FFmpeg
avio_internal.h
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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 #ifndef AVFORMAT_AVIO_INTERNAL_H
20 #define AVFORMAT_AVIO_INTERNAL_H
21 
22 #include "avio.h"
23 #include "url.h"
24 
25 #include "libavutil/log.h"
26 
27 extern const AVClass ff_avio_class;
28 
29 typedef struct FFIOContext {
31  /**
32  * A callback that is used instead of short_seek_threshold.
33  */
34  int (*short_seek_get)(void *opaque);
35 
36  /**
37  * Threshold to favor readahead over seek.
38  */
40 
42  int64_t last_time;
43 
44  /**
45  * max filesize, used to limit allocations
46  */
47  int64_t maxsize;
48 
49  /**
50  * Bytes read statistic
51  */
52  int64_t bytes_read;
53 
54  /**
55  * Bytes written statistic
56  */
57  int64_t bytes_written;
58 
59  /**
60  * seek statistic
61  */
63 
64  /**
65  * writeout statistic
66  */
68 
69  /**
70  * Original buffer size
71  * used after probing to ensure seekback and to reset the buffer size
72  */
74 
75  /**
76  * Written output size
77  * is updated each time a successful writeout ends up further position-wise
78  */
80 } FFIOContext;
81 
83 {
84  return (FFIOContext*)ctx;
85 }
86 
88  unsigned char *buffer,
89  int buffer_size,
90  int write_flag,
91  void *opaque,
92  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
93  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
94  int64_t (*seek)(void *opaque, int64_t offset, int whence));
95 
96 
97 /**
98  * Read size bytes from AVIOContext, returning a pointer.
99  * Note that the data pointed at by the returned pointer is only
100  * valid until the next call that references the same IO context.
101  * @param s IO context
102  * @param buf pointer to buffer into which to assemble the requested
103  * data if it is not available in contiguous addresses in the
104  * underlying buffer
105  * @param size number of bytes requested
106  * @param data address at which to store pointer: this will be a
107  * a direct pointer into the underlying buffer if the requested
108  * number of bytes are available at contiguous addresses, otherwise
109  * will be a copy of buf
110  * @return number of bytes read or AVERROR
111  */
112 int ffio_read_indirect(AVIOContext *s, unsigned char *buf, int size, const unsigned char **data);
113 
114 void ffio_fill(AVIOContext *s, int b, int64_t count);
115 
116 static av_always_inline void ffio_wfourcc(AVIOContext *pb, const uint8_t *s)
117 {
118  avio_wl32(pb, MKTAG(s[0], s[1], s[2], s[3]));
119 }
120 
121 /**
122  * Rewind the AVIOContext using the specified buffer containing the first buf_size bytes of the file.
123  * Used after probing to avoid seeking.
124  * Joins buf and s->buffer, taking any overlap into consideration.
125  * @note s->buffer must overlap with buf or they can't be joined and the function fails
126  *
127  * @param s The read-only AVIOContext to rewind
128  * @param buf The probe buffer containing the first buf_size bytes of the file
129  * @param buf_size The size of buf
130  * @return >= 0 in case of success, a negative value corresponding to an
131  * AVERROR code in case of failure
132  */
133 int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char **buf, int buf_size);
134 
135 uint64_t ffio_read_varlen(AVIOContext *bc);
136 
137 /**
138  * Read size bytes from AVIOContext into buf.
139  * Check that exactly size bytes have been read.
140  * @return number of bytes read or AVERROR
141  */
142 int ffio_read_size(AVIOContext *s, unsigned char *buf, int size);
143 
144 /**
145  * Reallocate a given buffer for AVIOContext.
146  *
147  * @param s the AVIOContext to realloc.
148  * @param buf_size required new buffer size.
149  * @return 0 on success, a negative AVERROR on failure.
150  */
151 int ffio_realloc_buf(AVIOContext *s, int buf_size);
152 
153 /**
154  * Ensures that the requested seekback buffer size will be available
155  *
156  * Will ensure that when reading sequentially up to buf_size, seeking
157  * within the current pos and pos+buf_size is possible.
