Struct PageMap

pub struct PageMap<T: Default + Copy> { /* private fields */ }

PageMap is a map-like data structure that stores Copy elements in pages of 0x1000.

Its a good choice when representing lots of small elements that are found at contiguous indices. At the moment, indices are RVA.

Lookups should be quick, as they boil down to just a couple dereferences.

Implementations

impl<T: Default + Copy> PageMap<T>

pub fn with_capacity(capacity: RVA) -> PageMap<T>

pub fn from_items(items: &[T]) -> PageMap<T>

pub fn write(&mut self, rva: RVA, items: &[T]) -> Result<()>

map the given items at the given address.

error if rva or items are not in a valid page. panic due to:

• rva must be page aligned.
• must be multiple of PAGE_SIZE number of items.

see example under get.

pub fn map_empty(&mut self, rva: RVA, size: usize) -> Result<()>

map the default value (probably zero) at the given address for the given size.

error if rva is not in a valid page. panic due to:

• rva must be page aligned.
• size must be multiple of PAGE_SIZE.

see example under probe.

pub fn writezx(&mut self, rva: RVA, items: &[T]) -> Result<()>

map the given items at the given address, padding with the default value until the next page. (map zero-extend).

error if rva or items are not in a valid page. panic due to:

• rva must be page aligned.

use lancelot::pagemap::PageMap;

let mut d: PageMap<u32> = PageMap::with_capacity(0x2000);
assert_eq!(d.get(0x0), None);
assert_eq!(d.get(0x1), None);

d.writezx(0x0, &[0x1, ]).expect("failed to write");
assert_eq!(d.get(0x0), Some(0x1));
assert_eq!(d.get(0x1), Some(0x0));

pub fn probe(&self, rva: RVA) -> bool

is the given address mapped?

use lancelot::pagemap::PageMap;

let mut d: PageMap<u32> = PageMap::with_capacity(0x2000);
assert_eq!(d.probe(0x0), false);
assert_eq!(d.probe(0x1000), false);

d.map_empty(0x0, 0x1000).expect("failed to map");
assert_eq!(d.probe(0x0), true);
assert_eq!(d.probe(0x1000), false);

pub fn get(&self, rva: RVA) -> Option<T>

fetch one item from the given address. if the address is not mapped, then the result is None.

use lancelot::pagemap::PageMap;

let mut d: PageMap<u32> = PageMap::with_capacity(0x2000);
assert_eq!(d.get(0x0), None);
assert_eq!(d.get(0x1000), None);

d.write(0x1000, &[0x1; 0x1000]).expect("failed to map");
assert_eq!(d.get(0x0), None);
assert_eq!(d.get(0x1000), Some(0x1));

d.write(0x0, &[0x2; 0x2000]).expect("failed to map");
 assert_eq!(d.get(0x0), Some(0x2));
 assert_eq!(d.get(0x1000), Some(0x2));

pub fn get_mut(&mut self, rva: RVA) -> Option<&mut T>

fetch one mutable item from the given address.

use lancelot::pagemap::PageMap;

let mut d: PageMap<u32> = PageMap::with_capacity(0x2000);
d.map_empty(0x0, 0x1000).expect("failed to map");

// address 0x0 starts at 0
assert_eq!(d.get(0x0), Some(0x0));

// set address 0x0 to 1
let v = d.get_mut(0x0).expect("should be mapped");
*v = 1;

// address 0x0 is 1
assert_eq!(d.get(0x0), Some(0x1));

pub fn slice_into<'a>(&self, start: RVA, buf: &'a mut [T]) -> Result<&'a [T]>

fetch the items found in the given range, placing them into the given slice. compared with slice, this routine avoids an allocation.

errors:

• PageMapError::NotMapped: if any requested address is not mapped

pub fn slice(&self, start: RVA, end: RVA) -> Result<Vec<T>>

fetch the items found in the given range.

errors:

• PageMapError::NotMapped: if any requested address is not mapped

panic if:

• start > end

use lancelot::pagemap::PageMap;

let mut d: PageMap<u32> = PageMap::with_capacity(0x2000);
d.map_empty(0x0, 0x1000).expect("failed to map");

assert_eq!(d.slice(0x0, 0x2).unwrap(), [0x0, 0x0]);
assert!(d.slice(0x0, 0x1000).is_ok(), "read page");
assert!(d.slice(0x0, 0x1001).is_err(), "read more than a page");

Trait Implementations

impl<T: Clone + Default + Copy> Clone for PageMap<T>

fn clone(&self) -> PageMap<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Default + Copy> Debug for PageMap<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.