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from typing import Iterable
class MnemonicError(Exception):
pass
def _round_bits(n: int, radix_bits: int) -> int:
"""Get the number of `radix_bits`-sized digits required to store a `n`-bit value."""
return (n + radix_bits - 1) // radix_bits
def bits_to_bytes(n: int) -> int:
"""Round up bit count to whole bytes."""
return _round_bits(n, 8)
def bits_to_words(n: int) -> int:
"""Round up bit count to a multiple of word size."""
# XXX
# In order to properly functionally decompose the original 1-file implementation,
# function bits_to_words can only exist if it knows the value of RADIX_BITS (which
# informs us of the word size). However, constants.py make use of the function,
# because some constants count word-size of things.
#
# I considered the "least evil" solution to define bits_to_words in utils where it
# logically belongs, and import constants only inside the function. This will work
# as long as calls to bits_to_words only happens *after* RADIX_BITS are declared.
#
# An alternative is to have a private implementation of bits_to_words in constants
from . import constants
assert hasattr(constants, "RADIX_BITS"), "Declare RADIX_BITS *before* calling this"
return _round_bits(n, constants.RADIX_BITS)
def int_to_indices(value: int, length: int, radix_bits: int) -> Iterable[int]:
"""Convert an integer value to indices in big endian order."""
mask = (1 << radix_bits) - 1
return ((value >> (i * radix_bits)) & mask for i in reversed(range(length)))
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