215 lines
6.9 KiB
Go
215 lines
6.9 KiB
Go
// Copyright (c) 2014-2016 The btcsuite developers
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// Copyright (c) 2015-2019 The Decred developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package txscript_test
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import (
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"encoding/hex"
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"fmt"
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"github.com/lbryio/lbcd/btcec"
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"github.com/lbryio/lbcd/chaincfg"
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"github.com/lbryio/lbcd/chaincfg/chainhash"
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"github.com/lbryio/lbcd/txscript"
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"github.com/lbryio/lbcd/wire"
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btcutil "github.com/lbryio/lbcutil"
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)
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// This example demonstrates creating a script which pays to a bitcoin address.
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// It also prints the created script hex and uses the DisasmString function to
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// display the disassembled script.
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func ExamplePayToAddrScript() {
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// Parse the address to send the coins to into a btcutil.Address
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// which is useful to ensure the accuracy of the address and determine
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// the address type. It is also required for the upcoming call to
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// PayToAddrScript.
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addressStr := "bHW58d37s1hBjj3wPBkn5zpCX3F8ZW3uWf"
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address, err := btcutil.DecodeAddress(addressStr, &chaincfg.MainNetParams)
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if err != nil {
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fmt.Println(err)
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return
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}
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// Create a public key script that pays to the address.
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script, err := txscript.PayToAddrScript(address)
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if err != nil {
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fmt.Println(err)
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return
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}
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fmt.Printf("Script Hex: %x\n", script)
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disasm, err := txscript.DisasmString(script)
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if err != nil {
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fmt.Println(err)
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return
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}
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fmt.Println("Script Disassembly:", disasm)
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// Output:
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// Script Hex: 76a914345991dbf57bfb014b87006acdfafbfc5fe8292f88ac
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// Script Disassembly: OP_DUP OP_HASH160 345991dbf57bfb014b87006acdfafbfc5fe8292f OP_EQUALVERIFY OP_CHECKSIG
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}
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// This example demonstrates extracting information from a standard public key
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// script.
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func ExampleExtractPkScriptAddrs() {
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// Start with a standard pay-to-pubkey-hash script.
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scriptHex := "76a914128004ff2fcaf13b2b91eb654b1dc2b674f7ec6188ac"
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script, err := hex.DecodeString(scriptHex)
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if err != nil {
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fmt.Println(err)
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return
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}
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// Extract and print details from the script.
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scriptClass, addresses, reqSigs, err := txscript.ExtractPkScriptAddrs(
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script, &chaincfg.MainNetParams)
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if err != nil {
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fmt.Println(err)
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return
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}
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fmt.Println("Script Class:", scriptClass)
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fmt.Println("Addresses:", addresses)
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fmt.Println("Required Signatures:", reqSigs)
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// Output:
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// Script Class: pubkeyhash
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// Addresses: [bER6Ddq6YfRKDJDmmdeaqrP8XHmDJcYSJQ]
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// Required Signatures: 1
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}
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// This example demonstrates manually creating and signing a redeem transaction.
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func ExampleSignTxOutput() {
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// Ordinarily the private key would come from whatever storage mechanism
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// is being used, but for this example just hard code it.
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privKeyBytes, err := hex.DecodeString("22a47fa09a223f2aa079edf85a7c2" +
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"d4f8720ee63e502ee2869afab7de234b80c")
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if err != nil {
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fmt.Println(err)
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return
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}
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privKey, pubKey := btcec.PrivKeyFromBytes(btcec.S256(), privKeyBytes)
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pubKeyHash := btcutil.Hash160(pubKey.SerializeCompressed())
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addr, err := btcutil.NewAddressPubKeyHash(pubKeyHash,
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&chaincfg.MainNetParams)
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if err != nil {
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fmt.Println(err)
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return
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}
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// For this example, create a fake transaction that represents what
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// would ordinarily be the real transaction that is being spent. It
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// contains a single output that pays to address in the amount of 1 BTC.
