Circular Buffer

circular_buffer.py

class RingBuffer:
    index = 0
    value = None   
    
    def __init__(self, length):
        # create buffer using dequeue
        self.buffer = deque([], length)
        
        # establish end index number
        self._eix = length-1
        
        # Populate Buffer Length With None
        for n in range(length):
            self.buffer.append(None)
            
        
    def populate_buffer(self, value_array):
        "Init Buffer with array of values"
        rix = 0
        for item in value_array:
            self.buffer[rix] = item
            if rix == 0:
                self.v = item
            print(rix, item)
            rix += 1
  
        
    def move_right(self):
        if self.buffer == deque([]):
            raise Exception("Ring.buffer is empty.")
            
        # move index right by one
        
        self.index += 1
        
        # if index is greater or equal to end index
        # reset index to zero
        
        if self.index > self._eix:
            self.index = 0
            
        # pull value from buffer at new index
        
        self.value = self.buffer[self.index]
        # return index and value
        return self.index, self.value
    
    def peek_right(self, n=1):        
        if n == 0:
            raise Exception("n must be > 0")
        
        notional_index = self.index + n
        
        length = self._eix + 1
        
        index = notional_index % length
        
        return index, self.buffer[index]

    def peek_left(self, n=1):
        
        # Convert n to negative number
        if n > 0:
            n *= -1
        
        if n == 0:
            raise Exception("abs(n) must be > 0") 
            
        notional_index = self.index+n
        
        if notional_index > 0:
            return notional_index, self.buffer[notional_index]
        
        index = notional_value % _len
        return index, self.buffer[index]
            
        
            
    def move_left(self):
        if self.buffer == deque([]):
            raise Exception("Ring.buffer is empty.")
        
        # Move index left
        
        self.index -= 1
        
        # If index is less than zero
        # reset index to end index
        
        if self.index < 0:
            self.index = self._eix
        
        # pull value from buffer
        
        self.value = self.buffer[self.index]
  
        # return index and value
        return self.index, self.value