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
  27 #include "memblock.h"
  28 #include "memchunk.h"
  29
  30 /* A memblockq is a queue of pa_memchunks (yepp, the name is not
  31  * perfect). It is similar to the ring buffers used by most other
  32  * audio software. In contrast to a ring buffer this memblockq data
  33  * type doesn't need to copy any data around, it just maintains
  34  * references to reference counted memory blocks. */
  35
  36 typedef struct pa_memblockq pa_memblockq;
  37
  38 /* Parameters:
  39    - maxlength: maximum length of queue. If more data is pushed into the queue, data from the front is dropped
  40    - length:    the target length of the queue.
  41    - base:      a base value for all metrics. Only multiples of this value are popped from the queue
  42    - prebuf:    before passing the first byte out, make sure that enough bytes are in the queue
  43    - minreq:    pa_memblockq_missing() will only return values greater than this value
  44 */
  45 pa_memblockq* pa_memblockq_new(size_t maxlength,
  46                                       size_t tlength,
  47                                       size_t base,
  48                                       size_t prebuf,
  49                                       size_t minreq,
  50                                       pa_memblock_stat *s);
  51 void pa_memblockq_free(pa_memblockq*bq);
  52
  53 /* Push a new memory chunk into the queue. Optionally specify a value for future cancellation. */
  54 void pa_memblockq_push(pa_memblockq* bq, const pa_memchunk *chunk, size_t delta);
  55
  56 /* Same as pa_memblockq_push(), however chunks are filtered through a mcalign object, and thus aligned to multiples of base */
  57 void pa_memblockq_push_align(pa_memblockq* bq, const pa_memchunk *chunk, size_t delta);
  58
  59 /* Return a copy of the next memory chunk in the queue. It is not removed from the queue */
  60 int pa_memblockq_peek(pa_memblockq* bq, pa_memchunk *chunk);
  61
  62 /* Drop the specified bytes from the queue, only valid aufter pa_memblockq_peek() */
  63 void pa_memblockq_drop(pa_memblockq *bq, const pa_memchunk *chunk, size_t length);
  64
  65 /* Drop the specified bytes from the queue */
  66 void pa_memblockq_skip(pa_memblockq *bq, size_t length);
  67
  68 /* Shorten the pa_memblockq to the specified length by dropping data at the end of the queue */
  69 void pa_memblockq_shorten(pa_memblockq *bq, size_t length);
  70
  71 /* Empty the pa_memblockq */
  72 void pa_memblockq_empty(pa_memblockq *bq);
  73
  74 /* Test if the pa_memblockq is currently readable, that is, more data than base */
  75 int pa_memblockq_is_readable(pa_memblockq *bq);
  76
  77 /* Test if the pa_memblockq is currently writable for the specified amount of bytes */
  78 int pa_memblockq_is_writable(pa_memblockq *bq, size_t length);
  79
  80 /* Return the length of the queue in bytes */
  81 uint32_t pa_memblockq_get_length(pa_memblockq *bq);
  82
  83 /* Return how many bytes are missing in queue to the specified fill amount */
  84 uint32_t pa_memblockq_missing(pa_memblockq *bq);
  85
  86 /* Returns the minimal request value */
  87 uint32_t pa_memblockq_get_minreq(pa_memblockq *bq);
  88
  89 /* Force disabling of pre-buf even when the pre-buffer is not yet filled */
  90 void pa_memblockq_prebuf_disable(pa_memblockq *bq);
  91
  92 /* Reenable pre-buf to the initial level */
  93 void pa_memblockq_prebuf_reenable(pa_memblockq *bq);
  94
  95 /* Manipulate the write pointer */
  96 void pa_memblockq_seek(pa_memblockq *bq, size_t delta);
  97
  98 /* Flush the queue */
  99 void pa_memblockq_flush(pa_memblockq *bq);
 100
 101 /* Get Target length */
 102 uint32_t pa_memblockq_get_tlength(pa_memblockq *bq);
 103
 104 #endif