obs-StreamFX/source/util-memory.cpp

/*
* Modern effects for a modern Streamer
* Copyright (C) 2017 Michael Fabian Dirks
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
*/

#include "util-memory.h"
#include <cstdlib>

inline size_t aligned_offset(size_t align, size_t size) {
	return ((size / align) + 1) * align;
}

void* util::malloc_aligned(size_t align, size_t size) {
	// Ensure that we have space for the pointer and the data.
	size_t asize = aligned_offset(align, size + sizeof(void*));

	// Allocate memory and store integer representation of pointer.
	void* ptr = malloc(asize);

	// Calculate actual aligned position
	intptr_t ptr_off = aligned_offset(align, reinterpret_cast<size_t>(ptr)+sizeof(void*));

	// Store actual pointer at ptr_off - sizeof(void*).
	*reinterpret_cast<intptr_t*>(ptr_off - sizeof(void*)) = reinterpret_cast<intptr_t>(ptr);

	// Return aligned pointer
	return reinterpret_cast<void*>(ptr_off);
}

void util::free_aligned(void* mem) {
	void* ptr = reinterpret_cast<void*>(*reinterpret_cast<intptr_t*>(static_cast<char*>(mem)-sizeof(void*)));
	free(ptr);
}