1 /******************************************************************************
2 *
3 * Copyright 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 <base/logging.h>
20 #include <stdlib.h>
21
22 #include "check.h"
23 #include "osi/include/allocator.h"
24 #include "osi/include/ringbuffer.h"
25
26 struct ringbuffer_t {
27 size_t total;
28 size_t available;
29 uint8_t* base;
30 uint8_t* head;
31 uint8_t* tail;
32 };
33
ringbuffer_init(const size_t size)34 ringbuffer_t* ringbuffer_init(const size_t size) {
35 ringbuffer_t* p =
36 static_cast<ringbuffer_t*>(osi_calloc(sizeof(ringbuffer_t)));
37
38 p->base = static_cast<uint8_t*>(osi_calloc(size));
39 p->head = p->tail = p->base;
40 p->total = p->available = size;
41
42 return p;
43 }
44
ringbuffer_free(ringbuffer_t * rb)45 void ringbuffer_free(ringbuffer_t* rb) {
46 if (rb != NULL) osi_free(rb->base);
47 osi_free(rb);
48 }
49
ringbuffer_available(const ringbuffer_t * rb)50 size_t ringbuffer_available(const ringbuffer_t* rb) {
51 CHECK(rb);
52 return rb->available;
53 }
54
ringbuffer_size(const ringbuffer_t * rb)55 size_t ringbuffer_size(const ringbuffer_t* rb) {
56 CHECK(rb);
57 return rb->total - rb->available;
58 }
59
ringbuffer_insert(ringbuffer_t * rb,const uint8_t * p,size_t length)60 size_t ringbuffer_insert(ringbuffer_t* rb, const uint8_t* p, size_t length) {
61 CHECK(rb);
62 CHECK(p);
63
64 if (length > ringbuffer_available(rb)) 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)) rb->tail = rb->base;
69 }
70
71 rb->available -= length;
72 return length;
73 }
74
ringbuffer_delete(ringbuffer_t * rb,size_t length)75 size_t ringbuffer_delete(ringbuffer_t* rb, size_t length) {
76 CHECK(rb);
77
78 if (length > ringbuffer_size(rb)) length = ringbuffer_size(rb);
79
80 rb->head += length;
81 if (rb->head >= (rb->base + rb->total)) rb->head -= rb->total;
82
83 rb->available += length;
84 return length;
85 }
86
ringbuffer_peek(const ringbuffer_t * rb,off_t offset,uint8_t * p,size_t length)87 size_t ringbuffer_peek(const ringbuffer_t* rb, off_t offset, uint8_t* p,
88 size_t length) {
89 CHECK(rb);
90 CHECK(p);
91 CHECK(offset >= 0);
92 CHECK((size_t)offset <= ringbuffer_size(rb));
93
94 uint8_t* b = ((rb->head - rb->base + offset) % rb->total) + rb->base;
95 const size_t bytes_to_copy = (offset + length > ringbuffer_size(rb))
96 ? ringbuffer_size(rb) - offset
97 : length;
98
99 for (size_t copied = 0; copied < bytes_to_copy; ++copied) {
100 *p++ = *b++;
101 if (b >= (rb->base + rb->total)) b = rb->base;
102 }
103
104 return bytes_to_copy;
105 }
106
ringbuffer_pop(ringbuffer_t * rb,uint8_t * p,size_t length)107 size_t ringbuffer_pop(ringbuffer_t* rb, uint8_t* p, size_t length) {
108 CHECK(rb);
109 CHECK(p);
110
111 const size_t copied = ringbuffer_peek(rb, 0, p, length);
112 rb->head += copied;
113 if (rb->head >= (rb->base + rb->total)) rb->head -= rb->total;
114
115 rb->available += copied;
116 return copied;
117 }
118