Header

1/**
2 * The `RowBinaryWithNamesAndTypes` HEADER: the column names and their type
3 * strings the server writes before the row data. Parsing the type strings into
4 * readers lives in `compile.ts`; this module is just the wire read.
5 */
6
7import type { Cursor } from "./core.js";
8import { readUVarint } from "./varint.js";
9import { readString } from "./strings.js";
10
11/** Column names and their type strings, in stream order. */
12export interface RowBinaryHeader {
13  names: string[];
14  types: string[];
15}
16
17/**
18 * Read the `RowBinaryWithNamesAndTypes` header off the cursor: a LEB128 column
19 * count, then that many column-name `String`s, then that many type-string
20 * `String`s. Leaves the cursor at the first row's bytes.
21 */
22export function readHeader(state: Cursor): RowBinaryHeader {
23  const count = readUVarint(state);
24  const names: string[] = new Array(count);
25  for (let i = 0; i < count; i++) names[i] = readString(state);
26  const types: string[] = new Array(count);
27  for (let i = 0; i < count; i++) types[i] = readString(state);
28  return { names, types };
29}