Package Exports

byte-data

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (byte-data) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

byte-data

Readable data to and from byte buffers.
Copyright (c) 2017 Rafael da Silva Rocha.
https://github.com/rochars/byte-data

Works in Node.js and in the browser.

Support:

char
booleans
2-bit integers (signed/unsigned)
4-bit integers (signed/unsigned)
8-bit integers (signed/unsigned)
16-bit integers (signed/unsigned)
16-bit half-precision floating point numbers
24-bit integers (signed/unsigned)
32-bit integers (signed/unsigned)
32-bit single-precision floating point numbers
40-bit integers (signed/unsigned)
48-bit integers (signed/unsigned)
64-bit double-precision floating point numbers
little-endian and big-endian
strings of fixed and variable length

Install

npm install byte-data

Example

let byteData = require('byte-data');

// Pack a float32 number, output bytes to hex
byteData.pack(2.1474836, byteData.float32, 16),
//["5f","70","09","40"]

// Pack an array of uInt16 numbers, output to base 10 (default)
byteData.packArray([65535, 0], byteData.uInt16)
// [255, 255, 0, 0]);

// Pack an array of int32 numbers, output to base 10 (default)
byteData.packArray([-2147483648, 2147483647], byteData.int32),
//[0, 0, 0, 128, 255, 255, 255, 127]

// unpack an array of uInt16 numbers from bytes represented as hex values
byteData.unpackArray(["ff", "ff", "00", "00"], byteData.uInt16, 16),
// [65535, 0]

Use

/**
 * Turn a number or string into a byte buffer.
 * @param {number|string} value The value.
 * @param {Object} type One of the available types.
 * @param {number} base The base of the output. Optional. Default is 10.
 * @return {!Array<number>|!Array<string>}
 */
function pack(value, type, base=10) {}

/**
 * Turn a byte buffer into a readable value.
 * @param {!Array<number>|!Array<string>|Uint8Array} buffer An array of bytes.
 * @param {Object} type One of the available types.
 * @param {number} base The base of the input. Optional. Default is 10.
 * @return {number|string}
 */
function unpack(buffer, type, base=10) {}

/**
 * Turn a array of numbers into a byte buffer.
 * @param {!Array<number>|string} values The values.
 * @param {Object} type One of the available types.
 * @param {number} base The base of the output. Optional. Default is 10.
 * @return {!Array<number>|!Array<string>}
 */
function packArray(values, type, base=10) {}

/**
 * Turn a byte array into a sequence of readable values.
 * @param {!Array<number>|!Array<string>|Uint8Array} buffer The byte array.
 * @param {Object} type One of the available types.
 * @param {number} base The base of the input. Optional. Default is 10.
 * @return {!Array<number>|string}
 */
function unpackArray(buffer, type, base=10) {}

/**
 * Find and return the start index of some string.
 * Return -1 if the string is not found.
 * @param {!Array<number>|Uint8Array} bytes Array of bytes.
 * @param {string} text Some string to look for.
 * @return {number} The start index of the first occurrence, -1 if not found
 */
function findString(bytes, text) {}

Available types

/**
 * The available types:
 *  - chr
 *  - fourCC
 *  - bool
 *  - int2
 *  - uInt2
 *  - int4
 *  - uInt4
 *  - int8
 *  - uInt8
 *  - int16
 *  - uInt16
 *  - float16
 *  - int24
 *  - uInt24
 *  - int32
 *  - uInt32
 *  - float32
 *  - int40
 *  - uInt40
 *  - int48
 *  - uInt48
 *  - float64
 *
 * big-endian:
 *  - int16BE
 *  - uInt16BE
 *  - float16BE
 *  - int24BE
 *  - uInt24BE
 *  - int32BE
 *  - uInt32BE
 *  - float32BE
 *  - int40BE
 *  - uInt40BE
 *  - int48BE
 *  - uInt48BE
 *  - float64BE
 */

// Example:
byteData.pack(value, byteData.float16);

byte-data types are objects like this:

{
    "bits": 16, // 1, 2, 4, 8, 16, 24, 32, 40, 48, 64
    "signed": true, // signed or unsigned
    "float": false, // float or int (64-bit is always float)
    "be": false // big-endian or little-endian
    "char": false // if the type represent a string
}

Overflow

Integer values will be truncated according to the bit depth of the type. There is no overflow or underflow check for floating-point values.

// Values in the correct range
byteData.pack(254, uInt8); // [254]
byteData.pack(255, uInt8); // [255]

// Overflow
byteData.pack(300, uInt8); // [255]

// Underflow
byteData.pack(-1, uInt8); // [0]

LICENSE

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.