1/* 2 * 3 * This file is part of FFmpeg. 4 * 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. 9 * 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. 14 * 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 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 28extern const AVClass ffio_url_class; 29 30int 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 */ 55int 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 */ 63int ffio_read_partial(AVIOContext *s, unsigned char *buf, int size); 64 65void ffio_fill(AVIOContext *s, int b, int count); 66 67static 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 */ 84int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char **buf, int buf_size); 85 86uint64_t ffio_read_varlen(AVIOContext *bc); 87 88/** @warning must be called before any I/O */ 89int ffio_set_buf_size(AVIOContext *s, int buf_size); 90 91/** 92 * Ensures that the requested seekback buffer size will be available 93 * 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 guarantee is lost. 97 */ 98int ffio_ensure_seekback(AVIOContext *s, int buf_size); 99 100int ffio_limit(AVIOContext *s, int size); 101 102void ffio_init_checksum(AVIOContext *s, 103 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len), 104 unsigned long checksum); 105unsigned long ffio_get_checksum(AVIOContext *s); 106unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf, 107 unsigned int len); 108unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf, 109 unsigned int len); 110 111/** 112 * Open a write only packetized memory stream with a maximum packet 113 * size of 'max_packet_size'. The stream is stored in a memory buffer 114 * with a big-endian 4 byte header giving the packet size in bytes. 115 * 116 * @param s new IO context 117 * @param max_packet_size maximum packet size (must be > 0) 118 * @return zero if no error. 119 */ 120int ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size); 121 122/** 123 * Create and initialize a AVIOContext for accessing the 124 * resource referenced by the URLContext h. 125 * @note When the URLContext h has been opened in read+write mode, the 126 * AVIOContext can be used only for writing. 127 * 128 * @param s Used to return the pointer to the created AVIOContext. 129 * In case of failure the pointed to value is set to NULL. 130 * @return >= 0 in case of success, a negative value corresponding to an 131 * AVERROR code in case of failure 132 */ 133int ffio_fdopen(AVIOContext **s, URLContext *h); 134 135/** 136 * Open a write-only fake memory stream. The written data is not stored 137 * anywhere - this is only used for measuring the amount of data 138 * written. 139 * 140 * @param s new IO context 141 * @return zero if no error. 142 */ 143int ffio_open_null_buf(AVIOContext **s); 144 145/** 146 * Close a null buffer. 147 * 148 * @param s an IO context opened by ffio_open_null_buf 149 * @return the number of bytes written to the null buffer 150 */ 151int ffio_close_null_buf(AVIOContext *s); 152 153#endif /* AVFORMAT_AVIO_INTERNAL_H */ 154