Merge pull request #626 from visvirial/impl-vsize

Implement `Block.get_strippedsize()` and `Transaction.get_vsize()`
This commit is contained in:
Dr. Maxim Orlovsky 2021-09-11 00:09:22 +02:00 committed by GitHub
commit 697e8f5194
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 68 additions and 5 deletions

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@ -233,17 +233,27 @@ impl Block {
bitcoin_merkle_root(hashes).into() bitcoin_merkle_root(hashes).into()
} }
/// The size of the header + the size of the varint with the tx count + the txs themselves
#[inline]
fn get_base_size(&self) -> usize {
80 + VarInt(self.txdata.len() as u64).len()
}
/// Get the size of the block /// Get the size of the block
pub fn get_size(&self) -> usize { pub fn get_size(&self) -> usize {
// The size of the header + the size of the varint with the tx count + the txs themselves
let base_size = 80 + VarInt(self.txdata.len() as u64).len();
let txs_size: usize = self.txdata.iter().map(Transaction::get_size).sum(); let txs_size: usize = self.txdata.iter().map(Transaction::get_size).sum();
base_size + txs_size self.get_base_size() + txs_size
}
/// Get the strippedsize of the block
pub fn get_strippedsize(&self) -> usize {
let txs_size: usize = self.txdata.iter().map(Transaction::get_strippedsize).sum();
self.get_base_size() + txs_size
} }
/// Get the weight of the block /// Get the weight of the block
pub fn get_weight(&self) -> usize { pub fn get_weight(&self) -> usize {
let base_weight = WITNESS_SCALE_FACTOR * (80 + VarInt(self.txdata.len() as u64).len()); let base_weight = WITNESS_SCALE_FACTOR * self.get_base_size();
let txs_weight: usize = self.txdata.iter().map(Transaction::get_weight).sum(); let txs_weight: usize = self.txdata.iter().map(Transaction::get_weight).sum();
base_weight + txs_weight base_weight + txs_weight
} }
@ -372,6 +382,7 @@ mod tests {
// [test] TODO: check the transaction data // [test] TODO: check the transaction data
assert_eq!(real_decode.get_size(), some_block.len()); assert_eq!(real_decode.get_size(), some_block.len());
assert_eq!(real_decode.get_strippedsize(), some_block.len());
assert_eq!(real_decode.get_weight(), some_block.len() * 4); assert_eq!(real_decode.get_weight(), some_block.len() * 4);
// should be also ok for a non-witness block as commitment is optional in that case // should be also ok for a non-witness block as commitment is optional in that case
@ -406,6 +417,7 @@ mod tests {
// [test] TODO: check the transaction data // [test] TODO: check the transaction data
assert_eq!(real_decode.get_size(), segwit_block.len()); assert_eq!(real_decode.get_size(), segwit_block.len());
assert_eq!(real_decode.get_strippedsize(), 4283);
assert_eq!(real_decode.get_weight(), 17168); assert_eq!(real_decode.get_weight(), 17168);
assert!(real_decode.check_witness_commitment()); assert!(real_decode.check_witness_commitment());

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@ -429,6 +429,39 @@ impl Transaction {
self.get_scaled_size(1) self.get_scaled_size(1)
} }
/// Gets the "vsize" of this transaction. Will be `ceil(weight / 4.0)`.
#[inline]
pub fn get_vsize(&self) -> usize {
let weight = self.get_weight();
(weight + WITNESS_SCALE_FACTOR - 1) / WITNESS_SCALE_FACTOR
}
/// Gets the size of this transaction excluding the witness data.
pub fn get_strippedsize(&self) -> usize {
let mut input_size = 0;
for input in &self.input {
input_size += 32 + 4 + 4 + // outpoint (32+4) + nSequence
VarInt(input.script_sig.len() as u64).len() +
input.script_sig.len();
}
let mut output_size = 0;
for output in &self.output {
output_size += 8 + // value
VarInt(output.script_pubkey.len() as u64).len() +
output.script_pubkey.len();
}
let non_input_size =
// version:
4 +
// count varints:
VarInt(self.input.len() as u64).len() +
VarInt(self.output.len() as u64).len() +
output_size +
// lock_time
4;
non_input_size + input_size
}
/// Internal utility function for get_{size,weight} /// Internal utility function for get_{size,weight}
fn get_scaled_size(&self, scale_factor: usize) -> usize { fn get_scaled_size(&self, scale_factor: usize) -> usize {
let mut input_weight = 0; let mut input_weight = 0;
@ -857,6 +890,8 @@ mod tests {
"a6eab3c14ab5272a58a5ba91505ba1a4b6d7a3a9fcbd187b6cd99a7b6d548cb7".to_string()); "a6eab3c14ab5272a58a5ba91505ba1a4b6d7a3a9fcbd187b6cd99a7b6d548cb7".to_string());
assert_eq!(realtx.get_weight(), tx_bytes.len()*WITNESS_SCALE_FACTOR); assert_eq!(realtx.get_weight(), tx_bytes.len()*WITNESS_SCALE_FACTOR);
assert_eq!(realtx.get_size(), tx_bytes.len()); assert_eq!(realtx.get_size(), tx_bytes.len());
assert_eq!(realtx.get_vsize(), tx_bytes.len());
assert_eq!(realtx.get_strippedsize(), tx_bytes.len());
} }
#[test] #[test]
@ -887,8 +922,24 @@ mod tests {
"f5864806e3565c34d1b41e716f72609d00b55ea5eac5b924c9719a842ef42206".to_string()); "f5864806e3565c34d1b41e716f72609d00b55ea5eac5b924c9719a842ef42206".to_string());
assert_eq!(format!("{:x}", realtx.wtxid()), assert_eq!(format!("{:x}", realtx.wtxid()),
"80b7d8a82d5d5bf92905b06f2014dd699e03837ca172e3a59d51426ebbe3e7f5".to_string()); "80b7d8a82d5d5bf92905b06f2014dd699e03837ca172e3a59d51426ebbe3e7f5".to_string());
assert_eq!(realtx.get_weight(), 442); const EXPECTED_WEIGHT: usize = 442;
assert_eq!(realtx.get_weight(), EXPECTED_WEIGHT);
assert_eq!(realtx.get_size(), tx_bytes.len()); assert_eq!(realtx.get_size(), tx_bytes.len());
assert_eq!(realtx.get_vsize(), 111);
// Since
// size = stripped_size + witness_size
// weight = WITNESS_SCALE_FACTOR * stripped_size + witness_size
// then,
// stripped_size = (weight - size) / (WITNESS_SCALE_FACTOR - 1)
let expected_strippedsize = (EXPECTED_WEIGHT - tx_bytes.len()) / (WITNESS_SCALE_FACTOR - 1);
assert_eq!(realtx.get_strippedsize(), expected_strippedsize);
// Construct a transaction without the witness data.
let mut tx_without_witness = realtx.clone();
tx_without_witness.input.iter_mut().for_each(|input| input.witness.clear());
assert_eq!(tx_without_witness.get_weight(), expected_strippedsize*WITNESS_SCALE_FACTOR);
assert_eq!(tx_without_witness.get_size(), expected_strippedsize);
assert_eq!(tx_without_witness.get_vsize(), expected_strippedsize);
assert_eq!(tx_without_witness.get_strippedsize(), expected_strippedsize);
} }
#[test] #[test]