Module: Musicality::BiInfiniteSequence

Included in:
AddingSequence, RepeatingSequence
Defined in:
lib/musicality/composition/util/biinfinite_sequence.rb

Instance Method Summary collapse

Instance Method Details

#at(offset) ⇒ Object 



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# File 'lib/musicality/composition/util/biinfinite_sequence.rb', line 14

def at offset
  if offset.is_a? Enumerable
    return enum_for(:at,offset) unless block_given?
  else
    return at_one(offset)
  end
  
  offset_index_pairs = offset.map_with_index {|x,i| [x,i] }.sort
  results = Array.new(offset.size)
  
  past = offset_index_pairs.select {|p| p[0] < 0 }
  present = offset_index_pairs.select {|p| p[0] == 0 }
  future = offset_index_pairs.select {|p| p[0] > 0 }
  
  start_val = start_value
  
  if past.any?
    value = start_val
    j = past.size - 1
    tgt_offset = past[j][0]
    0.downto(past.first[0]+1) do |i|
      value = prev_value(value,i)
      while (i-1) == tgt_offset
        results[past[j][1]] = value
        j -= 1
        tgt_offset = j >= 0 ? past[j][0] : nil
      end
    end
  end
  
  if present.any?
    present.each do |off,index|
      results[index] = start_val
    end
  end
  
  if future.any?
    value = start_val
    j = 0
    tgt_offset = future[j][0]
    0.upto(future.last[0]-1) do |i|
      value = next_value(value,i)
      while (i+1) == tgt_offset
        results[future[j][1]] = value
        j += 1
        tgt_offset = j < future.size ? future[j][0] : nil
      end
    end
  end
  
  results.each {|x| yield x }
end

#over(range) ⇒ Object

Raises:



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# File 'lib/musicality/composition/util/biinfinite_sequence.rb', line 90

def over range
  min, max = range.minmax
  raise EmptyError, "given range (#{range}) is empty" if min.nil?
  return enum_for(:over,range) unless block_given?

  if min >= 0 && max >= 0
    value = at(min)
    range.each do |i|
      yield value
      value = next_value(value,i)
    end
  elsif max < 0
    value = at(max+1)
    values = range.entries.reverse.map do |i|
      value = prev_value(value,i+1)
    end
    values.reverse_each {|x| yield x }
  else
    take_back(-min).reverse_each {|x| yield x }
    take(max + 1){ |x| yield x }
  end
end

#take(n) ⇒ Object

Raises:



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# File 'lib/musicality/composition/util/biinfinite_sequence.rb', line 67

def take n
  raise NegativeError if n < 0
  return enum_for(:take,n) unless block_given?
  return if n == 0
  
  value = start_value
  0.upto(n - 1) do |i|
    yield value
    value = next_value(value,i)
  end
end

#take_back(n) ⇒ Object

Raises:



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# File 'lib/musicality/composition/util/biinfinite_sequence.rb', line 79

def take_back n
  raise NegativeError if n < 0
  return enum_for(:take_back,n) unless block_given?
  return if n == 0
  
  value = start_value
  0.downto(1 - n) do |i|
    yield value = prev_value(value,i)
  end
end