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Change integer literals to constants

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This commit is contained in:
Paul Hauner 2018-10-21 20:07:57 +11:00
parent 1acfb87e77
commit 6ee3ad10da
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GPG Key ID: 303E4494BB28068C
1 changed files with 38 additions and 35 deletions
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73
beacon_chain/utils/ssz_helpers/src/ssz_beacon_block.rs
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@ -14,7 +14,16 @@ pub enum SszBeaconBlockError {
TooLong,
}
const LENGTH_BYTES: usize = 4;
/*
* Constants used for navigating the SSZ bytes.
*/
const LENGTH_PREFIX_BYTES: usize = 4;
const SLOT_BYTES: usize = 8;
const HASH_SIZE: usize = 32;
const RANDAO_REVEAL_BYTES: usize = HASH_SIZE;
const POW_CHAIN_REF_BYTES: usize = HASH_SIZE;
const ACTIVE_STATE_BYTES: usize = HASH_SIZE;
const CRYSTALLIZED_STATE_BYTES: usize = HASH_SIZE;
/// Allows for reading of block values directly from serialized ssz bytes.
///
@ -74,41 +83,35 @@ impl<'a> SszBeaconBlock<'a> {
* Determine how many bytes are used to store ancestor hashes.
*/
let ancestors_position =
8 + // slot
32 + // randao_reveal
32; // pow_chain_reference
let ancestors_len = decode_length(untrimmed_ssz, ancestors_position, LENGTH_BYTES)
SLOT_BYTES +
RANDAO_REVEAL_BYTES +
POW_CHAIN_REF_BYTES;
let ancestors_len = decode_length(untrimmed_ssz, ancestors_position, LENGTH_PREFIX_BYTES)
.map_err(|_| SszBeaconBlockError::TooShort)?;
/*
* Determine how many bytes are used to store attestation records.
*/
let attestations_position =
ancestors_position + LENGTH_BYTES + ancestors_len + // end of ancestor bytes
32 + // active_state_root
32; // crystallized_state_root
let attestations_len = decode_length(untrimmed_ssz, attestations_position, LENGTH_BYTES)
ancestors_position + LENGTH_PREFIX_BYTES + ancestors_len + // end of ancestor bytes
ACTIVE_STATE_BYTES +
CRYSTALLIZED_STATE_BYTES;
let attestations_len = decode_length(untrimmed_ssz, attestations_position, LENGTH_PREFIX_BYTES)
.map_err(|_| SszBeaconBlockError::TooShort)?;
/*
* Determine how many bytes are used to store specials.
*/
let specials_position =
attestations_position + // location of attestations
LENGTH_BYTES + // attestations length prefix
attestations_len; // # of attestation bytes
let specials_len = decode_length(untrimmed_ssz, specials_position, LENGTH_BYTES)
let specials_position = attestations_position + LENGTH_PREFIX_BYTES + attestations_len;
let specials_len = decode_length(untrimmed_ssz, specials_position, LENGTH_PREFIX_BYTES)
.map_err(|_| SszBeaconBlockError::TooShort)?;
/*
* Now that all variable field lengths are known (ancestors, attestations, specials) we can
* know the exact length of the block and reject it if the slice is too short.
*/
let block_ssz_len = {
MIN_SSZ_BLOCK_LENGTH + ancestors_len + attestations_len + specials_len
};
let block_ssz_len = MIN_SSZ_BLOCK_LENGTH + ancestors_len + attestations_len + specials_len;
if vec.len() < block_ssz_len {
println!("block_ssz_len: {:?}, len: {:?}", block_ssz_len, vec.len());
return Err(SszBeaconBlockError::TooShort);
}
@ -162,54 +165,54 @@ impl<'a> SszBeaconBlock<'a> {
/// Return the `randao_reveal` field.
pub fn randao_reveal(&self) -> &[u8] {
let start = 8; // slot is 8 bytes
&self.ssz[start..start + 32]
let start = SLOT_BYTES;
&self.ssz[start..start + RANDAO_REVEAL_BYTES]
}
/// Return the `pow_chain_reference` field.
pub fn pow_chain_reference(&self) -> &[u8] {
let start =
8 + // slot
32; // randao_reveal
&self.ssz[start..start + 32]
SLOT_BYTES +
RANDAO_REVEAL_BYTES;
&self.ssz[start..start + POW_CHAIN_REF_BYTES]
}
/// Return the serialized `ancestor_hashes` bytes, including length prefix.
