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101 lines
3.4 KiB
C++
101 lines
3.4 KiB
C++
//===- IndexedViewRange.h - Iterators for indexed projections ---*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines IndexedViewRange, a template class which makes it
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// easy to define a range for a "collection" that is normally just vended
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// with an indexed accessor.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_BASIC_INDEXEDVIEWRANGE_H
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#define SWIFT_BASIC_INDEXEDVIEWRANGE_H
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#include <iterator>
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#include <memory>
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#include "llvm/ADT/iterator_range.h"
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namespace swift {
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/// An iterator over a range of values provided by an indexed accessor
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/// on a base type.
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template <class BaseType, class ProjectedType,
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ProjectedType (&Project)(BaseType, size_t)>
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class IndexedViewIterator {
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public:
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using value_type = ProjectedType;
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using reference = ProjectedType;
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using pointer = void;
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using difference_type = ptrdiff_t;
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using iterator_category = std::random_access_iterator_tag;
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private:
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BaseType Base;
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size_t Index;
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public:
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IndexedViewIterator(BaseType base, size_t index)
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: Base(base), Index(index) {}
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public:
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ProjectedType operator*() const { return Project(Base, Index); }
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ProjectedType operator->() const { return Project(Base, Index); }
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IndexedViewIterator &operator++() { Index++; return *this; }
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IndexedViewIterator operator++(int) { return iterator(Base, Index++); }
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IndexedViewIterator &operator--() { Index--; return *this; }
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IndexedViewIterator operator--(int) { return iterator(Base, Index--); }
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bool operator==(IndexedViewIterator rhs) const { return Index == rhs.Index; }
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bool operator!=(IndexedViewIterator rhs) const { return Index != rhs.Index; }
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IndexedViewIterator &operator+=(difference_type i) {
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Index += i;
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return *this;
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}
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IndexedViewIterator operator+(difference_type i) const {
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return IndexedViewIterator(Base, Index + i);
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}
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friend IndexedViewIterator operator+(difference_type i,
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IndexedViewIterator rhs) {
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return IndexedViewIterator(rhs.Base, rhs.Index + i);
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}
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IndexedViewIterator &operator-=(difference_type i) {
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Index -= i;
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return *this;
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}
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IndexedViewIterator operator-(difference_type i) const {
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return IndexedViewIterator(Base, Index - i);
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}
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difference_type operator-(IndexedViewIterator rhs) const {
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return Index - rhs.Index;
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}
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ProjectedType operator[](difference_type i) const {
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return Project(Base, Index + i);
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}
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bool operator<(IndexedViewIterator rhs) const {
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return Index < rhs.Index;
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}
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bool operator<=(IndexedViewIterator rhs) const {
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return Index <= rhs.Index;
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}
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bool operator>(IndexedViewIterator rhs) const {
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return Index > rhs.Index;
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}
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bool operator>=(IndexedViewIterator rhs) const {
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return Index >= rhs.Index;
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}
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};
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template <class BaseType, class ProjectedType,
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ProjectedType (&Project)(BaseType, size_t)>
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using IndexedViewRange =
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llvm::iterator_range<IndexedViewIterator<BaseType, ProjectedType, Project>>;
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} // end namespace swift
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#endif // SWIFT_BASIC_INDEXEDVIEWRANGE_H
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