Differential D4501 Diff 14521 extern/draco/dracoenc/src/draco/core/draco_index_type.h

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extern/draco/dracoenc/src/draco/core/draco_index_type.h

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				// Copyright 2016 The Draco Authors.
				//
				// Licensed under the Apache License, Version 2.0 (the "License");
				// you may not use this file except in compliance with the License.
				// You may obtain a copy of the License at
				//
				// http://www.apache.org/licenses/LICENSE-2.0
				//
				// Unless required by applicable law or agreed to in writing, software
				// distributed under the License is distributed on an "AS IS" BASIS,
				// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
				// See the License for the specific language governing permissions and
				// limitations under the License.
				//
				// This files provides a basic framework for strongly typed indices that are
				// used within the Draco library. The motivation of using strongly typed indices
				// is to prevent bugs caused by mixing up incompatible indices, such as indexing
				// mesh faces with point indices and vice versa.
				//
				// Usage:
				// Define strongly typed index using macro:
				//
				// DEFINE_NEW_DRACO_INDEX_TYPE(value_type, name)
				//
				// where \|value_type\| is the data type of the index value (such as int32_t)
				// and \|name\| is a unique typename of the new index.
				//
				// E.g., we can define new index types as:
				//
				// DEFINE_NEW_DRACO_INDEX_TYPE(int, PointIndex)
				// DEFINE_NEW_DRACO_INDEX_TYPE(int, FaceIndex)
				//
				// The new types can then be used in the similar way as the regular weakly
				// typed indices (such as int32, int64, ...), but they cannot be
				// accidentally misassigned. E.g.:
				//
				// PointIndex point_index(10);
				// FaceIndex face_index;
				// face_index = point_index; // Compile error!
				//
				// One can still cast one type to another explicitly by accessing the index
				// value directly using the .value() method:
				//
				// face_index = FaceIndex(point_index.value()); // Compiles OK.
				//
				// Strongly typed indices support most of the common binary and unary
				// operators and support for additional operators can be added if
				// necessary.

				#ifndef DRACO_CORE_DRACO_INDEX_TYPE_H_
				#define DRACO_CORE_DRACO_INDEX_TYPE_H_

				#include <ostream>

				#include "draco/draco_features.h"

				namespace draco {

				#define DEFINE_NEW_DRACO_INDEX_TYPE(value_type, name) \
				struct name##_tag_type_ {}; \
				typedef IndexType<value_type, name##_tag_type_> name;

				template <class ValueTypeT, class TagT>
				class IndexType {
				public:
				typedef IndexType<ValueTypeT, TagT> ThisIndexType;
				typedef ValueTypeT ValueType;

				constexpr IndexType() : value_(ValueTypeT()) {}
				constexpr explicit IndexType(ValueTypeT value) : value_(value) {}

				constexpr ValueTypeT value() const { return value_; }

				constexpr bool operator==(const IndexType &i) const {
				return value_ == i.value_;
				}
				constexpr bool operator==(const ValueTypeT &val) const {
				return value_ == val;
				}
				constexpr bool operator!=(const IndexType &i) const {
				return value_ != i.value_;
				}
				constexpr bool operator!=(const ValueTypeT &val) const {
				return value_ != val;
				}
				constexpr bool operator<(const IndexType &i) const {
				return value_ < i.value_;
				}
				constexpr bool operator<(const ValueTypeT &val) const { return value_ < val; }
				constexpr bool operator>(const IndexType &i) const {
				return value_ > i.value_;
				}
				constexpr bool operator>(const ValueTypeT &val) const { return value_ > val; }
				constexpr bool operator>=(const IndexType &i) const {
				return value_ >= i.value_;
				}
				constexpr bool operator>=(const ValueTypeT &val) const {
				return value_ >= val;
				}

				inline ThisIndexType &operator++() {
				++value_;
				return *this;
				}
				inline ThisIndexType operator++(int) {
				const ThisIndexType ret(value_);
				++value_;
				return ret;
				}

				inline ThisIndexType &operator--() {
				--value_;
				return *this;
				}
				inline ThisIndexType operator--(int) {
				const ThisIndexType ret(value_);
				--value_;
				return ret;
				}

				constexpr ThisIndexType operator+(const IndexType &i) const {
				return ThisIndexType(value_ + i.value_);
				}
				constexpr ThisIndexType operator+(const ValueTypeT &val) const {
				return ThisIndexType(value_ + val);
				}
				constexpr ThisIndexType operator-(const IndexType &i) const {
				return ThisIndexType(value_ - i.value_);
				}
				constexpr ThisIndexType operator-(const ValueTypeT &val) const {
				return ThisIndexType(value_ - val);
				}

				inline ThisIndexType &operator+=(const IndexType &i) {
				value_ += i.value_;
				return *this;
				}
				inline ThisIndexType operator+=(const ValueTypeT &val) {
				value_ += val;
				return *this;
				}
				inline ThisIndexType &operator-=(const IndexType &i) {
				value_ -= i.value_;
				return *this;
				}
				inline ThisIndexType operator-=(const ValueTypeT &val) {
				value_ -= val;
				return *this;
				}
				inline ThisIndexType &operator=(const ThisIndexType &i) {
				value_ = i.value_;
				return *this;
				}
				inline ThisIndexType &operator=(const ValueTypeT &val) {
				value_ = val;
				return *this;
				}

				private:
				ValueTypeT value_;
				};

				// Stream operator << provided for logging purposes.
				template <class ValueTypeT, class TagT>
				std::ostream &operator<<(std::ostream &os, IndexType<ValueTypeT, TagT> index) {
				return os << index.value();
				}

				} // namespace draco

				// Specialize std::hash for the strongly indexed types.
				namespace std {

				template <class ValueTypeT, class TagT>
				struct hash<draco::IndexType<ValueTypeT, TagT>> {
				size_t operator()(const draco::IndexType<ValueTypeT, TagT> &i) const {
				return static_cast<size_t>(i.value());
				}
				};

				} // namespace std

				#endif // DRACO_CORE_DRACO_INDEX_TYPE_H_