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