@zlattice/lattice-js
Version:
Lattice blockchain TypeScript SDK with dual module support (CJS + ESM)
83 lines • 3.16 kB
JavaScript
const u8a = (a) => a instanceof Uint8Array;
// Cast array to different type
export const u8 = (arr) => new Uint8Array(arr.buffer, arr.byteOffset, arr.byteLength);
export const u32 = (arr) => new Uint32Array(arr.buffer, arr.byteOffset, Math.floor(arr.byteLength / 4));
// Cast array to view
export const createView = (arr) => new DataView(arr.buffer, arr.byteOffset, arr.byteLength);
// The rotate right (circular right shift) operation for uint32
export const rotr = (word, shift) => (word << (32 - shift)) | (word >>> shift);
// big-endian hardware is rare. Just in case someone still decides to run hashes:
// early-throw an error because we don't support BE yet.
export const isLE = new Uint8Array(new Uint32Array([0x11223344]).buffer)[0] === 0x44;
if (!isLE)
throw new Error('Non little-endian hardware is not supported');
const hexes = Array.from({ length: 256 }, (v, i) => i.toString(16).padStart(2, '0'));
/**
* @example bytesToHex(Uint8Array.from([0xca, 0xfe, 0x01, 0x23])) // 'cafe0123'
*/
export function bytesToHex(bytes) {
if (!u8a(bytes))
throw new Error('Uint8Array expected');
// pre-caching improves the speed 6x
let hex = '';
for (let i = 0; i < bytes.length; i++) {
hex += hexes[bytes[i]];
}
return hex;
}
/**
* @example hexToBytes('cafe0123') // Uint8Array.from([0xca, 0xfe, 0x01, 0x23])
*/
export function hexToBytes(hex) {
if (typeof hex !== 'string')
throw new Error(`hexToBytes expected string, got ${typeof hex}`);
const len = hex.length;
if (len % 2)
throw new Error(`padded hex string expected, got unpadded hex of length ${len}`);
const array = new Uint8Array(len / 2);
for (let i = 0; i < array.length; i++) {
const j = i * 2;
const hexByte = hex.slice(j, j + 2);
const byte = Number.parseInt(hexByte, 16);
if (Number.isNaN(byte) || byte < 0)
throw new Error('Invalid byte sequence');
array[i] = byte;
}
return array;
}
/**
* @example utf8ToBytes('abc') // new Uint8Array([97, 98, 99])
*/
export function utf8ToBytes(str) {
if (typeof str !== 'string')
throw new Error(`utf8ToBytes expected string, got ${typeof str}`);
return new Uint8Array(new TextEncoder().encode(str)); // https://bugzil.la/1681809
}
/**
* Normalizes (non-hex) string or Uint8Array to Uint8Array.
* Warning: when Uint8Array is passed, it would NOT get copied.
* Keep in mind for future mutable operations.
*/
export function toBytes(data) {
if (typeof data === 'string')
data = utf8ToBytes(data);
if (!u8a(data))
throw new Error(`expected Uint8Array, got ${typeof data}`);
return data;
}
// For runtime check if class implements interface
export class Hash {
// Safe version that clones internal state
clone() {
return this._cloneInto();
}
}
export function wrapConstructor(hashCons) {
const hashC = (msg) => hashCons().update(toBytes(msg)).digest();
const tmp = hashCons();
hashC.outputLen = tmp.outputLen;
hashC.blockLen = tmp.blockLen;
hashC.create = () => hashCons();
return hashC;
}
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