feat: add base45 multibase

Ref: https://datatracker.ietf.org/doc/html/rfc9285
Ref: multiformats/multibase#123
Ref: multiformats/multibase#125

Author: rvagg

README.md

@@ -181,7 +181,7 @@ import the ones you need yourself.
 | `base64`, `base64pad`, `base64url`, `base64urlpad`            | `multiformats/bases/base64` | [multiformats/js-multiformats](https://github.com/multiformats/js-multiformats/tree/master/bases) |
 | `base58btc`, `base58flick4`                                   | `multiformats/bases/base58` | [multiformats/js-multiformats](https://github.com/multiformats/js-multiformats/tree/master/bases) |
 
-Other (less useful) bases implemented in [multiformats/js-multiformats](https://github.com/multiformats/js-multiformats/tree/master/bases) include: `base2`, `base8`, `base10`, `base36` and `base256emoji`.
+Other (less useful) bases implemented in [multiformats/js-multiformats](https://github.com/multiformats/js-multiformats/tree/master/bases) include: `base2`, `base8`, `base10`, `base36`, `base45` and `base256emoji`.
 
 ### Multihash hashers
 

package.json

@@ -70,6 +70,10 @@
       "types": "./dist/src/bases/base36.d.ts",
       "import": "./dist/src/bases/base36.js"
     },
+    "./bases/base45": {
+      "types": "./dist/src/bases/base45.d.ts",
+      "import": "./dist/src/bases/base45.js"
+    },
     "./bases/base58": {
       "types": "./dist/src/bases/base58.d.ts",
       "import": "./dist/src/bases/base58.js"

src/bases/base45.ts

@@ -0,0 +1,51 @@
+import { from } from './base.js'
+
+const alphabet = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:'
+
+function indexOf (char: string) {
+  const index = alphabet.indexOf(char)
+  if (index === -1) {
+    throw new Error(`Non-base45 character: ${char}`)
+  }
+  return index
+}
+
+export const base45 = from({
+  name: 'base45',
+  prefix: 'R',
+  encode: (input: Uint8Array): string => {
+    var ret = ''
+    for (let i = 0; i < input.length; i += 2) {
+      if (i + 1 === input.length) {
+        const v = input[i]
+        const a = v / 45 | 0
+        const b = v % 45 | 0
+        ret += alphabet[b] + alphabet[a]
+        break
+      }
+      const v = input[i] << 8 | input[i + 1]
+      const a = v / 45 ** 2 | 0
+      const b = v / 45 % 45 | 0
+      const c = v % 45
+      ret += alphabet[c] + alphabet[b] + alphabet[a]
+    }
+    return ret
+  },
+  decode: (input: string): Uint8Array => {
+    if ((input.length * 2) % 3 === 2) {
+      throw new Error('Unexpected end of data')
+    }
+    const out = new Uint8Array(Math.floor(input.length * 2 / 3))
+    for (let i = 0; i < input.length; i += 3) {
+      if (i + 2 === input.length) {
+        const v = indexOf(input[i]) + indexOf(input[i + 1]) * 45
+        out[i / 3 * 2] = v
+        break
+      }
+      const v = indexOf(input[i]) + indexOf(input[i + 1]) * 45 + indexOf(input[i + 2]) * 45 ** 2
+      out[i / 3 * 2] = v >> 8
+      out[i / 3 * 2 + 1] = v & 0xff
+    }
+    return out
+  }
+})

src/basics.ts

@@ -4,6 +4,7 @@ import * as base2 from './bases/base2.js'
 import * as base256emoji from './bases/base256emoji.js'
 import * as base32 from './bases/base32.js'
 import * as base36 from './bases/base36.js'
+import * as base45 from './bases/base45.js'
 import * as base58 from './bases/base58.js'
 import * as base64 from './bases/base64.js'
 import * as base8 from './bases/base8.js'
@@ -14,7 +15,7 @@ import * as identity from './hashes/identity.js'
 import * as sha2 from './hashes/sha2.js'
 import { CID, hasher, digest, varint, bytes } from './index.js'
 
