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 "osi/include/ringbuffer.h"
20 
21 #include <bluetooth/log.h>
22 #include <stdlib.h>
23 
24 #include "osi/include/allocator.h"
25 
26 using namespace bluetooth;
27 
28 struct ringbuffer_t {
29   size_t total;
30   size_t available;
31   uint8_t* base;
32   uint8_t* head;
33   uint8_t* tail;
34 };
35 
ringbuffer_init(const size_t size)36 ringbuffer_t* ringbuffer_init(const size_t size) {
37   ringbuffer_t* p = static_cast<ringbuffer_t*>(osi_calloc(sizeof(ringbuffer_t)));
38 
39   p->base = static_cast<uint8_t*>(osi_calloc(size));
40   p->head = p->tail = p->base;
41   p->total = p->available = size;
42 
43   return p;
44 }
45 
ringbuffer_free(ringbuffer_t * rb)46 void ringbuffer_free(ringbuffer_t* rb) {
47   if (rb != NULL) {
48     osi_free(rb->base);
49   }
50   osi_free(rb);
51 }
52 
ringbuffer_available(const ringbuffer_t * rb)53 size_t ringbuffer_available(const ringbuffer_t* rb) {
54   log::assert_that(rb != nullptr, "assert failed: rb != nullptr");
55   return rb->available;
56 }
57 
ringbuffer_size(const ringbuffer_t * rb)58 size_t ringbuffer_size(const ringbuffer_t* rb) {
59   log::assert_that(rb != nullptr, "assert failed: rb != nullptr");
60   return rb->total - rb->available;
61 }
62 
ringbuffer_insert(ringbuffer_t * rb,const uint8_t * p,size_t length)63 size_t ringbuffer_insert(ringbuffer_t* rb, const uint8_t* p, size_t length) {
64   log::assert_that(rb != nullptr, "assert failed: rb != nullptr");
65   log::assert_that(p != nullptr, "assert failed: p != nullptr");
66 
67   if (length > ringbuffer_available(rb)) {
68     length = ringbuffer_available(rb);
69   }
70 
71   for (size_t i = 0; i != length; ++i) {
72     *rb->tail++ = *p++;
73     if (rb->tail >= (rb->base + rb->total)) {
74       rb->tail = rb->base;
75     }
76   }
77 
78   rb->available -= length;
79   return length;
80 }
81 
ringbuffer_delete(ringbuffer_t * rb,size_t length)82 size_t ringbuffer_delete(ringbuffer_t* rb, size_t length) {
83   log::assert_that(rb != nullptr, "assert failed: rb != nullptr");
84 
85   if (length > ringbuffer_size(rb)) {
86     length = ringbuffer_size(rb);
87   }
88 
89   rb->head += length;
90   if (rb->head >= (rb->base + rb->total)) {
91     rb->head -= rb->total;
92   }
93 
94   rb->available += length;
95   return length;
96 }
97 
ringbuffer_peek(const ringbuffer_t * rb,off_t offset,uint8_t * p,size_t length)98 size_t ringbuffer_peek(const ringbuffer_t* rb, off_t offset, uint8_t* p, size_t length) {
99   log::assert_that(rb != nullptr, "assert failed: rb != nullptr");
100   log::assert_that(p != nullptr, "assert failed: p != nullptr");
101   log::assert_that(offset >= 0, "assert failed: offset >= 0");
102   log::assert_that((size_t)offset <= ringbuffer_size(rb),
103                    "assert failed: (size_t)offset <= ringbuffer_size(rb)");
104 
105   uint8_t* b = ((rb->head - rb->base + offset) % rb->total) + rb->base;
106   const size_t bytes_to_copy =
107           (offset + length > ringbuffer_size(rb)) ? ringbuffer_size(rb) - offset : length;
108 
109   for (size_t copied = 0; copied < bytes_to_copy; ++copied) {
110     *p++ = *b++;
111     if (b >= (rb->base + rb->total)) {
112       b = rb->base;
113     }
114   }
115 
116   return bytes_to_copy;
117 }
118 
ringbuffer_pop(ringbuffer_t * rb,uint8_t * p,size_t length)119 size_t ringbuffer_pop(ringbuffer_t* rb, uint8_t* p, size_t length) {
120   log::assert_that(rb != nullptr, "assert failed: rb != nullptr");
121   log::assert_that(p != nullptr, "assert failed: p != nullptr");
122 
123   const size_t copied = ringbuffer_peek(rb, 0, p, length);
124   rb->head += copied;
125   if (rb->head >= (rb->base + rb->total)) {
126     rb->head -= rb->total;
127   }
128 
129   rb->available += copied;
130   return copied;
131 }
132