mpv/misc/ring.c

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/*
* This file is part of mpv.
* Copyright (c) 2012 wm4
* Copyright (c) 2013 Stefano Pigozzi <stefano.pigozzi@gmail.com>
*
Relicense some non-MPlayer source files to LGPL 2.1 or later This covers source files which were added in mplayer2 and mpv times only, and where all code is covered by LGPL relicensing agreements. There are probably more files to which this applies, but I'm being conservative here. A file named ao_sdl.c exists in MPlayer too, but the mpv one is a complete rewrite, and was added some time after the original ao_sdl.c was removed. The same applies to vo_sdl.c, for which the SDL2 API is radically different in addition (MPlayer supports SDL 1.2 only). common.c contains only code written by me. But common.h is a strange case: although it originally was named mp_common.h and exists in MPlayer too, by now it contains only definitions written by uau and me. The exceptions are the CONTROL_ defines - thus not changing the license of common.h yet. codec_tags.c contained once large tables generated from MPlayer's codecs.conf, but all of these tables were removed. From demux_playlist.c I'm removing a code fragment from someone who was not asked; this probably could be done later (see commit 15dccc37). misc.c is a bit complicated to reason about (it was split off mplayer.c and thus contains random functions out of this file), but actually all functions have been added post-MPlayer. Except get_relative_time(), which was written by uau, but looks similar to 3 different versions of something similar in each of the Unix/win32/OSX timer source files. I'm not sure what that means in regards to copyright, so I've just moved it into another still-GPL source file for now. screenshot.c once had some minor parts of MPlayer's vf_screenshot.c, but they're all gone.
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* mpv is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* mpv 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
Relicense some non-MPlayer source files to LGPL 2.1 or later This covers source files which were added in mplayer2 and mpv times only, and where all code is covered by LGPL relicensing agreements. There are probably more files to which this applies, but I'm being conservative here. A file named ao_sdl.c exists in MPlayer too, but the mpv one is a complete rewrite, and was added some time after the original ao_sdl.c was removed. The same applies to vo_sdl.c, for which the SDL2 API is radically different in addition (MPlayer supports SDL 1.2 only). common.c contains only code written by me. But common.h is a strange case: although it originally was named mp_common.h and exists in MPlayer too, by now it contains only definitions written by uau and me. The exceptions are the CONTROL_ defines - thus not changing the license of common.h yet. codec_tags.c contained once large tables generated from MPlayer's codecs.conf, but all of these tables were removed. From demux_playlist.c I'm removing a code fragment from someone who was not asked; this probably could be done later (see commit 15dccc37). misc.c is a bit complicated to reason about (it was split off mplayer.c and thus contains random functions out of this file), but actually all functions have been added post-MPlayer. Except get_relative_time(), which was written by uau, but looks similar to 3 different versions of something similar in each of the Unix/win32/OSX timer source files. I'm not sure what that means in regards to copyright, so I've just moved it into another still-GPL source file for now. screenshot.c once had some minor parts of MPlayer's vf_screenshot.c, but they're all gone.
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* GNU Lesser General Public License for more details.
*
Relicense some non-MPlayer source files to LGPL 2.1 or later This covers source files which were added in mplayer2 and mpv times only, and where all code is covered by LGPL relicensing agreements. There are probably more files to which this applies, but I'm being conservative here. A file named ao_sdl.c exists in MPlayer too, but the mpv one is a complete rewrite, and was added some time after the original ao_sdl.c was removed. The same applies to vo_sdl.c, for which the SDL2 API is radically different in addition (MPlayer supports SDL 1.2 only). common.c contains only code written by me. But common.h is a strange case: although it originally was named mp_common.h and exists in MPlayer too, by now it contains only definitions written by uau and me. The exceptions are the CONTROL_ defines - thus not changing the license of common.h yet. codec_tags.c contained once large tables generated from MPlayer's codecs.conf, but all of these tables were removed. From demux_playlist.c I'm removing a code fragment from someone who was not asked; this probably could be done later (see commit 15dccc37). misc.c is a bit complicated to reason about (it was split off mplayer.c and thus contains random functions out of this file), but actually all functions have been added post-MPlayer. Except get_relative_time(), which was written by uau, but looks similar to 3 different versions of something similar in each of the Unix/win32/OSX timer source files. I'm not sure what that means in regards to copyright, so I've just moved it into another still-GPL source file for now. screenshot.c once had some minor parts of MPlayer's vf_screenshot.c, but they're all gone.
