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'use strict';
var _ = require('lodash');
var Base58 = require('./base58');
var buffer = require('buffer');
var sha256sha256 = require('../crypto/hash').sha256sha256;
var Base58Check = function Base58Check(obj) {
if (!(this instanceof Base58Check))
return new Base58Check(obj);
if (Buffer.isBuffer(obj)) {
var buf = obj;
this.fromBuffer(buf);
} else if (typeof obj === 'string') {
var str = obj;
this.fromString(str);
} else if (obj) {
this.set(obj);
}
};
Base58Check.prototype.set = function(obj) {
this.buf = obj.buf || this.buf || undefined;
return this;
};
Base58Check.validChecksum = function validChecksum(data, checksum) {
if (_.isString(data)) {
data = new buffer.Buffer(Base58.decode(data));
}
if (_.isString(checksum)) {
checksum = new buffer.Buffer(Base58.decode(checksum));
}
if (!checksum) {
checksum = data.slice(-4);
data = data.slice(0, -4);
}
return Base58Check.checksum(data).toString('hex') === checksum.toString('hex');
};
Base58Check.decode = function(s) {
if (typeof s !== 'string')
throw new Error('Input must be a string');
var buf = new Buffer(Base58.decode(s));
if (buf.length < 4)
throw new Error("Input string too short");
var data = buf.slice(0, -4);
var csum = buf.slice(-4);
var hash = sha256sha256(data);
var hash4 = hash.slice(0, 4);
if (csum.toString('hex') !== hash4.toString('hex'))
throw new Error("Checksum mismatch");
return data;
};
Base58Check.checksum = function(buffer) {
return sha256sha256(buffer).slice(0, 4);
};
Base58Check.encode = function(buf) {
if (!Buffer.isBuffer(buf))
throw new Error('Input must be a buffer');
var checkedBuf = new Buffer(buf.length + 4);
var hash = Base58Check.checksum(buf);
buf.copy(checkedBuf);
hash.copy(checkedBuf, buf.length);
return Base58.encode(checkedBuf);
};
Base58Check.prototype.fromBuffer = function(buf) {
this.buf = buf;
return this;
};
Base58Check.prototype.fromString = function(str) {
var buf = Base58Check.decode(str);
this.buf = buf;
return this;
};
Base58Check.prototype.toBuffer = function() {
return this.buf;
};
Base58Check.prototype.toString = function() {
return Base58Check.encode(this.buf);
};
module.exports = Base58Check;