158  * Once the stream position moves outside this window or another
159  * ffio_ensure_seekback call requests a buffer outside this window this
160  * guarantee is lost.
161  */
162 int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size);
163 
164 int ffio_limit(AVIOContext *s, int size);
165 
167  unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
168  unsigned long checksum);
169 unsigned long ffio_get_checksum(AVIOContext *s);
170 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
171  unsigned int len);
172 unsigned long ff_crcEDB88320_update(unsigned long checksum, const uint8_t *buf,
173  unsigned int len);
174 unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf,
175  unsigned int len);
176 
177 /**
178  * Open a write only packetized memory stream with a maximum packet
179  * size of 'max_packet_size'. The stream is stored in a memory buffer
180  * with a big-endian 4 byte header giving the packet size in bytes.
181  *
182  * @param s new IO context
183  * @param max_packet_size maximum packet size (must be > 0)
184  * @return zero if no error.
185  */
186 int ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size);
187 
188 /**
189  * Create and initialize a AVIOContext for accessing the
190  * resource referenced by the URLContext h.
191  * @note When the URLContext h has been opened in read+write mode, the
192  * AVIOContext can be used only for writing.
193  *
194  * @param s Used to return the pointer to the created AVIOContext.
195  * In case of failure the pointed to value is set to NULL.
196  * @return >= 0 in case of success, a negative value corresponding to an
197  * AVERROR code in case of failure
198  */
200 
201 /**
202  * Return the URLContext associated with the AVIOContext
203  *
204  * @param s IO context
205  * @return pointer to URLContext or NULL.
206  */
208 
209 /**
210  * Open a write-only fake memory stream. The written data is not stored
211  * anywhere - this is only used for measuring the amount of data
212  * written.
213  *
214  * @param s new IO context
215  * @return zero if no error.
216  */
218 
219 int ffio_open_whitelist(AVIOContext **s, const char *url, int flags,
221  const char *whitelist, const char *blacklist);
222 
223 /**
224  * Close a null buffer.
225  *
226  * @param s an IO context opened by ffio_open_null_buf
227  * @return the number of bytes written to the null buffer
228  */
230 
231 /**
232  * Reset a dynamic buffer.
233  *
234  * Resets everything, but keeps the allocated buffer for later use.
235  */
237 
238 /**
239  * Free a dynamic buffer.
240  *
241  * @param s a pointer to an IO context opened by avio_open_dyn_buf()
242  */
244 
245 struct AVBPrint;
246 /**
247  * Read a whole line of text from AVIOContext to an AVBPrint buffer overwriting
248  * its contents. Stop reading after reaching a \\r, a \\n, a \\r\\n, a \\0 or
249  * EOF. The line ending characters are NOT included in the buffer, but they
250  * are skipped on the input.
251  *
252  * @param s the read-only AVIOContext
253  * @param bp the AVBPrint buffer
254  * @return the length of the read line not including the line endings,
255  * negative on error, or if the buffer becomes truncated.
256  */
257 int64_t ff_read_line_to_bprint_overwrite(AVIOContext *s, struct AVBPrint *bp);
258 
259 /**
260  * Read a whole null-terminated string of text from AVIOContext to an AVBPrint
261  * buffer overwriting its contents. Stop reading after reaching the maximum
262  * length, a \\0 or EOF.
263  *
264  * @param s the read-only AVIOContext
265  * @param bp the AVBPrint buffer
266  * @param max_len the maximum length to be read from the AVIOContext.
267  * Negative (< 0) values signal that there is no known maximum
268  * length applicable. A maximum length of zero means that the
269  * AVIOContext is not touched, and the function returns
270  * with a read length of zero. In all cases the AVBprint
271  * is cleared.
272  * @return the length of the read string not including the terminating null,
273  * negative on error, or if the buffer becomes truncated.
