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construct/include/ircd/strl.h
2019-07-11 18:58:17 -07:00

110 lines
2.7 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2019 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_STRL_H
// Vintage
namespace ircd
{
struct strlcpy;
struct strlcat;
}
/// This is a function. It works the same as the standard strlcpy() but it has
/// some useful modernizations and may be informally referred to as strlcpy++.
///
/// - It optionally works with string_view inputs and ircd::buffer outputs.
/// This allows for implicit size parameters and increases its safety while
/// simplifying its usage (no more sizeof(buf) where buf coderots into char*).
///
/// - Its objectification allows for a configurable return type. The old
/// strlcpy() returned a size integer type. When using string_view's and
/// buffers this would generally lead to the pattern { dst, strlcpy(dst, src) }
/// and this is no longer necessary.
///
struct ircd::strlcpy
{
mutable_buffer ret;
public:
operator string_view() const
{
return ret;
}
operator size_t() const
{
return size(ret);
}
strlcpy(char *const &dst, const string_view &src, const size_t &max)
:ret{[&]() -> mutable_buffer
{
if(!max)
return {};
const auto len(std::min(src.size(), max - 1));
buffer::copy(mutable_buffer(dst, len), src);
dst[len] = '\0';
return { dst, len };
}()}
{}
#ifndef HAVE_STRLCPY
strlcpy(char *const &dst, const char *const &src, const size_t &max)
:strlcpy{dst, string_view{src, strnlen(src, max)}, max}
{}
#endif
strlcpy(const mutable_buffer &dst, const string_view &src)
:strlcpy{data(dst), src, size(dst)}
{}
};
/// This is a function. It works the same as the standard strlcat() but it has
/// some useful modernizations and may be informally referred to as strlcat++.
/// see: ircd::strlcpy().
///
struct ircd::strlcat
{
mutable_buffer ret;
public:
operator string_view() const
{
return ret;
}
operator size_t() const
{
return size(ret);
}
strlcat(char *const &dst, const string_view &src, const size_t &max)
:ret{[&]() -> mutable_buffer
{
const auto pos{strnlen(dst, max)};
const auto remain{max - pos};
strlcpy(dst + pos, src, remain);
return { dst, pos + src.size() };
}()}
{}
#ifndef HAVE_STRLCAT
strlcat(char *const &dst, const char *const &src, const size_t &max)
:strlcat{dst, string_view{src, ::strnlen(src, max)}, max}
{}
#endif
strlcat(const mutable_buffer &dst, const string_view &src)
:strlcat{data(dst), src, size(dst)}
{}
};