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 2.1 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    - name:      name for debugging purposes
  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    - ss:        Sample spec describing the queue contents. Only multiples
  53                 of the frame size as implied by the sample spec are
  54                 popped from the queue or should be pushed into it.
  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    - maxrewind: how many bytes of history to keep in the queue
  66
  67    - silence:   return this memchunk when reading uninitialized data
  68 */
  69 pa_memblockq* pa_memblockq_new(
  70         const char *name,
  71         int64_t idx,
  72         size_t maxlength,
  73         size_t tlength,
  74         const pa_sample_spec *sample_spec,
  75         size_t prebuf,
  76         size_t minreq,
  77         size_t maxrewind,
  78         pa_memchunk *silence);
  79
  80 void pa_memblockq_free(pa_memblockq*bq);
  81
  82 /* Push a new memory chunk into the queue.  */
  83 int pa_memblockq_push(pa_memblockq* bq, const pa_memchunk *chunk);
  84
  85 /* Push a new memory chunk into the queue, but filter it through a
  86  * pa_mcalign object. Don't mix this with pa_memblockq_seek() unless
  87  * you know what you do. */
  88 int pa_memblockq_push_align(pa_memblockq* bq, const pa_memchunk *chunk);
  89
  90 /* Manipulate the write pointer */
  91 void pa_memblockq_seek(pa_memblockq *bq, int64_t offset, pa_seek_mode_t seek, pa_bool_t account);
  92
  93 /* Return a copy of the next memory chunk in the queue. It is not
  94  * removed from the queue. There are two reasons this function might
  95  * fail: 1. prebuffering is active, 2. queue is empty and no silence
  96  * memblock was passed at initialization. If the queue is not empty,
  97  * but we're currently at a hole in the queue and no silence memblock
  98  * was passed we return the length of the hole in chunk->length. */
  99 int pa_memblockq_peek(pa_memblockq* bq, pa_memchunk *chunk);
 100
 101 /* Much like pa_memblockq_peek, but guarantees that the returned chunk
 102  * will have a length of the block size passed. You must configure a
 103  * silence memchunk for this memblockq if you use this call. */
 104 int pa_memblockq_peek_fixed_size(pa_memblockq *bq, size_t block_size, pa_memchunk *chunk);
 105
 106 /* Drop the specified bytes from the queue. */
 107 void pa_memblockq_drop(pa_memblockq *bq, size_t length);
 108
 109 /* Rewind the read index. If the history is shorter than the specified length we'll point to silence afterwards. */
 110 void pa_memblockq_rewind(pa_memblockq *bq, size_t length);
 111
 112 /* Test if the pa_memblockq is currently readable, that is, more data than base */
 113 pa_bool_t pa_memblockq_is_readable(pa_memblockq *bq);
 114
 115 /* Return the length of the queue in bytes */
 116 size_t pa_memblockq_get_length(pa_memblockq *bq);
 117
 118 /* Return how many bytes are missing in queue to the specified fill amount */
 119 size_t pa_memblockq_missing(pa_memblockq *bq);
 120
 121 /* Return the number of bytes that are missing since the last call to
 122  * this function, reset the internal counter to 0. */
 123 size_t pa_memblockq_pop_missing(pa_memblockq *bq);
 124
 125 /* Directly moves the data from the source memblockq into bq */
 126 int pa_memblockq_splice(pa_memblockq *bq, pa_memblockq *source);
 127
 128 /* Set the queue to silence, set write index to read index */
 129 void pa_memblockq_flush_write(pa_memblockq *bq, pa_bool_t account);
 130
 131 /* Set the queue to silence, set write read index to write index*/
 132 void pa_memblockq_flush_read(pa_memblockq *bq);
 133
 134 /* Ignore prebuf for now */
 135 void pa_memblockq_prebuf_disable(pa_memblockq *bq);
 136
 137 /* Force prebuf */
 138 void pa_memblockq_prebuf_force(pa_memblockq *bq);
 139
 140 /* Return the maximum length of the queue in bytes */
 141 size_t pa_memblockq_get_maxlength(pa_memblockq *bq);
 142
 143 /* Get Target length */
 144 size_t pa_memblockq_get_tlength(pa_memblockq *bq);
 145
 146 /* Return the prebuffer length in bytes */
 147 size_t pa_memblockq_get_prebuf(pa_memblockq *bq);
 148
 149 /* Returns the minimal request value */
 150 size_t pa_memblockq_get_minreq(pa_memblockq *bq);
 151
 152 /* Returns the maximal rewind value */
 153 size_t pa_memblockq_get_maxrewind(pa_memblockq *bq);
 154
 155 /* Return the base unit in bytes */
 156 size_t pa_memblockq_get_base(pa_memblockq *bq);
 157
 158 /* Return the current read index */
 159 int64_t pa_memblockq_get_read_index(pa_memblockq *bq);
 160
 161 /* Return the current write index */
 162 int64_t pa_memblockq_get_write_index(pa_memblockq *bq);
 163
 164 /* Change metrics. Always call in order. */
 165 void pa_memblockq_set_maxlength(pa_memblockq *memblockq, size_t maxlength); /* might modify tlength, prebuf, minreq too */
 166 void pa_memblockq_set_tlength(pa_memblockq *memblockq, size_t tlength); /* might modify minreq, too */
 167 void pa_memblockq_set_prebuf(pa_memblockq *memblockq, size_t prebuf); /* might modify minreq, too */
 168 void pa_memblockq_set_minreq(pa_memblockq *memblockq, size_t minreq);
 169 void pa_memblockq_set_maxrewind(pa_memblockq *memblockq, size_t maxrewind); /* Set the maximum history size */
 170 void pa_memblockq_set_silence(pa_memblockq *memblockq, pa_memchunk *silence);
 171
 172 /* Apply the data from pa_buffer_attr */
 173 void pa_memblockq_apply_attr(pa_memblockq *memblockq, const pa_buffer_attr *a);
 174 void pa_memblockq_get_attr(pa_memblockq *bq, pa_buffer_attr *a);
 175
 176 /* Call pa_memchunk_will_need() for every chunk in the queue from the current read pointer to the end */
 177 void pa_memblockq_willneed(pa_memblockq *bq);
 178
 179 /* Check whether the memblockq is completely empty, i.e. no data
 180  * neither left nor right of the read pointer, and hence no buffered
 181  * data for the future nor data in the backlog. */
 182 pa_bool_t pa_memblockq_is_empty(pa_memblockq *bq);
 183
 184 /* Drop everything in the queue, but don't modify the indexes */
 185 void pa_memblockq_silence(pa_memblockq *bq);
 186
 187 /* Check whether we currently are in prebuf state */
 188 pa_bool_t pa_memblockq_prebuf_active(pa_memblockq *bq);
 189
 190 /* Return how many items are currently stored in the queue */
 191 unsigned pa_memblockq_get_nblocks(pa_memblockq *bq);
 192
 193 #endif