274  */
275 int64_t ff_read_string_to_bprint_overwrite(AVIOContext *s, struct AVBPrint *bp,
276  int64_t max_len);
277 
278 #endif /* AVFORMAT_AVIO_INTERNAL_H */
ffio_realloc_buf
int ffio_realloc_buf(AVIOContext *s, int buf_size)
Reallocate a given buffer for AVIOContext.
Definition: aviobuf.c:1110
ffio_wfourcc
static av_always_inline void ffio_wfourcc(AVIOContext *pb, const uint8_t *s)
Definition: avio_internal.h:116
ffiocontext
static av_always_inline FFIOContext * ffiocontext(AVIOContext *ctx)
Definition: avio_internal.h:82
ffio_read_indirect
int ffio_read_indirect(AVIOContext *s, unsigned char *buf, int size, const unsigned char **data)
Read size bytes from AVIOContext, returning a pointer.
Definition: aviobuf.c:701
FFIOContext::written_output_size
int64_t written_output_size
Written output size is updated each time a successful writeout ends up further position-wise.
Definition: avio_internal.h:79
ff_read_line_to_bprint_overwrite
int64_t ff_read_line_to_bprint_overwrite(AVIOContext *s, struct AVBPrint *bp)
Read a whole line of text from AVIOContext to an AVBPrint buffer overwriting its contents.
Definition: aviobuf.c:884
b
#define b
Definition: input.c:40
data
const char data[16]
Definition: mxf.c:143
FFIOContext::short_seek_get
int(* short_seek_get)(void *opaque)
A callback that is used instead of short_seek_threshold.
Definition: avio_internal.h:34
ffio_open_whitelist
int ffio_open_whitelist(AVIOContext **s, const char *url, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options, const char *whitelist, const char *blacklist)
Definition: aviobuf.c:1203
ff_avio_class
const AVClass ff_avio_class
Definition: aviobuf.c:67
AVDictionary
Definition: dict.c:30
AVIODataMarkerType
AVIODataMarkerType
Different data types that can be returned via the AVIO write_data_type callback.
Definition: avio.h:111
FFIOContext::short_seek_threshold
int short_seek_threshold
Threshold to favor readahead over seek.
Definition: avio_internal.h:39
FFIOContext
Definition: avio_internal.h:29
ffio_get_checksum
unsigned long ffio_get_checksum(AVIOContext *s)
Definition: aviobuf.c:612
update_checksum
static void update_checksum(AVIOContext *s)
Definition: aviobuf.c:1025
AVIOInterruptCB
Callback for checking whether to abort blocking functions.
Definition: avio.h:58
ffio_open_null_buf
int ffio_open_null_buf(AVIOContext **s)
Open a write-only fake memory stream.
Definition: aviobuf.c:1538
FFIOContext::bytes_read
int64_t bytes_read
Bytes read statistic.
Definition: avio_internal.h:52
FFIOContext::seek_count
int seek_count
seek statistic
Definition: avio_internal.h:62
s
#define s(width, name)
Definition: cbs_vp9.c:257
ctx
AVFormatContext * ctx
Definition: movenc.c:48
ff_crcEDB88320_update
unsigned long ff_crcEDB88320_update(unsigned long checksum, const uint8_t *buf, unsigned int len)
Definition: aviobuf.c:600
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
ffio_close_null_buf
int ffio_close_null_buf(AVIOContext *s)
Close a null buffer.
Definition: aviobuf.c:1548
FFIOContext::orig_buffer_size
int orig_buffer_size
Original buffer size used after probing to ensure seekback and to reset the buffer size.
Definition: avio_internal.h:73
ffio_fill
void ffio_fill(AVIOContext *s, int b, int64_t count)
Definition: aviobuf.c:218
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
FFIOContext::maxsize
int64_t maxsize
max filesize, used to limit allocations
Definition: avio_internal.h:47
options
const OptionDef options[]
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
ffio_reset_dyn_buf
void ffio_reset_dyn_buf(AVIOContext *s)
Reset a dynamic buffer.
