fix(std/encoding): base64 properly encodes mbc and handles Uint8Arrays (#7807)

Fixes #6094
Fixes #4794

4 files changed, 84 insertions, 78 deletions

diff --git a/std/encoding/base64.ts b/std/encoding/base64.ts
index 4c9aa4059..e631e5b88 100644
--- a/std/encoding/base64.ts
+++ b/std/encoding/base64.ts
@@ -1,41 +1,59 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
-/**
- * Converts given data with base64 encoding
- * @param data input to encode
- */
-export function encode(data: string | ArrayBuffer): string {
-  if (typeof data === "string") {
-    return btoa(data);
-  } else {
-    const d = new Uint8Array(data);
-    let dataString = "";
-    for (let i = 0; i < d.length; ++i) {
-      dataString += String.fromCharCode(d[i]);
-    }
-
-    return btoa(dataString);
-  }
-}
+// deno-fmt-ignore
+const base64abc = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", 
+  "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "a", 
+  "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", 
+  "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "0", "1", "2", "3", "4", 
+  "5", "6", "7", "8", "9", "+", "/"];
 
 /**
- * Converts given base64 encoded data back to original
- * @param data input to decode
+ * CREDIT: https://gist.github.com/enepomnyaschih/72c423f727d395eeaa09697058238727
+ * Encodes a given Uint8Array, ArrayBuffer or string into RFC4648 base64 representation
+ * @param data
  */
-export function decode(data: string): ArrayBuffer {
-  const binaryString = decodeString(data);
-  const binary = new Uint8Array(binaryString.length);
-  for (let i = 0; i < binary.length; ++i) {
-    binary[i] = binaryString.charCodeAt(i);
+export function encode(data: ArrayBuffer | string): string {
+  const uint8 =
+    typeof data === "string"
+      ? new TextEncoder().encode(data)
+      : data instanceof Uint8Array
+      ? data
+      : new Uint8Array(data);
+  let result = "",
+    i;
+  const l = uint8.length;
+  for (i = 2; i < l; i += 3) {
+    result += base64abc[uint8[i - 2] >> 2];
+    result += base64abc[((uint8[i - 2] & 0x03) << 4) | (uint8[i - 1] >> 4)];
+    result += base64abc[((uint8[i - 1] & 0x0f) << 2) | (uint8[i] >> 6)];
+    result += base64abc[uint8[i] & 0x3f];
   }
-
-  return binary.buffer;
+  if (i === l + 1) {
+    // 1 octet yet to write
+    result += base64abc[uint8[i - 2] >> 2];
+    result += base64abc[(uint8[i - 2] & 0x03) << 4];
+    result += "==";
+  }
+  if (i === l) {
+    // 2 octets yet to write
+    result += base64abc[uint8[i - 2] >> 2];
+    result += base64abc[((uint8[i - 2] & 0x03) << 4) | (uint8[i - 1] >> 4)];
+    result += base64abc[(uint8[i - 1] & 0x0f) << 2];
+    result += "=";
+  }
+  return result;
 }
 
 /**
- * Decodes data assuming the output is in string type
- * @param data input to decode
+ * Decodes a given RFC4648 base64 encoded string
+ * @param b64
  */
-export function decodeString(data: string): string {
-  return atob(data);
+export function decode(b64: string): Uint8Array {
+  const binString = atob(b64);
+  const size = binString.length;
+  const bytes = new Uint8Array(size);
+  for (let i = 0; i < size; i++) {
+    bytes[i] = binString.charCodeAt(i);
+  }
+  return bytes;
 }
diff --git a/std/encoding/base64_test.ts b/std/encoding/base64_test.ts
index 5fe89410b..65c62f4cd 100644
--- a/std/encoding/base64_test.ts
+++ b/std/encoding/base64_test.ts
@@ -1,9 +1,11 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { assertEquals } from "../testing/asserts.ts";
-import { decode, decodeString, encode } from "./base64.ts";
+import { decode, encode } from "./base64.ts";
 
 const testsetString = [
   ["", ""],
+  ["ß", "w58="],
   ["f", "Zg=="],
   ["fo", "Zm8="],
   ["foo", "Zm9v"],
@@ -12,12 +14,10 @@ const testsetString = [
   ["foobar", "Zm9vYmFy"],
 ];
 
-const testsetBinary = [
-  [new TextEncoder().encode("\x00"), "AA=="],
-  [new TextEncoder().encode("\x00\x00"), "AAA="],
-  [new TextEncoder().encode("\x00\x00\x00"), "AAAA"],
-  [new TextEncoder().encode("\x00\x00\x00\x00"), "AAAAAA=="],
-];
+const testsetBinary = testsetString.map(([str, b64]) => [
+  new TextEncoder().encode(str),
+  b64,
+]) as Array<[Uint8Array, string]>;
 
 Deno.test("[encoding/base64] testBase64EncodeString", () => {
   for (const [input, output] of testsetString) {
@@ -25,21 +25,21 @@ Deno.test("[encoding/base64] testBase64EncodeString", () => {
   }
 });
 
-Deno.test("[encoding/base64] testBase64DecodeString", () => {
-  for (const [input, output] of testsetString) {
-    assertEquals(decodeString(output), input);
+Deno.test("[encoding/base64] testBase64EncodeBinary", () => {
+  for (const [input, output] of testsetBinary) {
+    assertEquals(encode(input), output);
   }
 });
 
