328 lines
8.6 KiB
JavaScript
328 lines
8.6 KiB
JavaScript
'use strict';
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var BufferReader = require('./encoding/bufferreader');
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var BufferWriter = require('./encoding/bufferwriter');
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var Opcode = require('./opcode');
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var Script = function Script(from) {
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if (!(this instanceof Script)) {
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return new Script(from);
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}
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this.chunks = [];
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if (Buffer.isBuffer(from)) {
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return Script.fromBuffer(from);
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} else if (typeof from === 'string') {
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return Script.fromString(from);
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} else if (typeof from !== 'undefined') {
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this.set(from);
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}
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};
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Script.prototype.set = function(obj) {
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this.chunks = obj.chunks || this.chunks;
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return this;
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};
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Script.fromBuffer = function(buffer) {
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var script = new Script();
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script.chunks = [];
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var br = new BufferReader(buffer);
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while (!br.eof()) {
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var opcodenum = br.readUInt8();
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var len, buf;
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if (opcodenum > 0 && opcodenum < Opcode.map.OP_PUSHDATA1) {
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len = opcodenum;
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script.chunks.push({
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buf: br.read(len),
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len: len,
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opcodenum: opcodenum
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});
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} else if (opcodenum === Opcode.map.OP_PUSHDATA1) {
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len = br.readUInt8();
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buf = br.read(len);
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script.chunks.push({
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buf: buf,
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len: len,
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opcodenum: opcodenum
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});
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} else if (opcodenum === Opcode.map.OP_PUSHDATA2) {
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len = br.readUInt16LE();
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buf = br.read(len);
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script.chunks.push({
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buf: buf,
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len: len,
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opcodenum: opcodenum
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});
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} else if (opcodenum === Opcode.map.OP_PUSHDATA4) {
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len = br.readUInt32LE();
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buf = br.read(len);
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script.chunks.push({
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buf: buf,
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len: len,
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opcodenum: opcodenum
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});
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} else {
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script.chunks.push(opcodenum);
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}
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}
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return script;
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};
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Script.prototype.toBuffer = function() {
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var bw = new BufferWriter();
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for (var i = 0; i < this.chunks.length; i++) {
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var chunk = this.chunks[i];
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var opcodenum;
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if (typeof chunk === 'number') {
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opcodenum = chunk;
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bw.writeUInt8(opcodenum);
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} else {
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opcodenum = chunk.opcodenum;
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bw.writeUInt8(chunk.opcodenum);
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if (opcodenum < Opcode.map.OP_PUSHDATA1) {
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bw.write(chunk.buf);
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} else if (opcodenum === Opcode.map.OP_PUSHDATA1) {
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bw.writeUInt8(chunk.len);
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bw.write(chunk.buf);
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} else if (opcodenum === Opcode.map.OP_PUSHDATA2) {
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bw.writeUInt16LE(chunk.len);
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bw.write(chunk.buf);
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} else if (opcodenum === Opcode.map.OP_PUSHDATA4) {
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bw.writeUInt32LE(chunk.len);
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bw.write(chunk.buf);
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}
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}
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}
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return bw.concat();
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};
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Script.fromString = function(str) {
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var script = new Script();
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script.chunks = [];
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var tokens = str.split(' ');
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var i = 0;
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while (i < tokens.length) {
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var token = tokens[i];
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var opcode = Opcode(token);
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var opcodenum = opcode.toNumber();
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if (typeof opcodenum === 'undefined') {
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opcodenum = parseInt(token);
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if (opcodenum > 0 && opcodenum < Opcode.map.OP_PUSHDATA1) {
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script.chunks.push({
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buf: new Buffer(tokens[i + 1].slice(2), 'hex'),
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len: opcodenum,
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opcodenum: opcodenum
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});
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i = i + 2;
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} else {
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throw new Error('Invalid script');
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}
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} else if (opcodenum === Opcode.map.OP_PUSHDATA1 ||
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opcodenum === Opcode.map.OP_PUSHDATA2 ||
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opcodenum === Opcode.map.OP_PUSHDATA4) {
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if (tokens[i + 2].slice(0, 2) !== '0x') {
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throw new Error('Pushdata data must start with 0x');
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}
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script.chunks.push({
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buf: new Buffer(tokens[i + 2].slice(2), 'hex'),
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len: parseInt(tokens[i + 1]),
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opcodenum: opcodenum
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});
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i = i + 3;
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} else {
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script.chunks.push(opcodenum);
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i = i + 1;
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}
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}
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return script;
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};
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Script.prototype.toString = function() {
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var str = '';
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for (var i = 0; i < this.chunks.length; i++) {
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var chunk = this.chunks[i];
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var opcodenum;
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if (typeof chunk === 'number') {
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opcodenum = chunk;
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str = str + Opcode(opcodenum).toString() + ' ';
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} else {
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opcodenum = chunk.opcodenum;
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if (opcodenum === Opcode.map.OP_PUSHDATA1 ||
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opcodenum === Opcode.map.OP_PUSHDATA2 ||
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opcodenum === Opcode.map.OP_PUSHDATA4) {
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str = str + Opcode(opcodenum).toString() + ' ';
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}
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str = str + chunk.len + ' ';
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str = str + '0x' + chunk.buf.toString('hex') + ' ';
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}
