import { assertU8 } from './_utils.js'
import { nativeEncoder, nativeDecoder, isHermes } from './platform.js'
import { encodeAscii, decodeAscii } from './latin1.js'
// See https://datatracker.ietf.org/doc/html/rfc4648
const BASE32_HELPERS = [{}, {}, {}]
const BASE32_ALPHABETS = [
[...'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'], // RFC 4648, #6
[...'0123456789ABCDEFGHIJKLMNOPQRSTUV'], // RFC 4648, #7
[...'0123456789ABCDEFGHJKMNPQRSTVWXYZ'], // Crockford, base (see extra below in fromMap)
]
export const E_CHAR = 'Invalid character in base32 input'
export const E_PADDING = 'Invalid base32 padding'
export const E_LENGTH = 'Invalid base32 length'
export const E_LAST = 'Invalid last chunk'
const useTemplates = isHermes // Faster on Hermes and JSC, but we use it only on Hermes
// We construct output by concatenating chars, this seems to be fine enough on modern JS engines
export function toBase32(arr, mode, padding) {
assertU8(arr)
const fullChunks = Math.floor(arr.length / 5)
const fullChunksBytes = fullChunks * 5
let o = ''
let i = 0
const alphabet = BASE32_ALPHABETS[mode]
const helpers = BASE32_HELPERS[mode]
if (!helpers.pairs) {
helpers.pairs = []
if (nativeDecoder) {
// Lazy to save memory in case if this is not needed
helpers.codepairs = new Uint16Array(32 * 32)
const u16 = helpers.codepairs
const u8 = new Uint8Array(u16.buffer, u16.byteOffset, u16.byteLength) // write as 1-byte to ignore BE/LE difference
for (let i = 0; i < 32; i++) {
const ic = alphabet[i].charCodeAt(0)
for (let j = 0; j < 32; j++) u8[(i << 6) | (j << 1)] = u8[(j << 6) | ((i << 1) + 1)] = ic
}
} else {
const p = helpers.pairs
for (let i = 0; i < 32; i++) {
for (let j = 0; j < 32; j++) p.push(`${alphabet[i]}${alphabet[j]}`)
}
}
}
const { pairs, codepairs } = helpers
// Fast path for complete blocks
// This whole loop can be commented out, the algorithm won't change, it's just an optimization of the next loop
if (nativeDecoder) {
const oa = new Uint16Array(fullChunks * 4)
for (let j = 0; i < fullChunksBytes; i += 5) {
const a = arr[i]
const b = arr[i + 1]
const c = arr[i + 2]
const d = arr[i + 3]
const e = arr[i + 4]
const x0 = (a << 2) | (b >> 6) // 8 + 8 - 5 - 5 = 6 left
const x1 = ((b & 0x3f) << 4) | (c >> 4) // 6 + 8 - 5 - 5 = 4 left
const x2 = ((c & 0xf) << 6) | (d >> 2) // 4 + 8 - 5 - 5 = 2 left
const x3 = ((d & 0x3) << 8) | e // 2 + 8 - 5 - 5 = 0 left
oa[j] = codepairs[x0]
oa[j + 1] = codepairs[x1]
oa[j + 2] = codepairs[x2]
oa[j + 3] = codepairs[x3]
j += 4
}
o = decodeAscii(oa)
} else if (useTemplates) {
// Templates are faster only on Hermes and JSC. Browsers have TextDecoder anyway
for (; i < fullChunksBytes; i += 5) {
const a = arr[i]
const b = arr[i + 1]
const c = arr[i + 2]
const d = arr[i + 3]
const e = arr[i + 4]
const x0 = (a << 2) | (b >> 6) // 8 + 8 - 5 - 5 = 6 left
const x1 = ((b & 0x3f) << 4) | (c >> 4) // 6 + 8 - 5 - 5 = 4 left
const x2 = ((c & 0xf) << 6) | (d >> 2) // 4 + 8 - 5 - 5 = 2 left
const x3 = ((d & 0x3) << 8) | e // 2 + 8 - 5 - 5 = 0 left
o += `${pairs[x0]}${pairs[x1]}${pairs[x2]}${pairs[x3]}`
}
} else {
for (; i < fullChunksBytes; i += 5) {
const a = arr[i]
const b = arr[i + 1]
const c = arr[i + 2]
const d = arr[i + 3]
const e = arr[i + 4]
const x0 = (a << 2) | (b >> 6) // 8 + 8 - 5 - 5 = 6 left
const x1 = ((b & 0x3f) << 4) | (c >> 4) // 6 + 8 - 5 - 5 = 4 left
const x2 = ((c & 0xf) << 6) | (d >> 2) // 4 + 8 - 5 - 5 = 2 left
const x3 = ((d & 0x3) << 8) | e // 2 + 8 - 5 - 5 = 0 left
o += pairs[x0]
o += pairs[x1]
o += pairs[x2]
o += pairs[x3]
}
}
// If we have something left, process it with a full algo
let carry = 0
let shift = 3 // First byte needs to be shifted by 3 to get 5 bits
for (; i < arr.length; i++) {
const x = arr[i]
o += alphabet[carry | (x >> shift)] // shift >= 3, so this fits
if (shift >= 5) {
shift -= 5
o += alphabet[(x >> shift) & 0x1f]
}
carry = (x << (5 - shift)) & 0x1f
