aboutsummaryrefslogtreecommitdiffstats
path: root/src/outputBuffer.c
blob: d89dcb308ac34cdc355d3a06988adaaf6662dadc (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
/* the Music Player Daemon (MPD)
 * Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
 * This project's homepage is: http://www.musicpd.org
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "outputBuffer.h"
#include "notify.h"
#include "utils.h"

#include <assert.h>
#include <string.h>

struct output_buffer ob;

void
ob_init(unsigned int size, struct notify *notify)
{
	assert(size > 0);

	ob.chunks = xmalloc(size * sizeof(*ob.chunks));
	ob.size = size;
	ob.begin = 0;
	ob.end = 0;
	ob.lazy = 0;
	ob.notify = notify;
	ob.chunks[0].chunkSize = 0;
}

void ob_free(void)
{
	assert(ob.chunks != NULL);
	free(ob.chunks);
}

void ob_clear(void)
{
	ob.end = ob.begin;
	ob.chunks[ob.end].chunkSize = 0;
}

/** return the index of the chunk after i */
static inline unsigned successor(unsigned i)
{
	assert(i <= ob.size);

	++i;
	return i == ob.size ? 0 : i;
}

/**
 * Mark the tail chunk as "full" and wake up the player if is waiting
 * for the decoder.
 */
static void output_buffer_expand(unsigned i)
{
	int was_empty = ob.notify != NULL && (!ob.lazy || ob_is_empty());

	assert(i == (ob.end + 1) % ob.size);
	assert(i != ob.end);

	ob.end = i;
	ob.chunks[i].chunkSize = 0;
	if (was_empty)
		/* if the buffer was empty, the player thread might be
		   waiting for us; wake it up now that another decoded
		   buffer has become available. */
		notify_signal(ob.notify);
}

void ob_flush(void)
{
	ob_chunk *chunk = ob_get_chunk(ob.end);

	if (chunk->chunkSize > 0) {
		unsigned int next = successor(ob.end);
		if (next == ob.begin)
			/* all buffers are full; we have to wait for
			   the player to free one, so don't flush
			   right now */
			return;

		output_buffer_expand(next);
	}
}

void ob_set_lazy(int lazy)
{
	ob.lazy = lazy;
}

int ob_is_empty(void)
{
	return ob.begin == ob.end;
}

void ob_shift(void)
{
	assert(ob.begin != ob.end);
	assert(ob.begin < ob.size);

	ob.begin = successor(ob.begin);
}

unsigned int ob_relative(const unsigned i)
{
	if (i >= ob.begin)
		return i - ob.begin;
	else
		return i + ob.size - ob.begin;
}

unsigned ob_available(void)
{
	return ob_relative(ob.end);
}

int ob_absolute(const unsigned relative)
{
	unsigned i, max;

	max = ob.end;
	if (max < ob.begin)
		max += ob.size;
	i = (unsigned)ob.begin + relative;
	if (i >= max)
		return -1;

	if (i >= ob.size)
		i -= ob.size;

	return (int)i;
}

ob_chunk * ob_get_chunk(const unsigned i)
{
	assert(i < ob.size);

	return &ob.chunks[i];
}

/**
 * Return the tail chunk which has room for additional data.
 *
 * @return the chunk which has room for more data; NULL if there is no
 * room.
 */
static ob_chunk *tail_chunk(float data_time, uint16_t bitRate)
{
	unsigned int next;
	ob_chunk *chunk;

	chunk = ob_get_chunk(ob.end);
	assert(chunk->chunkSize <= sizeof(chunk->data));
	if (chunk->chunkSize == sizeof(chunk->data)) {
		/* this chunk is full; allocate a new chunk */
		next = successor(ob.end);
		if (ob.begin == next)
			/* no chunks available */
			return NULL;

		output_buffer_expand(next);
		chunk = ob_get_chunk(next);
		assert(chunk->chunkSize == 0);
	}

	if (chunk->chunkSize == 0) {
		/* if the chunk is empty, nobody has set bitRate and
		   times yet */

		chunk->bitRate = bitRate;
		chunk->times = data_time;
	}

	return chunk;
}

size_t ob_append(const void *data0, size_t datalen,
		 float data_time, uint16_t bitRate)
{
	const unsigned char *data = data0;
	size_t ret = 0, dataToSend;
	ob_chunk *chunk = NULL;

	while (datalen) {
		chunk = tail_chunk(data_time, bitRate);
		if (chunk == NULL)
			return ret;

		dataToSend = sizeof(chunk->data) - chunk->chunkSize;
		if (dataToSend > datalen)
			dataToSend = datalen;

		memcpy(chunk->data + chunk->chunkSize, data, dataToSend);
		chunk->chunkSize += dataToSend;
		datalen -= dataToSend;
		data += dataToSend;
		ret += dataToSend;
	}

	if (chunk != NULL && chunk->chunkSize == sizeof(chunk->data))
		ob_flush();

	return ret;
}

void ob_skip(unsigned num)
{
	int i = ob_absolute(num);
	if (i >= 0)
		ob.begin = i;
}