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Access to non-available memory areas #71

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Merged
merged 3 commits into from
Nov 2, 2020
Merged

Access to non-available memory areas #71

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2ac88f7
Add Public Access to All Memory Regions
CalebLBaker Nov 1, 2020
c8f4501
Fix Syntax Error
CalebLBaker Nov 1, 2020
27dc1b6
Leverage filter function to simplify memory_areas implementation
CalebLBaker Nov 2, 2020
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36 changes: 29 additions & 7 deletions src/memory_map.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -23,9 +23,15 @@ pub struct MemoryMapTag {
impl MemoryMapTag {
/// Return an iterator over all AVAILABLE marked memory areas.
pub fn memory_areas(&self) -> MemoryAreaIter {
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@IsaacWoods IsaacWoods Nov 2, 2020 •
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I wonder if, rather than having two iteratory types, this could return impl Iterator<Item = &MemoryArea> (maybe you'll need a lifetime idk) and then the body could be self.all_memory_areas().filter(|entry| entry.typ == 1)? I think that'd be cleaner, if it works.

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@CalebLBaker CalebLBaker Nov 2, 2020 •
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That would be cleaner and it does work. Initially I was worried that filter wouldn't work without the standard library (I'm using this crate for work on an OS kernel where I don't have the standard library and I'm new to working without the standard library, so I haven't yet figured out what is part of the standard library vs what is part of core), so I chose to avoid using filter initially. On further investigation, it seems to work fine, so I will update my pull request to make use of fileter.

MemoryAreaIter {
iter: self.all_memory_areas(),
}
}
/// Return an iterator over all marked memory areas.
pub fn all_memory_areas(&self) -> AllMemoryAreaIter {
let self_ptr = self as *const MemoryMapTag;
let start_area = (&self.first_area) as *const MemoryArea;
MemoryAreaIter {
AllMemoryAreaIter {
current_area: start_area as u64,
last_area: (self_ptr as u64 + (self.size - self.entry_size) as u64),
entry_size: self.entry_size,
Expand Down Expand Up @@ -91,26 +97,42 @@ pub enum MemoryAreaType {
Defective,
}

/// An iterator over Available memory areas.
/// An iterator over all memory areas
#[derive(Clone, Debug)]
pub struct MemoryAreaIter<'a> {
pub struct AllMemoryAreaIter<'a> {
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EFIMemoryMap also could use an iterator over all memory areas.

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It looks to me like EFIMemoryMapTag already iterates over all memory areas.

current_area: u64,
last_area: u64,
entry_size: u32,
phantom: PhantomData<&'a MemoryArea>,
}

impl<'a> Iterator for MemoryAreaIter<'a> {
impl<'a> Iterator for AllMemoryAreaIter<'a> {
type Item = &'a MemoryArea;
fn next(&mut self) -> Option<&'a MemoryArea> {
if self.current_area > self.last_area {
None
} else {
let area = unsafe{&*(self.current_area as *const MemoryArea)};
self.current_area = self.current_area + (self.entry_size as u64);
if area.typ == 1 {
Some(area)
} else {self.next()}
Some(area)
}
}
}

/// An iterator over Available memory areas.
#[derive(Clone, Debug)]
pub struct MemoryAreaIter<'a> {
iter: AllMemoryAreaIter<'a>,
}

impl<'a> Iterator for MemoryAreaIter<'a> {
type Item = &'a MemoryArea;
fn next(&mut self) -> Option<&'a MemoryArea> {
let ret = self.iter.next()?;
if ret.typ == 1 {
Some(ret)
} else {
self.next()
}
}
}
Expand Down