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Commit Description:
Merge pull request #17 from nattee/master...
Commit Description:
Merge pull request #17 from nattee/master
upgrade to current working snapshot
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lib/assets/Lib/_random.py
| 99 lines
| 3.4 KiB
| text/x-python
| PythonLexer
|
| r584 | from browser import window, alert | |||
| def _randint(a, b): | ||||
| return int(window.Math.random()*(b-a+1)+a) | ||||
| def _rand_with_seed(x, rand_obj): | ||||
| # if rand_obj.state is not a safe integer, Math.sin will return the same | ||||
| # result for consecutive values : use the rest of division by 360 | ||||
| degrees = rand_obj._state % 360 | ||||
| x = window.Math.sin(degrees/(2*window.Math.PI)) * 10000 | ||||
| # Adding 1 is not reliable because of current integer implementation | ||||
| # If rand_obj._state is not a "safe integer" in the range [-2**53, 2**53] | ||||
| # the increment between 2 different values is a power of 2 | ||||
| # It is stored in an attribute of rand_obj to avoid having to compute it | ||||
| # for each iteration | ||||
| if not hasattr(rand_obj, 'incr'): | ||||
| rand_obj.incr = 1 | ||||
| rand_obj._state += rand_obj.incr | ||||
| return x - window.Math.floor(x) | ||||
| def _urandom(n, rand_obj=None): | ||||
| """urandom(n) -> str | ||||
| Return n random bytes suitable for cryptographic use.""" | ||||
| if rand_obj is None or rand_obj._state is None: | ||||
| randbytes= [_randint(0,255) for i in range(n)] | ||||
| else: | ||||
| randbytes= [] | ||||
| for i in range(n): | ||||
| randbytes.append(int(256*_rand_with_seed(i, rand_obj))) | ||||
| return bytes(randbytes) | ||||
| class Random: | ||||
| """Random number generator base class used by bound module functions. | ||||
| Used to instantiate instances of Random to get generators that don't | ||||
| share state. | ||||
| Class Random can also be subclassed if you want to use a different basic | ||||
| generator of your own devising: in that case, override the following | ||||
| methods: random(), seed(), getstate(), and setstate(). | ||||
| Optionally, implement a getrandbits() method so that randrange() | ||||
| can cover arbitrarily large ranges. | ||||
| """ | ||||
| #random | ||||
| #seed | ||||
| #getstate | ||||
| #setstate | ||||
| VERSION = 3 # used by getstate/setstate | ||||
| def __init__(self, x=None): | ||||
| """Initialize an instance. | ||||
| Optional argument x controls seeding, as for Random.seed(). | ||||
| """ | ||||
| self._state=x | ||||
| def seed(self, a=None, version=2): | ||||
| """Initialize internal state from hashable object. | ||||
| None or no argument seeds from current time or from an operating | ||||
| system specific randomness source if available. | ||||
| For version 2 (the default), all of the bits are used if *a* is a str, | ||||
| bytes, or bytearray. For version 1, the hash() of *a* is used instead. | ||||
| If *a* is an int, all bits are used. | ||||
| """ | ||||
| self._state=a | ||||
| self.gauss_next = None | ||||
| def getstate(self): | ||||
| """Return internal state; can be passed to setstate() later.""" | ||||
| return self._state | ||||
| def setstate(self, state): | ||||
| """Restore internal state from object returned by getstate().""" | ||||
| self._state=state | ||||
| def random(self): | ||||
| """Get the next random number in the range [0.0, 1.0).""" | ||||
| return window.Math.random() | ||||
| def getrandbits(self, k): | ||||
| """getrandbits(k) -> x. Generates a long int with k random bits.""" | ||||
| if k <= 0: | ||||
| raise ValueError('number of bits must be greater than zero') | ||||
| if k != int(k): | ||||
| raise TypeError('number of bits should be an integer') | ||||
| numbytes = (k + 7) // 8 # bits / 8 and rounded up | ||||
| x = int.from_bytes(_urandom(numbytes, self), 'big') | ||||
| return x >> (numbytes * 8 - k) # trim excess bits | ||||