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/************************************************************************
*
* Copyright (C) 2024 IRCAD France
*
* This file is part of Sight.
*
* Sight is free software: you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Sight is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Sight. If not, see <https://www.gnu.org/licenses/>.
*
***********************************************************************/
#pragma once
#include <sight/core/config.hpp>
#include <iostream>
#include <sstream>
#include <string>
namespace sight::core
{
class SIGHT_CORE_CLASS_API string final
{
public:
/// @brief Concatenate the given arguments into a string using the given separator.
/// @note This method uses variadic template as argument to concatenate.
/// @param[in] _separator : the separator to use. If the separator is an empty string, it will be ignored.
/// @param[in] _first : the first element to concatenate.
/// @param[in] _args : the other elements to concatenate.
template<typename S, typename T, typename ... Args>
static std::string join(const S& _separator, const T& _first, const Args& ... _args);
template<typename T, typename ... Args>
static std::string concat(const T& _first, const Args& ... _args);
private:
template<typename S, typename T>
static void join_impl(std::ostringstream& _stream, const S& _separator, const T& _t);
template<typename S, typename T, typename ... Args>
static void join_impl(
std::ostringstream& _stream,
const S& _separator,
const T& _first,
const Args& ... _args
);
};
//------------------------------------------------------------------------------
template<typename S, typename T>
void string::join_impl(std::ostringstream& _stream, const S& _separator, const T& _current)
{
// By default, we ignore empty elements.
bool skip = false;
// Nullptr is skipped.
if constexpr(std::is_null_pointer_v<T>)
{
skip = true;
}
// Empty string is skipped.
else if constexpr(std::is_base_of_v<std::string, T>|| std::is_base_of_v<std::string, T>)
{
skip = _current.empty();
}
// Empty char* like is skipped.
else if constexpr(std::is_same_v<typename std::decay<T>::type, char*>
|| std::is_same_v<typename std::decay<T>::type, const char*>)
{
if constexpr(std::is_pointer_v<T>)
{
skip = _current == nullptr || _current[0] == '\0';
}
else
{
skip = _current[0] == '\0';
}
}
if(!skip)
{
bool skip_separator = false;
// If the separator is not null, we add it if not the first elements.
// Of course, this is still a noop if the separator is empty.
if constexpr(std::is_null_pointer_v<S>)
{
skip_separator = true;
}
else if constexpr(std::is_base_of_v<std::string, S>|| std::is_base_of_v<std::string, S>)
{
skip_separator = _separator.empty();
}
else if constexpr(std::is_same_v<typename std::decay<S>::type, char*>
|| std::is_same_v<typename std::decay<S>::type, const char*>)
{
if constexpr(std::is_pointer_v<S>)
{
skip_separator = _separator == nullptr || _separator[0] == '\0';
}
else
{
skip_separator = _separator[0] == '\0';
}
}
// Add the separator if necessary (not for the first element).
if(!skip_separator && _stream.tellp() != 0)
{
_stream << _separator;
}
// Concatenate the current element.
_stream << _current;
}
}
//------------------------------------------------------------------------------
template<typename S, typename T, typename ... Args>
void string::join_impl(
std::ostringstream& _stream,
const S& _separator,
const T& _first,
const Args& ... _args
)
{
// Concatenate the first element.
join_impl(_stream, _separator, _first);
// Recursively concatenate the next elements.
join_impl(_stream, _separator, _args ...);
}
//------------------------------------------------------------------------------
template<typename S, typename T, typename ... Args>
std::string string::join(const S& _separator, const T& _first, const Args& ... _args)
{
// Create the stream buffer to concatenate the elements.
std::ostringstream stream;
join_impl(stream, _separator, _first, _args ...);
// Return the concatenated string.
return stream.str();
}
//------------------------------------------------------------------------------
template<typename T, typename ... Args>
std::string string::concat(const T& _first, const Args& ... _args)
{
// Join with an empty/null separator.
return join(nullptr, _first, _args ...);
}
} // namespace sight::core
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