__author__ = 'rony'

from ctypes import BigEndianStructure
from ctypes import sizeof, memmove, addressof
from ctypes import c_int32, c_uint32
from struct import pack, unpack


class BigEndianByteStructure(BigEndianStructure):
    # https://wiki.python.org/moin/ctypes
    @classmethod
    def from_bytes(cls, ibytes):
        return_val = cls()
        if len(ibytes) != sizeof(return_val):
            raise ValueError(
                '{0} Cannot unpack {2} bytes, it should be {1} bytes'.format(cls.__name__, sizeof(return_val),
                                                                             len(ibytes)))

        memmove(addressof(return_val), ibytes, len(ibytes))
        return return_val

    @classmethod
    def from_structure(cls, original):
        return_val = cls()
        for field in return_val._fields_:
            try:
                setattr(return_val, field[0], getattr(original, field[0]))
            except:
                print 'Attribute {0} not found in original'.format(field[0])

        return return_val


# POSITIVE
# IEEE754 HEX    0x428beb2a
# AN575 HEX      0x850beb2a

# NEGATIVE
# IEEE754 HEX    0xc28beb2a
# AN575 HEX      0x858beb2a

class IEEE754Float(BigEndianByteStructure):
    _pack_ = 1
    _fields_ = [('sign', c_int32, 1),
                ('exponent', c_int32, 8),
                ('number', c_int32, 23)]

    @classmethod
    def from_float(cls, f):
        return cls.from_bytes(pack('>f', f))

    def __float__(self):
        return unpack('>f', buffer(self))[0]

    def debug(self):
        f = self
        return hex(f.exponent), hex(f.number), f.sign, float(f), [hex(b) for b in bytearray(f)]


class AN575Float(BigEndianByteStructure):
    _pack_ = 1
    _fields_ = [('exponent', c_int32, 8),
                ('sign', c_int32, 1),
                ('number', c_int32, 23)]

    @classmethod
    def from_float(cls, f):
        return cls.from_structure(IEEE754Float.from_float(f))

    def __float__(self):
        a = IEEE754Float.from_structure(self)
        return float(a)

    def debug(self):
        f = self
        return hex(f.exponent), hex(f.number), f.sign, float(f), [hex(b) for b in bytearray(f)]


class IEEE754Float_u(BigEndianByteStructure):
    _pack_ = 1
    _fields_ = [('sign', c_uint32, 1),
                ('exponent', c_int32, 8),
                ('number', c_uint32, 23)]

    @classmethod
    def from_float(cls, f):
        return cls.from_bytes(pack('>f', f))

    def __float__(self):
        return unpack('>f', buffer(self))[0]

    def debug(self):
        f = self
        return hex(f.exponent), hex(f.number), f.sign, float(f), [hex(b) for b in bytearray(f)]


class AN575Float_uint(BigEndianByteStructure):
    _pack_ = 1
    _fields_ = [('exponent', c_int32, 8),
                ('sign', c_uint32, 1),
                ('number', c_int32, 23)]

    @classmethod
    def from_float(cls, f):
        return cls.from_structure(IEEE754Float_u.from_float(f))

    def __float__(self):
        a = IEEE754Float_u.from_structure(self)
        return float(a)

    def debug(self):
        f = self
        return hex(f.exponent), hex(f.number), f.sign, float(f), [hex(b) for b in bytearray(f)]


print '\n', 'c_int32 TESTS:'
print 'Class Name\t\t', 'exponent', '\tnumber', '\tSign', '\tfloat', '\t\t\t\t', 'binary repr'
f = IEEE754Float.from_float(69.9593067)
print type(f).__name__, f.debug()

f = IEEE754Float.from_bytes('\x42\x8b\xeb\x2a')
print type(f).__name__, f.debug()

f = AN575Float.from_float(69.9593067)
print type(f).__name__, f.debug()

f = AN575Float.from_structure(IEEE754Float.from_float(69.9593067))
print type(f).__name__, f.debug()

f = AN575Float.from_bytes('\x85\x0b\xeb\x2a')
print type(f).__name__, f.debug()

f = IEEE754Float.from_bytes('\xc2\x8b\xeb\x2a')
print type(f).__name__, f.debug()

f = AN575Float.from_bytes('\x85\x8b\xeb\x2a')
print type(f).__name__, f.debug()

print '\n', 'c_uint32 TESTS:'
print 'Class Name\t\t', 'exponent', '\tnumber', '\tSign', '\tfloat', '\t\t\t\t', 'binary repr'
f = IEEE754Float_u.from_float(69.9593067)
print type(f).__name__, f.debug()

f = IEEE754Float_u.from_bytes('\x42\x8b\xeb\x2a')
print type(f).__name__, f.debug()

f = AN575Float_uint.from_float(69.9593067)
print type(f).__name__, f.debug()

f = AN575Float_uint.from_structure(IEEE754Float.from_float(69.9593067))
print type(f).__name__, f.debug()

f = AN575Float_uint.from_bytes('\x85\x0b\xeb\x2a')
print type(f).__name__, f.debug()

f = IEEE754Float_u.from_bytes('\xc2\x8b\xeb\x2a')
print type(f).__name__, f.debug()

f = AN575Float_uint.from_bytes('\x85\x8b\xeb\x2a')
print type(f).__name__, f.debug()