102 lines
2.6 KiB
C
102 lines
2.6 KiB
C
/******************************************************************************
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*
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* Copyright (C) 2014 Google, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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******************************************************************************/
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#include <stdint.h>
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#include "bt_common.h"
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#include "osi/allocator.h"
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#include "osi/buffer.h"
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struct buffer_t {
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buffer_t *root;
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size_t refcount;
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size_t length;
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uint8_t data[];
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};
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buffer_t *buffer_new(size_t size)
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{
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assert(size > 0);
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buffer_t *buffer = osi_malloc(sizeof(buffer_t) + size);
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if (!buffer) {
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OSI_TRACE_ERROR("%s unable to allocate buffer of %zu bytes.", __func__, size);
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return NULL;
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}
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buffer->root = buffer;
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buffer->refcount = 1;
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buffer->length = size;
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return buffer;
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}
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buffer_t *buffer_new_ref(const buffer_t *buf)
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{
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assert(buf != NULL);
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return buffer_new_slice(buf, buf->length);
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}
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buffer_t *buffer_new_slice(const buffer_t *buf, size_t slice_size)
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{
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assert(buf != NULL);
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assert(slice_size > 0);
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assert(slice_size <= buf->length);
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buffer_t *ret = osi_calloc(sizeof(buffer_t));
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if (!ret) {
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OSI_TRACE_ERROR("%s unable to allocate new buffer for slice of length %zu.", __func__, slice_size);
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return NULL;
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}
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ret->root = buf->root;
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ret->refcount = SIZE_MAX;
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ret->length = slice_size;
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++buf->root->refcount;
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return ret;
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}
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void buffer_free(buffer_t *buffer)
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{
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if (!buffer) {
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return;
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}
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if (buffer->root != buffer) {
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// We're a leaf node. Delete the root node if we're the last referent.
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if (--buffer->root->refcount == 0) {
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osi_free(buffer->root);
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}
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osi_free(buffer);
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} else if (--buffer->refcount == 0) {
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// We're a root node. Roots are only deleted when their refcount goes to 0.
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osi_free(buffer);
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}
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}
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void *buffer_ptr(const buffer_t *buf)
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{
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assert(buf != NULL);
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return buf->root->data + buf->root->length - buf->length;
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}
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size_t buffer_length(const buffer_t *buf)
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{
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assert(buf != NULL);
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return buf->length;
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}
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