@plugnet/binary-encoding-utilities

Provides zero-dependency utility functions for plugnet's binary encoding needs.

Installing

npm install --save @plugnet/binary-encoding-utilities
// or
yarn add @plugnet/binary-encoding-utilities

Development

Testing:

npm test

Linting:

npm run lint

API

Interface {
  isObject,
  printBytes,
  flipEndianness,
  flipU8aEndianness,
  numberToLEBytes,
  LEBytesToNumber,
  getStringFromU8a,
}

isObject

Checks whether a value is an object. Returns a boolean.

isObject(value) -> Boolean

printBytes

A debug helper. Prints to stdout a Uint8Array, or a window onto a Uint8Array, in its binary representation.

• array is the Uint8Array to read from
• bytes is the byte count to read. Defaults to the array length.
• offset is the starting byte, or the first byte to read.

Returns undefined.

printBytes(
    array: Uint8Array,
    bytes:Number={array.length},
    offset:Number=0
) -> Undefined

flipEndianness

Recursively flips the endianness of a number or typed aray value of a particular bit length.

Note: Javascript Number is Big Endian.

• input is the number to be flipped.
• bits indicates the bit length of the number to be flipped.
• offset specifies how many places from the right recursion will start from.

Returns a number.

flipEndianness(
    input:Number,
    bits:Number=8,
    offset:Number=0
) -> Number

flipU8aEndianness

Flips the endianness of a window onto a Uint8Array.

• input is the Uint8Array to be operated on
• bytes is the number of bytes to flip, from left to right
• offset is the index to begin operating from

Modifies the Uint8Array in-place, and returns nothing.

flipU8aEndianness(
    input:Uint8Array,
    bytes:Number={input.length},
    offset:Number=0
) -> Undefined

numberToLEBytes

Takes a number and converts it to LE bytes representation, before writing it to a window onto a Uint8Array.

• number is the integer to be written
• array is the Uint8Array to have the number placed into
• bytes is the number of bytes to move into the Uint8Array
• offset is the Uint8Array index to begin writing to, left to right

Modifies the Uint8Array in-place, and returns nothing.

numberToLEBytes(
    number:Number,
    array:Uint8Array,
    bytes:Number=0,
    offset:Number=0
) -> Undefined

LEBytesToNumber

Takes a window onto a Uint8Array and converts it from a LE multi-byte representation of an integer into a Number.

• array is the Uint8Array to have the number placed into
• bytes is the number of bytes to move into the Uint8Array
• offset is the Uint8Array index to begin writing to, left to right

Returns a Number.

LEBytesToNumber(
    array:Uint8Array,
    bytes:Number={array.length},
    offset:Number=0
) -> Undefined

getStringFromU8a

Takes a window onto a Uint8Array and extracts an ASCII string, ignoring 0 values.

• array is the Uint8Array to extract the string from
• bytes is the number of bytes to extract from the Uint8Array
• offset is the index to start reading from

getStringFromU8a(
    array,
    bytes,
    offset,
) -> String