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