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

   1 #ifndef foomemblockqhfoo
   2 #define foomemblockqhfoo
   3
   4 /***
   5   This file is part of PulseAudio.
   6
   7   Copyright 2004-2006 Lennart Poettering
   8
   9   PulseAudio is free software; you can redistribute it and/or modify
  10   it under the terms of the GNU Lesser General Public License as
  11   published by the Free Software Foundation; either version 2 of the
  12   License, or (at your option) any later version.
  13
  14   PulseAudio is distributed in the hope that it will be useful, but
  15   WITHOUT ANY WARRANTY; without even the implied warranty of
  16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17   General Public License for more details.
  18
  19   You should have received a copy of the GNU Lesser General Public
  20   License along with PulseAudio; if not, write to the Free Software
  21   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  22   USA.
  23 ***/
  24
  25 #include <sys/types.h>
  26 #include <inttypes.h>
  27
  28 #include <pulsecore/memblock.h>
  29 #include <pulsecore/memchunk.h>
  30 #include <pulse/def.h>
  31
  32 /* A memblockq is a queue of pa_memchunks (yepp, the name is not
  33  * perfect). It is similar to the ring buffers used by most other
  34  * audio software. In contrast to a ring buffer this memblockq data
  35  * type doesn't need to copy any data around, it just maintains
  36  * references to reference counted memory blocks. */
  37
  38 typedef struct pa_memblockq pa_memblockq;
  39
  40
  41 /* Parameters:
  42
  43    - idx:       start value for both read and write index
  44
  45    - maxlength: maximum length of queue. If more data is pushed into
  46                 the queue, the operation will fail. Must not be 0.
  47
  48    - tlength:   the target length of the queue. Pass 0 for the default.
  49
  50    - base:      a base value for all metrics. Only multiples of this value
  51                 are popped from the queue or should be pushed into
  52                 it. Must not be 0.
  53
  54    - prebuf:    If the queue runs empty wait until this many bytes are in
  55                 queue again before passing the first byte out. If set
  56                 to 0 pa_memblockq_pop() will return a silence memblock
  57                 if no data is in the queue and will never fail. Pass
  58                 (size_t) -1 for the default.
  59
  60    - minreq:    pa_memblockq_missing() will only return values greater
  61                 than this value. Pass 0 for the default.
  62
  63    - maxrewind: how many bytes of history to keep in the queue
  64
  65    - silence:   return this memchunk 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         size_t maxrewind,
  75         pa_memchunk *silence);
  76
  77 void pa_memblockq_free(pa_memblockq*bq);
  78
  79 /* Push a new memory chunk into the queue.  */
  80 int pa_memblockq_push(pa_memblockq* bq, const pa_memchunk *chunk);
  81
  82 /* Push a new memory chunk into the queue, but filter it through a
  83  * pa_mcalign object. Don't mix this with pa_memblockq_seek() unless
  84  * you know what you do. */
  85 int pa_memblockq_push_align(pa_memblockq* bq, const pa_memchunk *chunk);
  86
  87 /* Return a copy of the next memory chunk in the queue. It is not
  88  * removed from the queue. There are two reasons this function might
  89  * fail: 1. prebuffering is active, 2. queue is empty and no silence
  90  * memblock was passed at initialization. If the queue is not empty,
  91  * but we're currently at a hole in the queue and no silence memblock
  92  * was passed we return the length of the hole in chunk->length. */
  93 int pa_memblockq_peek(pa_memblockq* bq, pa_memchunk *chunk);
  94
  95 /* Drop the specified bytes from the queue. */
  96 void pa_memblockq_drop(pa_memblockq *bq, size_t length);
  97
  98 /* Test if the pa_memblockq is currently readable, that is, more data than base */
  99 pa_bool_t pa_memblockq_is_readable(pa_memblockq *bq);
 100
 101 /* Return the length of the queue in bytes */
 102 size_t pa_memblockq_get_length(pa_memblockq *bq);
 103
 104 /* Return how many bytes are missing in queue to the specified fill amount */
 105 size_t pa_memblockq_missing(pa_memblockq *bq);
 106
 107 /* Return the number of bytes that are missing since the last call to
 108  * this function, reset the internal counter to 0. */
 109 size_t pa_memblockq_pop_missing(pa_memblockq *bq);
 110
 111 /* Directly moves the data from the source memblockq into bq */
 112 int pa_memblockq_splice(pa_memblockq *bq, pa_memblockq *source);
 113
 114 /* Returns the minimal request value */
 115 size_t pa_memblockq_get_minreq(pa_memblockq *bq);
 116
 117 /* Manipulate the write pointer */
 118 void pa_memblockq_seek(pa_memblockq *bq, int64_t offset, pa_seek_mode_t seek);
 119
 120 /* Set the queue to silence, set write index to read index */
 121 void pa_memblockq_flush(pa_memblockq *bq);
 122
 123 /* Get Target length */
 124 size_t pa_memblockq_get_tlength(pa_memblockq *bq);
 125
 126 /* Return the current read index */
 127 int64_t pa_memblockq_get_read_index(pa_memblockq *bq);
 128
 129 /* Return the current write index */
 130 int64_t pa_memblockq_get_write_index(pa_memblockq *bq);
 131
 132 /* Rewind the read index. If the history is shorter than the specified length we'll point to silence afterwards. */
 133 void pa_memblockq_rewind(pa_memblockq *bq, size_t length);
 134
 135 /* Ignore prebuf for now */
 136 void pa_memblockq_prebuf_disable(pa_memblockq *bq);
 137
 138 /* Force prebuf */
 139 void pa_memblockq_prebuf_force(pa_memblockq *bq);
 140
 141 /* Return the maximum length of the queue in bytes */
 142 size_t pa_memblockq_get_maxlength(pa_memblockq *bq);
 143
 144 /* Return the prebuffer length in bytes */
 145 size_t pa_memblockq_get_prebuf(pa_memblockq *bq);
 146
 147 /* Change metrics. Always call in order. */
 148 void pa_memblockq_set_maxlength(pa_memblockq *memblockq, size_t maxlength); /* might modify tlength, prebuf, minreq too */
 149 void pa_memblockq_set_tlength(pa_memblockq *memblockq, size_t tlength); /* might modify minreq, too */
 150 void pa_memblockq_set_prebuf(pa_memblockq *memblockq, size_t prebuf); /* might modify minreq, too */
 151 void pa_memblockq_set_minreq(pa_memblockq *memblockq, size_t minreq);
 152 void pa_memblockq_set_maxrewind(pa_memblockq *memblockq, size_t rewind); /* Set the maximum history size */
 153 void pa_memblockq_set_silence(pa_memblockq *memblockq, pa_memchunk *silence);
 154
 155 /* Call pa_memchunk_willneed() for every chunk in the queue from the current read pointer to the end */
 156 void pa_memblockq_willneed(pa_memblockq *bq);
 157
 158 /* Check whether the memblockq is completely empty, i.e. no data
 159  * neither left nor right of the read pointer, and hence no buffered
 160  * data for the future nor data in the backlog. */
 161 pa_bool_t pa_memblockq_is_empty(pa_memblockq *bq);
 162
 163 void pa_memblockq_silence(pa_memblockq *bq);
 164
 165 /* Check whether we currently are in prebuf state */
 166 pa_bool_t pa_memblockq_prebuf_active(pa_memblockq *bq);
 167
 168 unsigned pa_memblockq_get_nblocks(pa_memblockq *bq);
 169
 170 size_t pa_memblockq_get_base(pa_memblockq *bq);
 171
 172 #endif