datapay/dist/datapay.js

post data over bitcoin sv

(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.datapay = f()}})(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
(function (Buffer){
const mingo = require("mingo")
const _Buffer = require('buffer/')
const bitcoin = require('bsv');
const explorer = require('bitcore-explorers');
const defaults = {
  rpc: "api.mattercloud.net",
  fee: 400,
  feeb: 1.4
}
// The end goal of 'build' is to create a hex formated transaction object
// therefore this function must end with _tx() for all cases 
// and return a hex formatted string of either a tranaction or a script
var build = function(options, callback) {
  let script = null;
  let rpcaddr = (options.pay && options.pay.rpc) ? options.pay.rpc : defaults.rpc;
  if (options.tx) {
    // if tx exists, check to see if it's already been signed.
    // if it's a signed transaction
    // and the request is trying to override using 'data' or 'pay',
    // we should throw an error
    let tx = new bitcoin.Transaction(options.tx)
    // transaction is already signed
    if (tx.inputs.length > 0 && tx.inputs[0].script) {
      if (options.pay || options.data) {
        callback(new Error("the transaction is already signed and cannot be modified"))
        return;
      }
    }
  } else {
    // construct script only if transaction doesn't exist
    // if a 'transaction' attribute exists, the 'data' should be ignored to avoid confusion
    if (options.data) {
      script = _script(options)
    }
  }
  // Instantiate pay
  if (options.pay && options.pay.key) {
    // key exists => create a signed transaction
    let key = options.pay.key;
    const privateKey = new bitcoin.PrivateKey(key);
    const address = privateKey.toAddress();
    const insight = new explorer.Insight(rpcaddr)
    insight.getUnspentUtxos(address, function (err, res) {
      if (err) {
        callback(err);
        return;
      }

      if (options.pay.filter && options.pay.filter.q && options.pay.filter.q.find) {
        let f = new mingo.Query(options.pay.filter.q.find)
        res = res.filter(function(item) {
          return f.test(item)
        })
      }
      let tx = new bitcoin.Transaction(options.tx).from(res);

      if (script) {
        tx.addOutput(new bitcoin.Transaction.Output({ script: script, satoshis: 0 }));
      }
      if (options.pay.to && Array.isArray(options.pay.to)) {
        options.pay.to.forEach(function(receiver) {
          tx.to(receiver.address, receiver.value)
        })
      }

      tx.fee(defaults.fee).change(address);
      let opt_pay = options.pay || {};
      let myfee = opt_pay.fee || Math.ceil(tx._estimateSize()* (opt_pay.feeb || defaults.feeb));
      tx.fee(myfee);

      //Check all the outputs for dust
      for(var i=0;i<tx.outputs.length;i++){
        if(tx.outputs[i]._satoshis>0 && tx.outputs[i]._satoshis<546){
          tx.outputs.splice(i,1);
          i--;
        }
      }
      let transaction = tx.sign(privateKey);
      callback(null, transaction);
    })
  } else {
    // key doesn't exist => create an unsigned transaction
    let fee = (options.pay && options.pay.fee) ? options.pay.fee : defaults.fee;
    let tx = new bitcoin.Transaction(options.tx).fee(fee);
    if (script) {
      tx.addOutput(new bitcoin.Transaction.Output({ script: script, satoshis: 0 }));
    }
    callback(null, tx)
  }
}
var send = function(options, callback) {
  if (!callback) {
    callback = function() {};
  }

  build(options, function(err, tx) {
    if (err) {
      callback(err);
      return;
    }

    let rpcaddr = (options.pay && options.pay.rpc) ? options.pay.rpc : defaults.rpc;
    const insight = new explorer.Insight(rpcaddr)
    insight.broadcast(tx.toString(), callback)
  })
}
// compose script
var _script = function(options) {
  var s = null;
  if (options.data) {
    if (Array.isArray(options.data)) {
      s = new bitcoin.Script();
      if (!options.hasOwnProperty("safe")) {
        options.safe = true;
      }
      if (options.safe) {
        s.add(bitcoin.Opcode.OP_FALSE);
      }
      // Add op_return
      s.add(bitcoin.Opcode.OP_RETURN);
      options.data.forEach(function(item) {
        // add push data
        if (item.constructor.name === 'ArrayBuffer') {
          let buffer = _Buffer.Buffer.from(item)
          s.add(buffer)
        } else if (item.constructor.name === 'Buffer') {
          s.add(item)
        } else if (typeof item === 'string') {
          if (/^0x/i.test(item)) {
            // ex: 0x6d02
            s.add(Buffer.from(item.slice(2), "hex"))
          } else {
            // ex: "hello"
            s.add(Buffer.from(item))
          }
        } else if (typeof item === 'object' && item.hasOwnProperty('op')) {
          s.add({ opcodenum: item.op })
        }
      })
    } else if (typeof options.data === 'string') {
      // Exported transaction 
      s = bitcoin.Script.fromHex(options.data);
    }
  }
  return s;
}
var connect = function(endpoint) {
  var rpc = endpoint ? endpoint : defaults.rpc;
  return new explorer.Insight(rpc);
}
module.exports = {
  build: build,
  send: send,
  bsv: bitcoin,
  connect: connect,
}


}).call(this,require("buffer").Buffer)
},{"bitcore-explorers":3,"bsv":89,"buffer":218,"buffer/":82,"mingo":84}],2:[function(require,module,exports){
'use strict'

exports.byteLength = byteLength
exports.toByteArray = toByteArray
exports.fromByteArray = fromByteArray

var lookup = []
var revLookup = []
var Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array

var code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
for (var i = 0, len = code.length; i < len; ++i) {
  lookup[i] = code[i]
  revLookup[code.charCodeAt(i)] = i
}

// Support decoding URL-safe base64 strings, as Node.js does.
// See: https://en.wikipedia.org/wiki/Base64#URL_applications
revLookup['-'.charCodeAt(0)] = 62
revLookup['_'.charCodeAt(0)] = 63

function getLens (b64) {
  var len = b64.length

  if (len % 4 > 0) {
    throw new Error('Invalid string. Length must be a multiple of 4')
  }

