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/*
* Copyright 2021 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <functional>
#include <string_view>
#include <ftl/details/type_traits.h>
#include <ftl/string.h>
namespace android::ftl::details {
template <typename T, typename = void>
struct StaticString;
// Booleans.
template <typename T>
struct StaticString<T, std::enable_if_t<is_bool_v<T>>> {
static constexpr std::size_t N = 5; // Length of "false".
explicit constexpr StaticString(bool b) : view(b ? "true" : "false") {}
const std::string_view view;
};
// Characters.
template <typename T>
struct StaticString<T, std::enable_if_t<is_char_v<T>>> {
static constexpr std::size_t N = 1;
explicit constexpr StaticString(char c) : character(c) {}
const char character;
const std::string_view view{&character, 1u};
};
// Integers, including the integer value of other character types like char32_t.
template <typename T>
struct StaticString<
T, std::enable_if_t<std::is_integral_v<remove_cvref_t<T>> && !is_bool_v<T> && !is_char_v<T>>> {
using U = remove_cvref_t<T>;
static constexpr std::size_t N = to_chars_length_v<U>;
// TODO: Mark this and to_chars as `constexpr` in C++23.
explicit StaticString(U v) : view(to_chars(buffer, v)) {}
to_chars_buffer_t<U> buffer;
const std::string_view view;
};
// Character arrays.
template <std::size_t M>
struct StaticString<const char (&)[M], void> {
static constexpr std::size_t N = M - 1;
explicit constexpr StaticString(const char (&str)[M]) : view(str, N) {}
const std::string_view view;
};
template <std::size_t N>
struct Truncated {
std::string_view view;
};
// Strings with constrained length.
template <std::size_t M>
struct StaticString<Truncated<M>, void> {
static constexpr std::size_t N = M;
explicit constexpr StaticString(Truncated<M> str) : view(str.view.substr(0, N)) {}
const std::string_view view;
};
} // namespace android::ftl::details
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