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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 
30  unsigned char *buffer,
31  int buffer_size,
32  int write_flag,
33  void *opaque,
34  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
35  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
36  int64_t (*seek)(void *opaque, int64_t offset, int whence));
37 
38 
39 /**
40  * Read size bytes from AVIOContext, returning a pointer.
41  * Note that the data pointed at by the returned pointer is only
42  * valid until the next call that references the same IO context.
43  * @param s IO context
44  * @param buf pointer to buffer into which to assemble the requested
45  * data if it is not available in contiguous addresses in the
46  * underlying buffer
47  * @param size number of bytes requested
48  * @param data address at which to store pointer: this will be a
49  * a direct pointer into the underlying buffer if the requested
50  * number of bytes are available at contiguous addresses, otherwise
51  * will be a copy of buf
52  * @return number of bytes read or AVERROR
53  */
54 int ffio_read_indirect(AVIOContext *s, unsigned char *buf, int size, const unsigned char **data);
55 
56 /**
57  * Read size bytes from AVIOContext into buf.
58  * This reads at most 1 packet. If that is not enough fewer bytes will be
59  * returned.
60  * @return number of bytes read or AVERROR
61  */
62 int ffio_read_partial(AVIOContext *s, unsigned char *buf, int size);
63 
64 void ffio_fill(AVIOContext *s, int b, int count);
65 
67 {
68  avio_wl32(pb, MKTAG(s[0], s[1], s[2], s[3]));
69 }
70 
71 /**
72  * Rewind the AVIOContext using the specified buffer containing the first buf_size bytes of the file.
73  * Used after probing to avoid seeking.
74  * Joins buf and s->buffer, taking any overlap into consideration.
75  * @note s->buffer must overlap with buf or they can't be joined and the function fails
76  *
77  * @param s The read-only AVIOContext to rewind
78  * @param buf The probe buffer containing the first buf_size bytes of the file
79  * @param buf_size The size of buf
80  * @return >= 0 in case of success, a negative value corresponding to an
81  * AVERROR code in case of failure
82  */
83 int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char **buf, int buf_size);
84 
85 uint64_t ffio_read_varlen(AVIOContext *bc);
86 
87 /**
88  * Read size bytes from AVIOContext into buf.
89  * Check that exactly size bytes have been read.
90  * @return number of bytes read or AVERROR
91  */
92 int ffio_read_size(AVIOContext *s, unsigned char *buf, int size);
93 
94 /** @warning must be called before any I/O */
95 int ffio_set_buf_size(AVIOContext *s, int buf_size);
96 
97 /**
98  * Ensures that the requested seekback buffer size will be available
99  *
100  * Will ensure that when reading sequentially up to buf_size, seeking
101  * within the current pos and pos+buf_size is possible.
102  * Once the stream position moves outside this window this guarantee is lost.
103  */
104 int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size);
105 
106 int ffio_limit(AVIOContext *s, int size);
107 
109  unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
110  unsigned long checksum);
111 unsigned long ffio_get_checksum(AVIOContext *s);
112 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
113  unsigned int len);
114 unsigned long ff_crcEDB88320_update(unsigned long checksum, const uint8_t *buf,
115  unsigned int len);
116 unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf,
117  unsigned int len);
118 
119 /**
120  * Open a write only packetized memory stream with a maximum packet
121  * size of 'max_packet_size'. The stream is stored in a memory buffer
122  * with a big-endian 4 byte header giving the packet size in bytes.
123  *
124  * @param s new IO context
125  * @param max_packet_size maximum packet size (must be > 0)
126  * @return zero if no error.
127  */
128 int ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size);
129 
130 /**
131  * Create and initialize a AVIOContext for accessing the
132  * resource referenced by the URLContext h.
133  * @note When the URLContext h has been opened in read+write mode, the
134  * AVIOContext can be used only for writing.
135  *
136  * @param s Used to return the pointer to the created AVIOContext.
