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comparison ext/openal-soft/Alc/alcRing.c @ 0:4a0efb7baf70

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* Datasets becomes the new trunk and retires after that :-)
author mvbarracuda@33b003aa-7bff-0310-803a-e67f0ece8222
date Sun, 29 Jun 2008 18:44:17 +0000
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-1:000000000000 0:4a0efb7baf70
1 /**
2 * OpenAL cross platform audio library
3 * Copyright (C) 1999-2007 by authors.
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
18 * Or go to http://www.gnu.org/copyleft/lgpl.html
19 */
20
21 #include "config.h"
22
23 #include <string.h>
24 #include <stdlib.h>
25
26 #include "alMain.h"
27
28
29 struct RingBuffer {
30 ALubyte *mem;
31
32 ALsizei frame_size;
33 ALsizei length;
34 ALint read_pos;
35 ALint write_pos;
36
37 CRITICAL_SECTION cs;
38 };
39
40
41 RingBuffer *CreateRingBuffer(ALsizei frame_size, ALsizei length)
42 {
43 RingBuffer *ring = calloc(1, sizeof(*ring));
44 if(ring)
45 {
46 ring->frame_size = frame_size;
47 ring->length = length+1;
48 ring->write_pos = 1;
49 ring->mem = malloc((length+1)*frame_size);
50 if(!ring->mem)
51 {
52 free(ring);
53 ring = NULL;
54 }
55
56 InitializeCriticalSection(&ring->cs);
57 }
58 return ring;
59 }
60
61 void DestroyRingBuffer(RingBuffer *ring)
62 {
63 if(ring)
64 {
65 DeleteCriticalSection(&ring->cs);
66 free(ring->mem);
67 free(ring);
68 }
69 }
70
71 ALsizei RingBufferSize(RingBuffer *ring)
72 {
73 return (ring->write_pos-ring->read_pos-1+ring->length) % ring->length;
74 }
75
76 void WriteRingBuffer(RingBuffer *ring, const ALubyte *data, ALsizei len)
77 {
78 int remain = ring->length - ring->write_pos;
79
80 EnterCriticalSection(&ring->cs);
81
82 if((ring->read_pos-ring->write_pos+ring->length)%ring->length < len)
83 ring->read_pos = (ring->write_pos+len) % ring->length;
84
85 if(remain < len)
86 {
87 memcpy(ring->mem+(ring->write_pos*ring->frame_size), data, remain*ring->frame_size);
88 memcpy(ring->mem, data+(remain*ring->frame_size), (len-remain)*ring->frame_size);
89 }
90 else
91 memcpy(ring->mem+(ring->write_pos*ring->frame_size), data, len*ring->frame_size);
92
93 ring->write_pos += len;
94 ring->write_pos %= ring->length;
95
96 LeaveCriticalSection(&ring->cs);
97 }
98
99 void ReadRingBuffer(RingBuffer *ring, ALubyte *data, ALsizei len)
100 {
101 int remain = ring->length - ring->read_pos;
102
103 EnterCriticalSection(&ring->cs);
104
105 if(remain < len)
106 {
107 memcpy(data, ring->mem+(ring->read_pos*ring->frame_size), remain*ring->frame_size);
108 memcpy(data+(remain*ring->frame_size), ring->mem, (len-remain)*ring->frame_size);
109 }
110 else
111 memcpy(data, ring->mem+(ring->read_pos*ring->frame_size), len*ring->frame_size);
112
113 ring->read_pos += len;
114 ring->read_pos %= ring->length;
115
116 LeaveCriticalSection(&ring->cs);
117 }
118