blog_os/src/memory/mod.rs

// Copyright 2015 Philipp Oppermann. See the README.md
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

pub use self::area_frame_allocator::AreaFrameAllocator;
pub use self::paging::remap_the_kernel;
use self::paging::PhysicalAddress;

mod area_frame_allocator;
mod paging;

pub const PAGE_SIZE: usize = 4096;

#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
pub struct Frame {
    number: usize,
}

impl Frame {
    fn containing_address(address: usize) -> Frame {
        Frame { number: address / PAGE_SIZE }
    }

    fn start_address(&self) -> PhysicalAddress {
        self.number * PAGE_SIZE
    }

    fn clone(&self) -> Frame {
        Frame { number: self.number }
    }

    fn range_inclusive(start: Frame, end: Frame) -> FrameIter {
        FrameIter {
            start: start,
            end: end,
        }
    }
}

struct FrameIter {
    start: Frame,
    end: Frame,
}

impl Iterator for FrameIter {
    type Item = Frame;

    fn next(&mut self) -> Option<Frame> {
        if self.start <= self.end {
            let frame = self.start.clone();
            self.start.number += 1;
            Some(frame)
        } else {
            None
        }
    }
}

pub trait FrameAllocator {
    fn allocate_frame(&mut self) -> Option<Frame>;
    fn deallocate_frame(&mut self, frame: Frame);
}