  // Trim off extra bytes after placeholder bytes are found
  // See: https://github.com/beatgammit/base64-js/issues/42
  var validLen = b64.indexOf('=')
  if (validLen === -1) validLen = len

  var placeHoldersLen = validLen === len
    ? 0
    : 4 - (validLen % 4)

  return [validLen, placeHoldersLen]
}

// base64 is 4/3 + up to two characters of the original data
function byteLength (b64) {
  var lens = getLens(b64)
  var validLen = lens[0]
  var placeHoldersLen = lens[1]
  return ((validLen + placeHoldersLen) * 3 / 4) - placeHoldersLen
}

function _byteLength (b64, validLen, placeHoldersLen) {
  return ((validLen + placeHoldersLen) * 3 / 4) - placeHoldersLen
}

function toByteArray (b64) {
  var tmp
  var lens = getLens(b64)
  var validLen = lens[0]
  var placeHoldersLen = lens[1]

  var arr = new Arr(_byteLength(b64, validLen, placeHoldersLen))

  var curByte = 0

  // if there are placeholders, only get up to the last complete 4 chars
  var len = placeHoldersLen > 0
    ? validLen - 4
    : validLen

  for (var i = 0; i < len; i += 4) {
    tmp =
      (revLookup[b64.charCodeAt(i)] << 18) |
      (revLookup[b64.charCodeAt(i + 1)] << 12) |
      (revLookup[b64.charCodeAt(i + 2)] << 6) |
      revLookup[b64.charCodeAt(i + 3)]
    arr[curByte++] = (tmp >> 16) & 0xFF
    arr[curByte++] = (tmp >> 8) & 0xFF
    arr[curByte++] = tmp & 0xFF
  }

  if (placeHoldersLen === 2) {
    tmp =
      (revLookup[b64.charCodeAt(i)] << 2) |
      (revLookup[b64.charCodeAt(i + 1)] >> 4)
    arr[curByte++] = tmp & 0xFF
  }

  if (placeHoldersLen === 1) {
    tmp =
      (revLookup[b64.charCodeAt(i)] << 10) |
      (revLookup[b64.charCodeAt(i + 1)] << 4) |
      (revLookup[b64.charCodeAt(i + 2)] >> 2)
    arr[curByte++] = (tmp >> 8) & 0xFF
    arr[curByte++] = tmp & 0xFF
  }

  return arr
}

function tripletToBase64 (num) {
  return lookup[num >> 18 & 0x3F] +
    lookup[num >> 12 & 0x3F] +
    lookup[num >> 6 & 0x3F] +
    lookup[num & 0x3F]
}

function encodeChunk (uint8, start, end) {
  var tmp
  var output = []
  for (var i = start; i < end; i += 3) {
    tmp =
      ((uint8[i] << 16) & 0xFF0000) +
      ((uint8[i + 1] << 8) & 0xFF00) +
      (uint8[i + 2] & 0xFF)
    output.push(tripletToBase64(tmp))
  }
  return output.join('')
}

function fromByteArray (uint8) {
  var tmp
  var len = uint8.length
  var extraBytes = len % 3 // if we have 1 byte left, pad 2 bytes
  var parts = []
  var maxChunkLength = 16383 // must be multiple of 3

  // go through the array every three bytes, we'll deal with trailing stuff later
  for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
    parts.push(encodeChunk(
      uint8, i, (i + maxChunkLength) > len2 ? len2 : (i + maxChunkLength)
    ))
  }

  // pad the end with zeros, but make sure to not forget the extra bytes
  if (extraBytes === 1) {
    tmp = uint8[len - 1]
    parts.push(
      lookup[tmp >> 2] +
      lookup[(tmp << 4) & 0x3F] +
      '=='
    )
  } else if (extraBytes === 2) {
    tmp = (uint8[len - 2] << 8) + uint8[len - 1]
    parts.push(
      lookup[tmp >> 10] +
      lookup[(tmp >> 4) & 0x3F] +
      lookup[(tmp << 2) & 0x3F] +
      '='
    )
  }

  return parts.join('')
}

},{}],3:[function(require,module,exports){
module.exports = require('./lib');

},{"./lib":4}],4:[function(require,module,exports){
module.exports = {
  models: require('./models'),
  Insight: require('./insight')
};

},{"./insight":5,"./models":7}],5:[function(require,module,exports){
'use strict';

var request = require('request');

var bitcore = require('bitcore-lib');
var _ = bitcore.deps._;

var $ = bitcore.util.preconditions;
var Address = bitcore.Address;
var JSUtil = bitcore.util.js;
var Networks = bitcore.Networks;
var Transaction = bitcore.Transaction;
var UnspentOutput = Transaction.UnspentOutput;
var AddressInfo = require('./models/addressinfo');


/**
 * Allows the retrieval of information regarding the state of the blockchain
 * (and broadcasting of transactions) from/to a trusted Insight server.
 * @param {string=} url the url of the Insight server
 * @param {Network=} network whether to use livenet or testnet
 * @constructor
 */
function Insight(url, network) {
  if (!url && !network) {
    return new Insight(Networks.defaultNetwork);
  }
  if (Networks.get(url)) {
    network = Networks.get(url);
    if (network === Networks.livenet) {
      url = 'https://insight.bitpay.com';
    } else {
      url = 'https://test-insight.bitpay.com';
    }
  }
  JSUtil.defineImmutable(this, {
    url: url,
    network: Networks.get(network) || Networks.defaultNetwork
  });
  this.request = request;
  return this;
}

/**
 * @callback Insight.GetUnspentUtxosCallback
 * @param {Error} err
 * @param {Array.UnspentOutput} utxos
 */

/**
 * Retrieve a list of unspent outputs associated with an address or set of addresses
 * @param {Address|string|Array.Address|Array.string} addresses
 * @param {GetUnspentUtxosCallback} callback
 */
Insight.prototype.getUnspentUtxos = function(addresses, callback) {
  $.checkArgument(_.isFunction(callback));
  if (!_.isArray(addresses)) {
    addresses = [addresses];
  }
  addresses = _.map(addresses, function(address) {
    return new Address(address);
  });

  this.requestPost('/api/addrs/utxo', {
    addrs: _.map(addresses, function(address) {
      return address.toString();
    }).join(',')
  }, function(err, res, unspent) {
    if (err || res.statusCode !== 200) {
      return callback(err || res);
    }
    try {
      unspent = _.map(unspent, UnspentOutput);
    } catch (ex) {
      if (ex instanceof bitcore.errors.InvalidArgument) {
        return callback(ex);
      }
    }

    return callback(null, unspent);
  });
};

/**
 * @callback Insight.BroadcastCallback
 * @param {Error} err
 * @param {string} txid
 */