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}
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return str.substr(0, str.length - 1);
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};
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// script classification methods
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/**
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* @returns true if this is a pay to pubkey hash output script
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*/
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Script.prototype.isPublicKeyHashOut = function() {
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return this.chunks[0] === Opcode('OP_DUP').toNumber() &&
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this.chunks[1] === Opcode('OP_HASH160').toNumber() &&
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this.chunks[2].buf &&
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this.chunks[3] === Opcode('OP_EQUALVERIFY').toNumber() &&
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this.chunks[4] === Opcode('OP_CHECKSIG').toNumber();
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};
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/**
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* @returns true if this is a pay to public key hash input script
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*/
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Script.prototype.isPublicKeyHashIn = function() {
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return !!(this.chunks.length === 2 &&
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this.chunks[0].buf &&
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this.chunks[1].buf);
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};
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/**
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* @returns true if this is a p2sh output script
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*/
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Script.prototype.isScriptHashOut = function() {
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return this.chunks.length === 3 &&
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this.chunks[0] === Opcode('OP_HASH160').toNumber() &&
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this.chunks[1].buf &&
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this.chunks[1].buf.length === 20 &&
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this.chunks[2] === Opcode('OP_EQUAL').toNumber();
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};
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/**
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* @returns true if this is a p2sh input script
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* Note that these are frequently indistinguishable from pubkeyhashin
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*/
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Script.prototype.isScriptHashIn = function() {
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return this.chunks.every(function(chunk) {
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return Buffer.isBuffer(chunk.buf);
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});
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};
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/**
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* @returns true if this is a mutlsig output script
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*/
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Script.prototype.isMultisigOut = function() {
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return (this.chunks.length > 3 &&
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Opcode.isSmallIntOp(this.chunks[0]) &&
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this.chunks.slice(1, this.chunks.length - 2).every(function(obj) {
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return obj.buf && Buffer.isBuffer(obj.buf);
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}) &&
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Opcode.isSmallIntOp(this.chunks[this.chunks.length - 2]) &&
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this.chunks[this.chunks.length - 1] === Opcode.map.OP_CHECKMULTISIG);
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};
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/**
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* @returns true if this is an OP_RETURN data script
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*/
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Script.prototype.isOpReturn = function() {
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return (this.chunks[0] === Opcode('OP_RETURN').toNumber() &&
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(this.chunks.length === 1 ||
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(this.chunks.length === 2 &&
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this.chunks[1].buf &&
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this.chunks[1].buf.length <= 40 &&
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this.chunks[1].length === this.chunks.len)));
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};
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// Script construction methods
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/**
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* Adds a script element at the start of the script.
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* @param {*} obj a string, number, Opcode, Bufer, or object to add
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* @returns {Script} this script instance
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*/
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Script.prototype.prepend = function(obj) {
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this._addByType(obj, true);
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return this;
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};
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/**
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* Adds a script element to the end of the script.
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*
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* @param {*} obj a string, number, Opcode, Bufer, or object to add
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* @returns {Script} this script instance
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*
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*/
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Script.prototype.add = function(obj) {
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this._addByType(obj, false);
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return this;
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};
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Script.prototype._addByType = function(obj, prepend) {
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if (typeof obj === 'string') {
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this._addOpcode(obj, prepend);
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} else if (typeof obj === 'number') {
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this._addOpcode(obj, prepend);
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} else if (obj.constructor && obj.constructor.name && obj.constructor.name === 'Opcode') {
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this._addOpcode(obj, prepend);
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} else if (Buffer.isBuffer(obj)) {
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this._addBuffer(obj, prepend);
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} else if (typeof obj === 'object') {
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this._insertAtPosition(obj, prepend);
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} else {
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throw new Error('Invalid script chunk');
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}
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};
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Script.prototype._insertAtPosition = function(op, prepend) {
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if (prepend) {
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this.chunks.unshift(op);
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} else {
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this.chunks.push(op);
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}
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};
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Script.prototype._addOpcode = function(opcode, prepend) {
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var op;
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if (typeof opcode === 'number') {
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op = opcode;
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} else if (opcode.constructor && opcode.constructor.name && opcode.constructor.name === 'Opcode') {
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op = opcode.toNumber();
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} else {
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op = Opcode(opcode).toNumber();
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}
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this._insertAtPosition(op, prepend);
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return this;
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};
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Script.prototype._addBuffer = function(buf, prepend) {
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var opcodenum;
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var len = buf.length;
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if (buf.length > 0 && buf.length < Opcode.map.OP_PUSHDATA1) {
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opcodenum = buf.length;
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} else if (buf.length < Math.pow(2, 8)) {
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opcodenum = Opcode.map.OP_PUSHDATA1;
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} else if (buf.length < Math.pow(2, 16)) {
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opcodenum = Opcode.map.OP_PUSHDATA2;
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} else if (buf.length < Math.pow(2, 32)) {
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opcodenum = Opcode.map.OP_PUSHDATA4;
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} else {
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throw new Error('You can\'t push that much data');
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}
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this._insertAtPosition({
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buf: buf,
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len: len,
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opcodenum: opcodenum
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}, prepend);
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return this;
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};
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module.exports = Script;
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