@webassemblyjs/leb128

What is @webassemblyjs/leb128?

The @webassemblyjs/leb128 package is a utility library for encoding and decoding LEB128 (Little Endian Base 128) values. LEB128 is a variable-length encoding for arbitrary-precision integers, commonly used in the WebAssembly binary format. This package provides functions to read and write both signed and unsigned LEB128 integers.

What are @webassemblyjs/leb128's main functionalities?

Decode unsigned LEB128

This feature allows you to decode an unsigned LEB128 integer from a buffer. The provided code sample demonstrates how to decode a buffer containing an unsigned LEB128 encoded integer.

const { decodeU32 } = require('@webassemblyjs/leb128');
const buffer = Buffer.from([0xe5, 0x8e, 0x26]);
const result = decodeU32(buffer); // result is 624485

Decode signed LEB128

This feature allows you to decode a signed LEB128 integer from a buffer. The provided code sample demonstrates how to decode a buffer containing a signed LEB128 encoded integer.

const { decodeS32 } = require('@webassemblyjs/leb128');
const buffer = Buffer.from([0x9b, 0xf1, 0x59]);
const result = decodeS32(buffer); // result is -624485

Encode unsigned LEB128

This feature allows you to encode an unsigned integer into LEB128 format. The provided code sample demonstrates how to encode a JavaScript number into an unsigned LEB128 buffer.

const { encodeU32 } = require('@webassemblyjs/leb128');
const value = 624485;
const buffer = encodeU32(value); // buffer is <Buffer e5 8e 26>

Encode signed LEB128

This feature allows you to encode a signed integer into LEB128 format. The provided code sample demonstrates how to encode a JavaScript number into a signed LEB128 buffer.

const { encodeS32 } = require('@webassemblyjs/leb128');
const value = -624485;
const buffer = encodeS32(value); // buffer is <Buffer 9b f1 59>

Other packages similar to @webassemblyjs/leb128

leb

The 'leb' package is another npm package that provides similar functionality for encoding and decoding LEB128 values. It also supports both signed and unsigned integers, and it can be used in similar contexts as @webassemblyjs/leb128.

varint

The 'varint' package is used for encoding and decoding variable-length integers using a different encoding scheme than LEB128, but it serves a similar purpose in terms of representing integers in a compact form. It is commonly used in protocols like Protocol Buffers and is an alternative to LEB128 for certain use cases.