apps/buffering.h

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2007 Nicolas Pennequin
  11  *
  12  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19
  20 #ifndef _BUFFERING_H_
  21 #define _BUFFERING_H_
  22
  23 #include <sys/types.h>
  24 #include <stdbool.h>
  25
  26
  27 /* default point to start buffer refill */
  28 #define AUDIO_DEFAULT_WATERMARK      (1024*512)
  29 /* amount of data to read in one read() call */
  30 #define AUDIO_DEFAULT_FILECHUNK      (1024*32)
  31 /* point at which the file buffer will fight for CPU time */
  32 #define AUDIO_FILEBUF_CRITICAL       (1024*128)
  33 /* amount of guess-space to allow for codecs that must hunt and peck
  34  * for their correct seeek target, 32k seems a good size */
  35 #define AUDIO_REBUFFER_GUESS_SIZE    (1024*32)
  36
  37
  38 enum data_type {
  39     TYPE_CODEC,
  40     TYPE_AUDIO,
  41     TYPE_STREAM,
  42     TYPE_ID3,
  43     TYPE_CUESHEET,
  44     TYPE_IMAGE,
  45     TYPE_BUFFER,
  46     TYPE_UNKNOWN,
  47 };
  48
  49 /* Messages available to communicate with the buffering thread */
  50 enum {
  51     Q_BUFFER_HANDLE = 1,    /* Request buffering of a handle */
  52     Q_RESET_HANDLE,         /* (internal) Request resetting of a handle to its
  53                                offset (the offset has to be set beforehand) */
  54 };
  55
  56 struct event_queue          buffering_queue;
  57 struct queue_sender_list    buffering_queue_sender_list;
  58
  59 /* Initialise the buffering subsystem */
  60 bool buffering_init(char *filebuf, size_t filebuflen);
  61
  62 /* Amount of buffer space used */
  63 size_t bufused(void);
  64
  65 /* Reserve space in the buffer for a file */
  66 int bufopen(char *file, size_t offset, enum data_type type);
  67
  68 /* Open a new handle from data that needs to be copied from memory */
  69 int bufalloc(void *src, size_t size, enum data_type type);
  70
  71 /* Close a handle */
  72 int bufclose(int handle_id);
  73
  74 /* Set reading index in handle, relatively to the start of the file */
  75 int bufseek(int handle_id, size_t newpos);
  76
  77 /* Advance the reading index in a handle, relatively to its current position */
  78 int bufadvance(int handle_id, off_t offset);
  79
  80 /* Copy data from a handle to a buffer */
  81 ssize_t bufread(int handle_id, size_t size, void *dest);
  82
  83 /* Obtain a pointer for linear access to a "size" amount of data */
  84 ssize_t bufgetdata(int handle_id, size_t size, void **data);
  85
  86 /* Get a buffer offset from a pointer */
  87 ssize_t get_offset(int handle_id, void *ptr);
  88
  89 #endif