Icard/angular-clarity-master(work.../node_modules/jszip/lib/base64.js

107 lines
3.3 KiB
JavaScript

"use strict";
var utils = require("./utils");
var support = require("./support");
// private property
var _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
// public method for encoding
exports.encode = function(input) {
var output = [];
var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
var i = 0, len = input.length, remainingBytes = len;
var isArray = utils.getTypeOf(input) !== "string";
while (i < input.length) {
remainingBytes = len - i;
if (!isArray) {
chr1 = input.charCodeAt(i++);
chr2 = i < len ? input.charCodeAt(i++) : 0;
chr3 = i < len ? input.charCodeAt(i++) : 0;
} else {
chr1 = input[i++];
chr2 = i < len ? input[i++] : 0;
chr3 = i < len ? input[i++] : 0;
}
enc1 = chr1 >> 2;
enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
enc3 = remainingBytes > 1 ? (((chr2 & 15) << 2) | (chr3 >> 6)) : 64;
enc4 = remainingBytes > 2 ? (chr3 & 63) : 64;
output.push(_keyStr.charAt(enc1) + _keyStr.charAt(enc2) + _keyStr.charAt(enc3) + _keyStr.charAt(enc4));
}
return output.join("");
};
// public method for decoding
exports.decode = function(input) {
var chr1, chr2, chr3;
var enc1, enc2, enc3, enc4;
var i = 0, resultIndex = 0;
var dataUrlPrefix = "data:";
if (input.substr(0, dataUrlPrefix.length) === dataUrlPrefix) {
// This is a common error: people give a data url
// (data:image/png;base64,iVBOR...) with a {base64: true} and
// wonders why things don't work.
// We can detect that the string input looks like a data url but we
// *can't* be sure it is one: removing everything up to the comma would
// be too dangerous.
throw new Error("Invalid base64 input, it looks like a data url.");
}
input = input.replace(/[^A-Za-z0-9+/=]/g, "");
var totalLength = input.length * 3 / 4;
if(input.charAt(input.length - 1) === _keyStr.charAt(64)) {
totalLength--;
}
if(input.charAt(input.length - 2) === _keyStr.charAt(64)) {
totalLength--;
}
if (totalLength % 1 !== 0) {
// totalLength is not an integer, the length does not match a valid
// base64 content. That can happen if:
// - the input is not a base64 content
// - the input is *almost* a base64 content, with a extra chars at the
// beginning or at the end
// - the input uses a base64 variant (base64url for example)
throw new Error("Invalid base64 input, bad content length.");
}
var output;
if (support.uint8array) {
output = new Uint8Array(totalLength|0);
} else {
output = new Array(totalLength|0);
}
while (i < input.length) {
enc1 = _keyStr.indexOf(input.charAt(i++));
enc2 = _keyStr.indexOf(input.charAt(i++));
enc3 = _keyStr.indexOf(input.charAt(i++));
enc4 = _keyStr.indexOf(input.charAt(i++));
chr1 = (enc1 << 2) | (enc2 >> 4);
chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
chr3 = ((enc3 & 3) << 6) | enc4;
output[resultIndex++] = chr1;
if (enc3 !== 64) {
output[resultIndex++] = chr2;
}
if (enc4 !== 64) {
output[resultIndex++] = chr3;
}
}
return output;
};