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 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 44 void ringbuffer_free(ringbuffer_t* rb) { 45 if (rb != NULL) osi_free(rb->base); 46 osi_free(rb); 47 } 48 49 size_t ringbuffer_available(const ringbuffer_t* rb) { 50 CHECK(rb); 51 return rb->available; 52 } 53 54 size_t ringbuffer_size(const ringbuffer_t* rb) { 55 CHECK(rb); 56 return rb->total - rb->available; 57 } 58 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 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 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 } 105 106 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
