/*

 * Copyright (c) 2020 Red Hat, Inc.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA. 

 *

 * $Id: //eng/vdo-releases/aluminum/src/c++/vdo/base/blockMappingState.h#1 $

 */

#ifndef BLOCK_MAPPING_STATE_H

#define BLOCK_MAPPING_STATE_H

#include "common.h"

/**

 * Four bits of each five-byte block map entry contain a mapping state value

 * used to distinguish unmapped or trimmed logical blocks (which are treated

 * as mapped to the zero block) from entries that have been mapped to a

 * physical block, including the zero block.

 **/

typedef enum {

  MAPPING_STATE_UNMAPPED        = 0,  // Must be zero to be the default value

  MAPPING_STATE_UNCOMPRESSED    = 1,  // A normal (uncompressed) block

  MAPPING_STATE_COMPRESSED_BASE = 2,  // Compressed in slot 0

  MAPPING_STATE_COMPRESSED_MAX  = 15, // Compressed in slot 13

} BlockMappingState;

/**

 * The total number of compressed blocks that can live in a physical block.

 **/

enum {

  MAX_COMPRESSION_SLOTS =

    MAPPING_STATE_COMPRESSED_MAX - MAPPING_STATE_COMPRESSED_BASE + 1,

};

/**********************************************************************/

static inline BlockMappingState getStateForSlot(byte slotNumber)

{

  return (slotNumber + MAPPING_STATE_COMPRESSED_BASE);

}

/**********************************************************************/

static inline byte getSlotFromState(BlockMappingState mappingState)

{

  return (mappingState - MAPPING_STATE_COMPRESSED_BASE);

}

/**********************************************************************/

static inline bool isCompressed(const BlockMappingState mappingState)

{

  return (mappingState > MAPPING_STATE_UNCOMPRESSED);

}

#endif // BLOCK_MAPPING_STATE_H