@oazmi/build-tools
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general deno build tool scripts which I practically use in all of my typescript repos
184 lines (183 loc) • 7.08 kB
JavaScript
// Copyright 2018-2025 the Deno authors. MIT license.
// Copyright (c) 2014 Jameson Little. MIT License.
// This module is browser compatible.
/**
* common code for base32 and base32hex encodings.
*/
import { validateBinaryLike } from "./_validate_binary_like.js";
const placeHolderPadLookup = [0, 1, , 2, 3, , 4];
function getPadLength(placeHoldersLen) {
const maybeLen = placeHolderPadLookup[placeHoldersLen];
if (typeof maybeLen !== "number") {
throw new Error("Invalid pad length");
}
return maybeLen;
}
function getLens(b32) {
const len = b32.length;
if (len % 8 > 0) {
throw new Error(`Cannot decode base32 string as the length must be a multiple of 8: received length ${len}`);
}
let validLen = b32.indexOf("=");
if (validLen === -1)
validLen = len;
const placeHoldersLen = validLen === len ? 0 : 8 - (validLen % 8);
return [validLen, placeHoldersLen];
}
function getByteLength(validLen, placeHoldersLen) {
return ((validLen + placeHoldersLen) * 5) / 8 - getPadLength(placeHoldersLen);
}
/**
* Decodes an encoded string with the given lookup table.
*
* @param b32 The string to encode.
* @param lookup The lookup table
* @returns The encoded string.
*/
export function decode(b32, lookup) {
const revLookup = [];
lookup.forEach((c, i) => (revLookup[c.charCodeAt(0)] = i));
let tmp;
const [validLen, placeHoldersLen] = getLens(b32);
const arr = new Uint8Array(getByteLength(validLen, placeHoldersLen));
let curByte = 0;
// if there are placeholders, only get up to the last complete 8 chars
const len = placeHoldersLen > 0 ? validLen - 8 : validLen;
let i;
for (i = 0; i < len; i += 8) {
tmp = (revLookup[b32.charCodeAt(i)] << 20) |
(revLookup[b32.charCodeAt(i + 1)] << 15) |
(revLookup[b32.charCodeAt(i + 2)] << 10) |
(revLookup[b32.charCodeAt(i + 3)] << 5) |
revLookup[b32.charCodeAt(i + 4)];
arr[curByte++] = (tmp >> 17) & 0xff;
arr[curByte++] = (tmp >> 9) & 0xff;
arr[curByte++] = (tmp >> 1) & 0xff;
tmp = ((tmp & 1) << 15) |
(revLookup[b32.charCodeAt(i + 5)] << 10) |
(revLookup[b32.charCodeAt(i + 6)] << 5) |
revLookup[b32.charCodeAt(i + 7)];
arr[curByte++] = (tmp >> 8) & 0xff;
arr[curByte++] = tmp & 0xff;
}
if (placeHoldersLen === 1) {
tmp = (revLookup[b32.charCodeAt(i)] << 20) |
(revLookup[b32.charCodeAt(i + 1)] << 15) |
(revLookup[b32.charCodeAt(i + 2)] << 10) |
(revLookup[b32.charCodeAt(i + 3)] << 5) |
revLookup[b32.charCodeAt(i + 4)];
arr[curByte++] = (tmp >> 17) & 0xff;
arr[curByte++] = (tmp >> 9) & 0xff;
arr[curByte++] = (tmp >> 1) & 0xff;
tmp = ((tmp & 1) << 7) |
(revLookup[b32.charCodeAt(i + 5)] << 2) |
(revLookup[b32.charCodeAt(i + 6)] >> 3);
arr[curByte++] = tmp & 0xff;
}
else if (placeHoldersLen === 3) {
tmp = (revLookup[b32.charCodeAt(i)] << 19) |
(revLookup[b32.charCodeAt(i + 1)] << 14) |
(revLookup[b32.charCodeAt(i + 2)] << 9) |
(revLookup[b32.charCodeAt(i + 3)] << 4) |
(revLookup[b32.charCodeAt(i + 4)] >> 1);
arr[curByte++] = (tmp >> 16) & 0xff;
