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use crate::{
DecodeError, DecodeErrorHandler, EncodeErrorHandler, NestedDecode, NestedDecodeInput,
NestedEncode, NestedEncodeOutput, TopDecode, TopDecodeInput, TopEncode, TopEncodeOutput,
};
impl<T: NestedEncode> NestedEncode for Option<T> {
fn dep_encode_or_handle_err<O, H>(&self, dest: &mut O, h: H) -> Result<(), H::HandledErr>
where
O: NestedEncodeOutput,
H: EncodeErrorHandler,
{
match self {
Some(v) => {
dest.push_byte(1u8);
v.dep_encode_or_handle_err(dest, h)
},
None => {
dest.push_byte(0u8);
Ok(())
},
}
}
}
impl<T: NestedDecode> NestedDecode for Option<T> {
fn dep_decode_or_handle_err<I, H>(input: &mut I, h: H) -> Result<Self, H::HandledErr>
where
I: NestedDecodeInput,
H: DecodeErrorHandler,
{
match input.read_byte(h)? {
0 => Ok(None),
1 => Ok(Some(T::dep_decode_or_handle_err(input, h)?)),
_ => Err(h.handle_error(DecodeError::INVALID_VALUE)),
}
}
}
impl<T: NestedEncode> TopEncode for Option<T> {
fn top_encode_or_handle_err<O, H>(&self, output: O, h: H) -> Result<(), H::HandledErr>
where
O: TopEncodeOutput,
H: EncodeErrorHandler,
{
match self {
Some(v) => {
let mut buffer = output.start_nested_encode();
buffer.push_byte(1u8);
v.dep_encode_or_handle_err(&mut buffer, h)?;
output.finalize_nested_encode(buffer);
},
None => {
output.set_slice_u8(&[]);
},
}
Ok(())
}
}
impl<T: NestedDecode> TopDecode for Option<T> {
fn top_decode_or_handle_err<I, H>(input: I, h: H) -> Result<Self, H::HandledErr>
where
I: TopDecodeInput,
H: DecodeErrorHandler,
{
let mut buffer = input.into_nested_buffer();
if buffer.is_depleted() {
Ok(None) } else {
let first_byte = buffer.read_byte(h)?;
let value = match first_byte {
0 => None, 1 => Some(T::dep_decode_or_handle_err(&mut buffer, h)?),
_ => return Err(h.handle_error(DecodeError::INVALID_VALUE)),
};
if buffer.is_depleted() {
Ok(value)
} else {
Err(h.handle_error(DecodeError::INPUT_TOO_LONG))
}
}
}
}
#[cfg(test)]
pub mod tests {
use alloc::vec::Vec;
use crate::{
test_util::{check_top_decode, check_top_encode_decode},
DecodeError, TopDecode,
};
#[test]
fn test_top() {
let some_v = Some([1i32, 2i32, 3i32].to_vec());
let expected: &[u8] = &[
1, 0, 0, 0, 3, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0,
0, 3,
];
check_top_encode_decode(some_v, expected);
let none_v: Option<Vec<i32>> = None;
check_top_encode_decode(none_v, &[]);
}
#[test]
fn test_top_none() {
assert_eq!(None, check_top_decode::<Option<u32>>(&[][..]));
assert_eq!(None, check_top_decode::<Option<u32>>(&[0x00u8][..]));
assert_eq!(
Option::<u32>::top_decode(&[0x00u8, 0x00u8][..]),
Err(DecodeError::INPUT_TOO_LONG)
);
assert_eq!(
Option::<u32>::top_decode(&[0x00u8, 0x00u8, 0x00u8][..]),
Err(DecodeError::INPUT_TOO_LONG)
);
assert_eq!(
Option::<u32>::top_decode(&[0x02u8][..]),
Err(DecodeError::INVALID_VALUE)
);
}
}