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//===- AttrIterator.h - Classes for attribute iteration ---------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines the Attr vector and specific_attr_iterator interfaces.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_AST_ATTRITERATOR_H
#define LLVM_CLANG_AST_ATTRITERATOR_H
#include "clang/Basic/LLVM.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/Casting.h"
#include <cassert>
#include <cstddef>
#include <iterator>
namespace clang {
class Attr;
/// AttrVec - A vector of Attr, which is how they are stored on the AST.
using AttrVec = SmallVector<Attr *, 4>;
/// specific_attr_iterator - Iterates over a subrange of an AttrVec, only
/// providing attributes that are of a specific type.
template <typename SpecificAttr, typename Container = AttrVec>
class specific_attr_iterator {
using Iterator = typename Container::const_iterator;
/// Current - The current, underlying iterator.
/// In order to ensure we don't dereference an invalid iterator unless
/// specifically requested, we don't necessarily advance this all the
/// way. Instead, we advance it when an operation is requested; if the
/// operation is acting on what should be a past-the-end iterator,
/// then we offer no guarantees, but this way we do not dereference a
/// past-the-end iterator when we move to a past-the-end position.
mutable Iterator Current;
void AdvanceToNext() const {
while (!isa<SpecificAttr>(*Current))
++Current;
}
void AdvanceToNext(Iterator I) const {
while (Current != I && !isa<SpecificAttr>(*Current))
++Current;
}
public:
using value_type = SpecificAttr *;
using reference = SpecificAttr *;
using pointer = SpecificAttr *;
using iterator_category = std::forward_iterator_tag;
using difference_type = std::ptrdiff_t;
specific_attr_iterator() = default;
explicit specific_attr_iterator(Iterator i) : Current(i) {}
reference operator*() const {
AdvanceToNext();
return cast<SpecificAttr>(*Current);
}
pointer operator->() const {
AdvanceToNext();
return cast<SpecificAttr>(*Current);
}
specific_attr_iterator& operator++() {
++Current;
return *this;
}
specific_attr_iterator operator++(int) {
specific_attr_iterator Tmp(*this);
++(*this);
return Tmp;
}
friend bool operator==(specific_attr_iterator Left,
specific_attr_iterator Right) {
assert((Left.Current == nullptr) == (Right.Current == nullptr));
if (Left.Current < Right.Current)
Left.AdvanceToNext(Right.Current);
else
Right.AdvanceToNext(Left.Current);
return Left.Current == Right.Current;
}
friend bool operator!=(specific_attr_iterator Left,
specific_attr_iterator Right) {
return !(Left == Right);
}
};
template <typename SpecificAttr, typename Container>
inline specific_attr_iterator<SpecificAttr, Container>
specific_attr_begin(const Container& container) {
return specific_attr_iterator<SpecificAttr, Container>(container.begin());
}
template <typename SpecificAttr, typename Container>
inline specific_attr_iterator<SpecificAttr, Container>
specific_attr_end(const Container& container) {
return specific_attr_iterator<SpecificAttr, Container>(container.end());
}
template <typename SpecificAttr, typename Container>
inline bool hasSpecificAttr(const Container& container) {
return specific_attr_begin<SpecificAttr>(container) !=
specific_attr_end<SpecificAttr>(container);
}
template <typename SpecificAttr, typename Container>
inline SpecificAttr *getSpecificAttr(const Container& container) {
specific_attr_iterator<SpecificAttr, Container> i =
specific_attr_begin<SpecificAttr>(container);
if (i != specific_attr_end<SpecificAttr>(container))
return *i;
else
return nullptr;
}
} // namespace clang
#endif // LLVM_CLANG_AST_ATTRITERATOR_H
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