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#![no_std]
pub struct ByteReader<'a, T: Iterator<Item = &'a u8>>(T);
impl<'a, T> ByteReader<'a, T>
where
T: Iterator<Item = &'a u8>,
{
pub fn new(iter: T) -> ByteReader<'a, T> {
ByteReader(iter)
}
pub fn next_u8(&mut self) -> Option<u8> {
self.0.next().map(|&x| x)
}
pub fn next_u16(&mut self) -> Option<u16> {
let first = self.next_u8()? as u16;
let second = self.next_u8()? as u16;
Some((second << 8) | first)
}
pub fn next_u32(&mut self) -> Option<u32> {
let first = self.next_u16()? as u32;
let second = self.next_u16()? as u32;
Some((second << 16) | first)
}
pub fn next_u64(&mut self) -> Option<u64> {
let first = self.next_u32()? as u64;
let second = self.next_u32()? as u64;
Some((second << 32) | first)
}
}
#[cfg(test)]
mod tests {
use ByteReader;
#[test]
fn consume_slice() {
let slice = &[0x45, 0xf6, 0xde, 0x34, 0x98, 0x77];
let mut reader = ByteReader::new(slice.iter());
assert_eq!(reader.next_u8(), Some(0x45));
assert_eq!(reader.next_u32(), Some(0x98_34_de_f6));
assert_eq!(reader.next_u16(), None);
}
}