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originTx := wire.NewMsgTx(wire.TxVersion)
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prevOut := wire.NewOutPoint(&chainhash.Hash{}, ^uint32(0))
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txIn := wire.NewTxIn(prevOut, []byte{txscript.OP_0, txscript.OP_0}, nil)
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originTx.AddTxIn(txIn)
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pkScript, err := txscript.PayToAddrScript(addr)
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if err != nil {
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fmt.Println(err)
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return
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}
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txOut := wire.NewTxOut(100000000, pkScript)
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originTx.AddTxOut(txOut)
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originTxHash := originTx.TxHash()
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// Create the transaction to redeem the fake transaction.
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redeemTx := wire.NewMsgTx(wire.TxVersion)
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// Add the input(s) the redeeming transaction will spend. There is no
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// signature script at this point since it hasn't been created or signed
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// yet, hence nil is provided for it.
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prevOut = wire.NewOutPoint(&originTxHash, 0)
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txIn = wire.NewTxIn(prevOut, nil, nil)
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redeemTx.AddTxIn(txIn)
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// Ordinarily this would contain that actual destination of the funds,
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// but for this example don't bother.
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txOut = wire.NewTxOut(0, nil)
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redeemTx.AddTxOut(txOut)
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// Sign the redeeming transaction.
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lookupKey := func(a btcutil.Address) (*btcec.PrivateKey, bool, error) {
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// Ordinarily this function would involve looking up the private
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// key for the provided address, but since the only thing being
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// signed in this example uses the address associated with the
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// private key from above, simply return it with the compressed
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// flag set since the address is using the associated compressed
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// public key.
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//
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// NOTE: If you want to prove the code is actually signing the
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// transaction properly, uncomment the following line which
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// intentionally returns an invalid key to sign with, which in
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// turn will result in a failure during the script execution
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// when verifying the signature.
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//
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// privKey.D.SetInt64(12345)
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//
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return privKey, true, nil
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}
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// Notice that the script database parameter is nil here since it isn't
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// used. It must be specified when pay-to-script-hash transactions are
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// being signed.
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sigScript, err := txscript.SignTxOutput(&chaincfg.MainNetParams,
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redeemTx, 0, originTx.TxOut[0].PkScript, txscript.SigHashAll,
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txscript.KeyClosure(lookupKey), nil, nil)
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if err != nil {
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fmt.Println(err)
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return
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}
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redeemTx.TxIn[0].SignatureScript = sigScript
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// Prove that the transaction has been validly signed by executing the
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// script pair.
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flags := txscript.ScriptBip16 | txscript.ScriptVerifyDERSignatures |
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txscript.ScriptStrictMultiSig |
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txscript.ScriptDiscourageUpgradableNops
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vm, err := txscript.NewEngine(originTx.TxOut[0].PkScript, redeemTx, 0,
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flags, nil, nil, -1)
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if err != nil {
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fmt.Println(err)
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return
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}
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if err := vm.Execute(); err != nil {
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fmt.Println(err)
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return
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}
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fmt.Println("Transaction successfully signed")
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// Output:
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// Transaction successfully signed
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}
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// This example demonstrates creating a script tokenizer instance and using it
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// to count the number of opcodes a script contains.
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func ExampleScriptTokenizer() {
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// Create a script to use in the example. Ordinarily this would come from
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// some other source.
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hash160 := btcutil.Hash160([]byte("example"))
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script, err := txscript.NewScriptBuilder().AddOp(txscript.OP_DUP).
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AddOp(txscript.OP_HASH160).AddData(hash160).
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AddOp(txscript.OP_EQUALVERIFY).AddOp(txscript.OP_CHECKSIG).Script()
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if err != nil {
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fmt.Printf("failed to build script: %v\n", err)
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return
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}
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// Create a tokenizer to iterate the script and count the number of opcodes.
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const scriptVersion = 0
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var numOpcodes int
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tokenizer := txscript.MakeScriptTokenizer(scriptVersion, script)
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for tokenizer.Next() {
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numOpcodes++
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}
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if tokenizer.Err() != nil {
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fmt.Printf("script failed to parse: %v\n", err)
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} else {
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fmt.Printf("script contains %d opcode(s)\n", numOpcodes)
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}
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// Output:
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// script contains 5 opcode(s)
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}
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