code.delx.au - pulseaudio/blob - src/pulsecore/memblockq.h

   1 #ifndef foomemblockqhfoo
   2 #define foomemblockqhfoo
   3
   4 /* $Id$ */
   5
   6 /***
   7   This file is part of PulseAudio.
   8
   9   Copyright 2004-2006 Lennart Poettering
  10
  11   PulseAudio is free software; you can redistribute it and/or modify
  12   it under the terms of the GNU Lesser General Public License as
  13   published by the Free Software Foundation; either version 2 of the
  14   License, or (at your option) any later version.
  15
  16   PulseAudio is distributed in the hope that it will be useful, but
  17   WITHOUT ANY WARRANTY; without even the implied warranty of
  18   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  19   General Public License for more details.
  20
  21   You should have received a copy of the GNU Lesser General Public
  22   License along with PulseAudio; if not, write to the Free Software
  23   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  24   USA.
  25 ***/
  26
  27 #include <sys/types.h>
  28 #include <inttypes.h>
  29
  30 #include <pulsecore/memblock.h>
  31 #include <pulsecore/memchunk.h>
  32 #include <pulse/def.h>
  33
  34 /* A memblockq is a queue of pa_memchunks (yepp, the name is not
  35  * perfect). It is similar to the ring buffers used by most other
  36  * audio software. In contrast to a ring buffer this memblockq data
  37  * type doesn't need to copy any data around, it just maintains
  38  * references to reference counted memory blocks. */
  39
  40 typedef struct pa_memblockq pa_memblockq;
  41
  42
  43 /* Parameters:
  44
  45    - idx:       start value for both read and write index
  46
  47    - maxlength: maximum length of queue. If more data is pushed into
  48                 the queue, the operation will fail. Must not be 0.
  49
  50    - tlength:   the target length of the queue. Pass 0 for the default.
  51
  52    - base:      a base value for all metrics. Only multiples of this value
  53                 are popped from the queue or should be pushed into
  54                 it. Must not be 0.
  55
  56    - prebuf:    If the queue runs empty wait until this many bytes are in
  57                 queue again before passing the first byte out. If set
  58                 to 0 pa_memblockq_pop() will return a silence memblock
  59                 if no data is in the queue and will never fail. Pass
  60                 (size_t) -1 for the default.
  61
  62    - minreq:    pa_memblockq_missing() will only return values greater
  63                 than this value. Pass 0 for the default.
  64
  65    - silence:   return this memblock when reading unitialized data
  66 */
  67 pa_memblockq* pa_memblockq_new(
  68         int64_t idx,
  69         size_t maxlength,
  70         size_t tlength,
  71         size_t base,
  72         size_t prebuf,
  73         size_t minreq,
  74         pa_memblock *silence);
  75
  76 void pa_memblockq_free(pa_memblockq*bq);
  77
  78 /* Push a new memory chunk into the queue.  */
  79 int pa_memblockq_push(pa_memblockq* bq, const pa_memchunk *chunk);
  80
  81 /* Push a new memory chunk into the queue, but filter it through a
  82  * pa_mcalign object. Don't mix this with pa_memblockq_seek() unless
  83  * you know what you do. */
  84 int pa_memblockq_push_align(pa_memblockq* bq, const pa_memchunk *chunk);
  85
  86 /* Return a copy of the next memory chunk in the queue. It is not
  87  * removed from the queue. There are two reasons this function might
  88  * fail: 1. prebuffering is active, 2. queue is empty and no silence
  89  * memblock was passed at initialization. If the queue is not empty,
  90  * but we're currently at a hole in the queue and no silence memblock
  91  * was passed we return the length of the hole in chunk->length. */
  92 int pa_memblockq_peek(pa_memblockq* bq, pa_memchunk *chunk);
  93
  94 /* Drop the specified bytes from the queue. */
  95 void pa_memblockq_drop(pa_memblockq *bq, size_t length);
  96
  97 /* Test if the pa_memblockq is currently readable, that is, more data than base */
  98 int pa_memblockq_is_readable(pa_memblockq *bq);
  99
 100 /* Return the length of the queue in bytes */
 101 size_t pa_memblockq_get_length(pa_memblockq *bq);
 102
 103 /* Return how many bytes are missing in queue to the specified fill amount */
 104 size_t pa_memblockq_missing(pa_memblockq *bq);
 105
 106 /* Return the number of bytes that are missing since the last call to
 107  * this function, reset the internal counter to 0. */
 108 size_t pa_memblockq_pop_missing(pa_memblockq *bq);
 109
 110 /* Returns the minimal request value */
 111 size_t pa_memblockq_get_minreq(pa_memblockq *bq);
 112
 113 /* Manipulate the write pointer */
 114 void pa_memblockq_seek(pa_memblockq *bq, int64_t offset, pa_seek_mode_t seek);
 115
 116 /* Set the queue to silence, set write index to read index */
 117 void pa_memblockq_flush(pa_memblockq *bq);
 118
 119 /* Get Target length */
 120 size_t pa_memblockq_get_tlength(pa_memblockq *bq);
 121
 122 /* Return the current read index */
 123 int64_t pa_memblockq_get_read_index(pa_memblockq *bq);
 124
 125 /* Return the current write index */
 126 int64_t pa_memblockq_get_write_index(pa_memblockq *bq);
 127
 128 /* Shorten the pa_memblockq to the specified length by dropping data
 129  * at the read end of the queue. The read index is increased until the
 130  * queue has the specified length */
 131 void pa_memblockq_shorten(pa_memblockq *bq, size_t length);
 132
 133 /* Ignore prebuf for now */
 134 void pa_memblockq_prebuf_disable(pa_memblockq *bq);
 135
 136 /* Force prebuf */
 137 void pa_memblockq_prebuf_force(pa_memblockq *bq);
 138
 139 /* Return the maximum length of the queue in bytes */
 140 size_t pa_memblockq_get_maxlength(pa_memblockq *bq);
 141
 142 /* Return the prebuffer length in bytes */
 143 size_t pa_memblockq_get_prebuf(pa_memblockq *bq);
 144
 145 #endif