cid.ts

/**
 * Content addressing via CIDv1 (sha2-256, raw codec).
 *
 *   bafybei… = base32 multibase of (CIDv1 + raw + sha2-256 + 32-byte digest)
 *
 * Specification:
 *   https://github.com/multiformats/cid
 */
import { CID } from "multiformats/cid";
import * as raw from "multiformats/codecs/raw";
import { sha256 } from "multiformats/hashes/sha2";

/** Compute the CIDv1 (raw codec, sha2-256) for arbitrary bytes. */
export async function bytesToCid(bytes: Uint8Array): Promise<CID> {
  const digest = await sha256.digest(bytes);
  return CID.create(1, raw.code, digest);
}

/** Convenience: returns the canonical multibase string (e.g. `bafybei…`). */
export async function bytesToCidString(bytes: Uint8Array): Promise<string> {
  return (await bytesToCid(bytes)).toString();
}

/** Parse a CID string. Throws if malformed. */
export function parseCid(s: string): CID {
  return CID.parse(s);
}

/** Validate a string is a syntactically well-formed CID. */
export function isCid(s: string): boolean {
  try {
    CID.parse(s);
    return true;
  } catch {
    return false;
  }
}

/** Constant-time equality check for two CID strings. */
export function cidEqual(a: string, b: string): boolean {
  if (a.length !== b.length) return false;
  let diff = 0;
  for (let i = 0; i < a.length; i++) diff |= a.charCodeAt(i) ^ b.charCodeAt(i);
  return diff === 0;
}