bstruct

Declaratively encode and decode binary data

Inspired by restructure and binary-parser

Example

import * as b from "@sighmir/bstruct";

export const login = b.struct({
  length: b.int16le,
  op: b.int16le,
  s1: b.skip(20),
  account: b.string(33, "utf8"),
  s2: b.skip(26),
  password: b.string(16, "base64"),
});

const loginObj = {
  length: 4080,
  op: 3,
  account: "abcde",
  password: "ZWZnaGkK",
};

const buf = login.encode(loginObj);
const obj = login.decode<typeof loginObj>(buf);

API

b.struct({})

Create a binary structure encoder/decoder, functions encode and decode are available, property struct returns the argument used to build the structure encode/decoder, property size returns the added size of all binary parsers used on the structure.

b.skip(bytes)

Skip a certain amount of bytes, if the variable is a buffer on the encoded object, simply copy it to the new buffer, if it's something else, create a new buffer and fill it with zeros. When decoding it simply copies part of the buffer to the new object.

b.string(length, encoding)

Parse bytes as a string. Encoding can be any BufferEncoding.

b.bool

Parse bytes as boolean.

b.[u]int{8, 16, 32, 64}{le, be}

Parse bytes as integer.

b.float{le, be}

Parse bytes as float.

b.double{le, be}

Parse bytes as double.

b.buffer(bytes)

Copy part of the buffer to the object when decoding, or a buffer variable from the object to the new buffer when encoding.

b.array(length, parser)

Parse an array using one of the previous parsers.

b.choice(key, structs)

Uses the value of a variable on the parent object to pick a parser for a nested object. You can also use b.struct as a parser for nested objects.

License

bstruct - Declaratively encode and decode binary data
Copyright (C) 2020  Guilherme Caulada

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <https://www.gnu.org/licenses/>.