/**
 * Broadcast a transaction to the bitcoin network
 * @param {transaction|string} transaction
 * @param {BroadcastCallback} callback
 */
Insight.prototype.broadcast = function(transaction, callback) {
  $.checkArgument(JSUtil.isHexa(transaction) || transaction instanceof Transaction);
  $.checkArgument(_.isFunction(callback));
  if (transaction instanceof Transaction) {
    transaction = transaction.serialize();
  }

  this.requestPost('/api/tx/send', {
    rawtx: transaction
  }, function(err, res, body) {
    if (err || res.statusCode !== 200) {
      return callback(err || body);
    }
    return callback(null, body ? body.txid : null);
  });
};

/**
 * @callback Insight.AddressCallback
 * @param {Error} err
 * @param {AddressInfo} info
 */

/**
 * Retrieve information about an address
 * @param {Address|string} address
 * @param {AddressCallback} callback
 */
Insight.prototype.address = function(address, callback) {
  $.checkArgument(_.isFunction(callback));
  address = new Address(address);

  this.requestGet('/api/addr/' + address.toString(), function(err, res, body) {
    if (err || res.statusCode !== 200) {
      return callback(err || body);
    }
    var info;
    try {
      info = AddressInfo.fromInsight(body);
    } catch (e) {
      if (e instanceof SyntaxError) {
        return callback(e);
      }
      throw e;
    }
    return callback(null, info);
  });
};

/**
 * Internal function to make a post request to the server
 * @param {string} path
 * @param {?} data
 * @param {function} callback
 * @private
 */
Insight.prototype.requestPost = function(path, data, callback) {
  $.checkArgument(_.isString(path));
  $.checkArgument(_.isFunction(callback));
  this.request({
    method: 'POST',
    url: this.url + path,
    json: data
  }, callback);
};

/**
 * Internal function to make a get request with no params to the server
 * @param {string} path
 * @param {function} callback
 * @private
 */
Insight.prototype.requestGet = function(path, callback) {
  $.checkArgument(_.isString(path));
  $.checkArgument(_.isFunction(callback));
  this.request({
    method: 'GET',
    url: this.url + path
  }, callback);
};

module.exports = Insight;

},{"./models/addressinfo":6,"bitcore-lib":8,"request":81}],6:[function(require,module,exports){
'use strict';

var bitcore = require('bitcore-lib');

var _ = bitcore.deps._;
var $ = bitcore.util.preconditions;
var Address = bitcore.Address;
var JSUtil = bitcore.util.js;

function AddressInfo(param) {
  if (!(this instanceof AddressInfo)) {
    return new AddressInfo(param);
  }
  if (param instanceof AddressInfo) {
    return param;
  }

  $.checkArgument(param.address instanceof Address);
  $.checkArgument(_.isNumber(param.balance));
  $.checkArgument(_.isNumber(param.totalSent));
  $.checkArgument(_.isNumber(param.totalReceived));
  $.checkArgument(_.isNumber(param.unconfirmedBalance));
  $.checkArgument(_.isArray(param.transactionIds));
  $.checkArgument(_.all(_.map(param.transactionIds, JSUtil.isHexa)));

  JSUtil.defineImmutable(this, param);
}

AddressInfo.fromInsight = function(param) {
  if (_.isString(param)) {
    param = JSON.parse(param);
  }
  return new AddressInfo({
    address: new Address(param.addrStr),
    balance: param.balanceSat,
    totalReceived: param.totalReceivedSat,
    totalSent: param.totalSentSat,
    unconfirmedBalance: param.unconfirmedBalanceSat,
    transactionIds: param.transactions
  });
};

module.exports = AddressInfo;

},{"bitcore-lib":8}],7:[function(require,module,exports){
module.exports = {
  AddressInfo: require('./addressinfo')
};

},{"./addressinfo":6}],8:[function(require,module,exports){
(function (global,Buffer){
'use strict';

var bitcore = module.exports;

// module information
bitcore.version = 'v' + require('./package.json').version;
bitcore.versionGuard = function(version) {
  if (version !== undefined) {
    var message = 'More than one instance of bitcore-lib found. ' + 
      'Please make sure to require bitcore-lib and check that submodules do' +
      ' not also include their own bitcore-lib dependency.';
    throw new Error(message);
  }
};
bitcore.versionGuard(global._bitcore);
global._bitcore = bitcore.version;

// crypto
bitcore.crypto = {};
bitcore.crypto.BN = require('./lib/crypto/bn');
bitcore.crypto.ECDSA = require('./lib/crypto/ecdsa');
bitcore.crypto.Hash = require('./lib/crypto/hash');
bitcore.crypto.Random = require('./lib/crypto/random');
bitcore.crypto.Point = require('./lib/crypto/point');
bitcore.crypto.Signature = require('./lib/crypto/signature');

// encoding
bitcore.encoding = {};
bitcore.encoding.Base58 = require('./lib/encoding/base58');
bitcore.encoding.Base58Check = require('./lib/encoding/base58check');
bitcore.encoding.BufferReader = require('./lib/encoding/bufferreader');
bitcore.encoding.BufferWriter = require('./lib/encoding/bufferwriter');
bitcore.encoding.Varint = require('./lib/encoding/varint');

// utilities
bitcore.util = {};
bitcore.util.buffer = require('./lib/util/buffer');
bitcore.util.js = require('./lib/util/js');
bitcore.util.preconditions = require('./lib/util/preconditions');

// errors thrown by the library
bitcore.errors = require('./lib/errors');

// main bitcoin library
bitcore.Address = require('./lib/address');
bitcore.Block = require('./lib/block');
bitcore.MerkleBlock = require('./lib/block/merkleblock');
bitcore.BlockHeader = require('./lib/block/blockheader');
bitcore.HDPrivateKey = require('./lib/hdprivatekey.js');
bitcore.HDPublicKey = require('./lib/hdpublickey.js');
bitcore.Networks = require('./lib/networks');
bitcore.Opcode = require('./lib/opcode');
bitcore.PrivateKey = require('./lib/privatekey');
bitcore.PublicKey = require('./lib/publickey');
bitcore.Script = require('./lib/script');
bitcore.Transaction = require('./lib/transaction');
bitcore.URI = require('./lib/uri');
bitcore.Unit = require('./lib/unit');

