llvm-mirror/include/llvm/ADT/iterator_range.h
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

69 lines
2.4 KiB
C++

//===- iterator_range.h - A range adaptor for iterators ---------*- 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
//
//===----------------------------------------------------------------------===//
/// \file
/// This provides a very simple, boring adaptor for a begin and end iterator
/// into a range type. This should be used to build range views that work well
/// with range based for loops and range based constructors.
///
/// Note that code here follows more standards-based coding conventions as it
/// is mirroring proposed interfaces for standardization.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_ITERATOR_RANGE_H
#define LLVM_ADT_ITERATOR_RANGE_H
#include <iterator>
#include <utility>
namespace llvm {
/// A range adaptor for a pair of iterators.
///
/// This just wraps two iterators into a range-compatible interface. Nothing
/// fancy at all.
template <typename IteratorT>
class iterator_range {
IteratorT begin_iterator, end_iterator;
public:
//TODO: Add SFINAE to test that the Container's iterators match the range's
// iterators.
template <typename Container>
iterator_range(Container &&c)
//TODO: Consider ADL/non-member begin/end calls.
: begin_iterator(c.begin()), end_iterator(c.end()) {}
iterator_range(IteratorT begin_iterator, IteratorT end_iterator)
: begin_iterator(std::move(begin_iterator)),
end_iterator(std::move(end_iterator)) {}
IteratorT begin() const { return begin_iterator; }
IteratorT end() const { return end_iterator; }
};
/// Convenience function for iterating over sub-ranges.
///
/// This provides a bit of syntactic sugar to make using sub-ranges
/// in for loops a bit easier. Analogous to std::make_pair().
template <class T> iterator_range<T> make_range(T x, T y) {
return iterator_range<T>(std::move(x), std::move(y));
}
template <typename T> iterator_range<T> make_range(std::pair<T, T> p) {
return iterator_range<T>(std::move(p.first), std::move(p.second));
}
template <typename T>
iterator_range<decltype(adl_begin(std::declval<T>()))> drop_begin(T &&t,
int n) {
return make_range(std::next(adl_begin(t), n), adl_end(t));
}
}
#endif