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
|
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
enum {
Buffer_Free,
Buffer_Busy,
Buffer_Full,
Buffer_Done
};
typedef struct
{
int state;
int size;
int iptr;
int optr; // 0 <= optr <= iptr <= size
char *data;
} Buffer;
Buffer *Buffer_new(int size)
{
Buffer *b= (Buffer *)calloc(1, sizeof(Buffer));
if (b)
{
b->state= Buffer_Free;
b->size= size;
if ((b->data= (char *)calloc(1, size)))
return b;
free(b);
}
return 0;
}
void Buffer_delete(Buffer *b)
{
assert(b && b->data);
free(b->data);
free(b);
}
void Buffer_reset(Buffer *b)
{
b->state= Buffer_Free;
b->iptr= b->optr= 0;
}
int Buffer_avail(Buffer *b)
{
return b->iptr - b->optr;
}
int Buffer_free(Buffer *b)
{
return b->size - b->iptr;
}
typedef struct
{
Buffer *input;
Buffer *output;
} DBuffer;
DBuffer *DBuffer_new(int size)
{
DBuffer *d= (DBuffer *)calloc(1, sizeof(DBuffer));
if (d)
{
if ((d->input= Buffer_new(size)))
{
if ((d->output= Buffer_new(size)))
return d;
Buffer_delete(d->input);
}
free(d);
}
return 0;
}
void DBuffer_delete(DBuffer *d)
{
assert(d && d->input && d->output);
Buffer_delete(d->input);
Buffer_delete(d->output);
free(d);
}
int DBuffer_swap(DBuffer *d)
{
if (d->input->state == Buffer_Full)
{
Buffer *i= d->output;
Buffer *o= d->input;
d->input= i;
d->output= o;
Buffer_reset(i);
return 1;
}
d->output->state= Buffer_done;
return 0;
}
|
