FFmpeg
file.c
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1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * FFmpeg is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with FFmpeg; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 #include "config.h"
20 #include "error.h"
21 #include "file.h"
22 #include "file_open.h"
23 #include "internal.h"
24 #include "log.h"
25 #include "mem.h"
26 #include <fcntl.h>
27 #include <sys/stat.h>
28 #if HAVE_UNISTD_H
29 #include <unistd.h>
30 #endif
31 #if HAVE_IO_H
32 #include <io.h>
33 #endif
34 #if HAVE_MMAP
35 #include <sys/mman.h>
36 #elif HAVE_MAPVIEWOFFILE
37 #include <windows.h>
38 #endif
39 
40 typedef struct FileLogContext {
41  const AVClass *class;
42  int log_offset;
43  void *log_ctx;
44 } FileLogContext;
45 
46 static const AVClass file_log_ctx_class = {
47  .class_name = "FILE",
48  .item_name = av_default_item_name,
49  .option = NULL,
50  .version = LIBAVUTIL_VERSION_INT,
51  .log_level_offset_offset = offsetof(FileLogContext, log_offset),
52  .parent_log_context_offset = offsetof(FileLogContext, log_ctx),
53 };
54 
55 int av_file_map(const char *filename, uint8_t **bufptr, size_t *size,
56  int log_offset, void *log_ctx)
57 {
58  FileLogContext file_log_ctx = { &file_log_ctx_class, log_offset, log_ctx };
59  int err, fd = avpriv_open(filename, O_RDONLY);
60  struct stat st;
61  av_unused void *ptr;
62  off_t off_size;
63  char errbuf[128];
64  *bufptr = NULL;
65  *size = 0;
66 
67  if (fd < 0) {
68  err = AVERROR(errno);
69  av_strerror(err, errbuf, sizeof(errbuf));
70  av_log(&file_log_ctx, AV_LOG_ERROR, "Cannot read file '%s': %s\n", filename, errbuf);
71  return err;
72  }
73 
74  if (fstat(fd, &st) < 0) {
75  err = AVERROR(errno);
76  av_strerror(err, errbuf, sizeof(errbuf));
77  av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in fstat(): %s\n", errbuf);
78  close(fd);
79  return err;
80  }
81 
82  off_size = st.st_size;
83  if (off_size > SIZE_MAX) {
84  av_log(&file_log_ctx, AV_LOG_ERROR,
85  "File size for file '%s' is too big\n", filename);
86  close(fd);
87  return AVERROR(EINVAL);
88  }
89  *size = off_size;
90 
91  if (!*size) {
92  *bufptr = NULL;
93  goto out;
94  }
95 
96 #if HAVE_MMAP
97  ptr = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
98  if (ptr == MAP_FAILED) {
99  err = AVERROR(errno);
100  av_strerror(err, errbuf, sizeof(errbuf));
101  av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in mmap(): %s\n", errbuf);
102  close(fd);
103  *size = 0;
104  return err;
105  }
106  *bufptr = ptr;
107 #elif HAVE_MAPVIEWOFFILE
108  {
109  HANDLE mh, fh = (HANDLE)_get_osfhandle(fd);
110 
111  mh = CreateFileMapping(fh, NULL, PAGE_READONLY, 0, 0, NULL);
112  if (!mh) {
113  av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in CreateFileMapping()\n");
114  close(fd);
115  *size = 0;
116  return -1;
117  }
118 
119  ptr = MapViewOfFile(mh, FILE_MAP_READ, 0, 0, *size);
120  CloseHandle(mh);
121  if (!ptr) {
122  av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in MapViewOfFile()\n");
123  close(fd);
124  *size = 0;
125  return -1;
126  }
127 
128  *bufptr = ptr;
129  }
130 #else
131  *bufptr = av_malloc(*size);
132  if (!*bufptr) {
133  av_log(&file_log_ctx, AV_LOG_ERROR, "Memory allocation error occurred\n");
134  close(fd);
135  *size = 0;
136  return AVERROR(ENOMEM);
137  }
138  read(fd, *bufptr, *size);
139 #endif
140 
141 out:
142  close(fd);
143  return 0;
144 }
145 
146 void av_file_unmap(uint8_t *bufptr, size_t size)
147 {
148  if (!size || !bufptr)
149  return;
150 #if HAVE_MMAP
151  munmap(bufptr, size);
152 #elif HAVE_MAPVIEWOFFILE
153  UnmapViewOfFile(bufptr);
154 #else
155  av_free(bufptr);
156 #endif
157 }
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
av_unused
#define av_unused
Definition: attributes.h:131
FileLogContext::log_offset
int log_offset
Definition: file.c:42
mh
#define mh
Definition: vf_colormatrix.c:105
av_malloc
#define av_malloc(s)
Definition: tableprint_vlc.h:30
av_file_map
int av_file_map(const char *filename, uint8_t **bufptr, size_t *size, int log_offset, void *log_ctx)
Read the file with name filename, and put its content in a newly allocated buffer or map it with mmap...
Definition: file.c:55
av_strerror
int av_strerror(int errnum, char *errbuf, size_t errbuf_size)
Put a description of the AVERROR code errnum in errbuf.
Definition: error.c:108
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
avpriv_open
int avpriv_open(const char *filename, int flags,...)
A wrapper for open() setting O_CLOEXEC.
Definition: file_open.c:67
file_open.h
av_file_unmap
void av_file_unmap(uint8_t *bufptr, size_t size)
Unmap or free the buffer bufptr created by av_file_map().
Definition: file.c:146
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
NULL
#define NULL
Definition: coverity.c:32
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:237
error.h
size
int size
Definition: twinvq_data.h:10344
FileLogContext
Definition: file.c:40
log.h
internal.h
AVClass::class_name
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:71
FileLogContext::log_ctx
void * log_ctx
Definition: file.c:43
file_log_ctx_class
static const AVClass file_log_ctx_class
Definition: file.c:46
file.h
mem.h
av_free
#define av_free(p)
Definition: tableprint_vlc.h:33
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
read
static uint32_t BS_FUNC() read(BSCTX *bc, unsigned int n)
Return n bits from the buffer, n has to be in the 0-32 range.
Definition: bitstream_template.h:231
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