Recursive Length Prefix implementation
The purpose of RLP (Recursive Length Prefix) is to encode arbitrarily nested arrays of binary data, and RLP is the main encoding method used to serialize objects in Ethereum. The only purpose of RLP is to encode structure; encoding specific atomic data types (eg. strings, ints, floats) is left up to higher-order protocols; in Ethereum integers must be represented in big endian binary form with no leading zeroes (thus making the integer value zero be equivalent to the empty byte array).
npm install --save @polkajs/rlp
const RLP = require('@polkajs/rlp');
let encode = RLP.encode(['hello']);
console.log(encode);
// <Buffer c6 85 68 65 6c 6c 6f>c6 - represents an array with a 6 byte buffer to follow (0xc6 - 0xc0)
85 - represents a string or number with the size of 5 (0x85 - 0x80)
let decode = RLP.decode(encode);
console.log(decode);
// [ <Buffer 68 65 6c 6c 6f> ] (ascii)
let str = decode[0].toString();
console.log(str);
// 'hello'If you are only working with arrays and strings, this method has better decoding
const arr = ['a', 'abc', 5];
const encode = RLP.encode(arr);
const decode_str = RLP.decode_str(encode);
console.log(decode_str);
// ['a', 'abc', '\x05']First byte of an encoded item
x: single byte, itself
|
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0x7f == 127
0x80 == 128
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x: [0, 55] byte long string, x-0x80 == length
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0xb7 == 183
0xb8 == 184
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x: [55, ] long string, x-0xf8 == length of the length
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0xbf == 191
0xc0 == 192
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x: [0, 55] byte long list, x-0xc0 == length
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0xf7 == 247
0xf8 == 248
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x: [55, ] long list, x-0xf8 == length of the length
|
0xff == 255Copyright 2017 Copyright (c) 2004-2010 by Internet Systems Consortium, Inc. ("ISC") Copyright (c) 1995-2003 by Internet Software Consortium
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