hive-js-dev/lib/auth/serializer/src/precision.js

Steem.js the JavaScript API for Steem blockchain

'use strict';

var _my;
var _internal;
var v = require('./validation');
var BigInteger = require('bigi');

module.exports = _my =

// Result may be used for int64 types (like transfer amount).  Asset's
// precision is used to convert the number to a whole number with an implied
// decimal place.

// "1.01" with a precision of 2 returns long 101
// See http://cryptocoinjs.com/modules/misc/bigi/#example
{
    to_bigint64: function to_bigint64(number_or_string, precision) {
        var error_info = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : "";

        var long = _internal.to_long64(number_or_string, precision, error_info);
        return BigInteger(long.toString());
    },


    // 101 string or long with a precision of 2 returns "1.01" 
    to_string64: function to_string64(number_or_string, precision) {
        var error_info = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : "";

        v.required(number_or_string, error_info);
        v.number(precision, error_info);
        var number_long = v.to_long(number_or_string, error_info);
        var string64 = _internal.decimal_precision_string(number_long, precision, error_info);
        v.no_overflow64(string64, error_info);
        return string64;
    }
};

// _internal is for low-level transaction code
module.exports._internal = _internal =

// Warning: Long operations may over-flow without detection
{
    to_long64: function to_long64(number_or_string, precision) {
        var error_info = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : "";

        v.required(number_or_string, "number_or_string " + error_info);
        v.required(precision, "precision " + error_info);
        return v.to_long(_internal.decimal_precision_string(number_or_string, precision, error_info));
    },
    decimal_precision_string: function decimal_precision_string(number, precision) {
        var error_info = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : "";

        v.required(number, "number " + error_info);
        v.required(precision, "precision " + error_info);

        var number_string = v.to_string(number);
        number_string = number_string.trim();
        precision = v.to_number(precision);

        // remove leading zeros (not suffixing)
        var number_parts = number_string.match(/^-?0*([0-9]*)\.?([0-9]*)$/);
        if (!number_parts) {
            throw new Error('Invalid number: ' + number_string + ' ' + error_info);
        }

        var sign = number_string.charAt(0) === '-' ? '-' : '';
        var int_part = number_parts[1];
        var decimal_part = number_parts[2];
        if (!decimal_part) {
            decimal_part = "";
        }

        // remove trailing zeros
        while (/0$/.test(decimal_part)) {
            decimal_part = decimal_part.substring(0, decimal_part.length - 1);
        }

        var zero_pad_count = precision - decimal_part.length;
        if (zero_pad_count < 0) {
            throw new Error('overflow, up to ' + precision + ' decimals may be used ' + error_info);
        }

        if (sign === "-" && !/[1-9]/.test(int_part + decimal_part)) {
            sign = "";
        }
        if (int_part === "") {
            int_part = "0";
        }
        for (var i = 0; 0 < zero_pad_count ? i < zero_pad_count : i > zero_pad_count; 0 < zero_pad_count ? i++ : i++) {
            decimal_part += "0";
        }

        return sign + int_part + decimal_part;
    }
};