oppi.li
source dump of claude code
1/**
2 * djb2 string hash — fast non-cryptographic hash returning a signed 32-bit int.
3 * Deterministic across runtimes (unlike Bun.hash which uses wyhash). Use as a
4 * fallback when Bun.hash isn't available, or when you need on-disk-stable
5 * output (e.g. cache directory names that must survive runtime upgrades).
6 */
7export function djb2Hash(str: string): number {
8 let hash = 0
9 for (let i = 0; i < str.length; i++) {
10 hash = ((hash << 5) - hash + str.charCodeAt(i)) | 0
11 }
12 return hash
13}
14
15/**
16 * Hash arbitrary content for change detection. Bun.hash is ~100x faster than
17 * sha256 and collision-resistant enough for diff detection (not crypto-safe).
18 */
19export function hashContent(content: string): string {
20 if (typeof Bun !== 'undefined') {
21 return Bun.hash(content).toString()
22 }
23 // eslint-disable-next-line @typescript-eslint/no-require-imports
24 const crypto = require('crypto') as typeof import('crypto')
25 return crypto.createHash('sha256').update(content).digest('hex')
26}
27
28/**
29 * Hash two strings without allocating a concatenated temp string. Bun path
30 * seed-chains wyhash (hash(a) feeds as seed to hash(b)); Node path uses
31 * incremental SHA-256 update. Seed-chaining naturally disambiguates
32 * ("ts","code") vs ("tsc","ode") so no separator is needed under Bun.
33 */
34export function hashPair(a: string, b: string): string {
35 if (typeof Bun !== 'undefined') {
36 return Bun.hash(b, Bun.hash(a)).toString()
37 }
38 // eslint-disable-next-line @typescript-eslint/no-require-imports
39 const crypto = require('crypto') as typeof import('crypto')
40 return crypto
41 .createHash('sha256')
42 .update(a)
43 .update('\0')
44 .update(b)
45 .digest('hex')
46}