arr[curByte++] = (tmp >> 8) & 0xff;
arr[curByte++] = tmp & 0xff;
}
else if (placeHoldersLen === 4) {
tmp = (revLookup[b32.charCodeAt(i)] << 11) |
(revLookup[b32.charCodeAt(i + 1)] << 6) |
(revLookup[b32.charCodeAt(i + 2)] << 1) |
(revLookup[b32.charCodeAt(i + 3)] >> 4);
arr[curByte++] = (tmp >> 8) & 0xff;
arr[curByte++] = tmp & 0xff;
}
else if (placeHoldersLen === 6) {
tmp = (revLookup[b32.charCodeAt(i)] << 3) |
(revLookup[b32.charCodeAt(i + 1)] >> 2);
arr[curByte++] = tmp & 0xff;
}
return arr;
}
function encodeChunk(uint8, start, end, lookup) {
let tmp;
const output = [];
for (let i = start; i < end; i += 5) {
tmp = ((uint8[i] << 16) & 0xff0000) |
((uint8[i + 1] << 8) & 0xff00) |
(uint8[i + 2] & 0xff);
output.push(lookup[(tmp >> 19) & 0x1f]);
output.push(lookup[(tmp >> 14) & 0x1f]);
output.push(lookup[(tmp >> 9) & 0x1f]);
output.push(lookup[(tmp >> 4) & 0x1f]);
tmp = ((tmp & 0xf) << 16) |
((uint8[i + 3] << 8) & 0xff00) |
(uint8[i + 4] & 0xff);
output.push(lookup[(tmp >> 15) & 0x1f]);
output.push(lookup[(tmp >> 10) & 0x1f]);
output.push(lookup[(tmp >> 5) & 0x1f]);
output.push(lookup[tmp & 0x1f]);
}
return output.join("");
}
/**
* Encodes the given data using the lookup table.
*
* @param data The data to encode.
* @param lookup The lookup table.
* @returns The encoded string.
*/
export function encode(data, lookup) {
const uint8 = validateBinaryLike(data);
let tmp;
const len = uint8.length;
const extraBytes = len % 5;
const parts = [];
const maxChunkLength = 16385; // must be multiple of 5
const len2 = len - extraBytes;
// go through the array every 5 bytes, we'll deal with trailing stuff later
for (let i = 0; i < len2; i += maxChunkLength) {
parts.push(encodeChunk(uint8, i, i + maxChunkLength > len2 ? len2 : i + maxChunkLength, lookup));
}
// pad the end with zeros, but make sure to not forget the extra bytes
if (extraBytes === 4) {
tmp = ((uint8[len2] & 0xff) << 16) |
((uint8[len2 + 1] & 0xff) << 8) |
(uint8[len2 + 2] & 0xff);
parts.push(lookup[(tmp >> 19) & 0x1f]);
parts.push(lookup[(tmp >> 14) & 0x1f]);
parts.push(lookup[(tmp >> 9) & 0x1f]);
parts.push(lookup[(tmp >> 4) & 0x1f]);
tmp = ((tmp & 0xf) << 11) | (uint8[len2 + 3] << 3);
parts.push(lookup[(tmp >> 10) & 0x1f]);
parts.push(lookup[(tmp >> 5) & 0x1f]);
parts.push(lookup[tmp & 0x1f]);
parts.push("=");
}
else if (extraBytes === 3) {
tmp = ((uint8[len2] & 0xff) << 17) |
((uint8[len2 + 1] & 0xff) << 9) |
((uint8[len2 + 2] & 0xff) << 1);
parts.push(lookup[(tmp >> 20) & 0x1f]);
parts.push(lookup[(tmp >> 15) & 0x1f]);
parts.push(lookup[(tmp >> 10) & 0x1f]);
parts.push(lookup[(tmp >> 5) & 0x1f]);
parts.push(lookup[tmp & 0x1f]);
parts.push("===");
}
else if (extraBytes === 2) {
tmp = ((uint8[len2] & 0xff) << 12) | ((uint8[len2 + 1] & 0xff) << 4);
parts.push(lookup[(tmp >> 15) & 0x1f]);
parts.push(lookup[(tmp >> 10) & 0x1f]);
parts.push(lookup[(tmp >> 5) & 0x1f]);
parts.push(lookup[tmp & 0x1f]);
parts.push("====");
}
else if (extraBytes === 1) {
tmp = (uint8[len2] & 0xff) << 2;
parts.push(lookup[(tmp >> 5) & 0x1f]);
parts.push(lookup[tmp & 0x1f]);
parts.push("======");
}
return parts.join("");
}