// OpenVPN -- An application to securely tunnel IP networks
// over a single port, with support for SSL/TLS-based
// session authentication and key exchange,
// packet encryption, packet authentication, and
// packet compression.
//
// Copyright (C) 2023 OpenVPN Inc.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License Version 3
// as published by the Free Software Foundation.
//
// This program 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program in the COPYING file.
// If not, see .
#pragma once
#include "numeric_util.hpp"
#include
#include
#include // For OPENVPN_EXCEPTION_INHERIT
/***
* @brief Exception type for numeric conversion failures
*/
OPENVPN_EXCEPTION_INHERIT(std::range_error, numeric_out_of_range);
namespace openvpn::numeric_util {
/* ============================================================================================================= */
// numeric_cast
/* ============================================================================================================= */
/**
* @brief Tests attempted casts to ensure the input value does not exceed the capacity of the output type
*
* If the types are the same, or the range of the output type equals or exceeds the range of the input type
* we just cast and return the value which should ideally optimize away completely. Otherwise we do appropriate
* range checks and if those succeed we cast, otherwise the failure exception openvpn::numeric_out_of_range
* is thrown.
*
* Example:
*
* int64_t s64 = std::numeric_limits::max();
* EXPECT_THROW(numeric_cast(s64), numeric_out_of_range);
*
* @param inVal The value to be converted.
* @return The safely converted inVal.
* @tparam InT Source (input) type, inferred from 'inVal'
* @tparam OutT Desired result type
*/
template
OutT numeric_cast(InT inVal)
{
if constexpr (!numeric_util::is_int_rangesafe() && numeric_util::is_int_u2s())
{
// Conversion to uintmax_t should be safe for ::max() in all integral cases
if (static_cast(inVal) > static_cast(std::numeric_limits::max()))
{
throw numeric_out_of_range("Range exceeded for unsigned --> signed integer conversion");
}
}
else if constexpr (!numeric_util::is_int_rangesafe() && numeric_util::is_int_s2u())
{
// Cast to uintmax_t only applied if inVal is positive ...
if (inVal < 0 || static_cast(inVal) > static_cast(std::numeric_limits::max()))
{
throw numeric_out_of_range("Range exceeded for signed --> unsigned integer conversion");
}
}
else if constexpr (!numeric_util::is_int_rangesafe())
{
// We already know the in and out are sign compatible
if (std::numeric_limits::min() > inVal || std::numeric_limits::max() < inVal)
{
throw numeric_out_of_range("Range exceeded for integer conversion");
}
}
return static_cast(inVal);
}
} // namespace openvpn::numeric_util