Skip to main content
Using Deno in production at your company? Earn free Deno merch.
Give us feedback
Module

std/msgpack/encode.ts

Deno standard library
Go to Latest
File
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
import { concat } from "../bytes/concat.ts";
/** * Value types that can be encoded to MessagePack. */export type ValueType = | number | bigint | string | boolean | null | Uint8Array | ValueType[] | ValueMap;
/** * Value map that can be encoded to MessagePack. */export interface ValueMap { /** * Value types that can be encoded to MessagePack. */ [index: string | number]: ValueType;}
const FOUR_BITS = 16;const FIVE_BITS = 32;const SEVEN_BITS = 128;const EIGHT_BITS = 256;const FIFTEEN_BITS = 32768;const SIXTEEN_BITS = 65536;const THIRTY_ONE_BITS = 2147483648;const THIRTY_TWO_BITS = 4294967296;const SIXTY_THREE_BITS = 9223372036854775808n;const SIXTY_FOUR_BITS = 18446744073709551616n;
const encoder = new TextEncoder();
/** * Encode a value to MessagePack binary format. * * @example * ```ts * import { encode } from "https://deno.land/std@$STD_VERSION/msgpack/encode.ts"; * * const obj = { * str: "deno", * arr: [1, 2, 3], * map: { * foo: "bar" * } * } * * console.log(encode(obj)) * ``` */export function encode(object: ValueType): Uint8Array { const byteParts: Uint8Array[] = []; encodeSlice(object, byteParts); return concat(byteParts);}
function encodeFloat64(num: number) { const dataView = new DataView(new ArrayBuffer(9)); dataView.setFloat64(1, num); dataView.setUint8(0, 0xcb); return new Uint8Array(dataView.buffer);}
function encodeNumber(num: number) { if (!Number.isInteger(num)) { // float 64 return encodeFloat64(num); }
if (num < 0) { if (num >= -FIVE_BITS) { // negative fixint return new Uint8Array([num]); }
if (num >= -SEVEN_BITS) { // int 8 return new Uint8Array([0xd0, num]); }
if (num >= -FIFTEEN_BITS) { // int 16 const dataView = new DataView(new ArrayBuffer(3)); dataView.setInt16(1, num); dataView.setUint8(0, 0xd1); return new Uint8Array(dataView.buffer); }
if (num >= -THIRTY_ONE_BITS) { // int 32 const dataView = new DataView(new ArrayBuffer(5)); dataView.setInt32(1, num); dataView.setUint8(0, 0xd2); return new Uint8Array(dataView.buffer); }
// float 64 return encodeFloat64(num); }
// if the number fits within a positive fixint, use it if (num <= 0x7f) { return new Uint8Array([num]); }
if (num < EIGHT_BITS) { // uint8 return new Uint8Array([0xcc, num]); }
if (num < SIXTEEN_BITS) { // uint16 const dataView = new DataView(new ArrayBuffer(3)); dataView.setUint16(1, num); dataView.setUint8(0, 0xcd); return new Uint8Array(dataView.buffer); }
if (num < THIRTY_TWO_BITS) { // uint32 const dataView = new DataView(new ArrayBuffer(5)); dataView.setUint32(1, num); dataView.setUint8(0, 0xce); return new Uint8Array(dataView.buffer); }
// float 64 return encodeFloat64(num);}
function encodeSlice(object: ValueType, byteParts: Uint8Array[]) { if (object === null) { byteParts.push(new Uint8Array([0xc0])); return; }
if (object === false) { byteParts.push(new Uint8Array([0xc2])); return; }
if (object === true) { byteParts.push(new Uint8Array([0xc3])); return; }
if (typeof object === "number") { byteParts.push(encodeNumber(object)); return; }
if (typeof object === "bigint") { if (object < 0) { if (object < -SIXTY_THREE_BITS) { throw new Error("Cannot safely encode bigint larger than 64 bits"); }
const dataView = new DataView(new ArrayBuffer(9)); dataView.setBigInt64(1, object); dataView.setUint8(0, 0xd3); byteParts.push(new Uint8Array(dataView.buffer)); return; }
