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Add 'decode_ssz_list', update 'decode_length' to take index

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This commit is contained in:
NatoliChris 2018-09-18 23:19:45 +10:00
parent 199b7490b3
commit 0fed1997a2
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GPG Key ID: D3EA7DBA19945306
1 changed files with 84 additions and 6 deletions
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90
ssz/src/decode.rs
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@ -36,11 +36,11 @@ pub fn decode_ssz_list<T>(ssz_bytes: &[u8], index: usize)
{
if index + LENGTH_BYTES > ssz_bytes.len() {
return Err(DecodeError::OutOfBounds);
return Err(DecodeError::TooShort);
};
// get the length
let mut serialized_length = match decode_length(ssz_bytes, LENGTH_BYTES) {
let serialized_length = match decode_length(ssz_bytes, index, LENGTH_BYTES) {
Err(v) => return Err(v),
Ok(v) => v,
};
@ -48,7 +48,7 @@ pub fn decode_ssz_list<T>(ssz_bytes: &[u8], index: usize)
let final_len: usize = index + LENGTH_BYTES + serialized_length;
if final_len > ssz_bytes.len() {
return Err(DecodeError::OutOfBounds);
return Err(DecodeError::TooShort);
};
let mut tmp_index = index + LENGTH_BYTES;
@ -71,15 +71,15 @@ pub fn decode_ssz_list<T>(ssz_bytes: &[u8], index: usize)
/// Given some number of bytes, interpret the first four
/// bytes as a 32-bit big-endian integer and return the
/// result.
fn decode_length(bytes: &[u8], length_bytes: usize)
fn decode_length(bytes: &[u8], index: usize, length_bytes: usize)
-> Result<usize, DecodeError>
{
if bytes.len() < length_bytes {
return Err(DecodeError::TooShort);
};
let mut len: usize = 0;
for i in 0..length_bytes {
let offset = (length_bytes - i - 1) * 8;
for i in index..index+length_bytes {
let offset = (index+length_bytes - i - 1) * 8;
len = ((bytes[i] as usize) << offset) | len;
};
Ok(len)
@ -94,21 +94,25 @@ mod tests {
fn test_ssz_decode_length() {
let decoded = decode_length(
&vec![0, 0, 0, 1],
0,
LENGTH_BYTES);
assert_eq!(decoded.unwrap(), 1);
let decoded = decode_length(
&vec![0, 0, 1, 0],
0,
LENGTH_BYTES);
assert_eq!(decoded.unwrap(), 256);
let decoded = decode_length(
&vec![0, 0, 1, 255],
0,
LENGTH_BYTES);
assert_eq!(decoded.unwrap(), 511);
let decoded = decode_length(
&vec![255, 255, 255, 255],
0,
LENGTH_BYTES);
assert_eq!(decoded.unwrap(), 4294967295);
}
@ -125,8 +129,82 @@ mod tests {
for i in params {
let decoded = decode_length(
&encode_length(i, LENGTH_BYTES),
0,
LENGTH_BYTES).unwrap();
assert_eq!(i, decoded);
}
}
#[test]
fn test_decode_ssz_list() {
// u16
let v: Vec<u16> = vec![10, 10, 10, 10];
let decoded: (Vec<u16>, usize) = decode_ssz_list(
&vec![0, 0, 0, 8, 0, 10, 0, 10, 0, 10, 0, 10],
0
).unwrap();
assert_eq!(decoded.0, v);
assert_eq!(decoded.1, 12);
// u32
let v: Vec<u32> = vec![10, 10, 10, 10];
let decoded: (Vec<u32>, usize) = decode_ssz_list(
&vec![
0, 0, 0, 16,
0, 0, 0, 10, 0, 0, 0, 10, 0, 0, 0, 10, 0, 0, 0, 10
],
0
).unwrap();
assert_eq!(decoded.0, v);
assert_eq!(decoded.1, 20);
// u64
let v: Vec<u64> = vec![10,10,10,10];
let decoded: (Vec<u64>, usize) = decode_ssz_list(
&vec![0, 0, 0, 32,
0, 0, 0, 0, 0, 0, 0, 10,
0, 0, 0, 0, 0, 0, 0, 10,
0, 0, 0, 0, 0, 0, 0, 10,
0, 0, 0, 0, 0, 0, 0, 10,
],
0
).unwrap();
assert_eq!(decoded.0, v);
assert_eq!(decoded.1, 36);
// Check that it can accept index
let v: Vec<usize> = vec![15,15,15,15];
let decoded: (Vec<usize>, usize) = decode_ssz_list(
&vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
0, 0, 0, 32,
0, 0, 0, 0, 0, 0, 0, 15,
0, 0, 0, 0, 0, 0, 0, 15,
0, 0, 0, 0, 0, 0, 0, 15,
0, 0, 0, 0, 0, 0, 0, 15,
],
10
).unwrap();
assert_eq!(decoded.0, v);
assert_eq!(decoded.1, 46);
// Check that length > bytes throws error
let decoded: Result<(Vec<usize>, usize), DecodeError> = decode_ssz_list(
&vec![0, 0, 0, 32,
0, 0, 0, 0, 0, 0, 0, 15,
],
0
);
assert_eq!(decoded, Err(DecodeError::TooShort));
// Check that incorrect index throws error
let decoded: Result<(Vec<usize>, usize), DecodeError> = decode_ssz_list(
&vec![
0, 0, 0, 0, 0, 0, 0, 15,
],
16
);
assert_eq!(decoded, Err(DecodeError::TooShort));
}
}