shift += 3 // Each byte prints 5 bits and leaves 3 bits
}
if (shift !== 3) o += alphabet[carry] // shift 3 means we have no carry left
if (padding) o += ['', '======', '====', '===', '='][arr.length - fullChunksBytes]
return o
}
// TODO: can this be optimized? This only affects non-Hermes barebone engines though
const mapSize = nativeEncoder ? 128 : 65_536 // we have to store 64 KiB map or recheck everything if we can't decode to byte array
export function fromBase32(str, mode) {
let inputLength = str.length
while (str[inputLength - 1] === '=') inputLength--
const paddingLength = str.length - inputLength
const tailLength = inputLength % 8
const mainLength = inputLength - tailLength // multiples of 8
if (![0, 2, 4, 5, 7].includes(tailLength)) throw new SyntaxError(E_LENGTH) // fast verification
if (paddingLength > 7 || (paddingLength !== 0 && str.length % 8 !== 0)) {
throw new SyntaxError(E_PADDING)
}
const alphabet = BASE32_ALPHABETS[mode]
const helpers = BASE32_HELPERS[mode]
if (!helpers.fromMap) {
helpers.fromMap = new Int8Array(mapSize).fill(-1) // no regex input validation here, so we map all other bytes to -1 and recheck sign
const m = helpers.fromMap
alphabet.forEach((c, i) => {
m[c.charCodeAt(0)] = m[c.toLowerCase().charCodeAt(0)] = i
})
if (mode === 2) {
// Extra Crockford mapping
m[73] = m[76] = m[105] = m[108] = m[49] // ILil -> 1
m[79] = m[111] = m[48] // Oo -> 0
}
}
const m = helpers.fromMap
const arr = new Uint8Array(Math.floor((inputLength * 5) / 8))
let at = 0
let i = 0
if (nativeEncoder) {
const codes = encodeAscii(str, E_CHAR)
for (; i < mainLength; i += 8) {
// each 5 bits, grouped 5 * 4 = 20
const x0 = codes[i]
const x1 = codes[i + 1]
const x2 = codes[i + 2]
const x3 = codes[i + 3]
const x4 = codes[i + 4]
const x5 = codes[i + 5]
const x6 = codes[i + 6]
const x7 = codes[i + 7]
const a = (m[x0] << 15) | (m[x1] << 10) | (m[x2] << 5) | m[x3]
const b = (m[x4] << 15) | (m[x5] << 10) | (m[x6] << 5) | m[x7]
if (a < 0 || b < 0) throw new SyntaxError(E_CHAR)
arr[at] = a >> 12
arr[at + 1] = (a >> 4) & 0xff
arr[at + 2] = ((a << 4) & 0xff) | (b >> 16)
arr[at + 3] = (b >> 8) & 0xff
arr[at + 4] = b & 0xff
at += 5
}
} else {
for (; i < mainLength; i += 8) {
// each 5 bits, grouped 5 * 4 = 20
const x0 = str.charCodeAt(i)
const x1 = str.charCodeAt(i + 1)
const x2 = str.charCodeAt(i + 2)
const x3 = str.charCodeAt(i + 3)
const x4 = str.charCodeAt(i + 4)
const x5 = str.charCodeAt(i + 5)
const x6 = str.charCodeAt(i + 6)
const x7 = str.charCodeAt(i + 7)
const a = (m[x0] << 15) | (m[x1] << 10) | (m[x2] << 5) | m[x3]
const b = (m[x4] << 15) | (m[x5] << 10) | (m[x6] << 5) | m[x7]
if (a < 0 || b < 0) throw new SyntaxError(E_CHAR)
arr[at] = a >> 12
arr[at + 1] = (a >> 4) & 0xff
arr[at + 2] = ((a << 4) & 0xff) | (b >> 16)
arr[at + 3] = (b >> 8) & 0xff
arr[at + 4] = b & 0xff
at += 5
}
}
// Last block, valid tailLength: 0 2 4 5 7, checked already
// We check last chunk to be strict
if (tailLength < 2) return arr
const ab = (m[str.charCodeAt(i++)] << 5) | m[str.charCodeAt(i++)]
if (ab < 0) throw new SyntaxError(E_CHAR)
arr[at++] = ab >> 2
if (tailLength < 4) {
if (ab & 0x3) throw new SyntaxError(E_LAST)
return arr
}
const cd = (m[str.charCodeAt(i++)] << 5) | m[str.charCodeAt(i++)]
if (cd < 0) throw new SyntaxError(E_CHAR)
arr[at++] = ((ab << 6) & 0xff) | (cd >> 4)
if (tailLength < 5) {
if (cd & 0xf) throw new SyntaxError(E_LAST)
return arr
}
const e = m[str.charCodeAt(i++)]
if (e < 0) throw new SyntaxError(E_CHAR)
arr[at++] = ((cd << 4) & 0xff) | (e >> 1) // 4 + 4
if (tailLength < 7) {
if (e & 0x1) throw new SyntaxError(E_LAST)
return arr
}
const fg = (m[str.charCodeAt(i++)] << 5) | m[str.charCodeAt(i++)]
if (fg < 0) throw new SyntaxError(E_CHAR)
arr[at++] = ((e << 7) & 0xff) | (fg >> 3) // 1 + 5 + 2
// Can't be 8, so no h
if (fg & 0x7) throw new SyntaxError(E_LAST)
return arr
}