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// https://github.com/msgpack/msgpack/blob/master/spec.md#timestamp-extension-typeimport { getInt64, setInt64 } from "./utils/int.ts";
export const EXT_TIMESTAMP = -1;
export type TimeSpec = {  sec: number;  nsec: number;};
const TIMESTAMP32_MAX_SEC = 0x100000000 - 1; // 32-bit unsigned intconst TIMESTAMP64_MAX_SEC = 0x400000000 - 1; // 34-bit unsigned int
export function encodeTimeSpecToTimestamp({ sec, nsec }: TimeSpec): Uint8Array {  if (sec >= 0 && nsec >= 0 && sec <= TIMESTAMP64_MAX_SEC) {    // Here sec >= 0 && nsec >= 0    if (nsec === 0 && sec <= TIMESTAMP32_MAX_SEC) {      // timestamp 32 = { sec32 (unsigned) }      const rv = new Uint8Array(4);      const view = new DataView(rv.buffer);      view.setUint32(0, sec);      return rv;    } else {      // timestamp 64 = { nsec30 (unsigned), sec34 (unsigned) }      const secHigh = sec / 0x100000000;      const secLow = sec & 0xffffffff;      const rv = new Uint8Array(8);      const view = new DataView(rv.buffer);      // nsec30 | secHigh2      view.setUint32(0, (nsec << 2) | (secHigh & 0x3));      // secLow32      view.setUint32(4, secLow);      return rv;    }  } else {    // timestamp 96 = { nsec32 (unsigned), sec64 (signed) }    const rv = new Uint8Array(12);    const view = new DataView(rv.buffer);    view.setUint32(0, nsec);    setInt64(view, 4, sec);    return rv;  }}
export function encodeDateToTimeSpec(date: Date): TimeSpec {  const msec = date.getTime();  const sec = Math.floor(msec / 1e3);  const nsec = (msec - sec * 1e3) * 1e6;
  // Normalizes { sec, nsec } to ensure nsec is unsigned.  const nsecInSec = Math.floor(nsec / 1e9);  return {    sec: sec + nsecInSec,    nsec: nsec - nsecInSec * 1e9,  };}
export function encodeTimestampExtension(object: unknown): Uint8Array | null {  if (object instanceof Date) {    const timeSpec = encodeDateToTimeSpec(object);    return encodeTimeSpecToTimestamp(timeSpec);  } else {    return null;  }}
export function decodeTimestampToTimeSpec(data: Uint8Array): TimeSpec {  const view = new DataView(data.buffer, data.byteOffset, data.byteLength);
  // data may be 32, 64, or 96 bits  switch (data.byteLength) {    case 4: {      // timestamp 32 = { sec32 }      const sec = view.getUint32(0);      const nsec = 0;      return { sec, nsec };    }    case 8: {      // timestamp 64 = { nsec30, sec34 }      const nsec30AndSecHigh2 = view.getUint32(0);      const secLow32 = view.getUint32(4);      const sec = (nsec30AndSecHigh2 & 0x3) * 0x100000000 + secLow32;      const nsec = nsec30AndSecHigh2 >>> 2;      return { sec, nsec };    }    case 12: {      // timestamp 96 = { nsec32 (unsigned), sec64 (signed) }
      const sec = getInt64(view, 4);      const nsec = view.getUint32(0);      return { sec, nsec };    }    default:      throw new Error(`Unrecognized data size for timestamp: ${data.length}`);  }}
export function decodeTimestampExtension(data: Uint8Array): Date {  const timeSpec = decodeTimestampToTimeSpec(data);  return new Date(timeSpec.sec * 1e3 + timeSpec.nsec / 1e6);}
export const timestampExtension = {  type: EXT_TIMESTAMP,  encode: encodeTimestampExtension,  decode: decodeTimestampExtension,};