rust-bitcoin-unsafe-fast/bitcoin/src/blockdata/weight.rs

275 lines
7.6 KiB
Rust

//! Implements `Weight` and associated features.
use core::fmt;
use core::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign};
use crate::prelude::*;
/// Represents block weight - the weight of a transaction or block.
///
/// This is an integer newtype representing weigth in `wu`. It provides protection against mixing
/// up the types as well as basic formatting features.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[cfg_attr(feature = "serde", serde(crate = "actual_serde"))]
#[cfg_attr(feature = "serde", serde(transparent))]
pub struct Weight(u64);
impl Weight {
/// 0 wu.
///
/// Equivalent to [`MIN`](Self::MIN), may better express intent in some contexts.
pub const ZERO: Weight = Weight(0);
/// Minimum possible value (0 wu).
///
/// Equivalent to [`ZERO`](Self::ZERO), may better express intent in some contexts.
pub const MIN: Weight = Weight(u64::min_value());
/// Maximum possible value.
pub const MAX: Weight = Weight(u64::max_value());
/// Directly constructs `Weight` from weight units.
pub const fn from_wu(wu: u64) -> Self { Weight(wu) }
/// Constructs `Weight` from kilo weight units returning `None` if overflow occurred.
pub fn from_kwu(wu: u64) -> Option<Self> { wu.checked_mul(1000).map(Weight) }
/// Constructs `Weight` from virtual bytes.
///
/// # Errors
///
/// Returns `None` on overflow.
pub fn from_vb(vb: u64) -> Option<Self> { vb.checked_mul(4).map(Weight::from_wu) }
/// Constructs `Weight` from virtual bytes without overflow check.
pub const fn from_vb_unchecked(vb: u64) -> Self { Weight::from_wu(vb * 4) }
/// Constructs `Weight` from witness size.
pub const fn from_witness_data_size(witness_size: u64) -> Self { Weight(witness_size) }
/// Constructs `Weight` from non-witness size.
pub const fn from_non_witness_data_size(non_witness_size: u64) -> Self {
Weight(non_witness_size * 4)
}
/// Returns raw weight units.
///
/// Can be used instead of `into()` to avoid inference issues.
pub const fn to_wu(self) -> u64 { self.0 }
/// Converts to kilo weight units rounding down.
pub const fn to_kwu_floor(self) -> u64 { self.0 / 1000 }
/// Converts to vB rounding down.
pub const fn to_vbytes_floor(self) -> u64 { self.0 / 4 }
/// Converts to vB rounding up.
pub const fn to_vbytes_ceil(self) -> u64 { (self.0 + 3) / 4 }
/// Checked addition.
///
/// Computes `self + rhs` returning `None` if overflow occurred.
pub fn checked_add(self, rhs: Self) -> Option<Self> { self.0.checked_add(rhs.0).map(Self) }
/// Checked subtraction.
///
/// Computes `self - rhs` returning `None` if overflow occurred.
pub fn checked_sub(self, rhs: Self) -> Option<Self> { self.0.checked_sub(rhs.0).map(Self) }
/// Checked multiplication.
///
/// Computes `self * rhs` returning `None` if overflow occurred.
pub fn checked_mul(self, rhs: u64) -> Option<Self> { self.0.checked_mul(rhs).map(Self) }
/// Checked division.
///
/// Computes `self / rhs` returning `None` if `rhs == 0`.
pub fn checked_div(self, rhs: u64) -> Option<Self> { self.0.checked_div(rhs).map(Self) }
}
/// Alternative will display the unit.