137  * In case of failure the pointed to value is set to NULL.
138  * @return >= 0 in case of success, a negative value corresponding to an
139  * AVERROR code in case of failure
140  */
142 
143 /**
144  * Open a write-only fake memory stream. The written data is not stored
145  * anywhere - this is only used for measuring the amount of data
146  * written.
147  *
148  * @param s new IO context
149  * @return zero if no error.
150  */
152 
153 int ffio_open_whitelist(AVIOContext **s, const char *url, int flags,
155  const char *whitelist, const char *blacklist);
156 
157 /**
158  * Close a null buffer.
159  *
160  * @param s an IO context opened by ffio_open_null_buf
161  * @return the number of bytes written to the null buffer
162  */
164 
165 /**
166  * Free a dynamic buffer.
167  *
168  * @param s a pointer to an IO context opened by avio_open_dyn_buf()
169  */
171 
172 #endif /* AVFORMAT_AVIO_INTERNAL_H */
uint64_t ffio_read_varlen(AVIOContext *bc)
Definition: aviobuf.c:832
const char * s
Definition: avisynth_c.h:768
Bytestream IO Context.
Definition: avio.h:147
Buffered I/O operations.
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
int ffio_close_null_buf(AVIOContext *s)
Close a null buffer.
Definition: aviobuf.c:1336
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:989
int ffio_read_size(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:653
const char * b
Definition: vf_curves.c:113
int ffio_limit(AVIOContext *s, int size)
Definition: utils.c:197
void avio_wl32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:346
uint8_t
unsigned long ff_crcEDB88320_update(unsigned long checksum, const uint8_t *buf, unsigned int len)
Definition: aviobuf.c:563
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:661
const AVClass ff_avio_class
Definition: aviobuf.c:69
ptrdiff_t size
Definition: opengl_enc.c:101
static av_always_inline void ffio_wfourcc(AVIOContext *pb, const uint8_t *s)
Definition: avio_internal.h:66
const OptionDef options[]
Definition: ffserver.c:3969
Callback for checking whether to abort blocking functions.
Definition: avio.h:50
const AVIOInterruptCB int_cb
Definition: ffmpeg.c:457
int ffio_set_buf_size(AVIOContext *s, int buf_size)
Definition: aviobuf.c:959
int ffio_read_partial(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:673
static const uint8_t offset[127][2]
Definition: vf_spp.c:92
GLsizei count
Definition: opengl_enc.c:109
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:583
void ffio_fill(AVIOContext *s, int b, int count)
Definition: aviobuf.c:190
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:1271
unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf, unsigned int len)
Definition: aviobuf.c:557
unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf, unsigned int len)
Definition: aviobuf.c:569
static volatile int checksum
Definition: adler32.c:28
void ffio_free_dyn_buf(AVIOContext **s)
Free a dynamic buffer.
Definition: aviobuf.c:1306
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
void * buf
Definition: avisynth_c.h:690
Definition: url.h:38
Describe the class of an AVClass context structure.
Definition: log.h:67
unsigned long ffio_get_checksum(AVIOContext *s)
Definition: aviobuf.c:575
int ffio_open_null_buf(AVIOContext **s)
Open a write-only fake memory stream.
Definition: aviobuf.c:1326
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:1038
static int flags
Definition: cpu.c:47
int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size)
Ensures that the requested seekback buffer size will be available.
Definition: aviobuf.c:930
int ffio_init_context(AVIOContext *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
static double c[64]
int len
int ffio_fdopen(AVIOContext **s, URLContext *h)
Create and initialize a AVIOContext for accessing the resource referenced by the URLContext h...
Definition: aviobuf.c:877
unbuffered private I/O API
#define av_always_inline
Definition: attributes.h:39
#define MKTAG(a, b, c, d)
Definition: common.h:342
static int write_packet(AVFormatContext *s1, AVPacket *pkt)
Definition: v4l2enc.c:86
GLuint buffer
Definition: opengl_enc.c:102