if (object >= SIXTY_FOUR_BITS) { throw new Error("Cannot safely encode bigint larger than 64 bits"); }
const dataView = new DataView(new ArrayBuffer(9)); dataView.setBigUint64(1, object); dataView.setUint8(0, 0xcf); byteParts.push(new Uint8Array(dataView.buffer)); return; }
if (typeof object === "string") { const encoded = encoder.encode(object); const len = encoded.length;
if (len < FIVE_BITS) { // fixstr byteParts.push(new Uint8Array([0xa0 | len])); } else if (len < EIGHT_BITS) { // str 8 byteParts.push(new Uint8Array([0xd9, len])); } else if (len < SIXTEEN_BITS) { // str 16 const dataView = new DataView(new ArrayBuffer(3)); dataView.setUint16(1, len); dataView.setUint8(0, 0xda); byteParts.push(new Uint8Array(dataView.buffer)); } else if (len < THIRTY_TWO_BITS) { // str 32 const dataView = new DataView(new ArrayBuffer(5)); dataView.setUint32(1, len); dataView.setUint8(0, 0xdb); byteParts.push(new Uint8Array(dataView.buffer)); } else { throw new Error( "Cannot safely encode string with size larger than 32 bits", ); } byteParts.push(encoded); return; }
if (object instanceof Uint8Array) { if (object.length < EIGHT_BITS) { // bin 8 byteParts.push(new Uint8Array([0xc4, object.length])); } else if (object.length < SIXTEEN_BITS) { // bin 16 const dataView = new DataView(new ArrayBuffer(3)); dataView.setUint16(1, object.length); dataView.setUint8(0, 0xc5); byteParts.push(new Uint8Array(dataView.buffer)); } else if (object.length < THIRTY_TWO_BITS) { // bin 32 const dataView = new DataView(new ArrayBuffer(5)); dataView.setUint32(1, object.length); dataView.setUint8(0, 0xc6); byteParts.push(new Uint8Array(dataView.buffer)); } else { throw new Error( "Cannot safely encode Uint8Array with size larger than 32 bits", ); } byteParts.push(object); return; }
if (Array.isArray(object)) { if (object.length < FOUR_BITS) { // fixarray byteParts.push(new Uint8Array([0x90 | object.length])); } else if (object.length < SIXTEEN_BITS) { // array 16 const dataView = new DataView(new ArrayBuffer(3)); dataView.setUint16(1, object.length); dataView.setUint8(0, 0xdc); byteParts.push(new Uint8Array(dataView.buffer)); } else if (object.length < THIRTY_TWO_BITS) { // array 32 const dataView = new DataView(new ArrayBuffer(5)); dataView.setUint32(1, object.length); dataView.setUint8(0, 0xdd); byteParts.push(new Uint8Array(dataView.buffer)); } else { throw new Error( "Cannot safely encode array with size larger than 32 bits", ); }
for (const obj of object) { encodeSlice(obj, byteParts); } return; }
// If object is a plain object if (Object.getPrototypeOf(object) === Object.prototype) { const numKeys = Object.keys(object).length;
if (numKeys < FOUR_BITS) { // fixarray byteParts.push(new Uint8Array([0x80 | numKeys])); } else if (numKeys < SIXTEEN_BITS) { // map 16 const dataView = new DataView(new ArrayBuffer(3)); dataView.setUint16(1, numKeys); dataView.setUint8(0, 0xde); byteParts.push(new Uint8Array(dataView.buffer)); } else if (numKeys < THIRTY_TWO_BITS) { // map 32 const dataView = new DataView(new ArrayBuffer(5)); dataView.setUint32(1, numKeys); dataView.setUint8(0, 0xdf); byteParts.push(new Uint8Array(dataView.buffer)); } else { throw new Error("Cannot safely encode map with size larger than 32 bits"); }
for (const [key, value] of Object.entries(object)) { encodeSlice(key, byteParts); encodeSlice(value, byteParts); } return; }
throw new Error("Cannot safely encode value into messagepack");}