// dependencies, subject to change
bitcore.deps = {};
bitcore.deps.bnjs = require('bn.js');
bitcore.deps.bs58 = require('bs58');
bitcore.deps.Buffer = Buffer;
bitcore.deps.elliptic = require('elliptic');
bitcore.deps._ = require('lodash');

// Internal usage, exposed for testing/advanced tweaking
bitcore._HDKeyCache = require('./lib/hdkeycache');
bitcore.Transaction.sighash = require('./lib/transaction/sighash');

}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {},require("buffer").Buffer)
},{"./lib/address":9,"./lib/block":12,"./lib/block/blockheader":11,"./lib/block/merkleblock":13,"./lib/crypto/bn":14,"./lib/crypto/ecdsa":15,"./lib/crypto/hash":16,"./lib/crypto/point":17,"./lib/crypto/random":18,"./lib/crypto/signature":19,"./lib/encoding/base58":20,"./lib/encoding/base58check":21,"./lib/encoding/bufferreader":22,"./lib/encoding/bufferwriter":23,"./lib/encoding/varint":24,"./lib/errors":25,"./lib/hdkeycache":27,"./lib/hdprivatekey.js":28,"./lib/hdpublickey.js":29,"./lib/networks":30,"./lib/opcode":31,"./lib/privatekey":32,"./lib/publickey":33,"./lib/script":34,"./lib/transaction":37,"./lib/transaction/sighash":45,"./lib/unit":49,"./lib/uri":50,"./lib/util/buffer":51,"./lib/util/js":52,"./lib/util/preconditions":53,"./package.json":80,"bn.js":54,"bs58":55,"buffer":218,"elliptic":57,"lodash":79}],9:[function(require,module,exports){
(function (Buffer){
'use strict';

var _ = require('lodash');
var $ = require('./util/preconditions');
var errors = require('./errors');
var Base58Check = require('./encoding/base58check');
var Networks = require('./networks');
var Hash = require('./crypto/hash');
var JSUtil = require('./util/js');
var PublicKey = require('./publickey');

/**
 * Instantiate an address from an address String or Buffer, a public key or script hash Buffer,
 * or an instance of {@link PublicKey} or {@link Script}.
 *
 * This is an immutable class, and if the first parameter provided to this constructor is an
 * `Address` instance, the same argument will be returned.
 *
 * An address has two key properties: `network` and `type`. The type is either
 * `Address.PayToPublicKeyHash` (value is the `'pubkeyhash'` string)
 * or `Address.PayToScriptHash` (the string `'scripthash'`). The network is an instance of {@link Network}.
 * You can quickly check whether an address is of a given kind by using the methods
 * `isPayToPublicKeyHash` and `isPayToScriptHash`
 *
 * @example
 * ```javascript
 * // validate that an input field is valid
 * var error = Address.getValidationError(input, 'testnet');
 * if (!error) {
 *   var address = Address(input, 'testnet');
 * } else {
 *   // invalid network or checksum (typo?)
 *   var message = error.messsage;
 * }
 *
 * // get an address from a public key
 * var address = Address(publicKey, 'testnet').toString();
 * ```
 *
 * @param {*} data - The encoded data in various formats
 * @param {Network|String|number=} network - The network: 'livenet' or 'testnet'
 * @param {string=} type - The type of address: 'script' or 'pubkey'
 * @returns {Address} A new valid and frozen instance of an Address
 * @constructor
 */
function Address(data, network, type) {
  /* jshint maxcomplexity: 12 */
  /* jshint maxstatements: 20 */

  if (!(this instanceof Address)) {
    return new Address(data, network, type);
  }

  if (_.isArray(data) && _.isNumber(network)) {
    return Address.createMultisig(data, network, type);
  }

  if (data instanceof Address) {
    // Immutable instance
    return data;
  }

  $.checkArgument(data, 'First argument is required, please include address data.', 'guide/address.html');

  if (network && !Networks.get(network)) {
    throw new TypeError('Second argument must be "livenet" or "testnet".');
  }

  if (type && (type !== Address.PayToPublicKeyHash && type !== Address.PayToScriptHash)) {
    throw new TypeError('Third argument must be "pubkeyhash" or "scripthash".');
  }

  var info = this._classifyArguments(data, network, type);

  // set defaults if not set
  info.network = info.network || Networks.get(network) || Networks.defaultNetwork;
  info.type = info.type || type || Address.PayToPublicKeyHash;

  JSUtil.defineImmutable(this, {
    hashBuffer: info.hashBuffer,
    network: info.network,
    type: info.type
  });

  return this;
}

/**
 * Internal function used to split different kinds of arguments of the constructor
 * @param {*} data - The encoded data in various formats
 * @param {Network|String|number=} network - The network: 'livenet' or 'testnet'
 * @param {string=} type - The type of address: 'script' or 'pubkey'
 * @returns {Object} An "info" object with "type", "network", and "hashBuffer"
 */
Address.prototype._classifyArguments = function(data, network, type) {
  /* jshint maxcomplexity: 10 */
  // transform and validate input data
  if ((data instanceof Buffer || data instanceof Uint8Array) && data.length === 20) {
    return Address._transformHash(data);
  } else if ((data instanceof Buffer || data instanceof Uint8Array) && data.length === 21) {
    return Address._transformBuffer(data, network, type);
  } else if (data instanceof PublicKey) {
    return Address._transformPublicKey(data);
  } else if (data instanceof Script) {
    return Address._transformScript(data, network);
  } else if (typeof(data) === 'string') {
    return Address._transformString(data, network, type);
  } else if (_.isObject(data)) {
    return Address._transformObject(data);
  } else {
    throw new TypeError('First argument is an unrecognized data format.');
  }
};

/** @static */
Address.PayToPublicKeyHash = 'pubkeyhash';
/** @static */
Address.PayToScriptHash = 'scripthash';

/**
 * @param {Buffer} hash - An instance of a hash Buffer
 * @returns {Object} An object with keys: hashBuffer
 * @private
 */
Address._transformHash = function(hash) {
  var info = {};
  if (!(hash instanceof Buffer) && !(hash instanceof Uint8Array)) {
    throw new TypeError('Address supplied is not a buffer.');
  }
  if (hash.length !== 20) {
    throw new TypeError('Address hashbuffers must be exactly 20 bytes.');
  }
  info.hashBuffer = hash;
  return info;
};

