@trezor/utxo-lib/lib/txWeightCalculator.js

Client-side Bitcoin-like JavaScript library

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.TxWeightCalculator = void 0;
const coinselectUtils_1 = require("./coinselect/coinselectUtils");
const _TXSIZE_HEADER = 4;
const _TXSIZE_FOOTER = 4;
const _TXSIZE_SEGWIT_OVERHEAD = 2;
const _TXSIZE_INPUT = 40;
const _TXSIZE_OUTPUT = 8;
const _TXSIZE_PUBKEY = 33;
const _TXSIZE_DER_SIGNATURE = 72;
const _TXSIZE_SCHNORR_SIGNATURE = 64;
const _TXSIZE_MULTISIGSCRIPT = 3;
const _TXSIZE_WITNESSPKHASH = 22;
const _TXSIZE_WITNESSSCRIPT = 34;
const SCRIPT_TYPES = {
  p2pkh: 'SPENDADDRESS',
  p2sh: 'SPENDP2SHWITNESS',
  p2tr: 'SPENDTAPROOT',
  p2wpkh: 'SPENDWITNESS'
};
const SEGWIT_INPUT_SCRIPT_TYPES = ['SPENDP2SHWITNESS', 'SPENDWITNESS', 'SPENDTAPROOT'];
const NONSEGWIT_INPUT_SCRIPT_TYPES = ['SPENDADDRESS', 'SPENDMULTISIG'];
function getVarIntSize(length) {
  if (length < 253) return 1;
  if (length < 65536) return 3;
  return 5;
}
function getOpPushSize(length) {
  if (length < 76) return 1;
  if (length < 256) return 2;
  if (length < 65536) return 3;
  return 5;
}
class TxWeightCalculator {
  inputs_count = 0;
  outputs_count = 0;
  counter = 4 * (_TXSIZE_HEADER + _TXSIZE_FOOTER);
  segwit_inputs_count = 0;
  inputs = [];
  addInputByKey(type) {
    this.addInput({
      script_type: SCRIPT_TYPES[type]
    });
  }
  addInput(input) {
    this.inputs_count += 1;
    let input_script_size = 0;
    if (input.multisig) {
      if (input.script_type === 'SPENDTAPROOT') {
        throw new Error('Multisig not supported for Taproot yet');
      }
      const n = input.multisig.nodes ? input.multisig.nodes.length : input.multisig.pubkeys.length;
      let multisig_script_size = _TXSIZE_MULTISIGSCRIPT + n * (1 + _TXSIZE_PUBKEY);
      if (SEGWIT_INPUT_SCRIPT_TYPES.includes(input.script_type)) {
        multisig_script_size += getVarIntSize(multisig_script_size);
      } else {
        multisig_script_size += getOpPushSize(multisig_script_size);
        input_script_size = 1 + input.multisig.m * (1 + _TXSIZE_DER_SIGNATURE) + multisig_script_size;
      }
    } else if (input.script_type === 'SPENDTAPROOT') {
      input_script_size = 1 + _TXSIZE_SCHNORR_SIGNATURE;
    } else {
      input_script_size = 1 + _TXSIZE_DER_SIGNATURE + 1 + _TXSIZE_PUBKEY;
    }
    this.counter += 4 * _TXSIZE_INPUT;
    if (NONSEGWIT_INPUT_SCRIPT_TYPES.includes(input.script_type)) {
      input_script_size += getVarIntSize(input_script_size);
      this.counter += 4 * input_script_size;
    } else if (SEGWIT_INPUT_SCRIPT_TYPES.includes(input.script_type)) {
      this.segwit_inputs_count += 1;
      if (input.script_type === 'SPENDP2SHWITNESS') {
        if (input.multisig) {
          this.counter += 4 * (2 + _TXSIZE_WITNESSSCRIPT);
        } else {
          this.counter += 4 * (2 + _TXSIZE_WITNESSPKHASH);
        }
      } else {
        this.counter += 4;
      }
      this.counter += 1 + input_script_size;
    } else if (input.script_type === 'EXTERNAL') {
      const witness_size = 0;
      const script_sig_size = 0;
      if (input.ownership_proof) {} else {}
      if (witness_size > 1) {
        this.segwit_inputs_count += 1;
      }
      this.counter += 4 * (getVarIntSize(script_sig_size) + script_sig_size);
      this.counter += witness_size;
    } else {
      throw new Error('unknown input script_type');
    }
    this.inputs.push({
      length: input_script_size
    });
  }
  addOutputByKey(key) {
    this.addOutput({
      length: coinselectUtils_1.OUTPUT_SCRIPT_LENGTH[key]
    });
  }
  addOutput(script) {
    this.outputs_count += 1;
    const script_size = getVarIntSize(script.length) + script.length;
    this.counter += 4 * (_TXSIZE_OUTPUT + script_size);
  }
  getTotal() {
    let total = this.counter;
    total += 4 * getVarIntSize(this.inputs_count);
    total += 4 * getVarIntSize(this.outputs_count);
    if (this.segwit_inputs_count) {
      total += _TXSIZE_SEGWIT_OVERHEAD;
      total += this.inputs_count - this.segwit_inputs_count;
    }
    return total;
  }
  getVirtualBytes() {
    return Math.ceil(this.getTotal() / 4);
  }
}
exports.TxWeightCalculator = TxWeightCalculator;
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