RetroArch/network/netplay/netplay_delta.c
2017-01-22 13:40:32 +01:00

67 lines
2.0 KiB
C

/* RetroArch - A frontend for libretro.
* Copyright (C) 2010-2014 - Hans-Kristian Arntzen
* Copyright (C) 2011-2017 - Daniel De Matteis
* Copyright (C) 2016-2017 - Gregor Richards
*
* RetroArch 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 Found-
* ation, either version 3 of the License, or (at your option) any later version.
*
* RetroArch 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 RetroArch.
* If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <sys/types.h>
#include <boolean.h>
#include <encodings/crc32.h>
#include "netplay_private.h"
/**
* netplay_delta_frame_ready
*
* Prepares, if possible, a delta frame for input, and reports whether it is
* ready.
*
* Returns: True if the delta frame is ready for input at the given frame,
* false otherwise.
*/
bool netplay_delta_frame_ready(netplay_t *netplay, struct delta_frame *delta,
uint32_t frame)
{
void *remember_state;
if (delta->used)
{
if (delta->frame == frame) return true;
if (netplay->other_frame_count <= delta->frame)
{
/* We haven't even replayed this frame yet, so we can't overwrite it! */
return false;
}
}
remember_state = delta->state;
memset(delta, 0, sizeof(struct delta_frame));
delta->used = true;
delta->frame = frame;
delta->state = remember_state;
return true;
}
/**
* netplay_delta_frame_crc
*
* Get the CRC for the serialization of this frame.
*/
uint32_t netplay_delta_frame_crc(netplay_t *netplay, struct delta_frame *delta)
{
if (!netplay->state_size)
return 0;
return encoding_crc32(0L, (const unsigned char*)delta->state, netplay->state_size);
}