pub fn ancestor_hashes(&self) -> &[u8] {
let start = self.ancestors_position;
&self.ssz[start..(start + self.ancestors_len + LENGTH_BYTES)]
&self.ssz[start..(start + self.ancestors_len + LENGTH_PREFIX_BYTES)]
}
/// Return the `active_state_root` field.
pub fn act_state_root(&self) -> &[u8] {
let start = self.ancestors_position + LENGTH_BYTES + self.ancestors_len;
let start = self.ancestors_position + LENGTH_PREFIX_BYTES + self.ancestors_len;
&self.ssz[start..(start + 32)]
}
/// Return the `active_state_root` field.
pub fn cry_state_root(&self) -> &[u8] {
let start =
self.ancestors_position + LENGTH_BYTES + self.ancestors_len + // ancestors
32; // active_state_root;
self.ancestors_position + LENGTH_PREFIX_BYTES + self.ancestors_len +
ACTIVE_STATE_BYTES;
&self.ssz[start..(start + 32)]
}
/// Return the serialized `attestations` bytes, including length prefix.
pub fn attestations(&self) -> &[u8] {
let start = self.attestations_position;
&self.ssz[start..(start + self.attestations_len + LENGTH_BYTES)]
&self.ssz[start..(start + self.attestations_len + LENGTH_PREFIX_BYTES)]
}
/// Return the serialized `attestations` bytes _without_ the length prefix.
pub fn attestations_without_length(&self) -> &[u8] {
let start = self.attestations_position + LENGTH_BYTES;
let start = self.attestations_position + LENGTH_PREFIX_BYTES;
&self.ssz[start..start + self.attestations_len]
}
/// Return the serialized `specials` bytes, including length prefix.
pub fn specials(&self) -> &[u8] {
let start = self.specials_position;
&self.ssz[start..(start + self.specials_len + LENGTH_BYTES)]
&self.ssz[start..(start + self.specials_len + LENGTH_PREFIX_BYTES)]
}
}
@ -349,7 +352,7 @@ mod tests {
let serialized = get_block_ssz(&block);
let ssz_block = SszBeaconBlock::from_slice(&serialized).unwrap();
let mut expected = encode_length(32, LENGTH_BYTES);
let mut expected = encode_length(32, LENGTH_PREFIX_BYTES);
expected.append(&mut h.to_vec());
assert_eq!(ssz_block.ancestor_hashes(), &expected[..]);
@ -383,7 +386,7 @@ mod tests {
let ssz_block = SszBeaconBlock::from_slice(&serialized).unwrap();
let sr_ssz = get_special_record_ssz(&s);
let mut expected = encode_length(sr_ssz.len(), LENGTH_BYTES);
let mut expected = encode_length(sr_ssz.len(), LENGTH_PREFIX_BYTES);
expected.append(&mut sr_ssz.to_vec());
assert_eq!(ssz_block.specials(), &expected[..]);
@ -399,7 +402,7 @@ mod tests {
let ssz_block = SszBeaconBlock::from_slice(&serialized).unwrap();
let sr_ssz = get_special_record_ssz(&s);
let mut expected = encode_length(sr_ssz.len(), LENGTH_BYTES);
let mut expected = encode_length(sr_ssz.len(), LENGTH_PREFIX_BYTES);
expected.append(&mut sr_ssz.to_vec());
assert_eq!(ssz_block.specials(), &expected[..]);
@ -417,7 +420,7 @@ mod tests {
let ssz_block = SszBeaconBlock::from_slice(&serialized).unwrap();
let ssz_ar = get_attestation_record_ssz(&AttestationRecord::zero());
let mut expected = encode_length(ssz_ar.len(), LENGTH_BYTES);
let mut expected = encode_length(ssz_ar.len(), LENGTH_PREFIX_BYTES);
expected.append(&mut ssz_ar.to_vec());
assert_eq!(ssz_block.attestations(), &expected[..]);
@ -434,7 +437,7 @@ mod tests {
let mut ssz_ar = get_attestation_record_ssz(&AttestationRecord::zero());
ssz_ar.append(&mut get_attestation_record_ssz(&AttestationRecord::zero()));
let mut expected = encode_length(ssz_ar.len(), LENGTH_BYTES);
let mut expected = encode_length(ssz_ar.len(), LENGTH_PREFIX_BYTES);
expected.append(&mut ssz_ar.to_vec());
assert_eq!(ssz_block.attestations(), &expected[..]);