3 * This file is part of FFmpeg.
5 * FFmpeg is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
10 * FFmpeg is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with FFmpeg; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 #ifndef AVFORMAT_AVIO_INTERNAL_H
21 #define AVFORMAT_AVIO_INTERNAL_H
26 #include "libavutil/log.h"
28 extern const AVClass ffio_url_class;
30 int ffio_init_context(AVIOContext *s,
31 unsigned char *buffer,
35 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
36 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
37 int64_t (*seek)(void *opaque, int64_t offset, int whence));
41 * Read size bytes from AVIOContext, returning a pointer.
42 * Note that the data pointed at by the returned pointer is only
43 * valid until the next call that references the same IO context.
45 * @param buf pointer to buffer into which to assemble the requested
46 * data if it is not available in contiguous addresses in the
48 * @param size number of bytes requested
49 * @param data address at which to store pointer: this will be a
50 * a direct pointer into the underlying buffer if the requested
51 * number of bytes are available at contiguous addresses, otherwise
52 * will be a copy of buf
53 * @return number of bytes read or AVERROR
55 int ffio_read_indirect(AVIOContext *s, unsigned char *buf, int size, const unsigned char **data);
58 * Read size bytes from AVIOContext into buf.
59 * This reads at most 1 packet. If that is not enough fewer bytes will be
61 * @return number of bytes read or AVERROR
63 int ffio_read_partial(AVIOContext *s, unsigned char *buf, int size);
65 void ffio_fill(AVIOContext *s, int b, int count);
67 static av_always_inline void ffio_wfourcc(AVIOContext *pb, const uint8_t *s)
69 avio_wl32(pb, MKTAG(s[0], s[1], s[2], s[3]));
73 * Rewind the AVIOContext using the specified buffer containing the first buf_size bytes of the file.
74 * Used after probing to avoid seeking.
75 * Joins buf and s->buffer, taking any overlap into consideration.
76 * @note s->buffer must overlap with buf or they can't be joined and the function fails
78 * @param s The read-only AVIOContext to rewind
79 * @param buf The probe buffer containing the first buf_size bytes of the file
80 * @param buf_size The size of buf
81 * @return 0 in case of success, a negative value corresponding to an
82 * AVERROR code in case of failure
84 int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char **buf, int buf_size);
86 uint64_t ffio_read_varlen(AVIOContext *bc);
88 /** @warning must be called before any I/O */
89 int ffio_set_buf_size(AVIOContext *s, int buf_size);
92 * Ensures that the requested seekback buffer size will be available
94 * Will ensure that when reading sequentially up to buf_size, seeking
95 * within the current pos and pos+buf_size is possible.
96 * Once the stream position moves outside this window this gurantee is lost.
98 int ffio_ensure_seekback(AVIOContext *s, int buf_size);
100 int ffio_limit(AVIOContext *s, int size);
102 void ffio_init_checksum(AVIOContext *s,
103 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
104 unsigned long checksum);
105 unsigned long ffio_get_checksum(AVIOContext *s);
106 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
110 * Open a write only packetized memory stream with a maximum packet
111 * size of 'max_packet_size'. The stream is stored in a memory buffer
112 * with a big-endian 4 byte header giving the packet size in bytes.
114 * @param s new IO context
115 * @param max_packet_size maximum packet size (must be > 0)
116 * @return zero if no error.
118 int ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size);
121 * Create and initialize a AVIOContext for accessing the
122 * resource referenced by the URLContext h.
123 * @note When the URLContext h has been opened in read+write mode, the
124 * AVIOContext can be used only for writing.
126 * @param s Used to return the pointer to the created AVIOContext.
127 * In case of failure the pointed to value is set to NULL.
128 * @return 0 in case of success, a negative value corresponding to an
129 * AVERROR code in case of failure
131 int ffio_fdopen(AVIOContext **s, URLContext *h);
134 * Open a write-only fake memory stream. The written data is not stored
135 * anywhere - this is only used for measuring the amount of data
138 * @param s new IO context
139 * @return zero if no error.
141 int ffio_open_null_buf(AVIOContext **s);
144 * Close a null buffer.
146 * @param s an IO context opened by ffio_open_null_buf
147 * @return the number of bytes written to the null buffer
149 int ffio_close_null_buf(AVIOContext *s);
151 #endif /* AVFORMAT_AVIO_INTERNAL_H */