1 files changed, 149 insertions, 0 deletions
diff --git a/js/base64.ts b/js/base64.ts
new file mode 100644
index 000000000..38fd9824d
--- /dev/null
+++ b/js/base64.ts
@@ -0,0 +1,149 @@
+// Forked from https://github.com/beatgammit/base64-js
+// Copyright (c) 2014 Jameson Little. MIT License.
+
+const lookup: string[] = [];
+const revLookup: number[] = [];
+
+const code = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+for (var i = 0, len = code.length; i < len; ++i) {
+  lookup[i] = code[i];
+  revLookup[code.charCodeAt(i)] = i;
+}
+
+// Support decoding URL-safe base64 strings, as Node.js does.
+// See: https://en.wikipedia.org/wiki/Base64#URL_applications
+revLookup["-".charCodeAt(0)] = 62;
+revLookup["_".charCodeAt(0)] = 63;
+
+function getLens(b64: string): [number, number] {
+  var len = b64.length;
+
+  if (len % 4 > 0) {
+    throw new Error("Invalid string. Length must be a multiple of 4");
+  }
+
+  // Trim off extra bytes after placeholder bytes are found
+  // See: https://github.com/beatgammit/base64-js/issues/42
+  var validLen = b64.indexOf("=");
+  if (validLen === -1) validLen = len;
+
+  var placeHoldersLen = validLen === len ? 0 : 4 - (validLen % 4);
+
+  return [validLen, placeHoldersLen];
+}
+
+// base64 is 4/3 + up to two characters of the original data
+export function byteLength(b64: string): number {
+  var lens = getLens(b64);
+  var validLen = lens[0];
+  var placeHoldersLen = lens[1];
+  return ((validLen + placeHoldersLen) * 3) / 4 - placeHoldersLen;
+}
+
+function _byteLength(
+  b64: string,
+  validLen: number,
+  placeHoldersLen: number
+): number {
+  return ((validLen + placeHoldersLen) * 3) / 4 - placeHoldersLen;
+}
+
+export function toByteArray(b64: string): Uint8Array {
+  var tmp;
+  var lens = getLens(b64);
+  var validLen = lens[0];
+  var placeHoldersLen = lens[1];
+
+  var arr = new Uint8Array(_byteLength(b64, validLen, placeHoldersLen));
+
+  var curByte = 0;
+
+  // if there are placeholders, only get up to the last complete 4 chars
+  var len = placeHoldersLen > 0 ? validLen - 4 : validLen;
+
+  for (var i = 0; i < len; i += 4) {
+    tmp =
+      (revLookup[b64.charCodeAt(i)] << 18) |
+      (revLookup[b64.charCodeAt(i + 1)] << 12) |
+      (revLookup[b64.charCodeAt(i + 2)] << 6) |
+      revLookup[b64.charCodeAt(i + 3)];
+    arr[curByte++] = (tmp >> 16) & 0xff;
+    arr[curByte++] = (tmp >> 8) & 0xff;
+    arr[curByte++] = tmp & 0xff;
+  }
+
+  if (placeHoldersLen === 2) {
+    tmp =
+      (revLookup[b64.charCodeAt(i)] << 2) |
+      (revLookup[b64.charCodeAt(i + 1)] >> 4);
+    arr[curByte++] = tmp & 0xff;
+  }
+
+  if (placeHoldersLen === 1) {
+    tmp =
+      (revLookup[b64.charCodeAt(i)] << 10) |
+      (revLookup[b64.charCodeAt(i + 1)] << 4) |
+      (revLookup[b64.charCodeAt(i + 2)] >> 2);
+    arr[curByte++] = (tmp >> 8) & 0xff;
+    arr[curByte++] = tmp & 0xff;
+  }
+
+  return arr;
+}
+
+function tripletToBase64(num: number): string {
+  return (
+    lookup[(num >> 18) & 0x3f] +
+    lookup[(num >> 12) & 0x3f] +
+    lookup[(num >> 6) & 0x3f] +
+    lookup[num & 0x3f]
+  );
+}
+
+function encodeChunk(uint8: Uint8Array, start: number, end: number): string {
+  var tmp;
+  var output = [];
+  for (var i = start; i < end; i += 3) {
+    tmp =
+      ((uint8[i] << 16) & 0xff0000) +
+      ((uint8[i + 1] << 8) & 0xff00) +
+      (uint8[i + 2] & 0xff);
+    output.push(tripletToBase64(tmp));
+  }
+  return output.join("");
+}
+
+export function fromByteArray(uint8: Uint8Array): string {
+  var tmp;
+  var len = uint8.length;
+  var extraBytes = len % 3; // if we have 1 byte left, pad 2 bytes
+  var parts = [];
+  var maxChunkLength = 16383; // must be multiple of 3
+
+  // go through the array every three bytes, we'll deal with trailing stuff later
+  for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
+    parts.push(
+      encodeChunk(
+        uint8,
+        i,
+        i + maxChunkLength > len2 ? len2 : i + maxChunkLength
+      )
+    );
+  }
+
+  // pad the end with zeros, but make sure to not forget the extra bytes
+  if (extraBytes === 1) {
+    tmp = uint8[len - 1];
+    parts.push(lookup[tmp >> 2] + lookup[(tmp << 4) & 0x3f] + "==");
+  } else if (extraBytes === 2) {
+    tmp = (uint8[len - 2] << 8) + uint8[len - 1];
+    parts.push(
+      lookup[tmp >> 10] +
+        lookup[(tmp >> 4) & 0x3f] +
+        lookup[(tmp << 2) & 0x3f] +
+        "="
+    );
+  }
+
+  return parts.join("");
+}