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
|
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
// NOTE: requires the client to define min and max on ints
typedef struct
{
char *data;
int size;
int avail;
int iptr;
int optr;
} Buffer;
Buffer *Buffer_new(int size)
{
Buffer *b= (Buffer *)malloc(sizeof(Buffer));
if (!b)
return 0;
if (!(b->data= (char *)malloc(size)))
{
free(b);
return 0;
}
b->size= size;
b->avail= 0;
b->iptr= 0;
b->optr= 0;
return b;
}
void Buffer_delete(Buffer *b)
{
assert(b && b->data);
free(b->data);
free(b);
}
inline int Buffer_avail(Buffer *b)
{
assert(!(b->avail & 3));
return b->avail;
}
inline int Buffer_free(Buffer *b)
{
return b->size - Buffer_avail(b);
}
inline void Buffer_getOutputPointers(Buffer *b, char **p1, int *n1, char **p2, int *n2)
{
int optr= b->optr;
int avail= Buffer_avail(b);
int headroom= b->size - optr;
if (avail == 0)
{
*p1= *p2= 0;
*n1= *n2= 0;
}
else if (avail <= headroom)
{
*p1= b->data + optr; *p2= 0;
*n1= avail; *n2= 0;
}
else
{
*p1= b->data + optr; *p2= b->data;
*n1= headroom; *n2= avail - headroom;
}
assert(!(*n1 & 3));
assert(!(*n2 & 3));
}
inline int Buffer_getOutputPointer(Buffer *b, char **ptr)
{
int optr= b->optr;
int avail= Buffer_avail(b);
int headroom= b->size - optr;
if (headroom < avail) avail= headroom;
assert((optr + avail) <= b->size);
*ptr= b->data + optr;
return avail;
}
inline int Buffer_getInputPointer(Buffer *b, char **ptr)
{
int iptr= b->iptr;
int free= Buffer_free(b);
int headroom= b->size - iptr;
if (headroom < free) free= headroom;
assert((iptr + free) <= b->size);
*ptr= b->data + iptr;
return free;
}
inline void Buffer_advanceOutputPointer(Buffer *b, int size)
{
int optr= b->optr;
int avail= b->avail;
assert(!(size & 3));
optr+= size;
avail-= size;
assert(optr <= b->size);
assert(avail >= 0);
if (optr == b->size) optr= 0;
b->optr= optr;
b->avail= avail;
}
inline void Buffer_advanceInputPointer(Buffer *b, int size)
{
int iptr= b->iptr;
assert(!(size & 3));
{
int free= Buffer_free(b);
free-= size;
assert(free >= 0);
}
iptr += size;
assert(iptr <= b->size);
if (iptr == b->size) iptr= 0;
b->iptr= iptr;
b->avail += size;
}
inline void Buffer_prefill(Buffer *b, int bytes)
{
char *ptr;
int size= Buffer_getInputPointer(b, &ptr);
assert(!(bytes & 3));
assert(bytes <= size);
memset(ptr, 0, size);
Buffer_advanceInputPointer(b, bytes);
}
inline int Buffer_write(Buffer *b, char *buf, int nbytes)
{
int iptr= b->iptr;
int bytesToCopy= min(nbytes, Buffer_free(b));
int headroom= b->size - iptr;
int bytesCopied= 0;
assert(!(nbytes & 3));
if (bytesToCopy >= headroom)
{
memcpy(b->data + iptr, buf, headroom);
iptr= 0;
bytesToCopy -= headroom;
bytesCopied += headroom;
if (bytesToCopy)
{
memcpy(b->data, buf + bytesCopied, bytesToCopy);
iptr= bytesToCopy;
bytesCopied += bytesToCopy;
}
}
else
{
memcpy(b->data + iptr, buf, bytesToCopy);
iptr += bytesToCopy;
bytesCopied= bytesToCopy;
}
b->iptr= iptr;
b->avail += bytesCopied;
return bytesCopied;
}
inline int Buffer_read(Buffer *b, char *buf, int nbytes)
{
int optr= b->optr;
int bytesToCopy= min(nbytes, Buffer_avail(b));
int headroom= b->size - optr;
int bytesCopied= 0;
assert(!(nbytes & 3));
if (bytesToCopy >= headroom)
{
memcpy(buf, b->data + optr, headroom);
optr= 0;
bytesToCopy -= headroom;
bytesCopied += headroom;
if (bytesToCopy)
{
memcpy(buf + bytesCopied, b->data, bytesToCopy);
optr= bytesToCopy;
bytesCopied += bytesToCopy;
}
}
else
{
memcpy(buf, b->data + optr, bytesToCopy);
optr += bytesToCopy;
bytesCopied= bytesToCopy;
}
b->optr= optr;
b->avail -= bytesCopied;
return bytesCopied;
}
|