Definition: aviobuf.c:1477
FFIOContext::writeout_count
int writeout_count
writeout statistic
Definition: avio_internal.h:67
FFIOContext::pub
AVIOContext pub
Definition: avio_internal.h:30
size
int size
Definition: twinvq_data.h:10344
avio.h
ffio_init_checksum
void ffio_init_checksum(AVIOContext *s, unsigned long(*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len), unsigned long checksum)
Definition: aviobuf.c:620
ffio_open_dyn_packet_buf
int ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size)
Open a write only packetized memory stream with a maximum packet size of 'max_packet_size'.
Definition: aviobuf.c:1448
avio_wl32
void avio_wl32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:386
ffio_ensure_seekback
int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size)
Ensures that the requested seekback buffer size will be available.
Definition: aviobuf.c:1033
offset
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Definition: writing_filters.txt:86
ffio_read_varlen
uint64_t ffio_read_varlen(AVIOContext *bc)
Definition: aviobuf.c:945
ff_crc04C11DB7_update
unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf, unsigned int len)
Definition: aviobuf.c:594
ffio_limit
int ffio_limit(AVIOContext *s, int size)
Definition: aviobuf.c:1068
write_packet
static void write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int unqueue)
Definition: ffmpeg.c:731
ffio_fdopen
int ffio_fdopen(AVIOContext **s, URLContext *h)
Create and initialize a AVIOContext for accessing the resource referenced by the URLContext h.
Definition: aviobuf.c:956
URLContext
Definition: url.h:38
log.h
ffio_init_context
void ffio_init_context(FFIOContext *s, unsigned char *buffer, int buffer_size, int write_flag, void *opaque, int(*read_packet)(void *opaque, uint8_t *buf, int buf_size), int(*write_packet)(void *opaque, uint8_t *buf, int buf_size), int64_t(*seek)(void *opaque, int64_t offset, int whence))
Definition: aviobuf.c:81
av_always_inline
#define av_always_inline
Definition: attributes.h:49
url.h
ff_crcA001_update
unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf, unsigned int len)
Definition: aviobuf.c:606
len
int len
Definition: vorbis_enc_data.h:426
int_cb
const AVIOInterruptCB int_cb
Definition: ffmpeg.c:513
ff_read_string_to_bprint_overwrite
int64_t ff_read_string_to_bprint_overwrite(AVIOContext *s, struct AVBPrint *bp, int64_t max_len)
Read a whole null-terminated string of text from AVIOContext to an AVBPrint buffer overwriting its co...
Definition: aviobuf.c:889
ffio_free_dyn_buf
void ffio_free_dyn_buf(AVIOContext **s)
Free a dynamic buffer.
Definition: aviobuf.c:1516
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
FFIOContext::current_type
enum AVIODataMarkerType current_type
Definition: avio_internal.h:41
checksum
static volatile int checksum
Definition: adler32.c:30
buffer
the frame and frame reference mechanism is intended to as much as expensive copies of that data while still allowing the filters to produce correct results The data is stored in buffers represented by AVFrame structures Several references can point to the same frame buffer
Definition: filter_design.txt:49
ffio_rewind_with_probe_data
int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char **buf, int buf_size)
Rewind the AVIOContext using the specified buffer containing the first buf_size bytes of the file.
Definition: aviobuf.c:1155
FFIOContext::last_time
int64_t last_time
Definition: avio_internal.h:42
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
MKTAG
#define MKTAG(a, b, c, d)
Definition: macros.h:55
ffio_read_size
int ffio_read_size(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:691
h
h
Definition: vp9dsp_template.c:2038
int
int
Definition: ffmpeg_filter.c:156
ffio_geturlcontext
URLContext * ffio_geturlcontext(AVIOContext *s)
Return the URLContext associated with the AVIOContext.
Definition: aviobuf.c:1014
FFIOContext::bytes_written
int64_t bytes_written
Bytes written statistic.
Definition: avio_internal.h:57