Exemple #1
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def byte_to_float(b, mantissabits=5, zeroexp=2):
    """Decodes a floating point number stored in a single byte.
    """
    b = ord(b)
    if b == 0:
        return 0.0

    bits = (b & 0xff) << (24 - mantissabits)
    bits += (63 - zeroexp) << 24
    return unpack("f", pack("i", bits))[0]
Exemple #2
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def byte_to_float(b, mantissabits=5, zeroexp=2):
    """Decodes a floating point number stored in a single byte.
    """
    b = ord(b)
    if b == 0:
        return 0.0

    bits = (b & 0xff) << (24 - mantissabits)
    bits += (63 - zeroexp) << 24
    return unpack("f", pack("i", bits))[0]
Exemple #3
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def float_to_byte(value, mantissabits=5, zeroexp=2):
    """Encodes a floating point number in a single byte.
    """

    # Assume int size == float size

    fzero = (63 - zeroexp) << mantissabits
    bits = unpack("i", pack("f", value))[0]
    smallfloat = bits >> (24 - mantissabits)
    if smallfloat < fzero:
        # Map negative numbers and 0 to 0
        # Map underflow to next smallest non-zero number
        if bits <= 0:
            return chr(0)
        else:
            return chr(1)
    elif smallfloat >= fzero + 0x100:
        # Map overflow to largest number
        return chr(255)
    else:
        return chr(smallfloat - fzero)
Exemple #4
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def float_to_byte(value, mantissabits=5, zeroexp=2):
    """Encodes a floating point number in a single byte.
    """

    # Assume int size == float size

    fzero = (63 - zeroexp) << mantissabits
    bits = unpack("i", pack("f", value))[0]
    smallfloat = bits >> (24 - mantissabits)
    if smallfloat < fzero:
        # Map negative numbers and 0 to 0
        # Map underflow to next smallest non-zero number
        if bits <= 0:
            return chr(0)
        else:
            return chr(1)
    elif smallfloat >= fzero + 0x100:
        # Map overflow to largest number
        return chr(255)
    else:
        return chr(smallfloat - fzero)