Interval

1import { Cursor } from "./core.js";
2import { readInt64 } from "./integers.js";
3
4/** The 11 `Interval` units, in ClickHouse's ascending order. */
5export type IntervalUnit =
6  | "Nanosecond"
7  | "Microsecond"
8  | "Millisecond"
9  | "Second"
10  | "Minute"
11  | "Hour"
12  | "Day"
13  | "Week"
14  | "Month"
15  | "Quarter"
16  | "Year";
17
18/**
19 * `Interval` units indexed by the kind byte the binary type encoding writes
20 * after the `0x22` tag (`0x00` = Nanosecond ... `0x0a` = Year). Exported because
21 * the `Dynamic` reader needs it to decode an `Interval` nested in a `Dynamic`.
22 */
23export const INTERVAL_UNITS: readonly IntervalUnit[] = [
24  "Nanosecond",
25  "Microsecond",
26  "Millisecond",
27  "Second",
28  "Minute",
29  "Hour",
30  "Day",
31  "Week",
32  "Month",
33  "Quarter",
34  "Year",
35];
36
37/**
38 * An `Interval` decoded where the unit is carried IN the wire (inside a
39 * `Dynamic`): the signed `Int64` count plus its unit. A standalone `Interval*`
40 * column has no unit byte — there, use {@link readInterval} and take the unit
41 * from the column type instead.
42 */
43export type IntervalValue = readonly [count: bigint, unit: IntervalUnit];
44
45/**
46 * Read an `Interval` — any of `IntervalNanosecond` ... `IntervalYear`: a signed
47 * `Int64` count of the unit. The unit is in the type name, not the bytes, and
48 * all 11 interval types share this exact wire, so this one reader covers them
49 * all; the caller knows the unit from the column type. Returns a `bigint`; wrap
50 * in `Number(...)` if the counts are known to fit in 53 bits.
51 */
52export function readInterval(state: Cursor): bigint {
53  return readInt64(state);
54}