js的hex转base64

if (!window.atob) {
            var tableStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
            var table = tableStr.split("");

            window.atob = function (base64) {
                if (/(=[^=]+|={,})$/.test(base64)) throw new Error("String contains an invalid character");
                base64 = base64.replace(/=/g, "");
                var n = base64.length & ;
                if (n === ) throw new Error("String contains an invalid character");
                for (var i = , j = , len = base64.length / , bin = []; i < len; ++i) {
                    var a = tableStr.indexOf(base64[j++] || "A"), b = tableStr.indexOf(base64[j++] || "A");
                    var c = tableStr.indexOf(base64[j++] || "A"), d = tableStr.indexOf(base64[j++] || "A");
                    if ((a | b | c | d) < ) throw new Error("String contains an invalid character");
                    bin[bin.length] = ((a << ) | (b >> )) & ;
                    bin[bin.length] = ((b << ) | (c >> )) & ;
                    bin[bin.length] = ((c << ) | d) & ;
                };
                return String.fromCharCode.apply(null, bin).substr(, bin.length + n - );
            };

            window.btoa = function (bin) {
                for (var i = , j = , len = bin.length / , base64 = []; i < len; ++i) {
                    var a = bin.charCodeAt(j++), b = bin.charCodeAt(j++), c = bin.charCodeAt(j++);
                    if ((a | b | c) > ) throw new Error("String contains an invalid character");
                    base64[base64.length] = table[a >> ] + table[((a << ) & ) | (b >> )] +
                        (isNaN(b) ? "=" : table[((b << ) & ) | (c >> )]) +
                        (isNaN(b + c) ? "=" : table[c & ]);
                }
                return base64.join("");
            };

        }

        function hexToBase64(str) {
            return btoa(String.fromCharCode.apply(null,
                str.replace(/\r|\n/g, "").replace(/([\da-fA-F]{}) ?/g, "0x$1 ").replace(/ +$/, "").split(" "))
            );
        }

        function base64ToHex(str) {
            for (var i = , bin = atob(str.replace(/[ \r\n]+$/, "")), hex = []; i < bin.length; ++i) {
                var tmp = bin.charCodeAt(i).toString();
                if (tmp.length === ) tmp = "" + tmp;
                hex[hex.length] = tmp;
            }
            return hex.join(" ");
        }