kopia lustrzana https://github.com/NanoVNA-Saver/nanovna-saver
133 wiersze
4.6 KiB
Python
133 wiersze
4.6 KiB
Python
# NanoVNASaver
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# A python program to view and export Touchstone data from a NanoVNA
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# Copyright (C) 2019. Rune B. Broberg
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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import math
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import decimal
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from typing import NamedTuple
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from numbers import Number
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PREFIXES = ("y", "z", "a", "f", "p", "n", "µ", "m",
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"", "k", "M", "G", "T", "P", "E", "Z", "Y")
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class Format(NamedTuple):
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max_nr_digits: int = 6
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fix_decimals: bool = False
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space_str: str = ""
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assume_infinity: bool = True
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min_offset: int = -8
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max_offset: int = 8
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allow_strip: bool = False
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parse_sloppy_unit: bool = False
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parse_sloppy_kilo: bool = False
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parse_clamp_min: float = -math.inf
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parse_clamp_max: float = math.inf
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class Value:
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CTX = decimal.Context(prec=60, Emin=-27, Emax=27)
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def __init__(self, value: Number = 0, unit: str = "", fmt=Format()):
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assert 3 <= fmt.max_nr_digits <= 30
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assert -8 <= fmt.min_offset <= fmt.max_offset <= 8
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assert fmt.parse_clamp_min < fmt.parse_clamp_max
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self._value = decimal.Decimal(value, context=Value.CTX)
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self._unit = unit
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self.fmt = fmt
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def __repr__(self) -> str:
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return (f"{self.__class__.__name__}(" + repr(self._value) +
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f", '{self._unit}', {self.fmt})")
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def __str__(self) -> str:
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fmt = self.fmt
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if fmt.assume_infinity and \
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abs(self._value) >= 10 ** ((fmt.max_offset + 1) * 3):
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return (("-" if self._value < 0 else "") +
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"\N{INFINITY}" + fmt.space_str + self._unit)
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if self._value == 0:
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offset = 0
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else:
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offset = int(math.log10(abs(self._value)) // 3)
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if offset < fmt.min_offset:
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offset = fmt.min_offset
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elif offset > fmt.max_offset:
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offset = fmt.max_offset
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real = float(self._value) / (10 ** (offset * 3))
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if fmt.max_nr_digits < 4:
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formstr = ".0f"
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else:
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max_digits = fmt.max_nr_digits + (
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(1 if not fmt.fix_decimals and abs(real) < 10 else 0) +
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(1 if not fmt.fix_decimals and abs(real) < 100 else 0))
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formstr = "." + str(max_digits - 3) + "f"
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result = format(real, formstr)
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if float(result) == 0.0:
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offset = 0
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if self.fmt.allow_strip and "." in result:
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result = result.rstrip("0").rstrip(".")
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return result + fmt.space_str + PREFIXES[offset + 8] + self._unit
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@property
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def value(self):
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return float(self._value)
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def parse(self, value: str) -> float:
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value = value.replace(" ", "") # Ignore spaces
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if self._unit and (
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value.endswith(self._unit) or
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(self.fmt.parse_sloppy_unit and
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value.lower().endswith(self._unit.lower()))): # strip unit
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value = value[:-len(self._unit)]
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factor = 1
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if self.fmt.parse_sloppy_kilo and value[-1] == "K": # fix for e.g. KHz
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value = value[:-1] + "k"
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if value[-1] in PREFIXES:
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factor = 10 ** ((PREFIXES.index(value[-1]) - 8) * 3)
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value = value[:-1]
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if self.fmt.assume_infinity and value == "\N{INFINITY}":
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self._value = math.inf
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elif self.fmt.assume_infinity and value == "-\N{INFINITY}":
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self._value = -math.inf
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else:
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try:
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self._value = (decimal.Decimal(value, context=Value.CTX) *
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decimal.Decimal(factor, context=Value.CTX))
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except decimal.InvalidOperation:
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raise ValueError
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# TODO: get formating out of RFTools to be able to import clamp
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# and reuse code
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if self._value < self.fmt.parse_clamp_min:
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self._value = self.fmt.parse_clamp_min
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elif self._value > self.fmt.parse_clamp_max:
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self._value = self.fmt.parse_clamp_max
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return float(self._value)
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@property
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def unit(self) -> str:
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return self._unit
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