mirror of
https://github.com/gnif/LookingGlass.git
synced 2024-11-23 05:57:19 +00:00
113 lines
2.6 KiB
C
113 lines
2.6 KiB
C
/*
|
|
KVMGFX Client - A KVM Client for VGA Passthrough
|
|
Copyright (C) 2017-2019 Geoffrey McRae <geoff@hostfission.com>
|
|
https://looking-glass.hostfission.com
|
|
|
|
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., 59 Temple
|
|
Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
#include "common/framebuffer.h"
|
|
#include "common/debug.h"
|
|
|
|
#include <string.h>
|
|
#include <stdatomic.h>
|
|
|
|
#define FB_CHUNK_SIZE 1024
|
|
|
|
struct stFrameBuffer
|
|
{
|
|
atomic_uint_least32_t wp;
|
|
uint8_t data[0];
|
|
};
|
|
|
|
const size_t FrameBufferStructSize = sizeof(FrameBuffer);
|
|
|
|
void framebuffer_wait(const FrameBuffer * frame, size_t size)
|
|
{
|
|
while(atomic_load_explicit(&frame->wp, memory_order_relaxed) != size) {}
|
|
}
|
|
|
|
bool framebuffer_read(const FrameBuffer * frame, void * dst, size_t size)
|
|
{
|
|
uint8_t *d = (uint8_t*)dst;
|
|
uint64_t rp = 0;
|
|
while(rp < size)
|
|
{
|
|
uint_least32_t wp;
|
|
|
|
/* spinlock */
|
|
do
|
|
wp = atomic_load_explicit(&frame->wp, memory_order_relaxed);
|
|
while(rp == wp);
|
|
|
|
/* copy what we can */
|
|
uint64_t avail = wp - rp;
|
|
avail = avail > size ? size : avail;
|
|
|
|
memcpy(d, frame->data + rp, avail);
|
|
|
|
rp += avail;
|
|
d += avail;
|
|
size -= avail;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
bool framebuffer_read_fn(const FrameBuffer * frame, FrameBufferReadFn fn, size_t size, void * opaque)
|
|
{
|
|
uint64_t rp = 0;
|
|
while(rp < size)
|
|
{
|
|
uint_least32_t wp;
|
|
|
|
/* spinlock */
|
|
do
|
|
wp = atomic_load_explicit(&frame->wp, memory_order_relaxed);
|
|
while(rp == wp);
|
|
|
|
/* copy what we can */
|
|
uint64_t avail = wp - rp;
|
|
avail = avail > size ? size : avail;
|
|
|
|
if (!fn(opaque, frame->data + rp, avail))
|
|
return false;
|
|
|
|
rp += avail;
|
|
size -= avail;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Prepare the framebuffer for writing
|
|
*/
|
|
void framebuffer_prepare(FrameBuffer * frame)
|
|
{
|
|
atomic_store(&frame->wp, 0);
|
|
}
|
|
|
|
bool framebuffer_write(FrameBuffer * frame, const void * src, size_t size)
|
|
{
|
|
/* copy in chunks */
|
|
while(size)
|
|
{
|
|
size_t copy = size < FB_CHUNK_SIZE ? FB_CHUNK_SIZE : size;
|
|
memcpy(frame->data + frame->wp, src, copy);
|
|
atomic_fetch_add(&frame->wp, copy);
|
|
size -= copy;
|
|
}
|
|
return true;
|
|
}
|