txsizes

Documentation

Overview

Copyright (c) 2016 The btcsuite developers

Index

• Constants
• func EstimateSerializeSize(inputCount int, txOuts []*wire.TxOut, addChangeOutput bool) int
• func EstimateVirtualSize(numP2PKHIns, numP2WPKHIns, numNestedP2WPKHIns int, txOuts []*wire.TxOut, ...) int

Constants

const (
	// RedeemP2PKHSigScriptSize is the worst case (largest) serialize size
	// of a transaction input script that redeems a compressed P2PKH output.
	// It is calculated as:
	//
	//   - OP_DATA_73
	//   - 72 bytes DER signature + 1 byte sighash
	//   - OP_DATA_33
	//   - 33 bytes serialized compressed pubkey
	RedeemP2PKHSigScriptSize = 1 + 73 + 1 + 33
	// P2PKHPkScriptSize is the size of a transaction output script that
	// pays to a compressed pubkey hash.  It is calculated as:
	//
	//   - OP_DUP
	//   - OP_HASH160
	//   - OP_DATA_20
	//   - 20 bytes pubkey hash
	//   - OP_EQUALVERIFY
	//   - OP_CHECKSIG
	P2PKHPkScriptSize = 1 + 1 + 1 + 20 + 1 + 1
	// RedeemP2PKHInputSize is the worst case (largest) serialize size of a
	// transaction input redeeming a compressed P2PKH output.  It is
	// calculated as:
	//
	//   - 32 bytes previous tx
	//   - 4 bytes output index
	//   - 1 byte compact int encoding value 107
	//   - 107 bytes signature script
	//   - 4 bytes sequence
	RedeemP2PKHInputSize = 32 + 4 + 1 + RedeemP2PKHSigScriptSize + 4
	// P2PKHOutputSize is the serialize size of a transaction output with a
	// P2PKH output script.  It is calculated as:
	//
	//   - 8 bytes output value
	//   - 1 byte compact int encoding value 25
	//   - 25 bytes P2PKH output script
	P2PKHOutputSize = 8 + 1 + P2PKHPkScriptSize
	// P2WPKHPkScriptSize is the size of a transaction output script that
	// pays to a witness pubkey hash. It is calculated as:
	//
	//   - OP_0
	//   - OP_DATA_20
	//   - 20 bytes pubkey hash
	P2WPKHPkScriptSize = 1 + 1 + 20
	// P2WPKHOutputSize is the serialize size of a transaction output with a
	// P2WPKH output script. It is calculated as:
	//
	//   - 8 bytes output value
	//   - 1 byte compact int encoding value 22
	//   - 22 bytes P2PKH output script
	P2WPKHOutputSize = 8 + 1 + P2WPKHPkScriptSize
	// RedeemP2WPKHScriptSize is the size of a transaction input script
	// that spends a pay-to-witness-public-key hash (P2WPKH). The redeem
	// script for P2WPKH spends MUST be empty.
	RedeemP2WPKHScriptSize = 0
	// RedeemP2WPKHInputSize is the worst case size of a transaction
	// input redeeming a P2WPKH output. It is calculated as:
	//
	//   - 32 bytes previous tx
	//   - 4 bytes output index
	//   - 1 byte encoding empty redeem script
	//   - 0 bytes redeem script
	//   - 4 bytes sequence
	RedeemP2WPKHInputSize = 32 + 4 + 1 + RedeemP2WPKHScriptSize + 4
	// RedeemNestedP2WPKHScriptSize is the worst case size of a transaction
	// input script that redeems a pay-to-witness-key hash nested in P2SH
	// (P2SH-P2WPKH). It is calculated as:
	//
	//   - 1 byte compact int encoding value 22
	//   - OP_0
	//   - 1 byte compact int encoding value 20
	//   - 20 byte key hash
	RedeemNestedP2WPKHScriptSize = 1 + 1 + 1 + 20
	// RedeemNestedP2WPKHInputSize is the worst case size of a
	// transaction input redeeming a P2SH-P2WPKH output. It is
	// calculated as:
	//
	//   - 32 bytes previous tx
	//   - 4 bytes output index
	//   - 1 byte compact int encoding value 23
	//   - 23 bytes redeem script (scriptSig)
	//   - 4 bytes sequence
	RedeemNestedP2WPKHInputSize = 32 + 4 + 1 +
		RedeemNestedP2WPKHScriptSize + 4
	// RedeemP2WPKHInputWitnessWeight is the worst case weight of
	// a witness for spending P2WPKH and nested P2WPKH outputs. It
	// is calculated as:
	//
	//   - 1 wu compact int encoding value 2 (number of items)
	//   - 1 wu compact int encoding value 73
	//   - 72 wu DER signature + 1 wu sighash
	//   - 1 wu compact int encoding value 33
	//   - 33 wu serialized compressed pubkey
	RedeemP2WPKHInputWitnessWeight = 1 + 1 + 73 + 1 + 33
)

Worst case script and input/output size estimates.

Functions

func EstimateSerializeSize

func EstimateSerializeSize(inputCount int, txOuts []*wire.TxOut, addChangeOutput bool) int

EstimateSerializeSize returns a worst case serialize size estimate for a signed transaction that spends inputCount number of compressed P2PKH outputs and contains each transaction output from txOuts. The estimated size is incremented for an additional P2PKH change output if addChangeOutput is true.

func EstimateVirtualSize

func EstimateVirtualSize(numP2PKHIns, numP2WPKHIns, numNestedP2WPKHIns int,
	txOuts []*wire.TxOut, addChangeOutput bool) int

EstimateVirtualSize returns a worst case virtual size estimate for a signed transaction that spends the given number of P2PKH, P2WPKH and (nested) P2SH-P2WPKH outputs, and contains each transaction output from txOuts. The estimate is incremented for an additional P2PKH change output if addChangeOutput is true.