Package Exports

byte-data

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Readme

byte-data

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

Install

npm install byte-data

For Node.js and the browser.

Support:

booleans
crumbs (2-bit, signed/unsigned)
nibbles (4-bit, 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
Strings

Example

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

// Signed 24-bit integers from a byte buffer
let numbers = fromBytes(buffer, 24, {"signed": true});

// 16-bit half-precision float numbers from bytes represented as binary strings
console.log(
    fromBytes(
        ["00110101", "01010101"],
        16, 
        {"base": 2, "float": true}
    )
);
// 0.33325

// 32-bit floating point numbers to bytes represented as hexadecimal values
let bytes = toBytes(numbers, 32, {"base": 16,  "float": true});

// 32-bit signed integers to and from binary form
byteData.toBytes([-2147483648, 2147483647], 32);
//[0,0,0,128,255,255,255,127]
byteData.fromBytes([0,0,0,128,255,255,255,127], 32, {"signed": true});
//[-2147483648, 2147483647]

Use

/**
 * Turn numbers and strings to bytes.
 * @param {!Array<number>|string} numbers float64 numbers.
 * @param {number} bitDepth The desired bitDepth for the data.
 *   Possible values are 1, 2, 4, 8, 16, 24, 32, 40, 48 or 64.
 * @param {Object} options The options:
 *   - "float", defaults to false, true for floats.
 *       float is available for 16, 32 and 64-bit values.
 *   - "base", base of the output, defaults to 10. Can be 2, 10 or 16
 *   - "char", defaults to false, true for strings
 *   - "be", defaults to false, true for big endian
 * @return {!Array<number>} the bytes.
 */
toBytes(numbers, bitDepth);

/**
 * Turn a array of bytes into an array of what the bytes should represent.
 * @param {!Array<number>|Uint8Array} buffer An array of bytes.
 * @param {number} bitDepth The desired bitDepth for the data.
 *   Possible values are 1, 2, 4, 8, 16, 24, 32, 40, 48 or 64.
 * @param {Object} options The options. They are:
 *   - "signed", defaults to false
 *   - "float", defaults to false, true for floating point numbers.
 *       float is available for 16, 32 and 64 bit depths.
 *   - "base", defaults to 10, can be 2, 10 or 16
 *   - "char", defaults to false, true for strings
 *   - "be", defaults to false, true for big endian
 * @return {!Array<number>|string} The values represented in the bytes.
 */
fromBytes(buffer, bitDepth);

/**
 * 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} chunk Some string to look for.
 * @return {number} The start index of the first occurrence, -1 if not found
 */
byteData.findString(bytes, "chunk");

Pack your nibbles

Packing nibbles:

byteData.packNibbles([15, 15, 1, 4, 1, 15]);
//[255, 20, 31]);

This will pack 2 nibbles into one byte.

Unpacking nibbles:

byteData.unpackNibbles([255, 20, 31]);
//[15, 15, 1, 4, 1, 15]

Pack your crumbs

Packing crumbs:

byteData.packCrumbs([3,3,3,3,1,2,3,0,1,1,0,0]);
//[255, 108, 80]);

This will pack 4 crumbs into one byte.

Unpacking crumbs:

byteData.unpackCrumbs([108]);
//[1, 2, 3, 0]

Pack your booleans

Packing booleans:

byteData.packBooleans([0,0,0,0,0,0,0,0,0,1,0,0,1,1,0,0]);
//[0,76]);

This will pack 8 booleans into one byte.

Unpacking booleans:

byteData.unpackBooleans([77]);
//[0,1,0,0,1,1,0,1]

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.