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Witness: Fix nits from PR 1323

This commit is contained in:
junderw 2022-11-07 03:34:38 +09:00
parent 3c0d5aed73
commit 00c7b6e06f
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1 changed files with 12 additions and 14 deletions
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26
bitcoin/src/blockdata/witness.rs
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@ -17,8 +17,6 @@ use crate::io::{self, Read, Write};
use crate::prelude::*; use crate::prelude::*;
use crate::VarInt; use crate::VarInt;
const U32_SIZE: usize = core::mem::size_of::<u32>();
/// The Witness is the data used to unlock bitcoins since the [segwit upgrade](https://github.com/bitcoin/bips/blob/master/bip-0143.mediawiki) /// The Witness is the data used to unlock bitcoins since the [segwit upgrade](https://github.com/bitcoin/bips/blob/master/bip-0143.mediawiki)
/// ///
/// Can be logically seen as an array of byte-arrays `Vec<Vec<u8>>` and indeed you can convert from /// Can be logically seen as an array of byte-arrays `Vec<Vec<u8>>` and indeed you can convert from
@ -66,7 +64,7 @@ impl Decodable for Witness {
} else { } else {
// Leave space at the head for element positions. // Leave space at the head for element positions.
// We will rotate them to the end of the Vec later. // We will rotate them to the end of the Vec later.
let witness_index_space = witness_elements * U32_SIZE; let witness_index_space = witness_elements * 4;
let mut cursor = witness_index_space; let mut cursor = witness_index_space;
// this number should be determined as high enough to cover most witness, and low enough // this number should be determined as high enough to cover most witness, and low enough
@ -120,18 +118,18 @@ impl Decodable for Witness {
} }
/// Safety Requirements: value must always fit within u32 /// Correctness Requirements: value must always fit within u32
#[inline] #[inline]
fn encode_cursor(bytes: &mut [u8], start_of_indices: usize, index: usize, value: usize) { fn encode_cursor(bytes: &mut [u8], start_of_indices: usize, index: usize, value: usize) {
let start = start_of_indices + index * U32_SIZE; let start = start_of_indices + index * 4;
let end = start + U32_SIZE; let end = start + 4;
bytes[start..end].copy_from_slice(&(value as u32).to_ne_bytes()[..]); bytes[start..end].copy_from_slice(&u32::to_ne_bytes(value.try_into().expect("Larger than u32")));
} }
#[inline] #[inline]
fn decode_cursor(bytes: &[u8], start_of_indices: usize, index: usize) -> Option<usize> { fn decode_cursor(bytes: &[u8], start_of_indices: usize, index: usize) -> Option<usize> {
let start = start_of_indices + index * U32_SIZE; let start = start_of_indices + index * 4;
let end = start + U32_SIZE; let end = start + 4;
if end > bytes.len() { if end > bytes.len() {
None None
} else { } else {
@ -154,7 +152,7 @@ impl Encodable for Witness {
let len = VarInt(self.witness_elements as u64); let len = VarInt(self.witness_elements as u64);
len.consensus_encode(w)?; len.consensus_encode(w)?;
let content_with_indices_len = self.content.len(); let content_with_indices_len = self.content.len();
let indices_size = self.witness_elements * U32_SIZE; let indices_size = self.witness_elements * 4;
let content_len = content_with_indices_len - indices_size; let content_len = content_with_indices_len - indices_size;
w.emit_slice(&self.content[..content_len])?; w.emit_slice(&self.content[..content_len])?;
Ok(content_len + len.len()) Ok(content_len + len.len())
@ -170,7 +168,7 @@ impl Witness {
/// Creates [`Witness`] object from an array of byte-arrays /// Creates [`Witness`] object from an array of byte-arrays
pub fn from_vec(vec: Vec<Vec<u8>>) -> Self { pub fn from_vec(vec: Vec<Vec<u8>>) -> Self {
let witness_elements = vec.len(); let witness_elements = vec.len();
let index_size = witness_elements * U32_SIZE; let index_size = witness_elements * 4;
let content_size: usize = vec let content_size: usize = vec
.iter() .iter()
@ -245,7 +243,7 @@ impl Witness {
let current_content_len = self.content.len(); let current_content_len = self.content.len();
let new_item_total_len = element_len_varint.len() + new_element.len(); let new_item_total_len = element_len_varint.len() + new_element.len();
self.content self.content
.resize(current_content_len + new_item_total_len + U32_SIZE, 0); .resize(current_content_len + new_item_total_len + 4, 0);
self.content[previous_content_end..].rotate_right(new_item_total_len); self.content[previous_content_end..].rotate_right(new_item_total_len);
self.indices_start += new_item_total_len; self.indices_start += new_item_total_len;
@ -350,7 +348,7 @@ impl<'a> Iterator for Iter<'a> {
} }
fn size_hint(&self) -> (usize, Option<usize>) { fn size_hint(&self) -> (usize, Option<usize>) {
let total_count = (self.inner.len() - self.indices_start) / U32_SIZE; let total_count = (self.inner.len() - self.indices_start) / 4;
let remaining = total_count - self.current_index; let remaining = total_count - self.current_index;
(remaining, Some(remaining)) (remaining, Some(remaining))
} }
@ -459,7 +457,7 @@ mod test {
fn append_u32_vec(mut v: Vec<u8>, n: &[u32]) -> Vec<u8> { fn append_u32_vec(mut v: Vec<u8>, n: &[u32]) -> Vec<u8> {
for &num in n { for &num in n {
v.extend_from_slice(&num.to_ne_bytes()[..]); v.extend_from_slice(&num.to_ne_bytes());
} }
v v
} }