130 lines
3.2 KiB
C
130 lines
3.2 KiB
C
/**
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* OpenAL cross platform audio library
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* Copyright (C) 1999-2007 by authors.
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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* Or go to http://www.gnu.org/copyleft/lgpl.html
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*/
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#include "config.h"
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#include <string.h>
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#include <stdlib.h>
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#include "alMain.h"
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#include "threads.h"
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#include "compat.h"
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struct RingBuffer {
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ALubyte *mem;
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ALsizei frame_size;
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ALsizei length;
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ALint read_pos;
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ALint write_pos;
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almtx_t mtx;
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};
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RingBuffer *CreateRingBuffer(ALsizei frame_size, ALsizei length)
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{
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RingBuffer *ring = calloc(1, sizeof(*ring) + ((length+1) * frame_size));
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if(ring)
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{
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ring->mem = (ALubyte*)(ring+1);
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ring->frame_size = frame_size;
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ring->length = length+1;
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ring->read_pos = 0;
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ring->write_pos = 0;
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almtx_init(&ring->mtx, almtx_plain);
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}
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return ring;
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}
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void DestroyRingBuffer(RingBuffer *ring)
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{
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if(ring)
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{
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almtx_destroy(&ring->mtx);
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free(ring);
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}
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}
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ALsizei RingBufferSize(RingBuffer *ring)
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{
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ALsizei s;
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almtx_lock(&ring->mtx);
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s = (ring->write_pos-ring->read_pos+ring->length) % ring->length;
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almtx_unlock(&ring->mtx);
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return s;
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}
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void WriteRingBuffer(RingBuffer *ring, const ALubyte *data, ALsizei len)
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{
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int remain;
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almtx_lock(&ring->mtx);
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remain = (ring->read_pos-ring->write_pos-1+ring->length) % ring->length;
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if(remain < len) len = remain;
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if(len > 0)
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{
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remain = ring->length - ring->write_pos;
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if(remain < len)
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{
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memcpy(ring->mem+(ring->write_pos*ring->frame_size), data,
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remain*ring->frame_size);
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memcpy(ring->mem, data+(remain*ring->frame_size),
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(len-remain)*ring->frame_size);
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}
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else
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memcpy(ring->mem+(ring->write_pos*ring->frame_size), data,
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len*ring->frame_size);
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ring->write_pos += len;
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ring->write_pos %= ring->length;
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}
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almtx_unlock(&ring->mtx);
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}
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void ReadRingBuffer(RingBuffer *ring, ALubyte *data, ALsizei len)
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{
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int remain;
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almtx_lock(&ring->mtx);
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remain = ring->length - ring->read_pos;
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if(remain < len)
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{
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memcpy(data, ring->mem+(ring->read_pos*ring->frame_size), remain*ring->frame_size);
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memcpy(data+(remain*ring->frame_size), ring->mem, (len-remain)*ring->frame_size);
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}
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else
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memcpy(data, ring->mem+(ring->read_pos*ring->frame_size), len*ring->frame_size);
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ring->read_pos += len;
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ring->read_pos %= ring->length;
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almtx_unlock(&ring->mtx);
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}
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