dekun
33 lines
844 B
Python
33 lines
844 B
Python
"""金额与比率的定点运算。积分只向下取整，避免四舍五入把释放总额做超。"""
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from __future__ import annotations
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from decimal import Decimal, ROUND_DOWN
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QUANT = Decimal("0.00000001")
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def to_decimal(value: object) -> Decimal:
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if isinstance(value, Decimal):
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return value
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return Decimal(str(value))
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def money(value: object) -> Decimal:
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return to_decimal(value).quantize(QUANT, rounding=ROUND_DOWN)
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def rate(value: object) -> Decimal:
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number = to_decimal(value)
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if number < 0:
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number = Decimal("0")
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elif number > 1:
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number = Decimal("1")
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return number.quantize(QUANT, rounding=ROUND_DOWN)
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def ratio(numerator: int, denominator: int) -> Decimal:
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if denominator <= 0:
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return Decimal("0")
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return rate(Decimal(numerator) / Decimal(denominator))
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