apps/plugins/mpegplayer/disk_buf.h

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * AV disk buffer declarations
  11  *
  12  * Copyright (c) 2007 Michael Sevakis
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  * KIND, either express or implied.
  21  *
  22  ****************************************************************************/
  23 #ifndef DISK_BUF_H
  24 #define DISK_BUF_H
  25
  26 #define DISK_BUF_PAGE_SHIFT 15  /* 32KB cache lines */
  27 #define DISK_BUF_PAGE_SIZE (1 << DISK_BUF_PAGE_SHIFT)
  28 #define DISK_BUF_PAGE_MASK (DISK_BUF_PAGE_SIZE-1)
  29
  30 enum
  31 {
  32     DISK_BUF_NOTIFY_ERROR = -1,
  33     DISK_BUF_NOTIFY_NULL  =  0,
  34     DISK_BUF_NOTIFY_OK,
  35     DISK_BUF_NOTIFY_TIMEDOUT,
  36     DISK_BUF_NOTIFY_PROCESS_EVENT,
  37     DISK_BUF_NOTIFY_REGISTERED,
  38 };
  39
  40 /** Macros to map file offsets to cached data **/
  41
  42 /* Returns a cache tag given a file offset */
  43 #define MAP_OFFSET_TO_TAG(o) \
  44     ((o) >> DISK_BUF_PAGE_SHIFT)
  45
  46 /* Returns the cache page number given a file offset */
  47 #define MAP_OFFSET_TO_PAGE(o) \
  48     (MAP_OFFSET_TO_TAG(o) % disk_buf.pgcount)
  49
  50 /* Returns the buffer offset given a file offset */
  51 #define MAP_OFFSET_TO_BUFFER(o) \
  52     (MAP_OFFSET_TO_PAGE(o) * DISK_BUF_PAGE_SIZE)
  53
  54 struct dbuf_range
  55 {
  56     uint32_t tag_start;
  57     uint32_t tag_end;
  58     int pg_start;
  59 };
  60
  61 /* This object is an extension of the stream manager and handles some
  62  * playback events as well as buffering */
  63 struct disk_buf
  64 {
  65     unsigned int thread;
  66     struct event_queue *q;
  67     uint8_t *start;   /* Start pointer */
  68     uint8_t *end;     /* End of buffer pointer less MPEG_GUARDBUF_SIZE. The
  69                          guard space is used to wrap data at the buffer start to
  70                          pass continuous data packets */
  71     uint8_t *tail;    /* Location of last data + 1 filled into the buffer */
  72     ssize_t size;     /* The buffer length _not_ including the guard space (end-start) */
  73     int    pgcount;   /* Total number of available cached pages */
  74     uint32_t *cache;  /* Pointer to cache structure - allocated on buffer */
  75     int    in_file;   /* File being read */
  76     ssize_t filesize; /* Size of file in_file in bytes */
  77     int file_pages;   /* Number of pages in file (rounded up) */
  78     off_t offset;     /* Current position (random access) */
  79     off_t win_left;   /* Left edge of buffer window (streaming) */
  80     off_t win_right;  /* Right edge of buffer window (streaming) */
  81     uint32_t time_last; /* Last time watermark was checked */
  82     off_t pos_last;   /* Last position at watermark check time */
  83     ssize_t low_wm;   /* The low watermark for automatic rebuffering */
  84     int status;       /* Status as stream */
  85     int state;        /* Current thread state */
  86     bool need_seek;   /* Need to seek because a read was not contiguous */
  87 };
  88
  89 extern struct disk_buf disk_buf SHAREDBSS_ATTR;
  90
  91 static inline bool disk_buf_is_data_ready(struct stream_hdr *sh,
  92                                           ssize_t margin)
  93 {
  94     /* Data window available? */
  95     off_t right = sh->win_right;
  96
  97     /* Margins past end-of-file can still return true */
  98     if (right > disk_buf.filesize - margin)
  99        right = disk_buf.filesize - margin;
 100
 101     return sh->win_left >= disk_buf.win_left &&
 102            right + margin <= disk_buf.win_right;
 103 }
 104
 105
 106 bool disk_buf_init(void);
 107 void disk_buf_exit(void);
 108
 109 static inline int disk_buf_status(void)
 110     { return disk_buf.status; }
 111
 112 int disk_buf_open(const char *filename);
 113 void disk_buf_close(void);
 114 ssize_t _disk_buf_getbuffer(size_t size, void **pp, void **pwrap,
 115                             size_t *sizewrap);
 116 #define disk_buf_getbuffer(size, pp, pwrap, sizewrap) \
 117     _disk_buf_getbuffer((size), PUN_PTR(void **, (pp)), \
 118                         PUN_PTR(void **, (pwrap)), (sizewrap))
 119 ssize_t disk_buf_read(void *buffer, size_t size);
 120 ssize_t disk_buf_lseek(off_t offset, int whence);
 121
 122 static inline off_t disk_buf_ftell(void)
 123     { return disk_buf.offset; }
 124
 125 static inline ssize_t disk_buf_filesize(void)
 126     { return disk_buf.filesize; }
 127
 128 ssize_t disk_buf_prepare_streaming(off_t pos, size_t len);
 129 ssize_t disk_buf_set_streaming_window(off_t left, off_t right);
 130 void * disk_buf_offset2ptr(off_t offset);
 131 int disk_buf_check_streaming_window(off_t left, off_t right);
 132
 133 intptr_t disk_buf_send_msg(long id, intptr_t data);
 134 void disk_buf_post_msg(long id, intptr_t data);
 135 void disk_buf_reply_msg(intptr_t retval);
 136
 137 #endif /* DISK_BUF_H */