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rust-bitcoin-unsafe-fast
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Run cargo +nightly fmt 

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Tobin C. Harding 2024-08-12 20:17:43 +10:00
parent 9c4a629659
commit 100ce03643
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1 changed files with 86 additions and 86 deletions
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172
bitcoin/src/pow.rs
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@ -358,96 +358,96 @@ impl CompactTarget {
mod tmp {
use super::*;
impl CompactTarget {
/// Creates a `CompactTarget` from a prefixed hex string.
pub fn from_hex(s: &str) -> Result<Self, PrefixedHexError> {
let target = parse::hex_u32_prefixed(s)?;
Ok(Self::from_consensus(target))
}
/// Creates a `CompactTarget` from an unprefixed hex string.
pub fn from_unprefixed_hex(s: &str) -> Result<Self, UnprefixedHexError> {
let target = parse::hex_u32_unprefixed(s)?;
Ok(Self::from_consensus(target))
}
/// Computes the [`CompactTarget`] from a difficulty adjustment.
///
/// ref: <https://github.com/bitcoin/bitcoin/blob/0503cbea9aab47ec0a87d34611e5453158727169/src/pow.cpp>
///
/// Given the previous Target, represented as a [`CompactTarget`], the difficulty is adjusted
/// by taking the timespan between them, and multipling the current [`CompactTarget`] by a factor
/// of the net timespan and expected timespan. The [`CompactTarget`] may not adjust by more than
/// a factor of 4, or adjust beyond the maximum threshold for the network.
///
/// # Note
///
/// Under the consensus rules, the difference in the number of blocks between the headers does
/// not equate to the `difficulty_adjustment_interval` of [`Params`]. This is due to an off-by-one
/// error, and, the expected number of blocks in between headers is `difficulty_adjustment_interval - 1`
/// when calculating the difficulty adjustment.
///
/// Take the example of the first difficulty adjustment. Block 2016 introduces a new [`CompactTarget`],
/// which takes the net timespan between Block 2015 and Block 0, and recomputes the difficulty.
///
/// # Returns
///
/// The expected [`CompactTarget`] recalculation.
pub fn from_next_work_required(
last: CompactTarget,
timespan: u64,
params: impl AsRef<Params>,
) -> CompactTarget {
let params = params.as_ref();
if params.no_pow_retargeting {
return last;
impl CompactTarget {
/// Creates a `CompactTarget` from a prefixed hex string.
pub fn from_hex(s: &str) -> Result<Self, PrefixedHexError> {
let target = parse::hex_u32_prefixed(s)?;
Ok(Self::from_consensus(target))
}
// Comments relate to the `pow.cpp` file from Core.
// ref: <https://github.com/bitcoin/bitcoin/blob/0503cbea9aab47ec0a87d34611e5453158727169/src/pow.cpp>
let min_timespan = params.pow_target_timespan >> 2; // Lines 56/57
let max_timespan = params.pow_target_timespan << 2; // Lines 58/59
let actual_timespan = timespan.clamp(min_timespan, max_timespan);
let prev_target: Target = last.into();
let maximum_retarget = prev_target.max_transition_threshold(params); // bnPowLimit
let retarget = prev_target.0; // bnNew
let retarget = retarget.mul(actual_timespan.into());
let retarget = retarget.div(params.pow_target_timespan.into());
let retarget = Target(retarget);
if retarget.ge(&maximum_retarget) {
return maximum_retarget.to_compact_lossy();
}
retarget.to_compact_lossy()
}
/// Computes the [`CompactTarget`] from a difficulty adjustment,
/// assuming these are the relevant block headers.
///
/// Given two headers, representing the start and end of a difficulty adjustment epoch,
/// compute the [`CompactTarget`] based on the net time between them and the current
/// [`CompactTarget`].
///
/// # Note
///
/// See [`CompactTarget::from_next_work_required`]
///
/// For example, to successfully compute the first difficulty adjustment on the Bitcoin network,
/// one would pass the header for Block 2015 as `current` and the header for Block 0 as
/// `last_epoch_boundary`.
