1 /******************************************************************************
2 *
3 * Copyright (C) 2015 Google Inc.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at:
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 ******************************************************************************/
18
19 #include <assert.h>
20 #include <stdlib.h>
21
22 #include "osi/include/allocator.h"
23 #include "osi/include/ringbuffer.h"
24
25 struct ringbuffer_t {
26 size_t total;
27 size_t available;
28 uint8_t *base;
29 uint8_t *head;
30 uint8_t *tail;
31 };
32
ringbuffer_init(const size_t size)33 ringbuffer_t* ringbuffer_init(const size_t size) {
34 ringbuffer_t* p = osi_calloc(sizeof(ringbuffer_t));
35
36 p->base = osi_calloc(size);
37 p->head = p->tail = p->base;
38 p->total = p->available = size;
39
40 return p;
41 }
42
ringbuffer_free(ringbuffer_t * rb)43 void ringbuffer_free(ringbuffer_t *rb) {
44 if (rb != NULL)
45 osi_free(rb->base);
46 osi_free(rb);
47 }
48
ringbuffer_available(const ringbuffer_t * rb)49 size_t ringbuffer_available(const ringbuffer_t *rb) {
50 assert(rb);
51 return rb->available;
52 }
53
ringbuffer_size(const ringbuffer_t * rb)54 size_t ringbuffer_size(const ringbuffer_t *rb) {
55 assert(rb);
56 return rb->total - rb->available;
57 }
58
ringbuffer_insert(ringbuffer_t * rb,const uint8_t * p,size_t length)59 size_t ringbuffer_insert(ringbuffer_t *rb, const uint8_t *p, size_t length) {
60 assert(rb);
61 assert(p);
62
63 if (length > ringbuffer_available(rb))
64 length = ringbuffer_available(rb);
65
66 for (size_t i = 0; i != length; ++i) {
67 *rb->tail++ = *p++;
68 if (rb->tail >= (rb->base + rb->total))
69 rb->tail = rb->base;
70 }
71
72 rb->available -= length;
73 return length;
74 }
75
ringbuffer_delete(ringbuffer_t * rb,size_t length)76 size_t ringbuffer_delete(ringbuffer_t *rb, size_t length) {
77 assert(rb);
78
79 if (length > ringbuffer_size(rb))
80 length = ringbuffer_size(rb);
81
82 rb->head += length;
83 if (rb->head >= (rb->base + rb->total))
84 rb->head -= rb->total;
85
86 rb->available += length;
87 return length;
88 }
89
ringbuffer_peek(const ringbuffer_t * rb,off_t offset,uint8_t * p,size_t length)90 size_t ringbuffer_peek(const ringbuffer_t *rb, off_t offset, uint8_t *p, size_t length) {
91 assert(rb);
92 assert(p);
93 assert(offset >= 0);
94 assert((size_t)offset <= ringbuffer_size(rb));
95
96 uint8_t *b = ((rb->head - rb->base + offset) % rb->total) + rb->base;
97 const size_t bytes_to_copy = (offset + length > ringbuffer_size(rb)) ? ringbuffer_size(rb) - offset : length;
98
99 for (size_t copied = 0; copied < bytes_to_copy; ++copied) {
100 *p++ = *b++;
101 if (b >= (rb->base + rb->total))
102 b = rb->base;
103 }
104
105 return bytes_to_copy;
106 }
107
ringbuffer_pop(ringbuffer_t * rb,uint8_t * p,size_t length)108 size_t ringbuffer_pop(ringbuffer_t *rb, uint8_t *p, size_t length) {
109 assert(rb);
110 assert(p);
111
112 const size_t copied = ringbuffer_peek(rb, 0, p, length);
113 rb->head += copied;
114 if (rb->head >= (rb->base + rb->total))
115 rb->head -= rb->total;
116
117 rb->available += copied;
118 return copied;
119 }
120