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//! This module provides `Allocator` trait and few allocators that implements the trait.


mod dedicated;
mod dynamic;
mod linear;

use crate::block::Block;

pub use self::{
    dedicated::{DedicatedAllocator, DedicatedBlock},
    dynamic::{DynamicAllocator, DynamicBlock, DynamicConfig},
    linear::{LinearAllocator, LinearBlock, LinearConfig},
};

/// Allocator kind.

#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
pub enum Kind {
    /// Memory object per allocation.

    Dedicated,

    /// General purpose allocator.

    Dynamic,

    /// Allocates linearly.

    /// Fast and low overhead.

    /// Suitable for one-time-use allocations.

    Linear,
}

/// Allocator trait implemented for various allocators.

pub trait Allocator<B: gfx_hal::Backend> {
    /// Block type returned by allocator.

    type Block: Block<B>;

    /// Get allocator kind.

    fn kind() -> Kind;

    /// Allocate block of memory.

    /// On success returns allocated block and amount of memory consumed from device.

    fn alloc(
        &mut self,
        device: &B::Device,
        size: u64,
        align: u64,
    ) -> Result<(Self::Block, u64), gfx_hal::device::AllocationError>;

    /// Free block of memory.

    /// Returns amount of memory returned to the device.

    fn free(&mut self, device: &B::Device, block: Self::Block) -> u64;
}