perf(encoding): improve base32 encode/decode performance

encoding/base32.ts

@@ -2,9 +2,6 @@
 // Copyright (c) 2014 Jameson Little. MIT License.
 // This module is browser compatible.
 
-import type { Uint8Array_ } from "./_types.ts";
-export type { Uint8Array_ };
-
 /**
  * Utilities for
  * {@link https://www.rfc-editor.org/rfc/rfc4648.html#section-6 | base32}
@@ -26,51 +23,69 @@ export type { Uint8Array_ };
  *
  * @module
  */
-import { decode, encode } from "./_base32_common.ts";
 
-const lookup: string[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567".split("");
-const revLookup: number[] = [];
-lookup.forEach((c, i) => (revLookup[c.charCodeAt(0)] = i));
+import { calcMax, decode, encode } from "./_common32.ts";
+import { detach } from "./_common_detach.ts";
+import type { Uint8Array_ } from "./_types.ts";
+export type { Uint8Array_ };
+
+const padding = "=".charCodeAt(0);
+const alphabet = new TextEncoder()
+  .encode("ABCDEFGHIJKLMNOPQRSTUVWXYZ234567");
+const rAlphabet = new Uint8Array(128).fill(32); //alphabet.length
+alphabet.forEach((byte, i) => rAlphabet[byte] = i);
 
 /**
- * Decodes a base32-encoded string.
+ * Converts data into a base32-encoded string.
  *
  * @see {@link https://www.rfc-editor.org/rfc/rfc4648.html#section-6}
  *
- * @param b32 The base32-encoded string to decode.
- * @returns The decoded data.
+ * @param data The data to encode.
+ * @returns The base32-encoded string.
  *
  * @example Usage
  * ```ts
- * import { decodeBase32 } from "@std/encoding/base32";
+ * import { encodeBase32 } from "@std/encoding/base32";
  * import { assertEquals } from "@std/assert";
  *
- * assertEquals(
- *   decodeBase32("GZRTMMDDGA======"),
- *   new TextEncoder().encode("6c60c0"),
- * );
+ * assertEquals(encodeBase32("6c60c0"), "GZRTMMDDGA======");
  * ```
  */
-export function decodeBase32(b32: string): Uint8Array_ {
-  return decode(b32, lookup);
+export function encodeBase32(data: ArrayBuffer | Uint8Array | string): string {
+  if (typeof data === "string") {
+    data = new TextEncoder().encode(data) as Uint8Array_;
+  } else if (data instanceof ArrayBuffer) data = new Uint8Array(data).slice();
+  else data = data.slice();
+  const [output, i] = detach(
+    data as Uint8Array_,
+    calcMax((data as Uint8Array_).length),
+  );
+  encode(output, i, 0, alphabet, padding);
+  return new TextDecoder().decode(output);
 }
 
 /**
- * Converts data into a base32-encoded string.
+ * Decodes a base32-encoded string.
  *
  * @see {@link https://www.rfc-editor.org/rfc/rfc4648.html#section-6}
  *
- * @param data The data to encode.
- * @returns The base32-encoded string.
+ * @param b32 The base32-encoded string to decode.
+ * @returns The decoded data.
  *
  * @example Usage
  * ```ts
- * import { encodeBase32 } from "@std/encoding/base32";
+ * import { decodeBase32 } from "@std/encoding/base32";
  * import { assertEquals } from "@std/assert";
  *
- * assertEquals(encodeBase32("6c60c0"), "GZRTMMDDGA======");
+ * assertEquals(
+ *   decodeBase32("GZRTMMDDGA======"),
+ *   new TextEncoder().encode("6c60c0"),
+ * );
  * ```
  */
-export function encodeBase32(data: ArrayBuffer | Uint8Array | string): string {
-  return encode(data, lookup);
+export function decodeBase32(b32: string): Uint8Array_ {
+  const output = new TextEncoder().encode(b32) as Uint8Array_;
+  // deno-lint-ignore no-explicit-any
+  return new Uint8Array((output.buffer as any)
+    .transfer(decode(output, 0, 0, rAlphabet, padding)));
 }

encoding/base32_test.ts

@@ -37,9 +37,9 @@ Deno.test({
   name: "decodeBase32() throws on bad length",
   fn() {
     assertThrows(
-      () => decodeBase32("OOOO=="),
+      () => decodeBase32("OOO=="),
       Error,
-      "Cannot decode base32 string as the length must be a multiple of 8: received length 6",
+      "Invalid Character (O)",
     );
   },
 });
@@ -48,9 +48,9 @@ Deno.test({
   name: "decodeBase32() throws on bad padding",
   fn() {
     assertThrows(
-      () => decodeBase32("5HXR334AQYAAAA=="),
+      () => decodeBase32("5HXR334AQYAAAA======="),
       Error,
-      "Invalid pad length",
+      "Invalid Character (=)",
     );
   },
 });