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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

use std::{
    fmt,
    iter::Sum,
    ops::{Add, AddAssign, Deref, Div, Mul, Rem, Sub, SubAssign},
};

use serde;

/// disk sector size in bytes
pub const SECTOR_SIZE: usize = 512;

/// a kernel defined block size constant for any DM meta device
/// a DM meta device may store cache device or thinpool device metadata
/// defined in drivers/md/persistent-data/dm-space-map-metadata.h as
/// DM_SM_METADATA_BLOCK_SIZE.
const META_BLOCK_SIZE: Sectors = Sectors(8);

/// The maximum size of a metadata device.
/// defined in drivers/md/persistent-data/dm-space-map-metadata.h as
/// DM_SM_METADATA_MAX_BLOCKS.
/// As far as I can tell, this is not a limit on the size of a designated
/// metadata device, but instead on the possible usage of that device.
#[allow(dead_code)]
const MAX_META_DEV_SIZE: MetaBlocks = MetaBlocks(255 * ((1 << 14) - 64));

range!(DataBlocks, "data blocks");

range!(MetaBlocks, "meta blocks");

impl MetaBlocks {
    /// Return the number of Sectors in the MetaBlocks.
    pub fn sectors(self) -> Sectors {
        self.0 * META_BLOCK_SIZE
    }
}

range!(Bytes, "bytes");

impl Bytes {
    /// Return the number of Sectors fully contained in these bytes.
    pub fn sectors(self) -> Sectors {
        Sectors(self.0 / SECTOR_SIZE as u64)
    }
}

range!(Sectors, "sectors");

impl Sectors {
    /// The number of bytes in these sectors.
    pub fn bytes(self) -> Bytes {
        Bytes(self.0 * SECTOR_SIZE as u64)
    }

    /// The number of whole metablocks contained in these sectors.
    pub fn metablocks(self) -> MetaBlocks {
        MetaBlocks(self / META_BLOCK_SIZE)
    }
}