-export const bases = { ...identityBase, ...base2, ...base8, ...base10, ...base16, ...base32, ...base36, ...base58, ...base64, ...base256emoji }
+export const bases = { ...identityBase, ...base2, ...base8, ...base10, ...base16, ...base32, ...base36, ...base45, ...base58, ...base64, ...base256emoji }
 export const hashes = { ...sha2, ...identity }
 export const codecs = { raw, json }
 

src/index.ts

@@ -176,7 +176,7 @@
  * | `base64`, `base64pad`, `base64url`, `base64urlpad`            | `multiformats/bases/base64` | [multiformats/js-multiformats](https://github.com/multiformats/js-multiformats/tree/master/bases) |
  * | `base58btc`, `base58flick4`                                   | `multiformats/bases/base58` | [multiformats/js-multiformats](https://github.com/multiformats/js-multiformats/tree/master/bases) |
  *
- * Other (less useful) bases implemented in [multiformats/js-multiformats](https://github.com/multiformats/js-multiformats/tree/master/bases) include: `base2`, `base8`, `base10`, `base36` and `base256emoji`.
+ * Other (less useful) bases implemented in [multiformats/js-multiformats](https://github.com/multiformats/js-multiformats/tree/master/bases) include: `base2`, `base8`, `base10`, `base36`, `base45` and `base256emoji`.
  *
  * ### Multihash hashers
  *

test/test-multibase-spec.spec.ts

@@ -25,6 +25,7 @@ const encoded = [
       ['base32z', 'het1sg3mqqt3gn5djxj11y3msci3817depfzgqejb'],
       ['base36', 'k343ixo7d49hqj1ium15pgy1wzww5fxrid21td7l'],
       ['base36upper', 'K343IXO7D49HQJ1IUM15PGY1WZWW5FXRID21TD7L'],
+      ['base45', 'R4T8KPCG/DVKEXVDDLFD44O/EALEAWEZEDV1DX0'],
       ['base58flickr', 'Ztwe7gVTeK8wswS1gf8hrgAua9fcw9reboD'],
       ['base58btc', 'zUXE7GvtEk8XTXs1GF8HSGbVA9FCX9SEBPe'],
       ['base64', 'mRGVjZW50cmFsaXplIGV2ZXJ5dGhpbmchIQ'],
@@ -54,6 +55,7 @@ const encoded = [
       ['base32z', 'hxf1zgedpcfzg1ebb'],
       ['base36', 'k2lcpzo5yikidynfl'],
       ['base36upper', 'K2LCPZO5YIKIDYNFL'],
+      ['base45', 'RRFF.OEB$D5/DZ24'],
       ['base58flickr', 'Z7Pznk19XTTzBtx'],
       ['base58btc', 'z7paNL19xttacUY'],
       ['base64', 'meWVzIG1hbmkgIQ'],
@@ -83,6 +85,7 @@ const encoded = [
       ['base32z', 'hpb1sa5dxrb5s6hucco'],
       ['base36', 'kfuvrsivvnfrbjwajo'],
       ['base36upper', 'KFUVRSIVVNFRBJWAJO'],
+      ['base45', 'R+8D VD82EK4F.KEA2'],
       ['base58flickr', 'ZrTu1dk6cWsRYjYu'],
       ['base58btc', 'zStV1DL6CwTryKyV'],
       ['base64', 'maGVsbG8gd29ybGQ'],
@@ -112,6 +115,7 @@ const encoded = [
       ['base32z', 'hybhskh3ypiosh4jyrr'],
       ['base36', 'k02lcpzo5yikidynfl'],
       ['base36upper', 'K02LCPZO5YIKIDYNFL'],
+      ['base45', 'RV206$CL44CEC2DDX0'],
       ['base58flickr', 'Z17Pznk19XTTzBtx'],
       ['base58btc', 'z17paNL19xttacUY'],
       ['base64', 'mAHllcyBtYW5pICE'],
@@ -141,6 +145,7 @@ const encoded = [
       ['base32z', 'hyyy813murbssn5ujryoo'],
       ['base36', 'k002lcpzo5yikidynfl'],
       ['base36upper', 'K002LCPZO5YIKIDYNFL'],
+      ['base45', 'R000RFF.OEB$D5/DZ24'],
       ['base58flickr', 'Z117Pznk19XTTzBtx'],
       ['base58btc', 'z117paNL19xttacUY'],
       ['base64', 'mAAB5ZXMgbWFuaSAh'],
@@ -149,7 +154,12 @@ const encoded = [
       ['base64urlpad', 'UAAB5ZXMgbWFuaSAh'],
       ['base256emoji', '🚀🚀🚀🏃✋🌈😅🌷🤤😻🌟😅👏']
     ]
-  }
+  },
+  { input: 'AB', tests: [['base45', 'RBB8']] },
+  { input: 'Hello!!', tests: [['base45', 'R%69 VD92EX0']] },
+  { input: 'base-45', tests: [['base45', 'RUJCLQE7W581']] },
+  { input: 'ietf!', tests: [['base45', 'RQED8WEX0']] },
+  { input: 'ietf!', tests: [['base45', 'RQED8WEX0']] },
 ]
 
