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|
| """This module provides useful math functions on top of Python's |
| built-in :mod:`math` module. |
| """ |
|
|
| from math import ceil as _ceil, floor as _floor |
| import bisect |
| import binascii |
|
|
|
|
| def clamp(x, lower=float('-inf'), upper=float('inf')): |
| """Limit a value to a given range. |
| |
| Args: |
| x (int or float): Number to be clamped. |
| lower (int or float): Minimum value for x. |
| upper (int or float): Maximum value for x. |
| |
| The returned value is guaranteed to be between *lower* and |
| *upper*. Integers, floats, and other comparable types can be |
| mixed. |
| |
| >>> clamp(1.0, 0, 5) |
| 1.0 |
| >>> clamp(-1.0, 0, 5) |
| 0 |
| >>> clamp(101.0, 0, 5) |
| 5 |
| >>> clamp(123, upper=5) |
| 5 |
| |
| Similar to `numpy's clip`_ function. |
| |
| .. _numpy's clip: http://docs.scipy.org/doc/numpy/reference/generated/numpy.clip.html |
| |
| """ |
| if upper < lower: |
| raise ValueError('expected upper bound (%r) >= lower bound (%r)' |
| % (upper, lower)) |
| return min(max(x, lower), upper) |
|
|
|
|
| def ceil(x, options=None): |
| """Return the ceiling of *x*. If *options* is set, return the smallest |
| integer or float from *options* that is greater than or equal to |
| *x*. |
| |
| Args: |
| x (int or float): Number to be tested. |
| options (iterable): Optional iterable of arbitrary numbers |
| (ints or floats). |
| |
| >>> VALID_CABLE_CSA = [1.5, 2.5, 4, 6, 10, 25, 35, 50] |
| >>> ceil(3.5, options=VALID_CABLE_CSA) |
| 4 |
| >>> ceil(4, options=VALID_CABLE_CSA) |
| 4 |
| """ |
| if options is None: |
| return _ceil(x) |
| options = sorted(options) |
| i = bisect.bisect_left(options, x) |
| if i == len(options): |
| raise ValueError("no ceil options greater than or equal to: %r" % x) |
| return options[i] |
|
|
|
|
| def floor(x, options=None): |
| """Return the floor of *x*. If *options* is set, return the largest |
| integer or float from *options* that is less than or equal to |
| *x*. |
| |
| Args: |
| x (int or float): Number to be tested. |
| options (iterable): Optional iterable of arbitrary numbers |
| (ints or floats). |
| |
| >>> VALID_CABLE_CSA = [1.5, 2.5, 4, 6, 10, 25, 35, 50] |
| >>> floor(3.5, options=VALID_CABLE_CSA) |
| 2.5 |
| >>> floor(2.5, options=VALID_CABLE_CSA) |
| 2.5 |
| |
| """ |
| if options is None: |
| return _floor(x) |
| options = sorted(options) |
|
|
| i = bisect.bisect_right(options, x) |
| if not i: |
| raise ValueError("no floor options less than or equal to: %r" % x) |
| return options[i - 1] |
|
|
|
|
| class Bits: |
| ''' |
| An immutable bit-string or bit-array object. |
| Provides list-like access to bits as bools, |
| as well as bitwise masking and shifting operators. |
| Bits also make it easy to convert between many |
| different useful representations: |
| |
| * bytes -- good for serializing raw binary data |
| * int -- good for incrementing (e.g. to try all possible values) |
| * list of bools -- good for iterating over or treating as flags |
| * hex/bin string -- good for human readability |
| |
| ''' |
| __slots__ = ('val', 'len') |
|
|
| def __init__(self, val=0, len_=None): |
| if type(val) is not int: |
| if type(val) is list: |
| val = ''.join(['1' if e else '0' for e in val]) |
| if type(val) is bytes: |
| val = val.decode('ascii') |
| if type(val) is str: |
| if len_ is None: |
| len_ = len(val) |
| if val.startswith('0x'): |
| len_ = (len_ - 2) * 4 |
| if val.startswith('0x'): |
| val = int(val, 16) |
| else: |
| if val: |
| val = int(val, 2) |
| else: |
| val = 0 |
| if type(val) is not int: |
| raise TypeError(f'initialized with bad type: {type(val).__name__}') |
| if val < 0: |
| raise ValueError('Bits cannot represent negative values') |
| if len_ is None: |
| len_ = len(f'{val:b}') |
| if val > 2 ** len_: |
| raise ValueError(f'value {val} cannot be represented with {len_} bits') |
| self.val = val |
| self.len = len_ |
|
|
| def __getitem__(self, k): |
| if type(k) is slice: |
| return Bits(self.as_bin()[k]) |
| if type(k) is int: |
| if k >= self.len: |
| raise IndexError(k) |
| return bool((1 << (self.len - k - 1)) & self.val) |
| raise TypeError(type(k)) |
|
|
| def __len__(self): |
| return self.len |
|
|
| def __eq__(self, other): |
| if type(self) is not type(other): |
| return NotImplemented |
| return self.val == other.val and self.len == other.len |
|
|
| def __or__(self, other): |
| if type(self) is not type(other): |
| return NotImplemented |
| return Bits(self.val | other.val, max(self.len, other.len)) |
|
|
| def __and__(self, other): |
| if type(self) is not type(other): |
| return NotImplemented |
| return Bits(self.val & other.val, max(self.len, other.len)) |
|
|
| def __lshift__(self, other): |
| return Bits(self.val << other, self.len + other) |
|
|
| def __rshift__(self, other): |
| return Bits(self.val >> other, self.len - other) |
|
|
| def __hash__(self): |
| return hash(self.val) |
|
|
| def as_list(self): |
| return [c == '1' for c in self.as_bin()] |
|
|
| def as_bin(self): |
| return f'{{0:0{self.len}b}}'.format(self.val) |
|
|
| def as_hex(self): |
| |
| tmpl = f'%0{2 * (self.len // 8 + ((self.len % 8) != 0))}X' |
| ret = tmpl % self.val |
| return ret |
|
|
| def as_int(self): |
| return self.val |
|
|
| def as_bytes(self): |
| return binascii.unhexlify(self.as_hex()) |
|
|
| @classmethod |
| def from_list(cls, list_): |
| return cls(list_) |
|
|
| @classmethod |
| def from_bin(cls, bin): |
| return cls(bin) |
|
|
| @classmethod |
| def from_hex(cls, hex): |
| if isinstance(hex, bytes): |
| hex = hex.decode('ascii') |
| if not hex.startswith('0x'): |
| hex = '0x' + hex |
| return cls(hex) |
|
|
| @classmethod |
| def from_int(cls, int_, len_=None): |
| return cls(int_, len_) |
|
|
| @classmethod |
| def from_bytes(cls, bytes_): |
| return cls.from_hex(binascii.hexlify(bytes_)) |
|
|
| def __repr__(self): |
| cn = self.__class__.__name__ |
| return f"{cn}('{self.as_bin()}')" |
|
|