sourcemod/public/sm_argbuffer.h
2019-05-04 01:46:55 -07:00

78 lines
2.5 KiB
C++

/**
* vim: set ts=4 :
* =============================================================================
* SourceMod
* Copyright (C) 2004-2019 AlliedModders LLC. All rights reserved.
* =============================================================================
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License, version 3.0, 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 General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, AlliedModders LLC gives you permission to link the
* code of this program (as well as its derivative works) to "Half-Life 2," the
* "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software
* by the Valve Corporation. You must obey the GNU General Public License in
* all respects for all other code used. Additionally, AlliedModders LLC grants
* this exception to all derivative works. AlliedModders LLC defines further
* exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),
* or <http://www.sourcemod.net/license.php>.
*
* Version: $Id$
*/
/**
* A type-safe abstraction for creating a contiguous blob of memory used for
* vtable function calls. This blob contains the parameters to be passed into
* the function call.
*/
template <typename T, typename...Rest>
class ArgBuffer {
public:
ArgBuffer(const T& t, const Rest&... rest) {
unsigned char *ptr = buff;
buildbuffer(&ptr, t, rest...);
}
operator void*() { return buff; }
operator unsigned char*() { return buff; }
constexpr int size() const {
return sizeof(buff);
}
private:
template <typename K>
constexpr static int sizetypes() {
return sizeof(K);
}
template <typename K, typename K2, typename... Kn>
constexpr static int sizetypes() {
return sizeof(K) + sizetypes<K2, Kn...>();
}
template <typename K>
void buildbuffer(unsigned char **ptr, K& k) {
memcpy(*ptr, &k, sizeof(k));
*ptr += sizeof(K);
}
template <typename K, typename... Kn>
void buildbuffer(unsigned char **ptr, K& k, Kn&... kn) {
buildbuffer(ptr, k);
if (sizeof...(kn)!=0)
buildbuffer(ptr, kn...);
}
private:
unsigned char buff[sizetypes<T, Rest...>()];
};