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
|
/*
* a very simple circular buffer FIFO implementation
* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
* Copyright (c) 2006 Roman Shaposhnik
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "common.h"
#include "fifo.h"
AVFifoBuffer *av_fifo_alloc(unsigned int size)
{
AVFifoBuffer *f = av_mallocz(sizeof(AVFifoBuffer));
if (!f)
return NULL;
f->buffer = av_malloc(size);
f->end = f->buffer + size;
av_fifo_reset(f);
if (!f->buffer)
av_freep(&f);
return f;
}
void av_fifo_free(AVFifoBuffer *f)
{
if (f) {
av_free(f->buffer);
av_free(f);
}
}
void av_fifo_reset(AVFifoBuffer *f)
{
f->wptr = f->rptr = f->buffer;
f->wndx = f->rndx = 0;
}
int av_fifo_size(AVFifoBuffer *f)
{
return (uint32_t)(f->wndx - f->rndx);
}
int av_fifo_space(AVFifoBuffer *f)
{
return f->end - f->buffer - av_fifo_size(f);
}
int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size)
{
unsigned int old_size = f->end - f->buffer;
if (old_size < new_size) {
int len = av_fifo_size(f);
AVFifoBuffer *f2 = av_fifo_alloc(new_size);
if (!f2)
return -1;
av_fifo_generic_read(f, f2->buffer, len, NULL);
f2->wptr += len;
f2->wndx += len;
av_free(f->buffer);
*f = *f2;
av_free(f2);
}
return 0;
}
/* src must NOT be const as it can be a context for func that may need
* updating (like a pointer or byte counter) */
int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size,
int (*func)(void *, void *, int))
{
int total = size;
do {
int len = FFMIN(f->end - f->wptr, size);
if (func) {
if (func(src, f->wptr, len) <= 0)
break;
} else {
memcpy(f->wptr, src, len);
src = (uint8_t *)src + len;
}
// Write memory barrier needed for SMP here in theory
f->wptr += len;
if (f->wptr >= f->end)
f->wptr = f->buffer;
f->wndx += len;
size -= len;
} while (size > 0);
return total - size;
}
int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size,
void (*func)(void *, void *, int))
{
// Read memory barrier needed for SMP here in theory
do {
int len = FFMIN(f->end - f->rptr, buf_size);
if (func)
func(dest, f->rptr, len);
else {
memcpy(dest, f->rptr, len);
dest = (uint8_t *)dest + len;
}
// memory barrier needed for SMP here in theory
av_fifo_drain(f, len);
buf_size -= len;
} while (buf_size > 0);
return 0;
}
/** Discard data from the FIFO. */
void av_fifo_drain(AVFifoBuffer *f, int size)
{
f->rptr += size;
if (f->rptr >= f->end)
f->rptr -= f->end - f->buffer;
f->rndx += size;
}
|
