Files
RustIJVM/src/binread.rs

84 lines
2.0 KiB
Rust

use block::Block;
use ops::{num_to_op, Operation};
use Result;
pub trait BinReadable {
fn get(&mut self) -> Result<u8>;
fn cur(&self) -> usize;
fn len(&self) -> usize;
fn slice(&mut self, len: usize) -> &[u8];
fn is_empty(&self) -> bool;
}
pub trait BinRead {
fn has_i8(&self) -> bool;
fn has_i16(&self) -> bool;
fn has_i32(&self) -> bool;
fn read_u8(&mut self) -> Result<u8>;
fn read_u16(&mut self) -> Result<u16>;
fn read_u32(&mut self) -> Result<u32>;
fn read_i8(&mut self) -> Result<i8>;
fn read_i16(&mut self) -> Result<i16>;
fn read_i32(&mut self) -> Result<i32>;
fn read_block(&mut self) -> Result<Block>;
fn read_op(&mut self) -> Result<&'static Operation>;
}
impl<T: BinReadable> BinRead for T {
fn has_i8(&self) -> bool {
self.cur() < self.len()
}
fn has_i16(&self) -> bool {
self.cur() + 1 < self.len()
}
fn has_i32(&self) -> bool {
self.cur() + 3 < self.len()
}
fn read_u8(&mut self) -> Result<u8> {
self.get()
}
fn read_u16(&mut self) -> Result<u16> {
let a = u16::from(self.read_u8()?);
let b = u16::from(self.read_u8()?);
Ok(a << 8 | b)
}
fn read_u32(&mut self) -> Result<u32> {
let a = u32::from(self.read_u16()?);
let b = u32::from(self.read_u16()?);
Ok(a << 16 | b)
}
fn read_i8(&mut self) -> Result<i8> {
Ok(self.get()? as i8)
}
fn read_i16(&mut self) -> Result<i16> {
let a = i16::from(self.read_u8()?);
let b = i16::from(self.read_u8()?);
Ok((a << 8 | b) as i16)
}
fn read_i32(&mut self) -> Result<i32> {
let a = i32::from(self.read_u16()?);
let b = i32::from(self.read_u16()?);
Ok(a << 16 | b)
}
fn read_block(&mut self) -> Result<Block> {
let origin = self.read_u32()?;
let len = self.read_u32()? as usize;
Ok(Block::new(origin, self.slice(len)))
}
fn read_op(&mut self) -> Result<&'static Operation> {
Ok(num_to_op(self.read_u8()?))
}
}