Add util module to IfcOpenShell, including element, geolocation, unit, and selector. See #829.

src/ifcopenshell-python/ifcopenshell/util/unit.py

@@ -0,0 +1,64 @@
+from math import pi
+
+prefixes = {'EXA': 1e18, 'PETA': 1e15, 'TERA': 1e12, 'GIGA': 1e9, 'MEGA':
+    1e6, 'KILO': 1e3, 'HECTO': 1e2, 'DECA': 1e1, 'DECI': 1e-1, 'CENTI':
+    1e-2, 'MILLI': 1e-3, 'MICRO': 1e-6, 'NANO': 1e-9, 'PICO': 1e-12,
+    'FEMTO': 1e-15, 'ATTO': 1e-18}
+
+unit_names = ['AMPERE', 'BECQUEREL', 'CANDELA', 'COULOMB',
+    'CUBIC_METRE', 'DEGREE CELSIUS', 'FARAD', 'GRAM', 'GRAY', 'HENRY',
+    'HERTZ', 'JOULE', 'KELVIN', 'LUMEN', 'LUX', 'MOLE', 'NEWTON', 'OHM',
+    'PASCAL', 'RADIAN', 'SECOND', 'SIEMENS', 'SIEVERT', 'SQUARE METRE',
+    'METRE', 'STERADIAN', 'TESLA', 'VOLT', 'WATT', 'WEBER']
+
+si_conversions = {
+    'inch': 0.0254,
+    'foot': 0.3048,
+    'yard': 0.914,
+    'mile': 1609,
+    'square inch': 0.0006452,
+    'square foot': 0.09290,
+    'square yard': 0.83612736,
+    'acre': 4046.86,
+    'square mile': 2588881,
+    'cubic inch': 0.00001639,
+    'cubic foot': 0.02832,
+    'cubic yard': 0.7636,
+    'litre': 0.001,
+    'fluid ounce UK': 0.0000284130625,
+    'fluid ounce US': 0.00002957353,
+    'pint UK': 0.000568,
+    'pint US': 0.000473,
+    'gallon UK': 0.004546,
+    'gallon US': 0.003785,
+    'degree': pi/180,
+    'ounce': 0.02835,
+    'pound': 0.454,
+    'ton UK': 1016.0469088,
+    'ton US': 907.18474,
+    'lbf': 4.4482216153,
+    'kip': 4448.2216153,
+    'psi': 6894.7572932,
+    'ksi': 6894757.2932,
+    'minute': 60,
+    'hour': 3600,
+    'day': 86400,
+    'btu': 1055.056}
+
+def get_prefix(text):
+    for prefix in prefixes.keys():
+        if prefix in text.upper():
+            return prefix
+
+def get_prefix_multiplier(text):
+    if not text:
+        return 1
+    prefix = get_prefix(text)
+    if prefix:
+        return prefixes[prefix]
+    return 1
+
+def get_unit_name(text):
+    for name in unit_names:
+        if name in text.upper().replace('METER', 'METRE'):
+            return name