1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef _SLAB_H_
18 #define _SLAB_H_
19 
20 #include <stdint.h>
21 
22 struct SlabAllocator;
23 
24 
25 
26 //thread/interrupt safe. allocations will not fail if space exists. even in interrupts.
27 //itemAlign over 4 will not be guaranteed since the heap does not hand out chunks with that kind of alignment
28 struct SlabAllocator* slabAllocatorNew(uint32_t itemSz, uint32_t itemAlign, uint32_t numItems);
29 void slabAllocatorDestroy(struct SlabAllocator *allocator);
30 void* slabAllocatorAlloc(struct SlabAllocator *allocator);
31 void slabAllocatorFree(struct SlabAllocator *allocator, void *ptr);
32 
33 void* slabAllocatorGetNth(struct SlabAllocator *allocator, uint32_t idx); // -> pointer or NULL if that slot is empty   may be not int-safe. YMMV
34 uint32_t slabAllocatorGetIndex(struct SlabAllocator *allocator, void *ptr); // -> index or -1 if invalid pointer
35 uint32_t slabAllocatorGetNumItems(struct SlabAllocator *allocator); // simply say hwo many items it can hold max (numItems passed to constructor)
36 
37 #endif
38 
39