-Deno.test("[encoding/base64] testBase64EncodeBinary", () => {
+Deno.test("[encoding/base64] testBase64EncodeBinaryBuffer", () => {
   for (const [input, output] of testsetBinary) {
-    assertEquals(encode(input), output);
+    assertEquals(encode(input.buffer), output);
   }
 });
 
 Deno.test("[encoding/base64] testBase64DecodeBinary", () => {
   for (const [input, output] of testsetBinary) {
-    const outputBinary = new Uint8Array(decode(output as string));
-    assertEquals(outputBinary, input as Uint8Array);
+    const outputBinary = decode(output);
+    assertEquals(outputBinary, input);
   }
 });
diff --git a/std/encoding/base64url.ts b/std/encoding/base64url.ts
index b20878554..fe8019a29 100644
--- a/std/encoding/base64url.ts
+++ b/std/encoding/base64url.ts
@@ -1,13 +1,11 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
-import {
-  decode as convertBase64ToArrayBuffer,
-  encode as convertArrayBufferToBase64,
-} from "./base64.ts";
+import * as base64 from "./base64.ts";
 
 /*
  * Some variants allow or require omitting the padding '=' signs:
  * https://en.wikipedia.org/wiki/Base64#URL_applications
+ * @param base64url
  */
 export function addPaddingToBase64url(base64url: string): string {
   if (base64url.length % 4 === 2) return base64url + "==";
@@ -18,29 +16,26 @@ export function addPaddingToBase64url(base64url: string): string {
   return base64url;
 }
 
-function convertBase64urlToBase64(base64url: string): string {
-  return addPaddingToBase64url(base64url)
-    .replace(/\-/g, "+")
-    .replace(/_/g, "/");
+function convertBase64urlToBase64(b64url: string): string {
+  return addPaddingToBase64url(b64url).replace(/\-/g, "+").replace(/_/g, "/");
 }
 
-function convertBase64ToBase64url(base64: string): string {
-  return base64.replace(/=/g, "").replace(/\+/g, "-").replace(/\//g, "_");
+function convertBase64ToBase64url(b64: string): string {
+  return b64.replace(/=/g, "").replace(/\+/g, "-").replace(/\//g, "_");
 }
 
 /**
- * Converts given data with base64url encoding.
- * Removes paddings '='.
- * @param data input to encode
+ * Encodes a given Uint8Array into a base64url representation
+ * @param uint8
  */
-export function encode(data: string | ArrayBuffer): string {
-  return convertBase64ToBase64url(convertArrayBufferToBase64(data));
+export function encode(uint8: Uint8Array): string {
+  return convertBase64ToBase64url(base64.encode(uint8));
 }
 
 /**
  * Converts given base64url encoded data back to original
- * @param data input to decode
+ * @param b64url
  */
-export function decode(data: string): ArrayBuffer {
-  return convertBase64ToArrayBuffer(convertBase64urlToBase64(data));
+export function decode(b64url: string): Uint8Array {
+  return base64.decode(convertBase64urlToBase64(b64url));
 }
diff --git a/std/encoding/base64url_test.ts b/std/encoding/base64url_test.ts
index 59d67240f..99dcf260c 100644
--- a/std/encoding/base64url_test.ts
+++ b/std/encoding/base64url_test.ts
@@ -1,30 +1,24 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
 import { assertEquals } from "../testing/asserts.ts";
 import { decode, encode } from "./base64url.ts";
 
 const testsetString = [
   ["", ""],
+  ["ß", "w58"],
   ["f", "Zg"],
   ["fo", "Zm8"],
   ["foo", "Zm9v"],
   ["foob", "Zm9vYg"],
   ["fooba", "Zm9vYmE"],
   ["foobar", "Zm9vYmFy"],
-  [">?>d?ß", "Pj8-ZD_f"],
-];
-
-const testsetBinary = [
-  [new TextEncoder().encode("\x00"), "AA"],
-  [new TextEncoder().encode("\x00\x00"), "AAA"],
-  [new TextEncoder().encode("\x00\x00\x00"), "AAAA"],
-  [new TextEncoder().encode("\x00\x00\x00\x00"), "AAAAAA"],
+  [">?>d?ß", "Pj8-ZD_Dnw"],
 ];
 
-Deno.test("[encoding/base64url] testBase64urlEncodeString", () => {
-  for (const [input, output] of testsetString) {
-    assertEquals(encode(input), output);
-  }
-});
+const testsetBinary = testsetString.map(([str, b64]) => [
+  new TextEncoder().encode(str),
+  b64,
+]) as Array<[Uint8Array, string]>;
 
 Deno.test("[encoding/base64url] testBase64urlEncodeBinary", () => {
   for (const [input, output] of testsetBinary) {
@@ -32,9 +26,8 @@ Deno.test("[encoding/base64url] testBase64urlEncodeBinary", () => {
   }
 });
 
-Deno.test("[encoding/base64ur] testBase64urDecodeBinary", () => {
+Deno.test("[decoding/base64url] testBase64urlDecodeBinary", () => {
   for (const [input, output] of testsetBinary) {
-    const outputBinary = new Uint8Array(decode(output as string));
-    assertEquals(outputBinary, input as Uint8Array);
+    assertEquals(decode(output), input);
   }
 });