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use util::{U256, Uint};
pub trait Memory {
fn size(&self) -> usize;
fn resize(&mut self, new_size: usize);
fn expand(&mut self, new_size: usize);
fn write_byte(&mut self, offset: U256, value: U256);
fn write(&mut self, offset: U256, value: U256);
fn read(&self, offset: U256) -> U256;
fn write_slice(&mut self, offset: U256, &[u8]);
fn read_slice(&self, offset: U256, size: U256) -> &[u8];
fn writeable_slice(&mut self, offset: U256, size: U256) -> &mut[u8];
fn dump(&self);
}
fn is_valid_range(off: usize, size: usize) -> bool {
let overflow = off.overflowing_add(size).1;
size > 0 && !overflow
}
impl Memory for Vec<u8> {
fn dump(&self) {
println!("MemoryDump:");
for i in self.iter() {
println!("{:02x} ", i);
}
println!("");
}
fn size(&self) -> usize {
self.len()
}
fn read_slice(&self, init_off_u: U256, init_size_u: U256) -> &[u8] {
let off = init_off_u.low_u64() as usize;
let size = init_size_u.low_u64() as usize;
if !is_valid_range(off, size) {
&self[0..0]
} else {
&self[off..off+size]
}
}
fn read(&self, offset: U256) -> U256 {
let off = offset.low_u64() as usize;
U256::from(&self[off..off+32])
}
fn writeable_slice(&mut self, offset: U256, size: U256) -> &mut [u8] {
let off = offset.low_u64() as usize;
let s = size.low_u64() as usize;
if !is_valid_range(off, s) {
&mut self[0..0]
} else {
&mut self[off..off+s]
}
}
fn write_slice(&mut self, offset: U256, slice: &[u8]) {
let off = offset.low_u64() as usize;
for pos in off..off+slice.len() {
self[pos] = slice[pos - off];
}
}
fn write(&mut self, offset: U256, value: U256) {
let off = offset.low_u64() as usize;
value.to_big_endian(&mut self[off..off+32]);
}
fn write_byte(&mut self, offset: U256, value: U256) {
let off = offset.low_u64() as usize;
let val = value.low_u64() as u64;
self[off] = val as u8;
}
fn resize(&mut self, new_size: usize) {
self.resize(new_size, 0);
}
fn expand(&mut self, size: usize) {
if size > self.len() {
Memory::resize(self, size)
}
}
}
#[test]
fn test_memory_read_and_write() {
let mem: &mut Memory = &mut vec![];
mem.resize(0x80 + 32);
mem.write(U256::from(0x80), U256::from(0xabcdef));
assert_eq!(mem.read(U256::from(0x80)), U256::from(0xabcdef));
}
#[test]
fn test_memory_read_and_write_byte() {
let mem: &mut Memory = &mut vec![];
mem.resize(32);
mem.write_byte(U256::from(0x1d), U256::from(0xab));
mem.write_byte(U256::from(0x1e), U256::from(0xcd));
mem.write_byte(U256::from(0x1f), U256::from(0xef));
assert_eq!(mem.read(U256::from(0x00)), U256::from(0xabcdef));
}