txsizes

Documentation

Index

• Constants
• func EstimateInputSize(scriptSize int) int
• func EstimateSerializeSize(scriptSizers []ScriptSizer, txOuts []*wire.TxOut, addChangeOutput bool) int
• type ScriptSizer

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

	// RedeemP2SHSigScriptSize is the worst case (largest) serialize size
	// of a transaction input script that redeems a P2SH output.
	// It is calculated as:
	//
	//  - OP_DATA_73
	//  - 73-byte signature
	//  - OP_DATA_35
	//  - OP_DATA_33
	//  - 33 bytes serialized compressed pubkey
	//  - OP_CHECKSIG
	RedeemP2SHSigScriptSize = 1 + 73 + 1 + 1 + 33 + 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 tree
	//   - 8 bytes amount
	//   - 4 bytes block height
	//   - 4 bytes block index
	//   - 1 byte compact int encoding value 107
	//   - 107 bytes signature script
	//   - 4 bytes sequence
	RedeemP2PKHInputSize = 32 + 4 + 1 + 8 + 4 + 4 + 1 + RedeemP2PKHSigScriptSize + 4

	// 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

	// P2PKHOutputSize is the serialize size of a transaction output with a
	// P2PKH output script.  It is calculated as:
	//
	//   - 8 bytes output value
	//   - 2 bytes version
	//   - 1 byte compact int encoding value 25
	//   - 25 bytes P2PKH output script
	P2PKHOutputSize = 8 + 2 + 1 + 25

	// signature script definitions
	P2SHScriptSize  = sigScriptSize(RedeemP2SHSigScriptSize)
	P2PKHScriptSize = sigScriptSize(RedeemP2PKHSigScriptSize)
)

Worst case script and input/output size estimates.

Functions

func EstimateInputSize

func EstimateInputSize(scriptSize int) int

EstimateInputSize returns the worst case serialize size estimate for a tx input

• 32 bytes previous tx
• 4 bytes output index
• 1 byte tree
• 8 bytes amount
• 4 bytes block height
• 4 bytes block index
• the compact int representation of the script size
• the supplied script size
• 4 bytes sequence

func EstimateSerializeSize

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

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

Types

type ScriptSizer

type ScriptSizer interface {
	ScriptSize() int
}

ScriptSizer signature script sizing interface