✨ Add base32 to Buffer decode function

AckeeCZ · Jan 20, 2023 · 8fd8630 · 8fd8630
1 parent 02cd459
commit 8fd8630
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Showing 2 changed files with 40 additions and 3 deletions.
diff --git a/src/utils/index.ts b/src/utils/index.ts
@@ -46,7 +46,7 @@ const generateSecret = (secretLength: number | HMACAlgorithm) => {
  * @param data Buffer to convert to base32
  * @returns string which is the base32 encoding of the buffer
  */
-const convertBase32 = (data: Buffer) => {
+const convertToBase32 = (data: Buffer) => {
   const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'
   let bits = 0
   let value = 0
@@ -68,6 +68,24 @@ const convertBase32 = (data: Buffer) => {
   return output
 }
 
+const base32ToBuffer = (input: string) => {
+  const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'
+  let bits = 0
+  let value = 0
+  let index = 0
+  const output = Buffer.alloc(Math.ceil((input.length * 5) / 8))
+  for (let i = 0; i < input.length; i++) {
+    value = (value << 5) | alphabet.indexOf(input[i].toUpperCase())
+    bits += 5
+
+    if (bits >= 8) {
+      output.writeUInt8((value >>> (bits - 8)) & 255, index++)
+      bits -= 8
+    }
+  }
+  return output
+}
+
 interface URIMakerFunction {
   (
     secret: Buffer,
@@ -118,7 +136,7 @@ const generateURI: URIMakerFunction = (
   Object.entries({
     ...options,
     ...params,
-    secret: convertBase32(secret),
+    secret: convertToBase32(secret),
   }).forEach(([key, value]) =>
     result.searchParams.append(key, value.toString())
   )
@@ -131,4 +149,6 @@ export {
   generateURI,
   URItype,
   generateSecret,
+  convertToBase32,
+  base32ToBuffer,
 }
diff --git a/test/utils.test.ts b/test/utils.test.ts
@@ -1,5 +1,11 @@
 import { expect } from 'chai'
-import { HMACAlgorithm, URItype, generateURI } from '../src/utils'
+import {
+  HMACAlgorithm,
+  URItype,
+  base32ToBuffer,
+  convertToBase32,
+  generateURI,
+} from '../src/utils'
 
 describe('URI Generation', () => {
   it('should generate URI', () => {
@@ -26,3 +32,14 @@ describe('URI Generation', () => {
     expect(uri.searchParams.get('secret')).to.equal('JBSWY3DPEHPK3PXP')
   })
 })
+
+describe('Base32 conversion', () => {
+  it('should convert to base32', () => {
+    const originalData = [
+      0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x21, 0xde, 0xad, 0xbe, 0xef,
+    ]
+    const base32 = convertToBase32(Buffer.from(originalData))
+    const backToBuffer = base32ToBuffer(base32)
+    expect([...backToBuffer]).to.deep.equal(originalData)
+  })
+})