@node-dlc/bitcoin/lib/LexicographicalSorters.ts

DLC bitcoin

import { HashByteOrder } from './HashByteOrder';
import { TxIn } from './TxIn';
import { TxOut } from './TxOut';

/**
 * Compares two transaction inputs and lexicographically sorted in
 * ascending order using the reversed byte order (RPC) of the txids.
 * If the same txids are in both TxIn, then the output index is sorted
 * in ascending order.
 * @param a
 * @param b
 */
export function bip69InputSorter(a: TxIn, b: TxIn): number {
  const txid = a.outpoint.txid
    .serialize(HashByteOrder.RPC)
    .compare(b.outpoint.txid.serialize());
  if (txid !== 0) return txid;

  if (a.outpoint.outputIndex < b.outpoint.outputIndex) return -1;
  if (a.outpoint.outputIndex > b.outpoint.outputIndex) return 1;
  return 0;
}

/**
 * Sort transaction amounts in ascending order. Then ScriptPubKey values
 * will be sorted in ascending byte order next.
 * @param a
 * @param b
 */
export function bip69OutputSorter(a: TxOut, b: TxOut): number {
  // sort by amount desc first
  const amount = Number(a.value.sats - b.value.sats);
  if (amount !== 0) return amount;

  // then sort by script pub key
  return a.scriptPubKey.serializeCmds().compare(b.scriptPubKey.serializeCmds());
}