WangRunji
6 years ago
parent
52fe93188d
commit
18640b7537
@ -0,0 +1,66 @@
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use alloc::vec::Vec;
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use alloc::alloc::{Layout, GlobalAlloc};
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use core::marker::PhantomData;
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pub trait NoMMUSupport {
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type Alloc: GlobalAlloc;
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fn allocator() -> &'static Self::Alloc;
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}
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#[derive(Clone, Debug)]
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pub struct MemorySet<S: NoMMUSupport> {
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areas: Vec<MemoryArea<S>>,
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support: PhantomData<S>,
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}
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impl<S: NoMMUSupport> MemorySet<S> {
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pub fn new() -> Self {
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Self {
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areas: Vec::new(),
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support: PhantomData,
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}
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}
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/// Allocate `size` bytes space. Return the slice.
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pub fn push(&mut self, size: usize) -> &'static mut [u8] {
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let area = MemoryArea::new(size);
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let slice = unsafe { area.as_buf() };
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self.areas.push(area);
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slice
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}
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// empty impls
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pub fn with<T>(&self, f: impl FnOnce() -> T) -> T { f() }
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pub fn token(&self) -> usize { 0 }
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pub unsafe fn activate(&self) {}
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}
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#[derive(Debug)]
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struct MemoryArea<S: NoMMUSupport> {
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ptr: usize,
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layout: Layout,
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support: PhantomData<S>,
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}
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impl<S: NoMMUSupport> MemoryArea<S> {
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fn new(size: usize) -> Self {
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let layout = Layout::from_size_align(size, 1).unwrap();
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let ptr = unsafe { S::allocator().alloc(layout) } as usize;
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MemoryArea { ptr, layout, support: PhantomData }
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}
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unsafe fn as_buf(&self) -> &'static mut [u8] {
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core::slice::from_raw_parts_mut(self.ptr as *mut u8, self.layout.size())
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}
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}
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impl<S: NoMMUSupport> Clone for MemoryArea<S> {
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fn clone(&self) -> Self {
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let new_area = MemoryArea::new(self.layout.size());
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unsafe { new_area.as_buf().copy_from_slice(self.as_buf()) }
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new_area
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}
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}
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impl<S: NoMMUSupport> Drop for MemoryArea<S> {
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fn drop(&mut self) {
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unsafe { S::allocator().dealloc(self.ptr as *mut u8, self.layout) }
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}
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}
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