/**
 * Deserializes an address serialized through `Address#toObject()`
 * @param {Object} data
 * @param {string} data.hash - the hash that this address encodes
 * @param {string} data.type - either 'pubkeyhash' or 'scripthash'
 * @param {Network=} data.network - the name of the network associated
 * @return {Address}
 */
Address._transformObject = function(data) {
  $.checkArgument(data.hash || data.hashBuffer, 'Must provide a `hash` or `hashBuffer` property');
  $.checkArgument(data.type, 'Must provide a `type` property');
  return {
    hashBuffer: data.hash ? new Buffer(data.hash, 'hex') : data.hashBuffer,
    network: Networks.get(data.network) || Networks.defaultNetwork,
    type: data.type
  };
};

/**
 * Internal function to discover the network and type based on the first data byte
 *
 * @param {Buffer} buffer - An instance of a hex encoded address Buffer
 * @returns {Object} An object with keys: network and type
 * @private
 */
Address._classifyFromVersion = function(buffer) {
  var version = {};

  var pubkeyhashNetwork = Networks.get(buffer[0], 'pubkeyhash');
  var scripthashNetwork = Networks.get(buffer[0], 'scripthash');

  if (pubkeyhashNetwork) {
    version.network = pubkeyhashNetwork;
    version.type = Address.PayToPublicKeyHash;
  } else if (scripthashNetwork) {
    version.network = scripthashNetwork;
    version.type = Address.PayToScriptHash;
  }

  return version;
};

/**
 * Internal function to transform a bitcoin address buffer
 *
 * @param {Buffer} buffer - An instance of a hex encoded address Buffer
 * @param {string=} network - The network: 'livenet' or 'testnet'
 * @param {string=} type - The type: 'pubkeyhash' or 'scripthash'
 * @returns {Object} An object with keys: hashBuffer, network and type
 * @private
 */
Address._transformBuffer = function(buffer, network, type) {
  /* jshint maxcomplexity: 9 */
  var info = {};
  if (!(buffer instanceof Buffer) && !(buffer instanceof Uint8Array)) {
    throw new TypeError('Address supplied is not a buffer.');
  }
  if (buffer.length !== 1 + 20) {
    throw new TypeError('Address buffers must be exactly 21 bytes.');
  }

  network = Networks.get(network);
  var bufferVersion = Address._classifyFromVersion(buffer);

  if (!bufferVersion.network || (network && network !== bufferVersion.network)) {
    throw new TypeError('Address has mismatched network type.');
  }

  if (!bufferVersion.type || (type && type !== bufferVersion.type)) {
    throw new TypeError('Address has mismatched type.');
  }

  info.hashBuffer = buffer.slice(1);
  info.network = bufferVersion.network;
  info.type = bufferVersion.type;
  return info;
};

/**
 * Internal function to transform a {@link PublicKey}
 *
 * @param {PublicKey} pubkey - An instance of PublicKey
 * @returns {Object} An object with keys: hashBuffer, type
 * @private
 */
Address._transformPublicKey = function(pubkey) {
  var info = {};
  if (!(pubkey instanceof PublicKey)) {
    throw new TypeError('Address must be an instance of PublicKey.');
  }
  info.hashBuffer = Hash.sha256ripemd160(pubkey.toBuffer());
  info.type = Address.PayToPublicKeyHash;
  return info;
};

/**
 * Internal function to transform a {@link Script} into a `info` object.
 *
 * @param {Script} script - An instance of Script
 * @returns {Object} An object with keys: hashBuffer, type
 * @private
 */
Address._transformScript = function(script, network) {
  $.checkArgument(script instanceof Script, 'script must be a Script instance');
  var info = script.getAddressInfo(network);
  if (!info) {
    throw new errors.Script.CantDeriveAddress(script);
  }
  return info;
};

/**
 * Creates a P2SH address from a set of public keys and a threshold.
 *
 * The addresses will be sorted lexicographically, as that is the trend in bitcoin.
 * To create an address from unsorted public keys, use the {@link Script#buildMultisigOut}
 * interface.
 *
 * @param {Array} publicKeys - a set of public keys to create an address
 * @param {number} threshold - the number of signatures needed to release the funds
 * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
 * @return {Address}
 */
Address.createMultisig = function(publicKeys, threshold, network) {
  network = network || publicKeys[0].network || Networks.defaultNetwork;
  return Address.payingTo(Script.buildMultisigOut(publicKeys, threshold), network);
};

/**
 * Internal function to transform a bitcoin address string
 *
 * @param {string} data
 * @param {String|Network=} network - either a Network instance, 'livenet', or 'testnet'
 * @param {string=} type - The type: 'pubkeyhash' or 'scripthash'
 * @returns {Object} An object with keys: hashBuffer, network and type
 * @private
 */
Address._transformString = function(data, network, type) {
  if (typeof(data) !== 'string') {
    throw new TypeError('data parameter supplied is not a string.');
  }
  data = data.trim();
  var addressBuffer = Base58Check.decode(data);
  var info = Address._transformBuffer(addressBuffer, network, type);
  return info;
};

/**
 * Instantiate an address from a PublicKey instance
 *
 * @param {PublicKey} data
 * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
 * @returns {Address} A new valid and frozen instance of an Address
 */
Address.fromPublicKey = function(data, network) {
  var info = Address._transformPublicKey(data);
  network = network || Networks.defaultNetwork;
  return new Address(info.hashBuffer, network, info.type);
};

/**
 * Instantiate an address from a ripemd160 public key hash
 *
 * @param {Buffer} hash - An instance of buffer of the hash
 * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
 * @returns {Address} A new valid and frozen instance of an Address
 */
Address.fromPublicKeyHash = function(hash, network) {
  var info = Address._transformHash(hash);
  return new Address(info.hashBuffer, network, Address.PayToPublicKeyHash);
};

/**
 * Instantiate an address from a ripemd160 script hash
 *
 * @param {Buffer} hash - An instance of buffer of the hash
 * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
 * @returns {Address} A new valid and frozen instance of an Address
 */
Address.fromScriptHash = function(hash, network) {
  $.checkArgument(hash, 'hash parameter is required');
  var info = Address._transformHash(hash);
  return new Address(info.hashBuffer, network, Address.PayToScriptHash);
};

/**
 * Builds a p2sh address paying to script. This will hash the script and
 * use that to create the address.
 * If you want to extract an address associated with a script instead,
 * see {{Address#fromScript}}
 *
 * @param {Script} script - An instance of Script
 * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
 * @returns {Address} A new valid and frozen instance of an Address
 */
Address.payingTo = function(script, network) {
  $.checkArgument(script, 'script is required');
  $.checkArgument(script instanceof Script, 'script must be instance of Script');

  return Address.fromScriptHash(Hash.sha256ripemd160(script.toBuffer()), network);
};

