FFmpeg: libavformat/md5proto.c Source File

FFmpeg
md5proto.c
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1 /*
2  * Copyright (c) 2010 Mans Rullgard
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include <stdio.h>
22 #include "libavutil/avstring.h"
23 #include "libavutil/md5.h"
24 #include "libavutil/mem.h"
25 #include "libavutil/error.h"
26 #include "avformat.h"
27 #include "avio.h"
28 #include "internal.h"
29 #include "url.h"
30 
31  struct MD5Context {
32   struct AVMD5 *md5;
33 };
34 
35  static int md5_open(URLContext *h, const char *filename, int flags)
36 {
37  struct MD5Context *c = h->priv_data;
38 
39  if (!(flags & AVIO_FLAG_WRITE))
40  return AVERROR(EINVAL);
41 
42  c->md5 = av_md5_alloc();
43  if (!c->md5)
44  return AVERROR(ENOMEM);
45  av_md5_init(c->md5);
46 
47  return 0;
48 }
49 
50  static int md5_write(URLContext *h, const unsigned char *buf, int size)
51 {
52  struct MD5Context *c = h->priv_data;
53  av_md5_update(c->md5, buf, size);
54  return size;
55 }
56 
57  static int md5_close(URLContext *h)
58 {
59  struct MD5Context *c = h->priv_data;
60  const char *filename = h->filename;
61  uint8_t md5[16], buf[2 * sizeof(md5) + 1];
62  URLContext *out;
63  int err = 0;
64 
65  av_md5_final(c->md5, md5);
66  ff_data_to_hex(buf, md5, sizeof(md5), 1);
67  buf[2 * sizeof(md5)] = '\n';
68 
69  av_strstart(filename, "md5:", &filename);
70 
71  if (*filename) {
72  err = ffurl_open_whitelist(&out, filename, AVIO_FLAG_WRITE,
73  &h->interrupt_callback, NULL,
74  h->protocol_whitelist, h->protocol_blacklist, h);
75  if (err)
76  return err;
77  err = ffurl_write(out, buf, sizeof(buf));
78  ffurl_close(out);
79  } else {
80  if (fwrite(buf, 1, sizeof(buf), stdout) < sizeof(buf))
81  err = AVERROR(errno);
82  }
83 
84  av_freep(&c->md5);
85 
86  return err;
87 }
88 
89 
90  const URLProtocol ff_md5_protocol = {
91  .name = "md5",
92  .url_open = md5_open,
93  .url_write = md5_write,
94  .url_close = md5_close,
95  .priv_data_size = sizeof(struct MD5Context),
96 };
AVERROR
Filter the word "frame" indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
out
FILE * out
Definition: movenc.c:54
ffurl_close
int ffurl_close(URLContext *h)
Definition: avio.c:461
URLProtocol
Definition: url.h:54
md5
struct AVMD5 * md5
Definition: movenc.c:56
ff_data_to_hex
char * ff_data_to_hex(char *buf, const uint8_t *src, int size, int lowercase)
Write hexadecimal string corresponding to given binary data.
Definition: utils.c:1147
AVMD5
Definition: md5.c:40
ffurl_open_whitelist
int ffurl_open_whitelist(URLContext **puc, const char *filename, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options, const char *whitelist, const char *blacklist, URLContext *parent)
Create an URLContext for accessing to the resource indicated by url, and open it.
Definition: avio.c:306
md5_close
static int md5_close(URLContext *h)
Definition: md5proto.c:57
AVIO_FLAG_WRITE
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:622
internal.h
NULL
#define NULL
Definition: coverity.c:32
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
error.h
size
int size
Definition: twinvq_data.h:10344
avio.h
URLProtocol::name
const char * name
Definition: url.h:55
av_strstart
int av_strstart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str.
Definition: avstring.c:34
av_md5_init
void av_md5_init(AVMD5 *ctx)
Initialize MD5 hashing.
Definition: md5.c:141
md5_open
static int md5_open(URLContext *h, const char *filename, int flags)
Definition: md5proto.c:35
URLContext
Definition: url.h:38
md5.h
url.h
av_md5_final
void av_md5_final(AVMD5 *ctx, uint8_t *dst)
Finish hashing and output digest value.
Definition: md5.c:186
avformat.h
ff_md5_protocol
const URLProtocol ff_md5_protocol
Definition: md5proto.c:90
av_md5_alloc
struct AVMD5 * av_md5_alloc(void)
Allocate an AVMD5 context.
Definition: md5.c:48
ffurl_write
int ffurl_write(URLContext *h, const unsigned char *buf, int size)
Write size bytes from buf to the resource accessed by h.
Definition: avio.c:415
av_md5_update
void av_md5_update(AVMD5 *ctx, const uint8_t *src, size_t len)
Update hash value.
Definition: md5.c:151
md5_write
static int md5_write(URLContext *h, const unsigned char *buf, int size)
Definition: md5proto.c:50
mem.h
MD5Context
Definition: md5proto.c:31
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
h
h
Definition: vp9dsp_template.c:2038
MD5Context::md5
struct AVMD5 * md5
Definition: md5proto.c:32
avstring.h
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