kicad/old/scripts/KiBoM/bomlib/units.py

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2020-02-04 17:33:02 -07:00
# -*- coding: utf-8 -*-
"""
This file contains a set of functions for matching values which may be written in different formats
e.g.
0.1uF = 100n (different suffix specified, one has missing unit)
0R1 = 0.1Ohm (Unit replaces decimal, different units)
"""
from __future__ import unicode_literals
import re
PREFIX_MICRO = [u"μ", "u", "micro"]
PREFIX_MILLI = ["milli", "m"]
PREFIX_NANO = ["nano", "n"]
PREFIX_PICO = ["pico", "p"]
PREFIX_KILO = ["kilo", "k"]
PREFIX_MEGA = ["mega", "meg"]
PREFIX_GIGA = ["giga", "g"]
# All prefixes
PREFIX_ALL = PREFIX_PICO + PREFIX_NANO + PREFIX_MICRO + PREFIX_MILLI + PREFIX_KILO + PREFIX_MEGA + PREFIX_GIGA
# Common methods of expressing component units
UNIT_R = ["r", "ohms", "ohm", u"Ω"]
UNIT_C = ["farad", "f"]
UNIT_L = ["henry", "h"]
UNIT_ALL = UNIT_R + UNIT_C + UNIT_L
def getUnit(unit):
"""
Return a simplified version of a units string, for comparison purposes
"""
if not unit:
return None
unit = unit.lower()
if unit in UNIT_R:
return "R"
if unit in UNIT_C:
return "F"
if unit in UNIT_L:
return "H"
return None
def getPrefix(prefix):
"""
Return the (numerical) value of a given prefix
"""
if not prefix:
return 1
prefix = prefix.lower()
if prefix in PREFIX_PICO:
return 1.0e-12
if prefix in PREFIX_NANO:
return 1.0e-9
if prefix in PREFIX_MICRO:
return 1.0e-6
if prefix in PREFIX_MILLI:
return 1.0e-3
if prefix in PREFIX_KILO:
return 1.0e3
if prefix in PREFIX_MEGA:
return 1.0e6
if prefix in PREFIX_GIGA:
return 1.0e9
return 1
def groupString(group): # Return a reg-ex string for a list of values
return "|".join(group)
def matchString():
return "^([0-9\.]+)(" + groupString(PREFIX_ALL) + ")*(" + groupString(UNIT_ALL) + ")*(\d*)$"
def compMatch(component):
"""
Return a normalized value and units for a given component value string
e.g. compMatch("10R2") returns (10, R)
e.g. compMatch("3.3mOhm") returns (0.0033, R)
"""
# Remove any commas
component = component.strip().replace(",", "").lower()
match = matchString()
result = re.search(match, component)
if not result:
return None
if not len(result.groups()) == 4:
return None
value, prefix, units, post = result.groups()
# Special case where units is in the middle of the string
# e.g. "0R05" for 0.05Ohm
# In this case, we will NOT have a decimal
# We will also have a trailing number
if post and "." not in value:
try:
value = float(int(value))
postValue = float(int(post)) / (10 ** len(post))
value = value * 1.0 + postValue
except:
return None
try:
val = float(value)
except:
return None
val = "{0:.15f}".format(val * 1.0 * getPrefix(prefix))
return (val, getUnit(units))
def componentValue(valString):
result = compMatch(valString)
if not result:
return valString # Return the same string back
if not len(result) == 2: # Result length is incorrect
return valString
val = result[0]
return val
def compareValues(c1, c2):
""" Compare two values """
r1 = compMatch(c1)
r2 = compMatch(c2)
if not r1 or not r2:
return False
(v1, u1) = r1
(v2, u2) = r2
if v1 == v2:
# Values match
if u1 == u2:
return True # Units match
if not u1:
return True # No units for component 1
if not u2:
return True # No units for component 2
return False