mp3dec: decode more data from Info header
[libav.git] / libavformat / avio_internal.h
1 /*
2 *
3 * This file is part of Libav.
4 *
5 * Libav 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.
9 *
10 * Libav 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.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with Libav; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19
20 #ifndef AVFORMAT_AVIO_INTERNAL_H
21 #define AVFORMAT_AVIO_INTERNAL_H
22
23 #include "avio.h"
24 #include "url.h"
25
26 #include "libavutil/log.h"
27
28 extern const AVClass ffio_url_class;
29
30 int ffio_init_context(AVIOContext *s,
31 unsigned char *buffer,
32 int buffer_size,
33 int write_flag,
34 void *opaque,
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));
38
39
40 /**
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.
44 * @param s 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
47 * underlying buffer
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
54 */
55 int ffio_read_indirect(AVIOContext *s, unsigned char *buf, int size, const unsigned char **data);
56
57 /**
58 * Read size bytes from AVIOContext into buf.
59 * This reads at most 1 packet. If that is not enough fewer bytes will be
60 * returned.
61 * @return number of bytes read or AVERROR
62 */
63 int ffio_read_partial(AVIOContext *s, unsigned char *buf, int size);
64
65 void ffio_fill(AVIOContext *s, int b, int count);
66
67 static av_always_inline void ffio_wfourcc(AVIOContext *pb, const uint8_t *s)
68 {
69 avio_wl32(pb, MKTAG(s[0], s[1], s[2], s[3]));
70 }
71
72 /**
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
77 *
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
83 */
84 int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char *buf, int buf_size);
85
86 uint64_t ffio_read_varlen(AVIOContext *bc);
87
88 /** @warning must be called before any I/O */
89 int ffio_set_buf_size(AVIOContext *s, int buf_size);
90
91 void ffio_init_checksum(AVIOContext *s,
92 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
93 unsigned long checksum);
94 unsigned long ffio_get_checksum(AVIOContext *s);
95 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
96 unsigned int len);
97 unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf,
98 unsigned int len);
99
100 /**
101 * Open a write only packetized memory stream with a maximum packet
102 * size of 'max_packet_size'. The stream is stored in a memory buffer
103 * with a big-endian 4 byte header giving the packet size in bytes.
104 *
105 * @param s new IO context
106 * @param max_packet_size maximum packet size (must be > 0)
107 * @return zero if no error.
108 */
109 int ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size);
110
111 /**
112 * Create and initialize a AVIOContext for accessing the
113 * resource referenced by the URLContext h.
114 * @note When the URLContext h has been opened in read+write mode, the
115 * AVIOContext can be used only for writing.
116 *
117 * @param s Used to return the pointer to the created AVIOContext.
118 * In case of failure the pointed to value is set to NULL.
119 * @return 0 in case of success, a negative value corresponding to an
120 * AVERROR code in case of failure
121 */
122 int ffio_fdopen(AVIOContext **s, URLContext *h);
123
124 /**
125 * Open a write-only fake memory stream. The written data is not stored
126 * anywhere - this is only used for measuring the amount of data
127 * written.
128 *
129 * @param s new IO context
130 * @return zero if no error.
131 */
132 int ffio_open_null_buf(AVIOContext **s);
133
134 /**
135 * Close a null buffer.
136 *
137 * @param s an IO context opened by ffio_open_null_buf
138 * @return the number of bytes written to the null buffer
139 */
140 int ffio_close_null_buf(AVIOContext *s);
141
142 #endif /* AVFORMAT_AVIO_INTERNAL_H */