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 "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 =
35 static_cast<ringbuffer_t*>(osi_calloc(sizeof(ringbuffer_t)));
36
37 p->base = static_cast<uint8_t*>(osi_calloc(size));
38 p->head = p->tail = p->base;
39 p->total = p->available = size;
40
41 return p;
42 }
43
ringbuffer_free(ringbuffer_t * rb)44 void ringbuffer_free(ringbuffer_t* rb) {
45 if (rb != NULL) 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 CHECK(rb);
51 return rb->available;
52 }
53
ringbuffer_size(const ringbuffer_t * rb)54 size_t ringbuffer_size(const ringbuffer_t* rb) {
55 CHECK(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 CHECK(rb);
61 CHECK(p);
62
63 if (length > ringbuffer_available(rb)) length = ringbuffer_available(rb);
64
65 for (size_t i = 0; i != length; ++i) {
66 *rb->tail++ = *p++;
67 if (rb->tail >= (rb->base + rb->total)) rb->tail = rb->base;
68 }
69
70 rb->available -= length;
71 return length;
72 }
73
ringbuffer_delete(ringbuffer_t * rb,size_t length)74 size_t ringbuffer_delete(ringbuffer_t* rb, size_t length) {
75 CHECK(rb);
76
77 if (length > ringbuffer_size(rb)) length = ringbuffer_size(rb);
78
79 rb->head += length;
80 if (rb->head >= (rb->base + rb->total)) rb->head -= rb->total;
81
82 rb->available += length;
83 return length;
84 }
85
ringbuffer_peek(const ringbuffer_t * rb,off_t offset,uint8_t * p,size_t length)86 size_t ringbuffer_peek(const ringbuffer_t* rb, off_t offset, uint8_t* p,
87 size_t length) {
88 CHECK(rb);
89 CHECK(p);
90 CHECK(offset >= 0);
91 CHECK((size_t)offset <= ringbuffer_size(rb));
92
93 uint8_t* b = ((rb->head - rb->base + offset) % rb->total) + rb->base;
94 const size_t bytes_to_copy = (offset + length > ringbuffer_size(rb))
95 ? ringbuffer_size(rb) - offset
96 : length;
97
98 for (size_t copied = 0; copied < bytes_to_copy; ++copied) {
99 *p++ = *b++;
100 if (b >= (rb->base + rb->total)) b = rb->base;
101 }
102
103 return bytes_to_copy;
104 }
105
ringbuffer_pop(ringbuffer_t * rb,uint8_t * p,size_t length)106 size_t ringbuffer_pop(ringbuffer_t* rb, uint8_t* p, size_t length) {
107 CHECK(rb);
108 CHECK(p);
109
110 const size_t copied = ringbuffer_peek(rb, 0, p, length);
111 rb->head += copied;
112 if (rb->head >= (rb->base + rb->total)) rb->head -= rb->total;
113
114 rb->available += copied;
115 return copied;
116 }
117