buffer_utils.js 1.7 KB

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  1. import digest from '../runtime/digest.js';
  2. export const encoder = new TextEncoder();
  3. export const decoder = new TextDecoder();
  4. const MAX_INT32 = 2 ** 32;
  5. export function concat(...buffers) {
  6. const size = buffers.reduce((acc, { length }) => acc + length, 0);
  7. const buf = new Uint8Array(size);
  8. let i = 0;
  9. buffers.forEach((buffer) => {
  10. buf.set(buffer, i);
  11. i += buffer.length;
  12. });
  13. return buf;
  14. }
  15. export function p2s(alg, p2sInput) {
  16. return concat(encoder.encode(alg), new Uint8Array([0]), p2sInput);
  17. }
  18. function writeUInt32BE(buf, value, offset) {
  19. if (value < 0 || value >= MAX_INT32) {
  20. throw new RangeError(`value must be >= 0 and <= ${MAX_INT32 - 1}. Received ${value}`);
  21. }
  22. buf.set([value >>> 24, value >>> 16, value >>> 8, value & 0xff], offset);
  23. }
  24. export function uint64be(value) {
  25. const high = Math.floor(value / MAX_INT32);
  26. const low = value % MAX_INT32;
  27. const buf = new Uint8Array(8);
  28. writeUInt32BE(buf, high, 0);
  29. writeUInt32BE(buf, low, 4);
  30. return buf;
  31. }
  32. export function uint32be(value) {
  33. const buf = new Uint8Array(4);
  34. writeUInt32BE(buf, value);
  35. return buf;
  36. }
  37. export function lengthAndInput(input) {
  38. return concat(uint32be(input.length), input);
  39. }
  40. export async function concatKdf(secret, bits, value) {
  41. const iterations = Math.ceil((bits >> 3) / 32);
  42. const res = new Uint8Array(iterations * 32);
  43. for (let iter = 0; iter < iterations; iter++) {
  44. const buf = new Uint8Array(4 + secret.length + value.length);
  45. buf.set(uint32be(iter + 1));
  46. buf.set(secret, 4);
  47. buf.set(value, 4 + secret.length);
  48. res.set(await digest('sha256', buf), iter * 32);
  49. }
  50. return res.slice(0, bits >> 3);
  51. }