//===- ArrayRefView.h - Adapter for iterating over an ArrayRef --*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
//  This file defines ArrayRefView, a template class which provides a
//  proxied view of the elements of an array.
//
//===----------------------------------------------------------------------===//

#ifndef SWIFT_BASIC_ARRAYREFVIEW_H
#define SWIFT_BASIC_ARRAYREFVIEW_H

#include "llvm/ADT/ArrayRef.h"

namespace swift {

/// An adapter for iterating over a range of values as a range of
/// values of a different type.
template <class Orig, class Projected, Projected (&Project)(const Orig &)>
class ArrayRefView {
  ArrayRef<Orig> Array;
public:
  ArrayRefView(ArrayRef<Orig> array) : Array(array) {}

  class iterator {
    friend class ArrayRefView<Orig,Projected,Project>;
    const Orig *Ptr;
    iterator(const Orig *ptr) : Ptr(ptr) {}
  public:
    Projected operator*() const { return Project(*Ptr); }
    iterator &operator++() { Ptr++; return *this; }
    iterator operator++(int) { return iterator(Ptr++); }
    bool operator==(iterator rhs) { return Ptr == rhs.Ptr; }
    bool operator!=(iterator rhs) { return Ptr != rhs.Ptr; }
  };
  iterator begin() const { return iterator(Array.begin()); }
  iterator end() const { return iterator(Array.end()); }

  bool empty() const { return Array.empty(); }
  size_t size() const { return Array.size(); }
  Projected operator[](unsigned i) const { return Project(Array[i]); }
  Projected front() const { return Project(Array.front()); }
  Projected back() const { return Project(Array.back()); }

  ArrayRefView slice(unsigned start) const {
    return ArrayRefView(Array.slice(start));
  }
  ArrayRefView slice(unsigned start, unsigned length) const {
    return ArrayRefView(Array.slice(start, length));
  }
};

}

#endif