mirror of https://github.com/jkjoy/sunpeiwen.git
160 lines
3.3 KiB
JavaScript
160 lines
3.3 KiB
JavaScript
/*!
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* bytes
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* Copyright(c) 2012-2014 TJ Holowaychuk
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* Copyright(c) 2015 Jed Watson
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* MIT Licensed
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*/
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'use strict';
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/**
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* Module exports.
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* @public
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*/
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module.exports = bytes;
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module.exports.format = format;
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module.exports.parse = parse;
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/**
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* Module variables.
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* @private
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*/
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var formatThousandsRegExp = /\B(?=(\d{3})+(?!\d))/g;
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var formatDecimalsRegExp = /(?:\.0*|(\.[^0]+)0+)$/;
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var map = {
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b: 1,
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kb: 1 << 10,
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mb: 1 << 20,
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gb: 1 << 30,
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tb: ((1 << 30) * 1024)
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};
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var parseRegExp = /^((-|\+)?(\d+(?:\.\d+)?)) *(kb|mb|gb|tb)$/i;
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/**
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* Convert the given value in bytes into a string or parse to string to an integer in bytes.
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*
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* @param {string|number} value
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* @param {{
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* case: [string],
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* decimalPlaces: [number]
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* fixedDecimals: [boolean]
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* thousandsSeparator: [string]
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* unitSeparator: [string]
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* }} [options] bytes options.
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*
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* @returns {string|number|null}
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*/
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function bytes(value, options) {
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if (typeof value === 'string') {
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return parse(value);
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}
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if (typeof value === 'number') {
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return format(value, options);
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}
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return null;
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}
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/**
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* Format the given value in bytes into a string.
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*
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* If the value is negative, it is kept as such. If it is a float,
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* it is rounded.
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*
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* @param {number} value
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* @param {object} [options]
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* @param {number} [options.decimalPlaces=2]
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* @param {number} [options.fixedDecimals=false]
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* @param {string} [options.thousandsSeparator=]
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* @param {string} [options.unit=]
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* @param {string} [options.unitSeparator=]
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*
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* @returns {string|null}
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* @public
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*/
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function format(value, options) {
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if (!Number.isFinite(value)) {
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return null;
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}
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var mag = Math.abs(value);
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var thousandsSeparator = (options && options.thousandsSeparator) || '';
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var unitSeparator = (options && options.unitSeparator) || '';
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var decimalPlaces = (options && options.decimalPlaces !== undefined) ? options.decimalPlaces : 2;
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var fixedDecimals = Boolean(options && options.fixedDecimals);
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var unit = (options && options.unit) || '';
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if (!unit || !map[unit.toLowerCase()]) {
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if (mag >= map.tb) {
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unit = 'TB';
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} else if (mag >= map.gb) {
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unit = 'GB';
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} else if (mag >= map.mb) {
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unit = 'MB';
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} else if (mag >= map.kb) {
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unit = 'KB';
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} else {
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unit = 'B';
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}
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}
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var val = value / map[unit.toLowerCase()];
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var str = val.toFixed(decimalPlaces);
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if (!fixedDecimals) {
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str = str.replace(formatDecimalsRegExp, '$1');
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}
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if (thousandsSeparator) {
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str = str.replace(formatThousandsRegExp, thousandsSeparator);
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}
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return str + unitSeparator + unit;
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}
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/**
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* Parse the string value into an integer in bytes.
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*
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* If no unit is given, it is assumed the value is in bytes.
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*
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* @param {number|string} val
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*
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* @returns {number|null}
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* @public
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*/
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function parse(val) {
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if (typeof val === 'number' && !isNaN(val)) {
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return val;
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}
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if (typeof val !== 'string') {
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return null;
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}
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// Test if the string passed is valid
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var results = parseRegExp.exec(val);
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var floatValue;
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var unit = 'b';
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if (!results) {
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// Nothing could be extracted from the given string
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floatValue = parseInt(val, 10);
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unit = 'b'
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} else {
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// Retrieve the value and the unit
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floatValue = parseFloat(results[1]);
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unit = results[4].toLowerCase();
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}
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return Math.floor(map[unit] * floatValue);
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}
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