2016-01-19 17:36:06 +00:00
* You should have received a copy of the GNU Lesser General Public
* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <inttypes.h>
#include <libavutil/common.h>
#include <assert.h>
#include "mpv_talloc.h"
#include "osdep/atomic.h"
#include "ring.h"
struct mp_ring {
uint8_t *buffer;
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/* Positions of the first readable/writeable chunks. Do not read these
* fields. Use the atomic private accessors `mp_ring_get_wpos`
* and `mp_ring_get_rpos`. */
atomic_ullong rpos, wpos;
};
static unsigned long long mp_ring_get_wpos(struct mp_ring *buffer)
{
return atomic_load(&buffer->wpos);
}
static unsigned long long mp_ring_get_rpos(struct mp_ring *buffer)
{
return atomic_load(&buffer->rpos);
}
struct mp_ring *mp_ring_new(void *talloc_ctx, int size)
{
struct mp_ring *ringbuffer =
talloc_zero(talloc_ctx, struct mp_ring);
*ringbuffer = (struct mp_ring) {
.buffer = talloc_size(talloc_ctx, size),
};
return ringbuffer;
}
int mp_ring_read(struct mp_ring *buffer, unsigned char *dest, int len)
{
int size = mp_ring_size(buffer);
int buffered = mp_ring_buffered(buffer);
int read_len = FFMIN(len, buffered);
int read_ptr = mp_ring_get_rpos(buffer) % size;
int len1 = FFMIN(size - read_ptr, read_len);
int len2 = read_len - len1;
if (dest) {
memcpy(dest, buffer->buffer + read_ptr, len1);
memcpy(dest + len1, buffer->buffer, len2);
}
atomic_fetch_add(&buffer->rpos, read_len);
return read_len;
}
int mp_ring_drain(struct mp_ring *buffer, int len)
{
return mp_ring_read(buffer, NULL, len);
}
int mp_ring_write(struct mp_ring *buffer, unsigned char *src, int len)
{
int size = mp_ring_size(buffer);
int free = mp_ring_available(buffer);
int write_len = FFMIN(len, free);
int write_ptr = mp_ring_get_wpos(buffer) % size;
int len1 = FFMIN(size - write_ptr, write_len);
int len2 = write_len - len1;
memcpy(buffer->buffer + write_ptr, src, len1);
memcpy(buffer->buffer, src + len1, len2);
atomic_fetch_add(&buffer->wpos, write_len);
return write_len;
}
void mp_ring_reset(struct mp_ring *buffer)
{
atomic_store(&buffer->wpos, 0);
atomic_store(&buffer->rpos, 0);
}
int mp_ring_available(struct mp_ring *buffer)
{
return mp_ring_size(buffer) - mp_ring_buffered(buffer);
}
int mp_ring_size(struct mp_ring *buffer)
{
return talloc_get_size(buffer->buffer);
}
int mp_ring_buffered(struct mp_ring *buffer)
{
return (mp_ring_get_wpos(buffer) - mp_ring_get_rpos(buffer));
}
char *mp_ring_repr(struct mp_ring *buffer, void *talloc_ctx)
{
return talloc_asprintf(
talloc_ctx,
"Ringbuffer { .size = %dB, .buffered = %dB, .available = %dB }",
mp_ring_size(buffer),
mp_ring_buffered(buffer),
mp_ring_available(buffer));
}