function sqliteHeader
sqliteHeader(): Coder<SqliteHeader>

Creates a coder for the 100-byte SQLite database file header.

Nothing is validated on encode or decode — magic and every reserved or fixed-value field (maxEmbeddedPayloadFraction, minEmbeddedPayloadFraction, leafPayloadFraction, reservedForExpansion) are written and read exactly as given.

This coder only describes the fixed header. Page 1's B-tree page header follows immediately at byte offset 100 and is out of scope here.

Examples

Decode a known header from raw bytes

import { assertEquals } from "@std/assert";
import {
  sqliteHeader,
  SQLITE_HEADER_SIZE,
  SQLITE_MAGIC,
  SQLITE_TEXT_ENCODING,
} from "@binstruct/sqlite";

// deno-fmt-ignore
const wire = new Uint8Array([
  0x53, 0x51, 0x4c, 0x69, 0x74, 0x65, 0x20, 0x66, 0x6f, 0x72, 0x6d, 0x61, 0x74, 0x20, 0x33, 0x00,
  0x10, 0x00,
  0x01,
  0x01,
  0x00,
  0x40,
  0x20,
  0x20,
  0x00, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x02,
  0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x04,
  0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x2e, 0x76, 0x88,
  0x00, 0x2e, 0x76, 0x88,
]);

const [decoded, read] = sqliteHeader().decode(wire);

assertEquals(read, SQLITE_HEADER_SIZE);
assertEquals(decoded.magic, SQLITE_MAGIC);
assertEquals(decoded.pageSize, 4096);
assertEquals(decoded.textEncoding, SQLITE_TEXT_ENCODING.UTF8);
assertEquals(decoded.sqliteVersionNumber, 3045000);

Return Type

Coder<SqliteHeader>

A coder for SqliteHeader values.

Usage

import { sqliteHeader } from ".";