import numpy as np

def readDMPFile(fileName):
    '''
    Opens and reads DMP file. Returns numpy ndarray.
    '''
    
    fd = open(fileName, 'rb')
    
    #datatype is unsigned short
    datatype = 'h'
    numberOfHeaderValues = 3
    
    headerData = np.fromfile(fd, datatype, numberOfHeaderValues)
    
    imageShape = (headerData[1], headerData[0])
    
    imageData = np.fromfile(fd, np.float32, -1)
    imageData = imageData.reshape(imageShape)
    
    return imageData

def writeDMPFile(fileName, np_array):
    '''
    Writes numpy ndarray to DMP file.
    ndArray.dtype should be np.float32. If it not, it will be converted before saving.
    '''
    
    # opens file for writing (binary)
    fd = open(fileName, 'wb')
    
    # create header - must be dtype np.uint16 !!! 
    width = np.array(np_array.shape[1])
    height = np.array(np_array.shape[0])
    
    header = np.array([width, height, 0], np.uint16)
    header.tofile(fd)
    
    # img data/numpy ndarray
    # dtype has to be np.float32
    if np_array.dtype != 'float32':
        np_array = np_array.astype(np.float32)
        
    np_array.tofile(fd)