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@thi.ng/bencode

@thi.ng/bencode

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This project is part of the @thi.ng/umbrella monorepo.

About

Binary Bencode encoder & decoder for structured data. 1.15KB gzipped.

Features / behaviors

Booleans

Will be converted to 0 or 1.

String handling

All JS strings will be UTF-8 encoded. To write raw bytes without transformation, wrap them as Uint8Array. These too will be written as Bencode strings (e.g. len:xxx...), but are used as is.

Floating point values

This implementation has optional support for floating point values. If these are not desired (e.g. for compatibility reasons), all numeric values MUST be pre-rounded to integers. The encoder only chooses the custom float encoding iff a number has a fractional part. Floats are encoded similarly to standard ints (i.e. as text), but using f as prefix. Furthermore, only floats with an absolute value in the semi-open [1e-6,1e21) interval can be encoded.

Installation

yarn add @thi.ng/bencode

Dependencies

Usage examples

import { encode, decode } from "@thi.ng/bencode";
import { hexDump } from "@thi.ng/transducers-binary";

[...hexDump({}, encode({ foo: "bar", "baz": [0, 1, 2, 3], "pi": Math.PI }))]
// [ '00000000 | 64 33 3a 62 61 7a 6c 69 30 65 69 31 65 69 32 65 | d3:bazli0ei1ei2e',
//   '00000010 | 69 33 65 65 33 3a 66 6f 6f 33 3a 62 61 72 32 3a | i3ee3:foo3:bar2:',
//   '00000020 | 70 69 66 33 2e 31 34 31 35 39 32 36 35 33 35 38 | pif3.14159265358',
//   '00000030 | 39 37 39 33 65 65 00 00 00 00 00 00 00 00 00 00 | 9793ee..........' ]

// Uin8Array values are written verbatim (as Bencode strings)
[...hexDump({}, encode({ foo: new Uint8Array([0, 1 ,2, 3]) }))]
// [ '00000000 | 64 33 3a 66 6f 6f 34 3a 00 01 02 03 65 00 00 00 | d3:foo4:....e...' ]

const bytes = encode({ foo: [1, "a", { bar: "baz"}, [42]] });
// Uint8Array [ 100, 51, 58, 102, 111, 111, 108, 105, 49, 101, 49, ... ]


decode(bytes)
// { foo: [ 1, 'a', { bar: 'baz' }, [ 42 ] ] }

// decode w/o UTF8 decoding
// (note: dictionary keys will ALWAYS be utf8 decoded)
decode(bytes, false)
// { foo: [ 1, [ 97 ], { bar: [ 98, 97, 122 ] }, [ 42 ] ] }

Authors

  • Karsten Schmidt

License

© 2016 Karsten Schmidt // Apache Software License 2.0

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