/**
 * Extract address from a Script. The script must be of one
 * of the following types: p2pkh input, p2pkh output, p2sh input
 * or p2sh output.
 * This will analyze the script and extract address information from it.
 * If you want to transform any script to a p2sh Address paying
 * to that script's hash instead, use {{Address#payingTo}}
 *
 * @param {Script} script - An instance of Script
 * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
 * @returns {Address} A new valid and frozen instance of an Address
 */
Address.fromScript = function(script, network) {
  $.checkArgument(script instanceof Script, 'script must be a Script instance');
  var info = Address._transformScript(script, network);
  return new Address(info.hashBuffer, network, info.type);
};

/**
 * Instantiate an address from a buffer of the address
 *
 * @param {Buffer} buffer - An instance of buffer of the address
 * @param {String|Network=} network - either a Network instance, 'livenet', or 'testnet'
 * @param {string=} type - The type of address: 'script' or 'pubkey'
 * @returns {Address} A new valid and frozen instance of an Address
 */
Address.fromBuffer = function(buffer, network, type) {
  var info = Address._transformBuffer(buffer, network, type);
  return new Address(info.hashBuffer, info.network, info.type);
};

/**
 * Instantiate an address from an address string
 *
 * @param {string} str - An string of the bitcoin address
 * @param {String|Network=} network - either a Network instance, 'livenet', or 'testnet'
 * @param {string=} type - The type of address: 'script' or 'pubkey'
 * @returns {Address} A new valid and frozen instance of an Address
 */
Address.fromString = function(str, network, type) {
  var info = Address._transformString(str, network, type);
  return new Address(info.hashBuffer, info.network, info.type);
};

/**
 * Instantiate an address from an Object
 *
 * @param {string} json - An JSON string or Object with keys: hash, network and type
 * @returns {Address} A new valid instance of an Address
 */
Address.fromObject = function fromObject(obj) {
  $.checkState(
    JSUtil.isHexa(obj.hash),
    'Unexpected hash property, "' + obj.hash + '", expected to be hex.'
  );
  var hashBuffer = new Buffer(obj.hash, 'hex');
  return new Address(hashBuffer, obj.network, obj.type);
};

/**
 * Will return a validation error if exists
 *
 * @example
 * ```javascript
 * // a network mismatch error
 * var error = Address.getValidationError('15vkcKf7gB23wLAnZLmbVuMiiVDc1Nm4a2', 'testnet');
 * ```
 *
 * @param {string} data - The encoded data
 * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
 * @param {string} type - The type of address: 'script' or 'pubkey'
 * @returns {null|Error} The corresponding error message
 */
Address.getValidationError = function(data, network, type) {
  var error;
  try {
    /* jshint nonew: false */
    new Address(data, network, type);
  } catch (e) {
    error = e;
  }
  return error;
};

/**
 * Will return a boolean if an address is valid
 *
 * @example
 * ```javascript
 * assert(Address.isValid('15vkcKf7gB23wLAnZLmbVuMiiVDc1Nm4a2', 'livenet'));
 * ```
 *
 * @param {string} data - The encoded data
 * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
 * @param {string} type - The type of address: 'script' or 'pubkey'
 * @returns {boolean} The corresponding error message
 */
Address.isValid = function(data, network, type) {
  return !Address.getValidationError(data, network, type);
};

/**
 * Returns true if an address is of pay to public key hash type
 * @return boolean
 */
Address.prototype.isPayToPublicKeyHash = function() {
  return this.type === Address.PayToPublicKeyHash;
};

/**
 * Returns true if an address is of pay to script hash type
 * @return boolean
 */
Address.prototype.isPayToScriptHash = function() {
  return this.type === Address.PayToScriptHash;
};

/**
 * Will return a buffer representation of the address
 *
 * @returns {Buffer} Bitcoin address buffer
 */
Address.prototype.toBuffer = function() {
  var version = new Buffer([this.network[this.type]]);
  var buf = Buffer.concat([version, this.hashBuffer]);
  return buf;
};

/**
 * @returns {Object} A plain object with the address information
 */
Address.prototype.toObject = Address.prototype.toJSON = function toObject() {
  return {
    hash: this.hashBuffer.toString('hex'),
    type: this.type,
    network: this.network.toString()
  };
};

/**
 * Will return a the string representation of the address
 *
 * @returns {string} Bitcoin address
 */
Address.prototype.toString = function() {
  return Base58Check.encode(this.toBuffer());
};

/**
 * Will return a string formatted for the console
 *
 * @returns {string} Bitcoin address
 */
Address.prototype.inspect = function() {
  return '<Address: ' + this.toString() + ', type: ' + this.type + ', network: ' + this.network + '>';
};

module.exports = Address;

var Script = require('./script');

}).call(this,require("buffer").Buffer)
},{"./crypto/hash":16,"./encoding/base58check":21,"./errors":25,"./networks":30,"./publickey":33,"./script":34,"./util/js":52,"./util/preconditions":53,"buffer":218,"lodash":79}],10:[function(require,module,exports){
(function (Buffer){
'use strict';

var _ = require('lodash');
var BlockHeader = require('./blockheader');
var BN = require('../crypto/bn');
var BufferUtil = require('../util/buffer');
var BufferReader = require('../encoding/bufferreader');
var BufferWriter = require('../encoding/bufferwriter');
var Hash = require('../crypto/hash');
var Transaction = require('../transaction');
var $ = require('../util/preconditions');

/**
 * Instantiate a Block from a Buffer, JSON object, or Object with
 * the properties of the Block
 *
 * @param {*} - A Buffer, JSON string, or Object
 * @returns {Block}
 * @constructor
 */
function Block(arg) {
  if (!(this instanceof Block)) {
    return new Block(arg);
  }
  _.extend(this, Block._from(arg));
  return this;
}

// https://github.com/bitcoin/bitcoin/blob/b5fa132329f0377d787a4a21c1686609c2bfaece/src/primitives/block.h#L14
Block.MAX_BLOCK_SIZE = 1000000;