impl fmt::Display for Weight {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
if f.alternate() {
write!(f, "{} wu", self.0)
} else {
fmt::Display::fmt(&self.0, f)
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn weight_constructor_test() {
assert_eq!(Weight::ZERO, Weight::from_wu(0));
}
#[test]
fn kilo_weight_constructor_test() {
assert_eq!(Weight(1_000), Weight::from_kwu(1).expect("expected weight unit"));
}
#[test]
#[should_panic]
fn kilo_weight_constructor_panic_test() {
Weight::from_kwu(u64::max_value()).expect("expected weight unit");
}
#[test]
fn from_vb_test() {
let vb = Weight::from_vb(1).expect("expected weight unit");
assert_eq!(Weight(4), vb);
let vb = Weight::from_vb(u64::max_value());
assert_eq!(None, vb);
}
#[test]
fn from_vb_unchecked_test() {
let vb = Weight::from_vb_unchecked(1);
assert_eq!(Weight(4), vb);
}
#[test]
#[should_panic]
fn from_vb_unchecked_panic_test() { Weight::from_vb_unchecked(u64::max_value()); }
#[test]
fn from_witness_data_size_test() {
let witness_data_size = 1;
assert_eq!(Weight(witness_data_size), Weight::from_witness_data_size(witness_data_size));
}
#[test]
fn from_non_witness_data_size_test() {
assert_eq!(Weight(4), Weight::from_non_witness_data_size(1));
}
#[test]
fn to_kwu_floor_test() {
assert_eq!(1, Weight(1_000).to_kwu_floor());
}
#[test]
fn to_vb_floor_test() {
assert_eq!(1, Weight(4).to_vbytes_floor());
assert_eq!(1, Weight(5).to_vbytes_floor());
}
#[test]
fn to_vb_ceil_test() {
assert_eq!(1, Weight(4).to_vbytes_ceil());
assert_eq!(2, Weight(5).to_vbytes_ceil());
}
#[test]
fn checked_add_test() {
let result = Weight(1).checked_add(Weight(1)).expect("expected weight unit");
assert_eq!(Weight(2), result);
let result = Weight::MAX.checked_add(Weight(1));
assert_eq!(None, result);
}
#[test]
fn checked_sub_test() {
let result = Weight(1).checked_sub(Weight(1)).expect("expected weight unit");
assert_eq!(Weight::ZERO, result);
let result = Weight::MIN.checked_sub(Weight(1));
assert_eq!(None, result);
}
#[test]
fn checked_mul_test() {
let result = Weight(2).checked_mul(2).expect("expected weight unit");
assert_eq!(Weight(4), result);
let result = Weight::MAX.checked_mul(2);
assert_eq!(None, result);
}
#[test]
fn checked_div_test() {
let result = Weight(2).checked_div(2).expect("expected weight unit");
assert_eq!(Weight(1), result);
let result = Weight(2).checked_div(0);
assert_eq!(None, result);
}
}
impl From<Weight> for u64 {
fn from(value: Weight) -> Self { value.to_wu() }
}
impl Add for Weight {
type Output = Weight;
fn add(self, rhs: Weight) -> Self::Output { Weight(self.0 + rhs.0) }
}
impl AddAssign for Weight {
fn add_assign(&mut self, rhs: Self) { self.0 += rhs.0 }
}
impl Sub for Weight {
type Output = Weight;
fn sub(self, rhs: Weight) -> Self::Output { Weight(self.0 - rhs.0) }
}
impl SubAssign for Weight {
fn sub_assign(&mut self, rhs: Self) { self.0 -= rhs.0 }
}
impl Mul<u64> for Weight {
type Output = Weight;
fn mul(self, rhs: u64) -> Self::Output { Weight(self.0 * rhs) }
}
impl Mul<Weight> for u64 {
type Output = Weight;
fn mul(self, rhs: Weight) -> Self::Output { Weight(self * rhs.0) }
}
impl MulAssign<u64> for Weight {
fn mul_assign(&mut self, rhs: u64) { self.0 *= rhs }
}
impl Div<u64> for Weight {
type Output = Weight;
fn div(self, rhs: u64) -> Self::Output { Weight(self.0 / rhs) }
}
impl DivAssign<u64> for Weight {
fn div_assign(&mut self, rhs: u64) { self.0 /= rhs }
}
impl core::iter::Sum for Weight {
fn sum<I>(iter: I) -> Self
where
I: Iterator<Item = Self>,
{
Weight(iter.map(Weight::to_wu).sum())
}
}
impl<'a> core::iter::Sum<&'a Weight> for Weight {
fn sum<I>(iter: I) -> Self
where
I: Iterator<Item = &'a Weight>,
{
iter.cloned().sum()
}
}
crate::parse::impl_parse_str_from_int_infallible!(Weight, u64, from_wu);