bdk_coin_select 0.2.0

Tools for input selection for making bitcoin transactions.
Documentation 
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#![doc = include_str!("../README.md")]
#![no_std]
#![warn(missing_docs)]
#![deny(unsafe_code)]

#[allow(unused_imports)]
#[macro_use]
extern crate alloc;

#[cfg(feature = "std")]
#[macro_use]
extern crate std;

mod coin_selector;
pub mod float;
pub use coin_selector::*;

mod bnb;
pub use bnb::*;

pub mod metrics;

mod feerate;
pub use feerate::*;
mod change_policy;
pub use change_policy::*;

/// Txin "base" fields include `outpoint` (32+4) and `nSequence` (4) and 1 byte for the scriptSig
/// length.
pub const TXIN_BASE_WEIGHT: u32 = (32 + 4 + 4 + 1) * 4;

/// The weight of a TXOUT with a zero length `scriptPubKey`
#[allow(clippy::identity_op)]
pub const TXOUT_BASE_WEIGHT: u32 =
    // The value
    4 * core::mem::size_of::<u64>() as u32
    // The spk length
    + (4 * 1);

/// The additional weight over [`TXIN_BASE_WEIGHT`] incurred by satisfying an input with a keyspend
/// and the default sighash.
pub const TR_KEYSPEND_SATISFACTION_WEIGHT: u32 = 66;

/// The additional weight of an output with segwit `v1` (taproot) script pubkey over a blank output (i.e. with weight [`TXOUT_BASE_WEIGHT`]).
pub const TR_SPK_WEIGHT: u32 = (1 + 1 + 32) * 4; // version + push + key

/// The weight of a taproot TxIn with witness
pub const TR_KEYSPEND_TXIN_WEIGHT: u32 = TXIN_BASE_WEIGHT + TR_KEYSPEND_SATISFACTION_WEIGHT;

/// Helper to calculate varint size. `v` is the value the varint represents.
fn varint_size(v: usize) -> u32 {
    if v <= 0xfc {
        return 1;
    }
    if v <= 0xffff {
        return 3;
    }
    if v <= 0xffff_ffff {
        return 5;
    }
    9
}

#[allow(unused)]
fn txout_weight_from_spk_len(spk_len: usize) -> u32 {
    (TXOUT_BASE_WEIGHT + varint_size(spk_len) + (spk_len as u32)) * 4
}