>"value"}, "c"=>"d", 1=>{2=>{"e"=>"f", 3=>{4=>"value"}, 300=>{4=>"value"}}}} 
p h
p h.extract_keys    #=> [["a"], [1, 2, "e"], [1, 2, 300, 4], [1, 2, 3, 4], ["c"], [700, 4], [3, 4]]
p h.all_values      #=> ["b", "f", "value", "value", "d", "value", "value"]


#-----------------


paths = []
complex_hash = Hash[
  :a => { :aa => '1', :ab => '2' },
  :b => { :ba => '3', :bb => '4' }
]
complex_hash.each_path { |path, value| paths << [ path, value ] }

p paths    # => [[[:b, :ba], "3"], [[:b, :bb], "4"], [[:a, :ab], "2"], [[:a, :aa], "1"]]
puts


h = {"a"=>"b", "c"=>"d", 1=>{2=>{"e"=>"f", 3=>{4=>"value"}}}} 
h = {"a"=>"b", "l" => lambda { |x| x+1 }, 1=>{2=>{"e"=>"f", 3=>{4=>"value"}}}} 
h = {700=>{4=>"value"}, "a"=>"b", nil => "NILVALUE", 3=>{4=>"value"}, "c"=>"d", 1=>{2=>{"e"=>"f", 3=>{4=>"value"}, 300=>{4=>"value"}}}} 

p h
p h.extract_keys

keys = []
h.each_path { |path, value| keys << path }
p keys   # complete key sequences (with last key not pointing to another hash)

paths = []
h.each_path { |path, value| paths << [ path, value ] }
p paths   # complete key sequences plus values

vals = []
h.each_path { |path, value| vals << value }
p vals   # all values of complete key sequences

p h.all_values   # same

class Hash
  def mdh(*mkeys)
     value = mkeys.pop
     count = 0
     mdhash = lambda { |*keys|
                   count += 1
                   keys_clone = keys.clone if count == 1 # keys_clone will return nil for count > 1 in Hash.new
                   Hash.new(var = keys_clone || keys.shift).update(var => mdhash[*keys] || value) unless keys.empty? 
                 }
     mdhash.call(*mkeys)
  end
end

h = Hash.new.mdh(1, 2, 3, 4, "value")

puts h.inspect  # {[1, 2, 3, 4]=>{1=>{2=>{3=>{4=>"value"}}}}}

k = [1, 2, 3, 4]
puts h.has_key?(k)
puts h[k][k[0]][k[1]][k[2]][k[3]]  # value


     

state_abbr = {
  'AL' => 'Alabama',
  'AK' => 'Alaska',
  'AS' => 'America Samoa',
  'AZ' => 'Arizona',
  'AR' => 'Arkansas',
  'CA' => 'California',
  'CO' => 'Colorado',
  'CT' => 'Connecticut',
  'DE' => 'Delaware',
  'DC' => 'District of Columbia',
  'FM' => 'Micronesia1',
  'FL' => 'Florida',
  'GA' => 'Georgia',
  'GU' => 'Guam',
  'HI' => 'Hawaii',
  'ID' => 'Idaho',
  'IL' => 'Illinois',
  'IN' => 'Indiana',
  'IA' => 'Iowa',
  'KS' => 'Kansas',
  'KY' => 'Kentucky',
  'LA' => 'Louisiana',
  'ME' => 'Maine',
  'MH' => 'Islands1',
  'MD' => 'Maryland',
  'MA' => 'Massachusetts',
  'MI' => 'Michigan',
  'MN' => 'Minnesota',
  'MS' => 'Mississippi',
  'MO' => 'Missouri',
  'MT' => 'Montana',
  'NE' => 'Nebraska',
  'NV' => 'Nevada',
  'NH' => 'New Hampshire',
  'NJ' => 'New Jersey',
  'NM' => 'New Mexico',
  'NY' => 'New York',
  'NC' => 'North Carolina',
  'ND' => 'North Dakota',
  'OH' => 'Ohio',
  'OK' => 'Oklahoma',
  'OR' => 'Oregon',
  'PW' => 'Palau',
  'PA' => 'Pennsylvania',
  'PR' => 'Puerto Rico',
  'RI' => 'Rhode Island',
  'SC' => 'South Carolina',
  'SD' => 'South Dakota',
  'TN' => 'Tennessee',
  'TX' => 'Texas',
  'UT' => 'Utah',
  'VT' => 'Vermont',
  'VI' => 'Virgin Island',
  'VA' => 'Virginia',
  'WA' => 'Washington',
  'WV' => 'West Virginia',
  'WI' => 'Wisconsin',
  'WY' => 'Wyoming'
}