FFmpeg4/libavformat/data_uri.c

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2023-07-02 12:20:28 +00:00
/*
* Copyright (c) 2012 Nicolas George
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <string.h>
#include "libavutil/avstring.h"
#include "libavutil/base64.h"
#include "url.h"
typedef struct {
const uint8_t *data;
void *tofree;
size_t size;
size_t pos;
} DataContext;
static av_cold int data_open(URLContext *h, const char *uri, int flags)
{
DataContext *dc = h->priv_data;
const char *data, *opt, *next;
char *ddata;
int ret, base64 = 0;
size_t in_size;
/* data:content/type[;base64],payload */
av_strstart(uri, "data:", &uri);
data = strchr(uri, ',');
if (!data) {
av_log(h, AV_LOG_ERROR, "No ',' delimiter in URI\n");
return AVERROR(EINVAL);
}
opt = uri;
while (opt < data) {
next = av_x_if_null(memchr(opt, ';', data - opt), data);
if (opt == uri) {
if (!memchr(opt, '/', next - opt)) { /* basic validity check */
av_log(h, AV_LOG_ERROR, "Invalid content-type '%.*s'\n",
(int)(next - opt), opt);
return AVERROR(EINVAL);
}
av_log(h, AV_LOG_VERBOSE, "Content-type: %.*s\n",
(int)(next - opt), opt);
} else {
if (!av_strncasecmp(opt, "base64", next - opt)) {
base64 = 1;
} else {
av_log(h, AV_LOG_VERBOSE, "Ignoring option '%.*s'\n",
(int)(next - opt), opt);
}
}
opt = next + 1;
}
data++;
in_size = strlen(data);
if (base64) {
size_t out_size = 3 * (in_size / 4) + 1;
if (out_size > INT_MAX || !(ddata = av_malloc(out_size)))
return AVERROR(ENOMEM);
if ((ret = av_base64_decode(ddata, data, out_size)) < 0) {
av_free(ddata);
av_log(h, AV_LOG_ERROR, "Invalid base64 in URI\n");
return ret;
}
dc->data = dc->tofree = ddata;
dc->size = ret;
} else {
dc->data = data;
dc->size = in_size;
}
return 0;
}
static av_cold int data_close(URLContext *h)
{
DataContext *dc = h->priv_data;
av_freep(&dc->tofree);
return 0;
}
static int data_read(URLContext *h, unsigned char *buf, int size)
{
DataContext *dc = h->priv_data;
if (dc->pos >= dc->size)
return AVERROR_EOF;
size = FFMIN(size, dc->size - dc->pos);
memcpy(buf, dc->data + dc->pos, size);
dc->pos += size;
return size;
}
const URLProtocol ff_data_protocol = {
.name = "data",
.url_open = data_open,
.url_close = data_close,
.url_read = data_read,
.priv_data_size = sizeof(DataContext),
};