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mirror of https://github.com/mpv-player/mpv synced 2024-12-25 08:12:17 +00:00
mpv/audio/audio_buffer.c
wm4 4e4949b4dc audio_buffer: fix some more theoretical UB
This may call memmove() with size==0 and a NULL data pointer. In
addition to this being UB with memmove(), I think it's UB to do
arithmetic on a NULL pointer too. Of course, this doesn't matter in
practice at all, and is just stupidity to torture programmers.
2019-09-19 20:37:05 +02:00

161 lines
4.9 KiB
C

/*
* This file is part of mpv.
*
* 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
* GNU Lesser General Public License for more details.
*
* 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 <stddef.h>
#include <limits.h>
#include <assert.h>
#include "common/common.h"
#include "chmap.h"
#include "audio_buffer.h"
#include "format.h"
struct mp_audio_buffer {
int format;
struct mp_chmap channels;
int srate;
int sstride;
int num_planes;
uint8_t *data[MP_NUM_CHANNELS];
int allocated;
int num_samples;
};
struct mp_audio_buffer *mp_audio_buffer_create(void *talloc_ctx)
{
return talloc_zero(talloc_ctx, struct mp_audio_buffer);
}
// Reinitialize the buffer, set a new format, drop old data.
// The audio data in fmt is not used, only the format.
void mp_audio_buffer_reinit_fmt(struct mp_audio_buffer *ab, int format,
const struct mp_chmap *channels, int srate)
{
for (int n = 0; n < MP_NUM_CHANNELS; n++)
TA_FREEP(&ab->data[n]);
ab->format = format;
ab->channels = *channels;
ab->srate = srate;
ab->allocated = 0;
ab->num_samples = 0;
ab->sstride = af_fmt_to_bytes(ab->format);
ab->num_planes = 1;
if (af_fmt_is_planar(ab->format)) {
ab->num_planes = ab->channels.num;
} else {
ab->sstride *= ab->channels.num;
}
}
// Make the total size of the internal buffer at least this number of samples.
void mp_audio_buffer_preallocate_min(struct mp_audio_buffer *ab, int samples)
{
if (samples > ab->allocated) {
for (int n = 0; n < ab->num_planes; n++) {
ab->data[n] = talloc_realloc(ab, ab->data[n], char,
ab->sstride * samples);
}
ab->allocated = samples;
}
}
// Get number of samples that can be written without forcing a resize of the
// internal buffer.
int mp_audio_buffer_get_write_available(struct mp_audio_buffer *ab)
{
return ab->allocated - ab->num_samples;
}
// All integer parameters are in samples.
// dst and src can overlap.
static void copy_planes(struct mp_audio_buffer *ab,
uint8_t **dst, int dst_offset,
uint8_t **src, int src_offset, int length)
{
if (!length)
return;
for (int n = 0; n < ab->num_planes; n++) {
memmove((char *)dst[n] + dst_offset * ab->sstride,
(char *)src[n] + src_offset * ab->sstride,
length * ab->sstride);
}
}
// Append data to the end of the buffer.
// If the buffer is not large enough, it is transparently resized.
void mp_audio_buffer_append(struct mp_audio_buffer *ab, void **ptr, int samples)
{
mp_audio_buffer_preallocate_min(ab, ab->num_samples + samples);
copy_planes(ab, ab->data, ab->num_samples, (uint8_t **)ptr, 0, samples);
ab->num_samples += samples;
}
// Prepend silence to the start of the buffer.
void mp_audio_buffer_prepend_silence(struct mp_audio_buffer *ab, int samples)
{
assert(samples >= 0);
mp_audio_buffer_preallocate_min(ab, ab->num_samples + samples);
copy_planes(ab, ab->data, samples, ab->data, 0, ab->num_samples);
ab->num_samples += samples;
for (int n = 0; n < ab->num_planes; n++)
af_fill_silence(ab->data[n], samples * ab->sstride, ab->format);
}
void mp_audio_buffer_duplicate(struct mp_audio_buffer *ab, int samples)
{
assert(samples >= 0 && samples <= ab->num_samples);
mp_audio_buffer_preallocate_min(ab, ab->num_samples + samples);
copy_planes(ab, ab->data, ab->num_samples,
ab->data, ab->num_samples - samples, samples);
ab->num_samples += samples;
}
// Get the start of the current readable buffer.
void mp_audio_buffer_peek(struct mp_audio_buffer *ab, uint8_t ***ptr,
int *samples)
{
*ptr = ab->data;
*samples = ab->num_samples;
}
// Skip leading samples. (Used with mp_audio_buffer_peek() to read data.)
void mp_audio_buffer_skip(struct mp_audio_buffer *ab, int samples)
{
assert(samples >= 0 && samples <= ab->num_samples);
copy_planes(ab, ab->data, 0, ab->data, samples, ab->num_samples - samples);
ab->num_samples -= samples;
}
void mp_audio_buffer_clear(struct mp_audio_buffer *ab)
{
ab->num_samples = 0;
}
// Return number of buffered audio samples
int mp_audio_buffer_samples(struct mp_audio_buffer *ab)
{
return ab->num_samples;
}
// Return amount of buffered audio in seconds.
double mp_audio_buffer_seconds(struct mp_audio_buffer *ab)
{
return ab->num_samples / (double)ab->srate;
}