1 /****************************************************************************** 2 * 3 * Copyright 2014 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 #define LOG_TAG "bt_osi_buffer" 20 21 #include "osi/include/buffer.h" 22 23 #include <base/logging.h> 24 #include <stdint.h> 25 26 #include "check.h" 27 #include "osi/include/allocator.h" 28 #include "osi/include/log.h" 29 30 struct buffer_t { 31 buffer_t* root; 32 size_t refcount; 33 size_t length; 34 uint8_t data[]; 35 }; 36 buffer_new(size_t size)37buffer_t* buffer_new(size_t size) { 38 CHECK(size > 0); 39 40 buffer_t* buffer = 41 static_cast<buffer_t*>(osi_calloc(sizeof(buffer_t) + size)); 42 43 buffer->root = buffer; 44 buffer->refcount = 1; 45 buffer->length = size; 46 47 return buffer; 48 } 49 buffer_new_ref(const buffer_t * buf)50buffer_t* buffer_new_ref(const buffer_t* buf) { 51 CHECK(buf != NULL); 52 return buffer_new_slice(buf, buf->length); 53 } 54 buffer_new_slice(const buffer_t * buf,size_t slice_size)55buffer_t* buffer_new_slice(const buffer_t* buf, size_t slice_size) { 56 CHECK(buf != NULL); 57 CHECK(slice_size > 0); 58 CHECK(slice_size <= buf->length); 59 60 buffer_t* ret = static_cast<buffer_t*>(osi_calloc(sizeof(buffer_t))); 61 62 ret->root = buf->root; 63 ret->refcount = SIZE_MAX; 64 ret->length = slice_size; 65 66 ++buf->root->refcount; 67 68 return ret; 69 } 70 buffer_free(buffer_t * buffer)71void buffer_free(buffer_t* buffer) { 72 if (!buffer) return; 73 74 if (buffer->root != buffer) { 75 // We're a leaf node. Delete the root node if we're the last referent. 76 if (--buffer->root->refcount == 0) osi_free(buffer->root); 77 osi_free(buffer); 78 } else if (--buffer->refcount == 0) { 79 // We're a root node. Roots are only deleted when their refcount goes to 0. 80 osi_free(buffer); 81 } 82 } 83 buffer_ptr(const buffer_t * buf)84void* buffer_ptr(const buffer_t* buf) { 85 CHECK(buf != NULL); 86 return buf->root->data + buf->root->length - buf->length; 87 } 88 buffer_length(const buffer_t * buf)89size_t buffer_length(const buffer_t* buf) { 90 CHECK(buf != NULL); 91 return buf->length; 92 } 93