2 * This file is part of Libav.
4 * Libav 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.
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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.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with Libav; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 #ifndef AVFORMAT_AVIO_INTERNAL_H
20 #define AVFORMAT_AVIO_INTERNAL_H
25 #include "libavutil/log.h"
27 extern const AVClass ff_avio_class;
29 int ffio_init_context(AVIOContext *s,
30 unsigned char *buffer,
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));
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.
44 * @param buf pointer to buffer into which to assemble the requested
45 * data if it is not available in contiguous addresses in the
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
54 int ffio_read_indirect(AVIOContext *s, unsigned char *buf, int size, const unsigned char **data);
57 * Read size bytes from AVIOContext into buf.
58 * This reads at most 1 packet. If that is not enough fewer bytes will be
60 * @return number of bytes read or AVERROR
62 int ffio_read_partial(AVIOContext *s, unsigned char *buf, int size);
64 void ffio_fill(AVIOContext *s, int b, int count);
66 static av_always_inline void ffio_wfourcc(AVIOContext *pb, const uint8_t *s)
68 avio_wl32(pb, MKTAG(s[0], s[1], s[2], s[3]));
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
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
83 int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char *buf, int buf_size);
85 uint64_t ffio_read_varlen(AVIOContext *bc);
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
92 int ffio_read_size(AVIOContext *s, unsigned char *buf, int size);
94 /** @warning must be called before any I/O */
95 int ffio_set_buf_size(AVIOContext *s, int buf_size);
97 void ffio_init_checksum(AVIOContext *s,
98 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
99 unsigned long checksum);
100 unsigned long ffio_get_checksum(AVIOContext *s);
101 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
103 unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf,
107 * Open a write only packetized memory stream with a maximum packet
108 * size of 'max_packet_size'. The stream is stored in a memory buffer
109 * with a big-endian 4 byte header giving the packet size in bytes.
111 * @param s new IO context
112 * @param max_packet_size maximum packet size (must be > 0)
113 * @return zero if no error.
115 int ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size);
118 * Create and initialize a AVIOContext for accessing the
119 * resource referenced by the URLContext h.
120 * @note When the URLContext h has been opened in read+write mode, the
121 * AVIOContext can be used only for writing.
123 * @param s Used to return the pointer to the created AVIOContext.
124 * In case of failure the pointed to value is set to NULL.
125 * @return 0 in case of success, a negative value corresponding to an
126 * AVERROR code in case of failure
128 int ffio_fdopen(AVIOContext **s, URLContext *h);
131 * Open a write-only fake memory stream. The written data is not stored
132 * anywhere - this is only used for measuring the amount of data
135 * @param s new IO context
136 * @return zero if no error.
138 int ffio_open_null_buf(AVIOContext **s);
141 * Close a null buffer.
143 * @param s an IO context opened by ffio_open_null_buf
144 * @return the number of bytes written to the null buffer
146 int ffio_close_null_buf(AVIOContext *s);
149 * Free a dynamic buffer.
151 * @param s a pointer to an IO context opened by avio_open_dyn_buf()
153 void ffio_free_dyn_buf(AVIOContext **s);
155 #endif /* AVFORMAT_AVIO_INTERNAL_H */