Line data    Source code

       1              : /*
       2              :  *
       3              :  *    Copyright (c) 2021 Project CHIP Authors
       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              : #pragma once
      19              : 
      20              : #include <cstddef>
      21              : #include <cstdint>
      22              : 
      23              : namespace chip {
      24              : /**
      25              :  * Memory allocator that uses a fixed-size buffer.
      26              :  *
      27              :  * This class allocates subsequent memory regions out of a fixed-size buffer.
      28              :  * Deallocation of specific regions is unsupported and it is assumed that the entire
      29              :  * buffer will be released at once.
      30              :  */
      31              : class FixedBufferAllocator
      32              : {
      33              : public:
      34              :     FixedBufferAllocator() = default;
      35              :     FixedBufferAllocator(uint8_t * buffer, size_t capacity) { Init(buffer, capacity); }
      36              : 
      37              :     template <size_t N>
      38            2 :     explicit FixedBufferAllocator(uint8_t (&buffer)[N])
      39            2 :     {
      40            2 :         Init(buffer);
      41            2 :     }
      42              : 
      43            2 :     void Init(uint8_t * buffer, size_t capacity)
      44              :     {
      45            2 :         mBegin          = buffer;
      46            2 :         mEnd            = buffer + capacity;
      47            2 :         mAnyAllocFailed = false;
      48            2 :     }
      49              : 
      50              :     template <size_t N>
      51            2 :     void Init(uint8_t (&buffer)[N])
      52              :     {
      53            2 :         Init(buffer, N);
      54            2 :     }
      55              : 
      56              :     /**
      57              :      * Allocate a specified number of bytes.
      58              :      *
      59              :      * @param count     Number of bytes to allocate.
      60              :      * @return          Pointer to the allocated memory region or nullptr on failure.
      61              :      */
      62              :     uint8_t * Alloc(size_t count);
      63              : 
      64              :     /**
      65              :      * Allocate memory for the specified data and copy the data into the allocated region.
      66              :      *
      67              :      * @param data      Pointer to the data to be copied into the allocated memory region.
      68              :      * @param dataLen   Size of the data to be copied into the allocated memory region.
      69              :      * @return          Pointer to the allocated memory region or nullptr on failure.
      70              :      */
      71              :     uint8_t * Clone(const void * data, size_t dataLen);
      72              : 
      73              :     /**
      74              :      * Allocate memory for the specified string and copy the string, including
      75              :      * the null-character, into the allocated region.
      76              :      *
      77              :      * @param str       Pointer to the string to be copied into the allocated memory region.
      78              :      * @return          Pointer to the allocated memory region or nullptr on failure.
      79              :      */
      80              :     char * Clone(const char * str);
      81              : 
      82              :     /**
      83              :      * Returns whether any allocation has failed so far.
      84              :      */
      85            2 :     bool AnyAllocFailed() const { return mAnyAllocFailed; }
      86              : 
      87              : private:
      88              :     FixedBufferAllocator(const FixedBufferAllocator &) = delete;
      89              :     void operator=(const FixedBufferAllocator &)       = delete;
      90              : 
      91              :     uint8_t * mBegin     = nullptr;
      92              :     uint8_t * mEnd       = nullptr;
      93              :     bool mAnyAllocFailed = false;
      94              : };
      95              : 
      96              : } // namespace chip