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

   1 #ifndef foomemblockqhfoo
   2 #define foomemblockqhfoo
   3
   4 /* $Id$ */
   5
   6 /***
   7   This file is part of polypaudio.
   8
   9   polypaudio 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   polypaudio 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 polypaudio; 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 <polypcore/memblock.h>
  29 #include <polypcore/memchunk.h>
  30 #include <polyp/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    - silence:   return this memblock whzen reading unitialized data
  64 */
  65 pa_memblockq* pa_memblockq_new(
  66         int64_t idx,
  67         size_t maxlength,
  68         size_t tlength,
  69         size_t base,
  70         size_t prebuf,
  71         size_t minreq,
  72         pa_memblock *silence,
  73         pa_memblock_stat *s);
  74
  75 void pa_memblockq_free(pa_memblockq*bq);
  76
  77 /* Push a new memory chunk into the queue.  */
  78 int pa_memblockq_push(pa_memblockq* bq, const pa_memchunk *chunk);
  79
  80 /* Push a new memory chunk into the queue, but filter it through a
  81  * pa_mcalign object. Don't mix this with pa_memblockq_seek() unless
  82  * you know what you do. */
  83 int pa_memblockq_push_align(pa_memblockq* bq, const pa_memchunk *chunk);
  84
  85 /* Return a copy of the next memory chunk in the queue. It is not removed from the queue */
  86 int pa_memblockq_peek(pa_memblockq* bq, pa_memchunk *chunk);
  87
  88 /* Drop the specified bytes from the queue, but only if the first
  89  * chunk in the queue matches the one passed here. If NULL is passed,
  90  * this check isn't done. */
  91 void pa_memblockq_drop(pa_memblockq *bq, const pa_memchunk *chunk, size_t length);
  92
  93 /* Test if the pa_memblockq is currently readable, that is, more data than base */
  94 int pa_memblockq_is_readable(pa_memblockq *bq);
  95
  96 /* Test if the pa_memblockq is currently writable for the specified amount of bytes */
  97 int pa_memblockq_is_writable(pa_memblockq *bq, size_t length);
  98
  99 /* Return the length of the queue in bytes */
 100 size_t pa_memblockq_get_length(pa_memblockq *bq);
 101
 102 /* Return how many bytes are missing in queue to the specified fill amount */
 103 size_t pa_memblockq_missing(pa_memblockq *bq);
 104
 105 /* Returns the minimal request value */
 106 size_t pa_memblockq_get_minreq(pa_memblockq *bq);
 107
 108 /* Manipulate the write pointer */
 109 void pa_memblockq_seek(pa_memblockq *bq, int64_t offset, pa_seek_mode_t seek);
 110
 111 /* Set the queue to silence, set write index to read index */
 112 void pa_memblockq_flush(pa_memblockq *bq);
 113
 114 /* Get Target length */
 115 size_t pa_memblockq_get_tlength(pa_memblockq *bq);
 116
 117 /* Return the current read index */
 118 int64_t pa_memblockq_get_read_index(pa_memblockq *bq);
 119
 120 /* Return the current write index */
 121 int64_t pa_memblockq_get_write_index(pa_memblockq *bq);
 122
 123 /* Shorten the pa_memblockq to the specified length by dropping data
 124  * at the read end of the queue. The read index is increased until the
 125  * queue has the specified length */
 126 void pa_memblockq_shorten(pa_memblockq *bq, size_t length);
 127
 128 /* Ignore prebuf for now */
 129 void pa_memblockq_prebuf_disable(pa_memblockq *bq);
 130
 131 /* Force prebuf */
 132 void pa_memblockq_prebuf_force(pa_memblockq *bq);
 133
 134 /* Return the maximum length of the queue in bytes */
 135 size_t pa_memblockq_get_maxlength(pa_memblockq *bq);
 136
 137 /* Return the prebuffer length in bytes */
 138 size_t pa_memblockq_get_prebuf(pa_memblockq *bq);
 139
 140 #endif