1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/Alc/alcRing.c	Tue Oct 25 13:02:31 2011 -0700
     1.3 @@ -0,0 +1,127 @@
     1.4 +/**
     1.5 + * OpenAL cross platform audio library
     1.6 + * Copyright (C) 1999-2007 by authors.
     1.7 + * This library is free software; you can redistribute it and/or
     1.8 + *  modify it under the terms of the GNU Library General Public
     1.9 + *  License as published by the Free Software Foundation; either
    1.10 + *  version 2 of the License, or (at your option) any later version.
    1.11 + *
    1.12 + * This library is distributed in the hope that it will be useful,
    1.13 + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
    1.14 + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    1.15 + *  Library General Public License for more details.
    1.16 + *
    1.17 + * You should have received a copy of the GNU Library General Public
    1.18 + *  License along with this library; if not, write to the
    1.19 + *  Free Software Foundation, Inc., 59 Temple Place - Suite 330,
    1.20 + *  Boston, MA  02111-1307, USA.
    1.21 + * Or go to http://www.gnu.org/copyleft/lgpl.html
    1.22 + */
    1.23 +
    1.24 +#include "config.h"
    1.25 +
    1.26 +#include <string.h>
    1.27 +#include <stdlib.h>
    1.28 +
    1.29 +#include "alMain.h"
    1.30 +
    1.31 +
    1.32 +struct RingBuffer {
    1.33 +    ALubyte *mem;
    1.34 +
    1.35 +    ALsizei frame_size;
    1.36 +    ALsizei length;
    1.37 +    ALint read_pos;
    1.38 +    ALint write_pos;
    1.39 +
    1.40 +    CRITICAL_SECTION cs;
    1.41 +};
    1.42 +
    1.43 +
    1.44 +RingBuffer *CreateRingBuffer(ALsizei frame_size, ALsizei length)
    1.45 +{
    1.46 +    RingBuffer *ring = calloc(1, sizeof(*ring) + ((length+1) * frame_size));
    1.47 +    if(ring)
    1.48 +    {
    1.49 +        ring->mem = (ALubyte*)(ring+1);
    1.50 +
    1.51 +        ring->frame_size = frame_size;
    1.52 +        ring->length = length+1;
    1.53 +        ring->read_pos = 0;
    1.54 +        ring->write_pos = 0;
    1.55 +
    1.56 +        InitializeCriticalSection(&ring->cs);
    1.57 +    }
    1.58 +    return ring;
    1.59 +}
    1.60 +
    1.61 +void DestroyRingBuffer(RingBuffer *ring)
    1.62 +{
    1.63 +    if(ring)
    1.64 +    {
    1.65 +        DeleteCriticalSection(&ring->cs);
    1.66 +        free(ring);
    1.67 +    }
    1.68 +}
    1.69 +
    1.70 +ALsizei RingBufferSize(RingBuffer *ring)
    1.71 +{
    1.72 +    ALsizei s;
    1.73 +
    1.74 +    EnterCriticalSection(&ring->cs);
    1.75 +    s = (ring->write_pos-ring->read_pos+ring->length) % ring->length;
    1.76 +    LeaveCriticalSection(&ring->cs);
    1.77 +
    1.78 +    return s;
    1.79 +}
    1.80 +
    1.81 +void WriteRingBuffer(RingBuffer *ring, const ALubyte *data, ALsizei len)
    1.82 +{
    1.83 +    int remain;
    1.84 +
    1.85 +    EnterCriticalSection(&ring->cs);
    1.86 +
    1.87 +    remain = (ring->read_pos-ring->write_pos-1+ring->length) % ring->length;
    1.88 +    if(remain < len) len = remain;
    1.89 +
    1.90 +    if(len > 0)
    1.91 +    {
    1.92 +        remain = ring->length - ring->write_pos;
    1.93 +        if(remain < len)
    1.94 +        {
    1.95 +            memcpy(ring->mem+(ring->write_pos*ring->frame_size), data,
    1.96 +                   remain*ring->frame_size);
    1.97 +            memcpy(ring->mem, data+(remain*ring->frame_size),
    1.98 +                   (len-remain)*ring->frame_size);
    1.99 +        }
   1.100 +        else
   1.101 +            memcpy(ring->mem+(ring->write_pos*ring->frame_size), data,
   1.102 +                   len*ring->frame_size);
   1.103 +
   1.104 +        ring->write_pos += len;
   1.105 +        ring->write_pos %= ring->length;
   1.106 +    }
   1.107 +
   1.108 +    LeaveCriticalSection(&ring->cs);
   1.109 +}
   1.110 +
   1.111 +void ReadRingBuffer(RingBuffer *ring, ALubyte *data, ALsizei len)
   1.112 +{
   1.113 +    int remain;
   1.114 +
   1.115 +    EnterCriticalSection(&ring->cs);
   1.116 +
   1.117 +    remain = ring->length - ring->read_pos;
   1.118 +    if(remain < len)
   1.119 +    {
   1.120 +        memcpy(data, ring->mem+(ring->read_pos*ring->frame_size), remain*ring->frame_size);
   1.121 +        memcpy(data+(remain*ring->frame_size), ring->mem, (len-remain)*ring->frame_size);
   1.122 +    }
   1.123 +    else
   1.124 +        memcpy(data, ring->mem+(ring->read_pos*ring->frame_size), len*ring->frame_size);
   1.125 +
   1.126 +    ring->read_pos += len;
   1.127 +    ring->read_pos %= ring->length;
   1.128 +
   1.129 +    LeaveCriticalSection(&ring->cs);
   1.130 +}