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construct/include/ircd/util/string.h

101 lines
2.5 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_UTIL_STRING_H
//
// String generating patterns
//
namespace ircd {
namespace util {
/// This is the ubiquitous ircd::string() template serving as the "toString()"
/// for the project. Particpating types that want to have a string(T)
/// returning an std::string must friend an operator<<(std::ostream &, T);
/// this is primarily for debug strings, not meant for performance or service.
///
template<class T>
auto
string(const T &s)
{
std::stringstream ss;
ss << s;
return ss.str();
}
/// Alternative to ircd::string() using a provided buffer for the
/// std::stringstream to avoid allocating one.
template<class T>
auto
string(const mutable_buffer &buf,
const T &s)
{
std::stringstream ss;
pubsetbuf(ss, buf);
ss << s;
return ss.str();
}
inline auto
string(const char *const &buf,
const size_t &size)
{
return std::string{buf, size};
}
inline auto
string(const uint8_t *const &buf,
const size_t &size)
{
return string(reinterpret_cast<const char *>(buf), size);
}
/// Close over the common pattern to write directly into a post-C++11 standard
/// string through the data() member requiring a const_cast. Closure returns
/// the final size of the data written into the buffer.
inline auto
string(const size_t &size,
const std::function<size_t (const mutable_buffer &)> &closure)
{
std::string ret(size, char{});
const mutable_buffer buf
{
const_cast<char *>(ret.data()), ret.size()
};
const size_t consumed
{
closure(buf)
};
assert(consumed <= buffer::size(buf));
data(buf)[consumed] = '\0';
ret.resize(consumed);
return ret;
}
/// Close over the common pattern to write directly into a post-C++11 standard
/// string through the data() member requiring a const_cast. Closure returns
/// a view of the data actually written to the buffer.
inline auto
string(const size_t &size,
const std::function<string_view (const mutable_buffer &)> &closure)
{
return string(size, [&closure]
(const mutable_buffer &buffer)
{
return ircd::size(closure(buffer));
});
}
} // namespace util
} // namespace ircd