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 int ffio_init_context(AVIOContext *s,
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 void ffio_fill(AVIOContext *s, int b, int count);
57
ffio_wfourcc(AVIOContext * pb,const uint8_t * s)58 static av_always_inline void ffio_wfourcc(AVIOContext *pb, const uint8_t *s)
59 {
60 avio_wl32(pb, MKTAG(s[0], s[1], s[2], s[3]));
61 }
62
63 /**
64 * Rewind the AVIOContext using the specified buffer containing the first buf_size bytes of the file.
65 * Used after probing to avoid seeking.
66 * Joins buf and s->buffer, taking any overlap into consideration.
67 * @note s->buffer must overlap with buf or they can't be joined and the function fails
68 *
69 * @param s The read-only AVIOContext to rewind
70 * @param buf The probe buffer containing the first buf_size bytes of the file
71 * @param buf_size The size of buf
72 * @return >= 0 in case of success, a negative value corresponding to an
73 * AVERROR code in case of failure
74 */
75 int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char **buf, int buf_size);
76
77 uint64_t ffio_read_varlen(AVIOContext *bc);
78
79 /**
80 * Read size bytes from AVIOContext into buf.
81 * Check that exactly size bytes have been read.
82 * @return number of bytes read or AVERROR
83 */
84 int ffio_read_size(AVIOContext *s, unsigned char *buf, int size);
85
86 /** @warning must be called before any I/O */
87 int ffio_set_buf_size(AVIOContext *s, int buf_size);
88
89 /**
90 * Reallocate a given buffer for AVIOContext.
91 *
92 * @param s the AVIOContext to realloc.
93 * @param buf_size required new buffer size.
94 * @return 0 on success, a negative AVERROR on failure.
95 */
96 int ffio_realloc_buf(AVIOContext *s, int buf_size);
97
98 /**
99 * Ensures that the requested seekback buffer size will be available
100 *
101 * Will ensure that when reading sequentially up to buf_size, seeking
102 * within the current pos and pos+buf_size is possible.
103 * Once the stream position moves outside this window or another
104 * ffio_ensure_seekback call requests a buffer outside this window this
105 * guarantee is lost.
106 */
107 int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size);
108
109 int ffio_limit(AVIOContext *s, int size);
110
111 void ffio_init_checksum(AVIOContext *s,
112 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
113 unsigned long checksum);
114 unsigned long ffio_get_checksum(AVIOContext *s);
115 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
116 unsigned int len);
117 unsigned long ff_crcEDB88320_update(unsigned long checksum, const uint8_t *buf,
118 unsigned int len);
119 unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf,
120 unsigned int len);
121
122 /**
123 * Open a write only packetized memory stream with a maximum packet
124 * size of 'max_packet_size'. The stream is stored in a memory buffer
125 * with a big-endian 4 byte header giving the packet size in bytes.
126 *
127 * @param s new IO context
128 * @param max_packet_size maximum packet size (must be > 0)
129 * @return zero if no error.
130 */
131 int ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size);
132
133 /**
134 * Create and initialize a AVIOContext for accessing the
135 * resource referenced by the URLContext h.
136 * @note When the URLContext h has been opened in read+write mode, the
137 * AVIOContext can be used only for writing.
138 *
139 * @param s Used to return the pointer to the created AVIOContext.
140 * In case of failure the pointed to value is set to NULL.
141 * @return >= 0 in case of success, a negative value corresponding to an
142 * AVERROR code in case of failure
143 */
144 int ffio_fdopen(AVIOContext **s, URLContext *h);
145
146 /**
147 * Return the URLContext associated with the AVIOContext
148 *
149 * @param s IO context
150 * @return pointer to URLContext or NULL.
151 */
152 URLContext *ffio_geturlcontext(AVIOContext *s);
153
154 /**
155 * Open a write-only fake memory stream. The written data is not stored
156 * anywhere - this is only used for measuring the amount of data
157 * written.
158 *
159 * @param s new IO context
160 * @return zero if no error.
161 */
162 int ffio_open_null_buf(AVIOContext **s);
163
164 int ffio_open_whitelist(AVIOContext **s, const char *url, int flags,
165 const AVIOInterruptCB *int_cb, AVDictionary **options,
166 const char *whitelist, const char *blacklist);
167
168 /**
169 * Close a null buffer.
170 *
171 * @param s an IO context opened by ffio_open_null_buf
172 * @return the number of bytes written to the null buffer
173 */
174 int ffio_close_null_buf(AVIOContext *s);
175
176 /**
177 * Reset a dynamic buffer.
178 *
179 * Resets everything, but keeps the allocated buffer for later use.
180 */
181 void ffio_reset_dyn_buf(AVIOContext *s);
182
183 /**
184 * Free a dynamic buffer.
185 *
186 * @param s a pointer to an IO context opened by avio_open_dyn_buf()
187 */
188 void ffio_free_dyn_buf(AVIOContext **s);
189
190 #endif /* AVFORMAT_AVIO_INTERNAL_H */
191