/**
 * @param {*} - A Buffer, JSON string or Object
 * @returns {Object} - An object representing block data
 * @throws {TypeError} - If the argument was not recognized
 * @private
 */
Block._from = function _from(arg) {
  var info = {};
  if (BufferUtil.isBuffer(arg)) {
    info = Block._fromBufferReader(BufferReader(arg));
  } else if (_.isObject(arg)) {
    info = Block._fromObject(arg);
  } else {
    throw new TypeError('Unrecognized argument for Block');
  }
  return info;
};

/**
 * @param {Object} - A plain JavaScript object
 * @returns {Object} - An object representing block data
 * @private
 */
Block._fromObject = function _fromObject(data) {
  var transactions = [];
  data.transactions.forEach(function(tx) {
    if (tx instanceof Transaction) {
      transactions.push(tx);
    } else {
      transactions.push(Transaction().fromObject(tx));
    }
  });
  var info = {
    header: BlockHeader.fromObject(data.header),
    transactions: transactions
  };
  return info;
};

/**
 * @param {Object} - A plain JavaScript object
 * @returns {Block} - An instance of block
 */
Block.fromObject = function fromObject(obj) {
  var info = Block._fromObject(obj);
  return new Block(info);
};

/**
 * @param {BufferReader} - Block data
 * @returns {Object} - An object representing the block data
 * @private
 */
Block._fromBufferReader = function _fromBufferReader(br) {
  var info = {};
  $.checkState(!br.finished(), 'No block data received');
  info.header = BlockHeader.fromBufferReader(br);
  var transactions = br.readVarintNum();
  info.transactions = [];
  for (var i = 0; i < transactions; i++) {
    info.transactions.push(Transaction().fromBufferReader(br));
  }
  return info;
};

/**
 * @param {BufferReader} - A buffer reader of the block
 * @returns {Block} - An instance of block
 */
Block.fromBufferReader = function fromBufferReader(br) {
  $.checkArgument(br, 'br is required');
  var info = Block._fromBufferReader(br);
  return new Block(info);
};

/**
 * @param {Buffer} - A buffer of the block
 * @returns {Block} - An instance of block
 */
Block.fromBuffer = function fromBuffer(buf) {
  return Block.fromBufferReader(new BufferReader(buf));
};

/**
 * @param {string} - str - A hex encoded string of the block
 * @returns {Block} - A hex encoded string of the block
 */
Block.fromString = function fromString(str) {
  var buf = new Buffer(str, 'hex');
  return Block.fromBuffer(buf);
};

/**
 * @param {Binary} - Raw block binary data or buffer
 * @returns {Block} - An instance of block
 */
Block.fromRawBlock = function fromRawBlock(data) {
  if (!BufferUtil.isBuffer(data)) {
    data = new Buffer(data, 'binary');
  }
  var br = BufferReader(data);
  br.pos = Block.Values.START_OF_BLOCK;
  var info = Block._fromBufferReader(br);
  return new Block(info);
};

/**
 * @returns {Object} - A plain object with the block properties
 */
Block.prototype.toObject = Block.prototype.toJSON = function toObject() {
  var transactions = [];
  this.transactions.forEach(function(tx) {
    transactions.push(tx.toObject());
  });
  return {
    header: this.header.toObject(),
    transactions: transactions
  };
};

/**
 * @returns {Buffer} - A buffer of the block
 */
Block.prototype.toBuffer = function toBuffer() {
  return this.toBufferWriter().concat();
};

/**
 * @returns {string} - A hex encoded string of the block
 */
Block.prototype.toString = function toString() {
  return this.toBuffer().toString('hex');
};

/**
 * @param {BufferWriter} - An existing instance of BufferWriter
 * @returns {BufferWriter} - An instance of BufferWriter representation of the Block
 */
Block.prototype.toBufferWriter = function toBufferWriter(bw) {
  if (!bw) {
    bw = new BufferWriter();
  }
  bw.write(this.header.toBuffer());
  bw.writeVarintNum(this.transactions.length);
  for (var i = 0; i < this.transactions.length; i++) {
    this.transactions[i].toBufferWriter(bw);
  }
  return bw;
};

/**
 * Will iterate through each transaction and return an array of hashes
 * @returns {Array} - An array with transaction hashes
 */
Block.prototype.getTransactionHashes = function getTransactionHashes() {
  var hashes = [];
  if (this.transactions.length === 0) {
    return [Block.Values.NULL_HASH];
  }
  for (var t = 0; t < this.transactions.length; t++) {
    hashes.push(this.transactions[t]._getHash());
  }
  return hashes;
};

/**
 * Will build a merkle tree of all the transactions, ultimately arriving at
 * a single point, the merkle root.
 * @link https://en.bitcoin.it/wiki/Protocol_specification#Merkle_Trees
 * @returns {Array} - An array with each level of the tree after the other.
 */
Block.prototype.getMerkleTree = function getMerkleTree() {

  var tree = this.getTransactionHashes();

  var j = 0;
  for (var size = this.transactions.length; size > 1; size = Math.floor((size + 1) / 2)) {
    for (var i = 0; i < size; i += 2) {
      var i2 = Math.min(i + 1, size - 1);
      var buf = Buffer.concat([tree[j + i], tree[j + i2]]);
      tree.push(Hash.sha256sha256(buf));
    }
    j += size;
  }

  return tree;
};

/**
 * Calculates the merkleRoot from the transactions.
 * @returns {Buffer} - A buffer of the merkle root hash
 */
Block.prototype.getMerkleRoot = function getMerkleRoot() {
  var tree = this.getMerkleTree();
  return tree[tree.length - 1];
};

/**
 * Verifies that the transactions in the block match the header merkle root
 * @returns {Boolean} - If the merkle roots match
 */
Block.prototype.validMerkleRoot = function validMerkleRoot() {

  var h = new BN(this.header.merkleRoot.toString('hex'), 'hex');
  var c = new BN(this.getMerkleRoot().toString('hex'), 'hex');

  if (h.cmp(c) !== 0) {
    return false;
  }

  return true;
};

/**
 * @returns {Buffer} - The little endian hash buffer of the header
 */
Block.prototype._getHash = function() {
  return this.header._getHash();
};

var idProperty = {
  configurable: false,
  enumerable: true,
  /**
   * @returns {string} - The big endian hash buffer of the header
   */
  get: function() {
    if (!this._id) {
      this._id = this.header.id;
    }
    return this._id;
  },
  set: _.noop
};
Object.defineProperty(Block.prototype, 'id', idProperty);
Object.defineProperty(Block.prototype, 'hash', idProperty);

