a collection of lightweight TypeScript packages for AT Protocol, the protocol powering Bluesky
atproto
bluesky
typescript
npm
refactor(tid): faster encode/decode
+39
-9
+1
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.changeset/bright-snails-hide.md
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.changeset/bright-snails-hide.md
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.changeset/little-bars-care.md
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.changeset/little-bars-care.md
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-5
packages/utilities/tid/lib/index.ts
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-5
packages/utilities/tid/lib/index.ts
···
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import { random } from '#platform/random';
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-
import { s32decode, s32encode } from './s32.ts';
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import { S32_2CHAR_TABLE, s32decode, s32encode } from './s32.ts';
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let lastTimestamp = 0;
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let lastCurrentTime = 0;
···
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* Creates a TID based off provided timestamp and clockid, with no validation.
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*/
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export const createRaw = (timestamp: number, clockid: number): string => {
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return s32encode(timestamp).padStart(11, '2') + s32encode(clockid).padStart(2, '2');
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return s32encode(timestamp).padStart(11, '2') + S32_2CHAR_TABLE[clockid]!;
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};
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/**
···
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throw new Error(`invalid TID`);
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}
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const timestamp = s32decode(tid.slice(0, 11));
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const clockid = s32decode(tid.slice(11, 13));
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const timestamp = s32decode(tid, 0, 11);
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const clockid = s32decode(tid, 11, 2);
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return { timestamp: timestamp, clockid: clockid };
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return { timestamp, clockid };
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};
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/**
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-3
packages/utilities/tid/lib/s32.ts
+28
-3
packages/utilities/tid/lib/s32.ts
···
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const S32_CHAR = '234567abcdefghijklmnopqrstuvwxyz';
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const S32_DECODE_TABLE = (() => {
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const table = new Int16Array(123);
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table.fill(-1);
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for (let i = 0; i < S32_CHAR.length; i++) {
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const code = S32_CHAR.charCodeAt(i);
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table[code] = i;
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}
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return table;
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})();
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export const S32_2CHAR_TABLE = (() => {
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const table = Array.from<string>({ length: 1024 });
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for (let i = 0; i < 1024; i++) {
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const hi = S32_CHAR.charAt((i >> 5) & 31);
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const lo = S32_CHAR.charAt(i & 31);
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table[i] = hi + lo;
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}
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return table;
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})();
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+
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export const s32encode = (i: number): string => {
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let s = '';
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···
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return s;
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};
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export const s32decode = (s: string): number => {
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export const s32decode = (s: string, offset: number, length: number): number => {
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let i = 0;
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const end = offset + length;
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for (const c of s) {
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i = i * 32 + S32_CHAR.indexOf(c);
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for (let idx = offset; idx < end; idx++) {
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i = i * 32 + S32_DECODE_TABLE[s.charCodeAt(idx)]!;
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}
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return i;