system/ulib/fidl/include/lib/fidl/cpp/array.h

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#pragma once

#include <stddef.h>
#include <string.h>

namespace fidl {

template <typename T, size_t N>
class Array {
public:
    Array() {
        memset(data_, 0, sizeof(data_));
    }

    constexpr size_t count() const { return N; }

    const T* data() const { return data_; }
    T* mutable_data() { return data_; }

    const T& at(size_t offset) const { return data()[offset]; }
    T& at(size_t offset) { return mutable_data()[offset]; }

    const T& operator[](size_t offset) const { return at(offset); }
    T& operator[](size_t offset) { return at(offset); }

    T* begin() { return mutable_data(); }
    const T* begin() const { return data(); }
    const T* cbegin() const { return data(); }

    T* end() { return mutable_data() + count(); }
    const T* end() const { return data() + count(); }
    const T* cend() const { return data() + count(); }

private:
    static_assert(N > 0, "fid::Array cannot have zero elements.");

    T data_[N];
};

template <typename T, size_t N>
bool operator==(const Array<T, N>& lhs, const Array<T, N>& rhs) {
    for (size_t i = 0; i < N; ++i) {
        if (lhs[i] != rhs[i]) {
            return false;
        }
    }
    return true;
}

template <typename T, size_t N>
bool operator!=(const Array<T, N>& lhs, const Array<T, N>& rhs) {
    return !(lhs == rhs);
}

template <typename T, size_t N>
bool operator<(const Array<T, N>& lhs, const Array<T, N>& rhs) {
  for (size_t i = 0; i < N; i++) {
    if (lhs[i] != rhs[i]) {
      return lhs[i] < rhs[i];
    }
  }
  return false;
}

template <typename T, size_t N>
bool operator>(const Array<T, N>& lhs, const Array<T, N>& rhs) {
  for (size_t i = 0; i < N; i++) {
    if (lhs[i] != rhs[i]) {
      return lhs[i] > rhs[i];
    }
  }
  return false;
}

template <typename T, size_t N>
bool operator<=(const Array<T, N>& lhs, const Array<T, N>& rhs) {
  return !(lhs > rhs);
}

template <typename T, size_t N>
bool operator>=(const Array<T, N>& lhs, const Array<T, N>& rhs) {
  return !(lhs < rhs);
}

} // namespace fidl