Add SszEncoder

This commit is contained in:
Paul Hauner 2019-05-06 09:01:28 +10:00
parent daf6912d18
commit aeb17c73f6
No known key found for this signature in database
GPG Key ID: D362883A9218FCC6
3 changed files with 40 additions and 12 deletions

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@ -1,4 +1,4 @@
use ssz::{encode_length, Decodable, DecodeError, Encodable, SszDecoderBuilder, SszStream};
use ssz::{Decodable, DecodeError, Encodable, SszDecoderBuilder, SszEncoder, SszStream};
#[derive(Debug, PartialEq)]
pub struct Foo {
@ -17,18 +17,13 @@ impl Encodable for Foo {
+ <Vec<u16> as Encodable>::ssz_fixed_len()
+ <u16 as Encodable>::ssz_fixed_len();
let mut fixed = Vec::with_capacity(offset);
let mut variable = vec![];
let mut encoder = SszEncoder::container(offset);
if <u16 as Encodable>::is_ssz_fixed_len() {
self.a.ssz_append(&mut fixed);
} else {
fixed.append(encode_length())
}
encoder.append(&self.a);
encoder.append(&self.b);
encoder.append(&self.c);
if <Vec<u16> as Encodable>::is_ssz_fixed_len() {
self.a.ssz_append(&mut fixed);
}
buf.append(&mut encoder.drain());
}
}

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@ -25,6 +25,39 @@ pub trait Encodable {
}
}
pub struct SszEncoder {
offset: usize,
fixed_bytes: Vec<u8>,
variable_bytes: Vec<u8>,
}
impl SszEncoder {
pub fn container(num_fixed_bytes: usize) -> Self {
Self {
offset: num_fixed_bytes,
fixed_bytes: vec![],
variable_bytes: vec![],
}
}
pub fn append<T: Encodable>(&mut self, item: &T) {
if T::is_ssz_fixed_len() {
item.ssz_append(&mut self.fixed_bytes);
} else {
self.fixed_bytes
.append(&mut encode_length(self.offset + self.variable_bytes.len()));
item.ssz_append(&mut self.variable_bytes);
}
}
pub fn drain(mut self) -> Vec<u8> {
self.fixed_bytes.append(&mut self.variable_bytes);
self.fixed_bytes
}
}
pub struct VariableLengths {
pub fixed_bytes_position: usize,
pub variable_bytes_length: usize,

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@ -17,7 +17,7 @@ mod decode;
mod encode;
pub use decode::{Decodable, DecodeError, SszDecoderBuilder};
pub use encode::{Encodable, SszStream};
pub use encode::{Encodable, SszEncoder, SszStream};
pub const BYTES_PER_LENGTH_OFFSET: usize = 4;
pub const MAX_LENGTH_VALUE: usize = 1 << (BYTES_PER_LENGTH_OFFSET * 8) - 1;