mirror of
https://github.com/IfcOpenShell/IfcOpenShell.git
synced 2026-08-13 02:47:48 +00:00
Dion Moult
0d3849737c
Mirrors selected helpers from ifcopenshell.util.unit: SI prefix multipliers, the conversion-based-unit table (foot/inch/etc -> SI metres), siScaleFromNamedUnit (walks IfcConversionBasedUnit chains down to IfcSIUnit), getUnitAssignment / getProjectUnit / calculateUnitScale, and convert / convertUnit. Lives in src/ifcviewer/ for now alongside Geolocation; will move out when ifcopenshell.util is ported to C++. Needed by upcoming Geolocation fix (e/n/h on IfcMapConversion are in MapUnit, must be converted to metres for the meter-by-default iterator output) and by the federation module (display-unit conversion when the user changes the federation unit). Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
90 lines
4.5 KiB
C++
90 lines
4.5 KiB
C++
/********************************************************************************
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* *
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* This file is part of IfcOpenShell. *
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* *
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* IfcOpenShell is free software: you can redistribute it and/or modify *
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* it under the terms of the Lesser GNU General Public License as published by *
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* the Free Software Foundation, either version 3.0 of the License, or *
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* (at your option) any later version. *
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* *
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* IfcOpenShell 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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* Lesser GNU General Public License for more details. *
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* *
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* You should have received a copy of the Lesser GNU General Public License *
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* along with this program. If not, see <http://www.gnu.org/licenses/>. *
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* *
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********************************************************************************/
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// Port of selected helpers from
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// src/ifcopenshell-python/ifcopenshell/util/unit.py. Lives in src/ifcviewer/
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// for now alongside Geolocation; will move out once ifcopenshell.util is
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// ported to C++.
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#ifndef UNIT_H
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#define UNIT_H
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#include "../ifcparse/express.h"
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#include <optional>
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#include <string>
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#include <unordered_map>
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namespace ifcopenshell { class file; }
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// SI prefix multipliers, e.g. "MILLI" -> 1e-3. Empty key not present;
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// callers should pass an empty prefix string for "no prefix".
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extern const std::unordered_map<std::string, double> kSiPrefixes;
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// SI prefix display symbols, e.g. "MILLI" -> "m".
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extern const std::unordered_map<std::string, std::string> kSiPrefixSymbols;
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// Conversion-based unit name (lowercase, IFC convention) -> SI base scale.
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// e.g. "foot" -> 0.3048, "square foot" -> 0.09290304.
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extern const std::unordered_map<std::string, double> kSiConversions;
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// Conversion-based unit name -> IFC unit type, e.g. "foot" -> "LENGTHUNIT".
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extern const std::unordered_map<std::string, std::string> kImperialTypes;
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// Display symbol per unit name. Covers IfcSIUnit names ("METRE" -> "m") and
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// IfcConversionBasedUnit names ("foot" -> "ft").
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extern const std::unordered_map<std::string, std::string> kUnitSymbols;
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// Returns the multiplier for an SI prefix. Empty string returns 1.0.
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double getPrefixMultiplier(const std::string& prefix);
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// Returns the SI scale for an IfcNamedUnit such that
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// value_in_unit * scale == value_in_si_base
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// Walks IfcConversionBasedUnit chains down to IfcSIUnit. Returns nullopt
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// when the chain bottoms out in IfcContextDependentUnit (cannot convert).
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std::optional<double> siScaleFromNamedUnit(express::Base named_unit);
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// IfcProject.UnitsInContext (the IfcUnitAssignment). Returns nullopt if
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// the file has no project or no assignment.
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std::optional<express::Base> getUnitAssignment(ifcopenshell::file* ifc_file);
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// First unit in the project's IfcUnitAssignment matching `unit_type`
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// (e.g. "LENGTHUNIT"). Returns nullopt if not found.
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std::optional<express::Base> getProjectUnit(ifcopenshell::file* ifc_file,
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const std::string& unit_type);
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// Project unit -> SI base scale (e.g. project in mm => 0.001). Defaults
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// to 1.0 when no project unit of the requested type is set.
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double calculateUnitScale(ifcopenshell::file* ifc_file,
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const std::string& unit_type = "LENGTHUNIT");
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// Convert between two units identified by name + optional SI prefix.
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// SQUARE_/CUBIC_ prefixed SI names get the prefix multiplier squared/cubed
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// (matches python ifcopenshell.util.unit.convert).
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double convert(double value,
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const std::string& from_prefix, const std::string& from_unit,
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const std::string& to_prefix, const std::string& to_unit);
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// Convert between two IfcNamedUnit entities. Pulls Name and Prefix off each
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// and delegates to convert(). IfcConversionBasedUnit names that don't appear
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// in kSiConversions return the value unchanged.
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double convertUnit(double value, express::Base from_unit, express::Base to_unit);
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#endif // UNIT_H
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