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
225
226
227
228
|
/*
* Copyright (c) 2015-2018 Richard Braun.
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
* Upstream site with license notes :
* http://git.sceen.net/rbraun/librbraun.git/
*/
#include <assert.h>
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <kern/cbuf.h>
#include <kern/macros.h>
/* Negative close to 0 so that an overflow occurs early */
#define CBUF_INIT_INDEX ((size_t)-500)
void
cbuf_init(struct cbuf *cbuf, void *buf, size_t capacity)
{
assert(ISP2(capacity));
cbuf->buf = buf;
cbuf->capacity = capacity;
cbuf->start = CBUF_INIT_INDEX;
cbuf->end = cbuf->start;
}
static size_t
cbuf_index(const struct cbuf *cbuf, size_t abs_index)
{
return abs_index & (cbuf->capacity - 1);
}
static void
cbuf_update_start(struct cbuf *cbuf)
{
if (cbuf_size(cbuf) > cbuf->capacity) {
cbuf->start = cbuf->end - cbuf->capacity;
}
}
static void
cbuf_update_end(struct cbuf *cbuf)
{
if (cbuf_size(cbuf) > cbuf->capacity) {
cbuf->end = cbuf->start + cbuf->capacity;
}
}
int
cbuf_push(struct cbuf *cbuf, const void *buf, size_t size, bool erase)
{
if (!erase) {
size_t avail_size;
avail_size = cbuf_avail_size(cbuf);
if (size > avail_size) {
return EAGAIN;
}
}
return cbuf_write(cbuf, cbuf_end(cbuf), buf, size);
}
int
cbuf_pop(struct cbuf *cbuf, void *buf, size_t *sizep)
{
int error;
if (cbuf_size(cbuf) == 0) {
return EAGAIN;
}
error = cbuf_read(cbuf, cbuf_start(cbuf), buf, sizep);
assert(!error);
cbuf->start += *sizep;
return 0;
}
int
cbuf_pushb(struct cbuf *cbuf, uint8_t byte, bool erase)
{
if (!erase) {
size_t avail_size;
avail_size = cbuf_avail_size(cbuf);
if (avail_size == 0) {
return EAGAIN;
}
}
cbuf->buf[cbuf_index(cbuf, cbuf->end)] = byte;
cbuf->end++;
cbuf_update_start(cbuf);
return 0;
}
int
cbuf_popb(struct cbuf *cbuf, void *bytep)
{
uint8_t *ptr;
if (cbuf_size(cbuf) == 0) {
return EAGAIN;
}
ptr = bytep;
if (ptr) {
*ptr = cbuf->buf[cbuf_index(cbuf, cbuf->start)];
}
cbuf->start++;
return 0;
}
int
cbuf_write(struct cbuf *cbuf, size_t index, const void *buf, size_t size)
{
uint8_t *start, *end, *buf_end;
size_t new_end, skip;
if (!cbuf_index_valid(cbuf, index)) {
return EINVAL;
}
new_end = index + size;
if (!cbuf_index_valid(cbuf, new_end)) {
cbuf->end = new_end;
cbuf_update_start(cbuf);
if (size > cbuf->capacity) {
skip = size - cbuf->capacity;
buf += skip;
index += skip;
size = cbuf->capacity;
}
}
start = &cbuf->buf[cbuf_index(cbuf, index)];
end = start + size;
buf_end = cbuf->buf + cbuf->capacity;
if ((end < cbuf->buf) || (end > buf_end)) {
skip = buf_end - start;
memcpy(start, buf, skip);
buf += skip;
start = cbuf->buf;
size -= skip;
}
memcpy(start, buf, size);
return 0;
}
int
cbuf_read(const struct cbuf *cbuf, size_t index, void *buf, size_t *sizep)
{
const uint8_t *start, *end, *buf_end;
size_t size;
if (!cbuf_index_valid(cbuf, index)) {
return EINVAL;
}
size = cbuf->end - index;
if (*sizep > size) {
*sizep = size;
}
start = &cbuf->buf[cbuf_index(cbuf, index)];
end = start + *sizep;
buf_end = cbuf->buf + cbuf->capacity;
if ((end > cbuf->buf) && (end <= buf_end)) {
size = *sizep;
} else {
size = buf_end - start;
if (buf) {
memcpy(buf, start, size);
buf += size;
}
start = cbuf->buf;
size = *sizep - size;
}
if (buf) {
memcpy(buf, start, size);
}
return 0;
}
void
cbuf_set_start(struct cbuf *cbuf, size_t start)
{
cbuf->start = start;
cbuf_update_end(cbuf);
}
void
cbuf_set_end(struct cbuf *cbuf, size_t end)
{
cbuf->end = end;
cbuf_update_start(cbuf);
}
|
