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use Error;
use std;
pub type Address = u16;
pub struct Space
{
data: Vec<u8>,
}
impl Space
{
pub fn new(size: usize) -> Self {
let data = std::iter::repeat(0).take(size)
.collect();
Space {
data: data,
}
}
pub fn set_u8(&mut self, addr: usize, val: u8) -> Result<(), Error> {
if self.is_access_in_bounds(addr, 1) {
self.data[addr] = val;
Ok(())
} else {
Err(Error::SegmentationFault { address: addr + 1 })
}
}
pub fn set_u16(&mut self, addr: usize, val: u16) -> Result<(), Error> {
if self.is_access_in_bounds(addr, 2) {
self.data[addr] = ((val & 0xff00) >> 8) as u8;
self.data[addr+1] = (val & 0xff) as u8;
Ok(())
} else {
Err(Error::SegmentationFault { address: addr + 2 })
}
}
pub fn get_u8(&self, addr: usize) -> Result<u8, Error> {
self.data.get(addr).cloned().ok_or(Error::SegmentationFault { address: addr })
}
pub fn get_u16(&self, addr: usize) -> Result<u16, Error> {
let hi = self.get_u8(addr+0)? as u16;
let lo = self.get_u8(addr+1)? as u16;
Ok((hi << 8) | lo)
}
pub fn bytes<'a>(&'a self) -> std::slice::Iter<'a,u8> {
self.data.iter()
}
pub fn bytes_mut<'a>(&'a mut self) -> std::slice::IterMut<'a,u8> {
self.data.iter_mut()
}
pub fn load<I>(&mut self, mut bytes: I)
where I: Iterator<Item=u8> {
for byte in self.data.iter_mut() {
if let Some(b) = bytes.next() {
*byte = b;
} else {
break;
}
}
}
fn is_access_in_bounds(&self, addr: usize, byte_count: usize) -> bool {
let end_byte_offset = addr + byte_count;
end_byte_offset <= self.data.len()
}
}