///
/// # Returns
///
/// The expected [`CompactTarget`] recalculation.
pub fn from_header_difficulty_adjustment(
last_epoch_boundary: Header,
current: Header,
params: impl AsRef<Params>,
) -> CompactTarget {
let timespan = current.time - last_epoch_boundary.time;
let bits = current.bits;
CompactTarget::from_next_work_required(bits, timespan.into(), params)
/// Creates a `CompactTarget` from an unprefixed hex string.
pub fn from_unprefixed_hex(s: &str) -> Result<Self, UnprefixedHexError> {
let target = parse::hex_u32_unprefixed(s)?;
Ok(Self::from_consensus(target))
}
/// Computes the [`CompactTarget`] from a difficulty adjustment.
///
/// ref: <https://github.com/bitcoin/bitcoin/blob/0503cbea9aab47ec0a87d34611e5453158727169/src/pow.cpp>
///
/// Given the previous Target, represented as a [`CompactTarget`], the difficulty is adjusted
/// by taking the timespan between them, and multipling the current [`CompactTarget`] by a factor
/// of the net timespan and expected timespan. The [`CompactTarget`] may not adjust by more than
/// a factor of 4, or adjust beyond the maximum threshold for the network.
///
/// # Note
///
/// Under the consensus rules, the difference in the number of blocks between the headers does
/// not equate to the `difficulty_adjustment_interval` of [`Params`]. This is due to an off-by-one
/// error, and, the expected number of blocks in between headers is `difficulty_adjustment_interval - 1`
/// when calculating the difficulty adjustment.
///
/// Take the example of the first difficulty adjustment. Block 2016 introduces a new [`CompactTarget`],
/// which takes the net timespan between Block 2015 and Block 0, and recomputes the difficulty.
///
/// # Returns
///
/// The expected [`CompactTarget`] recalculation.
pub fn from_next_work_required(
last: CompactTarget,
timespan: u64,
params: impl AsRef<Params>,
) -> CompactTarget {
let params = params.as_ref();
if params.no_pow_retargeting {
return last;
}
// Comments relate to the `pow.cpp` file from Core.
// ref: <https://github.com/bitcoin/bitcoin/blob/0503cbea9aab47ec0a87d34611e5453158727169/src/pow.cpp>
let min_timespan = params.pow_target_timespan >> 2; // Lines 56/57
let max_timespan = params.pow_target_timespan << 2; // Lines 58/59
let actual_timespan = timespan.clamp(min_timespan, max_timespan);
let prev_target: Target = last.into();
let maximum_retarget = prev_target.max_transition_threshold(params); // bnPowLimit
let retarget = prev_target.0; // bnNew
let retarget = retarget.mul(actual_timespan.into());
let retarget = retarget.div(params.pow_target_timespan.into());
let retarget = Target(retarget);
if retarget.ge(&maximum_retarget) {
return maximum_retarget.to_compact_lossy();
}
retarget.to_compact_lossy()
}
/// Computes the [`CompactTarget`] from a difficulty adjustment,
/// assuming these are the relevant block headers.
///
/// Given two headers, representing the start and end of a difficulty adjustment epoch,
/// compute the [`CompactTarget`] based on the net time between them and the current
/// [`CompactTarget`].
///
/// # Note
///
/// See [`CompactTarget::from_next_work_required`]
///
/// For example, to successfully compute the first difficulty adjustment on the Bitcoin network,
/// one would pass the header for Block 2015 as `current` and the header for Block 0 as
/// `last_epoch_boundary`.
///
/// # Returns
///
/// The expected [`CompactTarget`] recalculation.
pub fn from_header_difficulty_adjustment(
last_epoch_boundary: Header,
current: Header,
params: impl AsRef<Params>,
) -> CompactTarget {
let timespan = current.time - last_epoch_boundary.time;
let bits = current.bits;
CompactTarget::from_next_work_required(bits, timespan.into(), params)
}
}
}
}
impl From<CompactTarget> for Target {
fn from(c: CompactTarget) -> Self { Target::from_compact(c) }