'''
Layer specification.
'''

class Layer(object):
    '''
    NN layer parameters.

    nifm: # ifmap channels.
    nofm: # ofmap channels.
    wifm: ifmap width.
    hifm: ifmap height.
    wofm: ofmap width.
    hofm: ofmap height.
    wfil: weight filter width.
    hfil: weight filter height.
    nimg: # input images (batch).
    wstd: stride size in width dimension.
    hstd: stride size in height dimension.
    '''

    def __init__(self, nifm, nofm, wofm, hofm, wfil, hfil, nimg=1, wstd=1, hstd=1):
        self.nifm = nifm
        self.nofm = nofm
        self.wofm = wofm
        self.hofm = hofm
        self.wifm = wfil + (wofm - 1) * wstd
        self.hifm = hfil + (hofm - 1) * hstd
        self.wfil = wfil
        self.hfil = hfil
        self.nimg = nimg
        self.wstd = wstd
        self.hstd = hstd
        assert self.wofm > 0
        assert self.hofm > 0
        assert self.nimg > 0
        self.sizes = [wfil, hfil, wofm, hofm, nofm, nifm, nimg]

    @classmethod
    def layer(cls, info):
        return cls(info["input_fmap_channel"], info["output_fmap_channel"], 
                     info["fmap_width"], info["fmap_height"], info["window_width"],
                     info["window_height"], info["batch_size"], 
                     info["stride_width"], info["stride_height"]) 
    
class FCLayer(Layer):
    '''
    NN fully-connected layer parameters.

    (wifm, hifm) = (wfil, hfil), wstd = hstd = 1, wofm = hofm = 1.
    '''

    def __init__(self, nifm, nofm, wfil, hfil, nimg=1):
        Layer.__init__(self, nifm, nofm, 1, 1, wfil, hfil, nimg)