[adapters] 增加小游戏适配部分源码

adapters/platforms/baidu/wrapper/builtin/Base64.js

@@ -0,0 +1,60 @@
+/* eslint-disable */
+let chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
+
+function InvalidCharacterError(message) {
+    this.message = message;
+}
+InvalidCharacterError.prototype = new Error;
+InvalidCharacterError.prototype.name = 'InvalidCharacterError';
+
+// encoder
+// [https://gist.github.com/999166] by [https://github.com/nignag]
+
+function btoa(input) {
+    let str = String(input);
+    let output = '';
+    for (
+        // initialize result and counter
+        let block, charCode, idx = 0, map = chars;
+        // if the next str index does not exist:
+        //   change the mapping table to "="
+        //   check if d has no fractional digits
+        str.charAt(idx | 0) || (map = '=', idx % 1);
+        // "8 - idx % 1 * 8" generates the sequence 2, 4, 6, 8
+        output += map.charAt(63 & block >> 8 - idx % 1 * 8)
+    ) {
+        charCode = str.charCodeAt(idx += 3 / 4);
+        if (charCode > 0xFF) {
+            throw new InvalidCharacterError("'btoa' failed: The string to be encoded contains characters outside of the Latin1 range.");
+        }
+        block = block << 8 | charCode;
+    }
+    return output;
+}
+
+// decoder
+// [https://gist.github.com/1020396] by [https://github.com/atk]
+function atob(input) {
+    let str = String(input).replace(/=+$/, '');
+    if (str.length % 4 === 1) {
+        throw new InvalidCharacterError("'atob' failed: The string to be decoded is not correctly encoded.");
+    }
+    let output = '';
+    for (
+        // initialize result and counters
+        let bc = 0, bs, buffer, idx = 0;
+        // get next character
+        buffer = str.charAt(idx++);
+        // character found in table? initialize bit storage and add its ascii value;
+        ~buffer && (bs = bc % 4 ? bs * 64 + buffer : buffer,
+            // and if not first of each 4 characters,
+            // convert the first 8 bits to one ascii character
+            bc++ % 4) ? output += String.fromCharCode(255 & bs >> (-2 * bc & 6)) : 0
+    ) {
+        // try to find character in table (0-63, not found => -1)
+        buffer = chars.indexOf(buffer);
+    }
+    return output;
+}
+
+export { btoa, atob }