// Copyright 2019 The Chromium Authors

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

#ifndef CRDTP_SPAN_H_

#define CRDTP_SPAN_H_

#include <cstdint>

#include <cstring>

#include <span>

#include <string>

#include <type_traits>

#include "export.h"

namespace crdtp {

// crdtp::span is a std::span which always holds const elements.

template <typename T>

using span = std::span<const T>;

template <size_t N>

constexpr span<char> MakeSpan(const char (&str)[N]) {

  return span<char>(str, N - 1);

}

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<9ul>(char const (&) [9ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<5ul>(char const (&) [5ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<6ul>(char const (&) [6ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<4ul>(char const (&) [4ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<10ul>(char const (&) [10ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<11ul>(char const (&) [11ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<19ul>(char const (&) [19ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<8ul>(char const (&) [8ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<23ul>(char const (&) [23ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<12ul>(char const (&) [12ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<13ul>(char const (&) [13ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<7ul>(char const (&) [7ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<18ul>(char const (&) [18ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<14ul>(char const (&) [14ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<22ul>(char const (&) [22ul])

Unexecuted instantiation: std::__1::span<char const, 18446744073709551615ul> crdtp::MakeSpan<16ul>(char const (&) [16ul])

template <size_t N>

constexpr span<uint8_t> SpanFrom(const char (&str)[N]) {

  return span<uint8_t>(reinterpret_cast<const uint8_t*>(str), N - 1);

}

constexpr inline span<uint8_t> SpanFrom(const char* str) {

  return str ? span<uint8_t>(reinterpret_cast<const uint8_t*>(str), strlen(str))

             : span<uint8_t>();

}

inline span<uint8_t> SpanFrom(const std::string& v) {

  return span<uint8_t>(reinterpret_cast<const uint8_t*>(v.data()), v.size());

}

// This SpanFrom routine works for std::vector<uint8_t> and

// std::vector<uint16_t>, but also for base::span<const uint8_t> in Chromium.

template <typename C,

          typename = std::enable_if_t<

              std::is_unsigned<typename C::value_type>{} &&

              std::is_member_function_pointer<decltype(&C::size)>{}>>

inline span<typename C::value_type> SpanFrom(const C& v) {

  return span<typename C::value_type>(v.data(), v.size());

}

// Less than / equality comparison functions for sorting / searching for byte

// spans.

CRDTP_EXPORT bool SpanLessThan(span<uint8_t> x, span<uint8_t> y) noexcept;

CRDTP_EXPORT bool SpanEquals(span<uint8_t> x, span<uint8_t> y) noexcept;

// Less than / equality comparison functions for sorting / searching for byte

// spans.

CRDTP_EXPORT bool SpanLessThan(span<char> x, span<char> y) noexcept;

CRDTP_EXPORT bool SpanEquals(span<char> x, span<char> y) noexcept;

struct SpanLt {

  bool operator()(span<uint8_t> l, span<uint8_t> r) const {

    return SpanLessThan(l, r);

  }

};

}  // namespace crdtp

#endif  // CRDTP_SPAN_H_