text: /* mbed Microcontroller Library
   * Copyright (c) 2017 ARM Limited
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  #ifndef MBED_CHAINING_BLOCK_DEVICE_H
  #define MBED_CHAINING_BLOCK_DEVICE_H
  
  #include "BlockDevice.h"
  #include "mbed.h"
  
  
  /** Block device for chaining multiple block devices
   *  with the similar block sizes at sequential addresses
   *
   *  @code
   *  #include "mbed.h"
   *  #include "HeapBlockDevice.h"
   *  #include "ChainingBlockDevice.h"
   *
   *  // Create two smaller block devices with
   *  // 64 and 32 blocks of size 512 bytes
   *  HeapBlockDevice mem1(64*512, 512);
   *  HeapBlockDevice mem2(32*512, 512);
   *
   *  // Create a block device backed by mem1 and mem2
   *  // contains 96 blocks of size 512 bytes
   *  BlockDevice *bds[] = {&mem1, &mem2};
   *  ChainingBlockDevice chainmem(bds);
   *  @endcode
   */
  class ChainingBlockDevice : public BlockDevice
  {
  public:
      /** Lifetime of the memory block device
       *
       *  @param bds         Array of block devices to chain with sequential block addresses
       *  @param bd_count    Number of block devices to chain
       *  @note All block devices must have the same block size
       */
      ChainingBlockDevice(BlockDevice **bds, size_t bd_count);
  
      /** Lifetime of the memory block device
       *
       *  @param bds          Array of block devices to chain with sequential block addresses
       *  @note All block devices must have the same block size
       */
      template <size_t Size>
      ChainingBlockDevice(BlockDevice *(&bds)[Size])
          : _bds(bds), _bd_count(sizeof(bds) / sizeof(bds[0]))
          , _read_size(0), _program_size(0), _erase_size(0), _size(0),  _init_ref_count(0)
      {
      }
  
      /** Lifetime of the memory block device
       *
       */
      virtual ~ChainingBlockDevice() {}
  
      /** Initialize a block device
       *
       *  @return         0 on success or a negative error code on failure
       */
      virtual int init();
  
      /** Deinitialize a block device
       *
       *  @return         0 on success or a negative error code on failure
       */
      virtual int deinit();
  
      /** Ensure data on storage is in sync with the driver
       *
       *  @return         0 on success or a negative error code on failure
       */
      virtual int sync();
  
      /** Read blocks from a block device
       *
       *  @param buffer   Buffer to write blocks to
       *  @param addr     Address of block to begin reading from
       *  @param size     Size to read in bytes, must be a multiple of read block size
       *  @return         0 on success, negative error code on failure
       */
      virtual int read(void *buffer, bd_addr_t addr, bd_size_t size);
  
      /** Program blocks to a block device
       *
       *  The blocks must have been erased prior to being programmed
       *
       *  @param buffer   Buffer of data to write to blocks
       *  @param addr     Address of block to begin writing to
       *  @param size     Size to write in bytes, must be a multiple of program block size
       *  @return         0 on success, negative error code on failure
       */
      virtual int program(const void *buffer, bd_addr_t addr, bd_size_t size);
  
      /** Erase blocks on a block device
       *
       *  The state of an erased block is undefined until it has been programmed,
       *  unless get_erase_value returns a non-negative byte value
       *
       *  @param addr     Address of block to begin erasing
       *  @param size     Size to erase in bytes, must be a multiple of erase block size
       *  @return         0 on success, negative error code on failure
       */
      virtual int erase(bd_addr_t addr, bd_size_t size);
  
      /** Get the size of a readable block
       *
       *  @return         Size of a readable block in bytes
       */
      virtual bd_size_t get_read_size() const;
  
      /** Get the size of a programmable block
       *
       *  @return         Size of a programmable block in bytes
       *  @note Must be a multiple of the read size
       */
      virtual bd_size_t get_program_size() const;
  
      /** Get the size of an eraseable block
       *
       *  @return         Size of an erasable block in bytes
       *  @note Must be a multiple of the program size
       */
      virtual bd_size_t get_erase_size() const;
  
      /** Get the size of an erasable block given address
       *
       *  @param addr     Address within the erasable block
       *  @return         Size of an erasable block in bytes
       *  @note Must be a multiple of the program size
       */
      virtual bd_size_t get_erase_size(bd_addr_t addr) const;
  
      /** Get the value of storage when erased
       *
       *  If get_erase_value returns a non-negative byte value, the underlying
       *  storage is set to that value when erased, and storage containing
       *  that value can be programmed without another erase.
       *
       *  @return         The value of storage when erased, or -1 if you can't
       *                  rely on the value of erased storage
       */
      virtual int get_erase_value() const;
  
      /** Get the total size of the underlying device
       *
       *  @return         Size of the underlying device in bytes
       */
      virtual bd_size_t size() const;
  
  protected:
      BlockDevice **_bds;
      size_t _bd_count;
      bd_size_t _read_size;
      bd_size_t _program_size;
      bd_size_t _erase_size;
      bd_size_t _size;
      int _erase_value;
      uint32_t _init_ref_count;
  };
  
  
  #endif
  