 describe('spec test', () => {
@@ -160,12 +170,12 @@ describe('spec test', () => {
         const base = bases[name as keyof typeof bases]
 
         describe(name, () => {
-          it('should encode buffer', () => {
+          it(`should encode from buffer [${input}]`, () => {
             const out = base.encode(fromString(input))
             assert.deepStrictEqual(out, output)
           })
 
-          it('should decode string', () => {
+          it(`should decode from string [${input}]`, () => {
             assert.deepStrictEqual(base.decode(output), fromString(input))
           })
         })
@@ -182,4 +192,9 @@ describe('spec test', () => {
       assert.throws(() => base.decode(base.prefix + '^!@$%!#$%@#y'), `Non-${base.name} character`)
     })
   }
+
+  it('base45 should fail with invalid input', () => {
+    // not enough input chars, should be multiple of 3 or multiple of 3 + 2
+    assert.throws(() => bases.base45.decode('R%69 VD92EX'), 'Unexpected end of data')
+  })
 })

test/test-multibase.spec.ts

@@ -6,6 +6,7 @@ import * as b16 from '../src/bases/base16.js'
 import * as b2 from '../src/bases/base2.js'
 import * as b32 from '../src/bases/base32.js'
 import * as b36 from '../src/bases/base36.js'
+import * as b45 from '../src/bases/base45.js'
 import * as b58 from '../src/bases/base58.js'
 import * as b64 from '../src/bases/base64.js'
 import * as b8 from '../src/bases/base8.js'
@@ -64,7 +65,7 @@ describe('multibase', () => {
   const buff = bytes.fromString('test')
   const nonPrintableBuff = Uint8Array.from([239, 250, 254])
 
-  const baseTest = (bases: typeof b2 | typeof b8 | typeof b10 | typeof b16 | typeof b32 | typeof b36 | typeof b58 | typeof b64): void => {
+  const baseTest = (bases: typeof b2 | typeof b8 | typeof b10 | typeof b16 | typeof b32 | typeof b36 | typeof b45 | typeof b58 | typeof b64): void => {
     for (const base of Object.values(bases)) {
       if (((base as { name: string })?.name) !== '') {
         it(`encode/decode ${base.name}`, () => {
@@ -110,6 +111,10 @@ describe('multibase', () => {
     baseTest(b36)
   })
 
+  describe('base45', () => {
+    baseTest(b45)
+  })
+
   describe('base58', () => {
     baseTest(b58)
   })

typedoc.json

@@ -7,6 +7,7 @@
     "./src/bases/base256emoji.ts",
     "./src/bases/base32.ts",
     "./src/bases/base36.ts",
+    "./src/bases/base45.ts",
     "./src/bases/base58.ts",
     "./src/bases/base64.ts",
     "./src/bases/base8.ts",