KiBot/kibot/bom/units.py

# -*- coding: utf-8 -*-
# Copyright (c) 2020 Salvador E. Tropea
# Copyright (c) 2020 Instituto Nacional de Tecnología Industrial
# Copyright (c) 2016-2020 Oliver Henry Walters (@SchrodingersGat)
# License: MIT
# Project: KiBot (formerly KiPlot)
# Adapted from: https://github.com/SchrodingersGat/KiBoM
"""
Units:
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)
Oriented to normalize and sort R, L and C values.
"""
import re
import locale
from .. import log
from ..misc import W_BADVAL1, W_BADVAL2, W_BADVAL3

logger = log.get_logger()

PREFIX_MICRO = [u"μ", u"µ", "u", "micro"]
PREFIX_MILLI = ["milli", "m"]
PREFIX_NANO = ["nano", "n"]
PREFIX_PICO = ["pico", "p"]
PREFIX_KILO = ["kilo", "k"]
PREFIX_MEGA = ["mega", "meg", "M"]
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
# Note: we match lowercase string, so both: Ω and Ω become the lowercase omega
UNIT_R = ["r", "ohms", "ohm", u'\u03c9']
UNIT_C = ["farad", "f"]
UNIT_L = ["henry", "h"]

UNIT_ALL = UNIT_R + UNIT_C + UNIT_L

# Compiled regex to match the values
match = None
# Current locale decimal point value
decimal_point = None
# Last warning
last_warning = ''


def get_last_warning():
    return last_warning


def get_unit(unit, ref_prefix):
    """ Return a simplified version of a units string, for comparison purposes  """
    if not unit:
        if ref_prefix == 'L':
            return "H"
        if ref_prefix == 'C':
            return "F"
        return u"Ω"
    unit = unit.lower()
    if unit in UNIT_R:
        return u"Ω"
    if unit in UNIT_C:
        return "F"
    if unit in UNIT_L:
        return "H"


def get_prefix(prefix):
    """ Return the (numerical) value of a given prefix """
    if not prefix:
        return 1, ''
    # 'M' is mega, 'm' is milli
    if prefix != 'M':
        prefix = prefix.lower()
    if prefix in PREFIX_PICO:
        return 1.0e-12, 'p'
    if prefix in PREFIX_NANO:
        return 1.0e-9, 'n'
    if prefix in PREFIX_MICRO:
        return 1.0e-6, u"µ"
    if prefix in PREFIX_MILLI:
        return 1.0e-3, 'm'
    if prefix in PREFIX_KILO:
        return 1.0e3, 'k'
    if prefix in PREFIX_MEGA:
        return 1.0e6, 'M'
    if prefix in PREFIX_GIGA:
        return 1.0e9, 'G'
    # Unknown, we shouldn't get here because the regex matched
    # BUT: I found that sometimes unexpected things happend, like mu matching micro and then we reaching this code
    #      Now is fixed, but I can't be sure some bizarre case is overlooked
    logger.error('Unknown prefix, please report')
    return 1, ''


def group_string(group):  # Return a reg-ex string for a list of values
    return "|".join(group)


def match_string():
    return r"(\d*\.?\d*)\s*(" + group_string(PREFIX_ALL) + ")*(" + group_string(UNIT_ALL) + r")*(\d*)$"


def comp_match(component, ref_prefix, ref=None):
    """
    Return a normalized value and units for a given component value string
    e.g. comp_match('10R2') returns (10, R)
    e.g. comp_match('3.3mOhm') returns (0.0033, R)
    """
    global last_warning
    original = component
    # Remove useless spaces
    component = component.strip()
    # ~ is the same as empty for KiCad
    if component == '~':
        component = ''
    # Convert the decimal point from the current locale to a '.'
    global decimal_point
    if decimal_point is None:
        decimal_point = locale.localeconv()['decimal_point']
        logger.debug('Decimal point `{}`'.format(decimal_point))
        # Avoid conversions for '.'
        if decimal_point == '.':
            decimal_point = ''
    if decimal_point:
        component = component.replace(decimal_point, ".")

    # Remove any commas
    component = component.strip().replace(",", "")

    # Get the compiled regex
    global match
    if not match:
        # Ignore case
        match = re.compile(match_string(), flags=re.IGNORECASE)

    where = ' in {}'.format(ref) if ref is not None else ''
    result = match.match(component)
    if not result:
        last_warning = W_BADVAL1
        logger.warning(W_BADVAL1 + "Malformed value: `{}` (no match{})".format(original, where))
        return None

    value, prefix, units, post = result.groups()
    if value == '.':
        last_warning = W_BADVAL2
        logger.warning(W_BADVAL2 + "Malformed value: `{}` (reduced to decimal point{})".format(original, where))
        return None
    if value == '':
        value = '0'

    # 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:
        if "." in value:
            last_warning = W_BADVAL3
            logger.warning(W_BADVAL3 + "Malformed value: `{}` (unit split, but contains decimal point{})".
                           format(original, where))
            return None
        value = float(value)
        postValue = float(post) / (10 ** len(post))
        val = value * 1.0 + postValue
    else:
        val = float(value)

    # Return all the data, let the caller join it
    return (val, get_prefix(prefix), get_unit(units, ref_prefix))


def compare_values(c1, c2):
    """ Compare two values """

    # These are the results from comp_match()
    r1 = c1.value_sort
    r2 = c2.value_sort

    if not r1 or not r2:
        return False

    # Join the data to compare
    (v1, (p1, ps1), u1) = r1
    (v2, (p2, ps2), u2) = r2

    v1 = "{0:.15f}".format(v1 * 1.0 * p1)
    v2 = "{0:.15f}".format(v2 * 1.0 * p2)

    if v1 == v2:
        # Values match
        if u1 == u2:
            return True  # Units match
        # No longer posible because now we use the prefix to determine absent units
        # if not u1:
        #     return True  # No units for component 1
        # if not u2:
        #     return True  # No units for component 2

    return False