/**
 * @returns {string} - A string formatted for the console
 */
Block.prototype.inspect = function inspect() {
  return '<Block ' + this.id + '>';
};

Block.Values = {
  START_OF_BLOCK: 8, // Start of block in raw block data
  NULL_HASH: new Buffer('0000000000000000000000000000000000000000000000000000000000000000', 'hex')
};

module.exports = Block;

}).call(this,require("buffer").Buffer)
},{"../crypto/bn":14,"../crypto/hash":16,"../encoding/bufferreader":22,"../encoding/bufferwriter":23,"../transaction":37,"../util/buffer":51,"../util/preconditions":53,"./blockheader":11,"buffer":218,"lodash":79}],11:[function(require,module,exports){
(function (Buffer){
'use strict';

var _ = require('lodash');
var BN = require('../crypto/bn');
var BufferUtil = require('../util/buffer');
var BufferReader = require('../encoding/bufferreader');
var BufferWriter = require('../encoding/bufferwriter');
var Hash = require('../crypto/hash');
var JSUtil = require('../util/js');
var $ = require('../util/preconditions');

var GENESIS_BITS = 0x1d00ffff;

/**
 * Instantiate a BlockHeader from a Buffer, JSON object, or Object with
 * the properties of the BlockHeader
 *
 * @param {*} - A Buffer, JSON string, or Object
 * @returns {BlockHeader} - An instance of block header
 * @constructor
 */
var BlockHeader = function BlockHeader(arg) {
  if (!(this instanceof BlockHeader)) {
    return new BlockHeader(arg);
  }
  var info = BlockHeader._from(arg);
  this.version = info.version;
  this.prevHash = info.prevHash;
  this.merkleRoot = info.merkleRoot;
  this.time = info.time;
  this.timestamp = info.time;
  this.bits = info.bits;
  this.nonce = info.nonce;

  if (info.hash) {
    $.checkState(
      this.hash === info.hash,
      'Argument object hash property does not match block hash.'
    );
  }

  return this;
};

/**
 * @param {*} - A Buffer, JSON string or Object
 * @returns {Object} - An object representing block header data
 * @throws {TypeError} - If the argument was not recognized
 * @private
 */
BlockHeader._from = function _from(arg) {
  var info = {};
  if (BufferUtil.isBuffer(arg)) {
    info = BlockHeader._fromBufferReader(BufferReader(arg));
  } else if (_.isObject(arg)) {
    info = BlockHeader._fromObject(arg);
  } else {
    throw new TypeError('Unrecognized argument for BlockHeader');
  }
  return info;
};

/**
 * @param {Object} - A JSON string
 * @returns {Object} - An object representing block header data
 * @private
 */
BlockHeader._fromObject = function _fromObject(data) {
  $.checkArgument(data, 'data is required');
  var prevHash = data.prevHash;
  var merkleRoot = data.merkleRoot;
  if (_.isString(data.prevHash)) {
    prevHash = BufferUtil.reverse(new Buffer(data.prevHash, 'hex'));
  }
  if (_.isString(data.merkleRoot)) {
    merkleRoot = BufferUtil.reverse(new Buffer(data.merkleRoot, 'hex'));
  }
  var info = {
    hash: data.hash,
    version: data.version,
    prevHash: prevHash,
    merkleRoot: merkleRoot,
    time: data.time,
    timestamp: data.time,
    bits: data.bits,
    nonce: data.nonce
  };
  return info;
};

/**
 * @param {Object} - A plain JavaScript object
 * @returns {BlockHeader} - An instance of block header
 */
BlockHeader.fromObject = function fromObject(obj) {
  var info = BlockHeader._fromObject(obj);
  return new BlockHeader(info);
};

/**
 * @param {Binary} - Raw block binary data or buffer
 * @returns {BlockHeader} - An instance of block header
 */
BlockHeader.fromRawBlock = function fromRawBlock(data) {
  if (!BufferUtil.isBuffer(data)) {
    data = new Buffer(data, 'binary');
  }
  var br = BufferReader(data);
  br.pos = BlockHeader.Constants.START_OF_HEADER;
  var info = BlockHeader._fromBufferReader(br);
  return new BlockHeader(info);
};

/**
 * @param {Buffer} - A buffer of the block header
 * @returns {BlockHeader} - An instance of block header
 */
BlockHeader.fromBuffer = function fromBuffer(buf) {
  var info = BlockHeader._fromBufferReader(BufferReader(buf));
  return new BlockHeader(info);
};

/**
 * @param {string} - A hex encoded buffer of the block header
 * @returns {BlockHeader} - An instance of block header
 */
BlockHeader.fromString = function fromString(str) {
  var buf = new Buffer(str, 'hex');
  return BlockHeader.fromBuffer(buf);
};

/**
 * @param {BufferReader} - A BufferReader of the block header
 * @returns {Object} - An object representing block header data
 * @private
 */
BlockHeader._fromBufferReader = function _fromBufferReader(br) {
  var info = {};
  info.version = br.readUInt32LE();
  info.prevHash = br.read(32);
  info.merkleRoot = br.read(32);
  info.time = br.readUInt32LE();
  info.bits = br.readUInt32LE();
  info.nonce = br.readUInt32LE();
  return info;
};

/**
 * @param {BufferReader} - A BufferReader of the block header
 * @returns {BlockHeader} - An instance of block header
 */
BlockHeader.fromBufferReader = function fromBufferReader(br) {
  var info = BlockHeader._fromBufferReader(br);
  return new BlockHeader(info);
};

/**
 * @returns {Object} - A plain object of the BlockHeader
 */
BlockHeader.prototype.toObject = BlockHeader.prototype.toJSON = function toObject() {
  return {
    hash: this.hash,
    version: this.version,
    prevHash: BufferUtil.reverse(this.prevHash).toString('hex'),
    merkleRoot: BufferUtil.reverse(this.merkleRoot).toString('hex'),
    time: this.time,
    bits: this.bits,
    nonce: this.nonce
  };
};

/**
 * @returns {Buffer} - A Buffer of the BlockHeader
 */
BlockHeader.prototype.toBuffer = function toBuffer() {
  return this.toBufferWriter().concat();
};

/**
 * @returns {string} - A hex encoded string of the BlockHeader
 */
BlockHeader.prototype.toString = function toString() {
  return this.toBuffer().toString('hex');
};

/**
 * @param {BufferWriter} - An existing instance BufferWriter
 * @returns {BufferWriter} - An instance of BufferW