/*

 * 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/fixedLayout.h#1 $

 */

#ifndef FIXED_LAYOUT_H

#define FIXED_LAYOUT_H

#include "buffer.h"

#include "types.h"

typedef enum {

  FROM_BEGINNING,

  FROM_END,

} PartitionDirection;

extern const BlockCount ALL_FREE_BLOCKS;

/**

 * A fixed layout is like a traditional disk partitioning scheme.  In the

 * beginning there is one large unused area, of which parts are carved off.

 * Each carved off section has its own internal offset and size.

 **/

typedef struct fixedLayout FixedLayout;

typedef struct partition Partition;

/**

 * Make an unpartitioned fixed layout.

 *

 * @param [in]  totalBlocks  The total size of the layout, in blocks

 * @param [in]  startOffset  The block offset in the underlying layer at which

 *                           the fixed layout begins

 * @param [out] layoutPtr    The pointer to hold the resulting layout

 *

 * @return a success or error code

 **/

int makeFixedLayout(BlockCount            totalBlocks,

                    PhysicalBlockNumber   startOffset,

                    FixedLayout         **layoutPtr)

  __attribute__((warn_unused_result));

/**

 * Free the fixed layout and null out the reference to it.

 *

 * @param layoutPtr  The reference to the layout to free

 *

 * @note all partitions created by this layout become invalid pointers

 **/

void freeFixedLayout(FixedLayout **layoutPtr);

/**

 * Get the total size of the layout in blocks.

 *

 * @param layout  The layout

 *

 * @return The size of the layout

 **/

BlockCount getTotalFixedLayoutSize(const FixedLayout *layout)

  __attribute__((warn_unused_result));

/**

 * Get a partition by id.

 *

 * @param layout        The layout from which to get a partition

 * @param id            The id of the partition

 * @param partitionPtr  A pointer to hold the partition

 *

 * @return VDO_SUCCESS or an error

 **/

int getPartition(FixedLayout *layout, PartitionID id, Partition **partitionPtr)

  __attribute__((warn_unused_result));

/**

 * Translate a block number from the partition's view to the layer's

 *

 * @param partition             The partition to use for translation

 * @param partitionBlockNumber  The block number relative to the partition

 * @param layerBlockNumber      The block number relative to the layer

 *

 * @return  VDO_SUCCESS or an error code

 **/

int translateToPBN(const Partition     *partition,

                   PhysicalBlockNumber  partitionBlockNumber,

                   PhysicalBlockNumber *layerBlockNumber)

  __attribute__((warn_unused_result));

/**

 * Translate a block number from the layer's view to the partition's.

 * This is the inverse of translateToPBN().

 *

 * @param partition             The partition to use for translation

 * @param layerBlockNumber      The block number relative to the layer

 * @param partitionBlockNumber  The block number relative to the partition

 *

 * @return  VDO_SUCCESS or an error code

 **/

int translateFromPBN(const Partition     *partition,

                     PhysicalBlockNumber  layerBlockNumber,

                     PhysicalBlockNumber *partitionBlockNumber)

  __attribute__((warn_unused_result));

/**

 * Return the number of unallocated blocks available.

 *

 * @param layout        the fixed layout

 *

 * @return the number of blocks yet unallocated to partitions

 **/

BlockCount getFixedLayoutBlocksAvailable(const FixedLayout *layout)

  __attribute__((warn_unused_result));

/**

 * Create a new partition from the beginning or end of the unused space

 * within a fixed layout.

 *

 * @param   layout          the fixed layout

 * @param   id              the id of the partition to make

 * @param   blockCount      the number of blocks to carve out, if set

 *                          to ALL_FREE_BLOCKS, all remaining blocks will

 *                          be used

 * @param   direction       whether to carve out from beginning or end

 * @param   base            the number of the first block in the partition

 *                          from the point of view of its users

 *

 * @return a success or error code, particularly

 *      VDO_NO_SPACE if there are less than blockCount blocks remaining

 **/

int makeFixedLayoutPartition(FixedLayout         *layout,

                             PartitionID          id,

                             BlockCount           blockCount,

                             PartitionDirection   direction,

                             PhysicalBlockNumber  base)

  __attribute__((warn_unused_result));

/**

 * Return the size in blocks of a partition.

 *

 * @param partition       a partition of the fixedLayout

 *

 * @return the size of the partition in blocks

 **/

BlockCount getFixedLayoutPartitionSize(const Partition *partition)

  __attribute__((warn_unused_result));

/**

 * Get the first block of the partition in the layout.

 *

 * @param partition       a partition of the fixedLayout

 *

 * @return the partition's offset in blocks

 **/

PhysicalBlockNumber getFixedLayoutPartitionOffset(const Partition *partition)

  __attribute__((warn_unused_result));

/**

 * Get the number of the first block in the partition from the partition users

 * point of view.

 *

 * @param partition a partition of the fixedLayout

 *

 * @return the number of the first block in the partition

 **/

PhysicalBlockNumber getFixedLayoutPartitionBase(const Partition *partition)

  __attribute__((warn_unused_result));

/**

 * Get the size of an encoded layout

 *

 * @param layout The layout

 *

 * @return The encoded size of the layout

 **/

size_t getFixedLayoutEncodedSize(const FixedLayout *layout)

  __attribute__((warn_unused_result));

/**

 * Encode a layout into a buffer.

 *

 * @param layout The layout to encode

 * @param buffer The buffer to encode into

 *

 * @return UDS_SUCCESS or an error

 **/

int encodeFixedLayout(const FixedLayout *layout, Buffer *buffer)

  __attribute__((warn_unused_result));

/**

 * Decode a fixed layout from a buffer.

 *

 * @param [in]  buffer    The buffer from which to decode

 * @param [out] layoutPtr A pointer to hold the layout

 *

 * @return VDO_SUCCESS or an error

 **/

int decodeFixedLayout(Buffer *buffer, FixedLayout **layoutPtr)

  __attribute__((warn_unused_result));

#endif // FIXED_LAYOUT_H