/
fifo.c
116 lines (103 loc) · 2.02 KB
/
fifo.c
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
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include "fifo.h"
/* maximum frame count : */
#define BUFFER_SIZE 25
struct Buffer {
void* data[BUFFER_SIZE];
int read; // zeigt auf das Feld mit dem ältesten Inhalt
int write; // zeigt immer auf leeres Feld
int skip;
} buffer = {{}, 0, 0, 0};
pthread_mutex_t mutex;
int BufferInit( int bufsize )
{
int i;
for( i = 0; i < BUFFER_SIZE; i ++ )
{
buffer.data[i] = malloc( bufsize );
if( !buffer.data[i] )
return 1;
}
pthread_mutex_init ( &mutex, NULL );
return 0;
}
void BufferClean( void )
{
int i;
for( i = 0; i < BUFFER_SIZE; i ++ )
{
free( buffer.data[i] );
}
pthread_mutex_destroy( &mutex );
}
void* BufferIn_Start( void )
{
//if (buffer.write >= BUFFER_SIZE)
// buffer.write = 0; // erhöht sicherheit
if( BufferFull() )
return NULL;
return buffer.data[buffer.write];
}
void BufferIn_Finish( void )
{
pthread_mutex_lock (&mutex);
if( !buffer.skip )
{
buffer.write = buffer.write + 1;
if (buffer.write >= BUFFER_SIZE)
buffer.write = 0;
}
else
{
fprintf( stderr, "Dropping buffer\n" );
buffer.skip = 0;
}
pthread_mutex_unlock (&mutex);
}
void* BufferOut_Start( void )
{
if( BufferEmpty() )
return NULL;
return buffer.data[buffer.read];
}
void BufferOut_Finish( void )
{
pthread_mutex_lock (&mutex);
buffer.read = buffer.read + 1;
if (buffer.read >= BUFFER_SIZE)
buffer.read = 0;
pthread_mutex_unlock (&mutex);
}
int BufferFull( void )
{
int val = 0;
pthread_mutex_lock (&mutex);
if ( (buffer.write + 1 == buffer.read) || ((buffer.read == 0) && (buffer.write + 1 == BUFFER_SIZE)) )
{
val = 1;
}
pthread_mutex_unlock (&mutex);
return val;
}
int BufferEmpty( void )
{
int val = 0;
pthread_mutex_lock (&mutex);
if (buffer.read == buffer.write)
{
val = 1;
}
pthread_mutex_unlock (&mutex);
return val;
}
void BufferSkip( void )
{
if( BufferEmpty() )
{
pthread_mutex_lock (&mutex);
buffer.skip = 1;
pthread_mutex_unlock (&mutex);
}
}