rochars / byte-data

 * byte-data

 * Readable data to and from byte buffers.

 * Copyright (c) 2017 Rafael da Silva Rocha.

 * https://github.com/rochars/byte-data

 *

 */

let toBytes = require('./src/to-bytes');

let fromBytes = require('./src/from-bytes');

let bitPacker = require('./src/bit-packer');

let bitDepth = require('./src/bit-depth');

/**

 * 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

 */

function findString(bytes, chunk) {

    let found = "";

    for (let i = 0; i < bytes.length; i++) {

        found = fromBytes.fromBytes(bytes.slice(i, i + chunk.length),

            8, {"char": true});

        if (found == chunk) {

            return i;

        }

    }

    return -1;

}

/**

 * 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 input. Optional. Default is 10.

 * @return {!Array<number>|!Array<string>}

 */

function pack(value, type, base=10) {

    let theType = getSingleType(type, base);

    value = theType.char ? value[0] : value;

    return toBytes.toBytes(turnToArray(value), theType.bits, theType);

}

/**

 * 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) {

    let theType = getSingleType(type, base);

    return fromBytes.fromBytes(buffer, theType.bits, theType);

}

/**

 * Turn a array of numbers into a byte buffer.

 * @param {!Array<number>} values The values.

 * @param {Object} type One of the available types.

 * @param {number} base The base of the input. Optional. Default is 10.

 * @return {!Array<number>|!Array<string>}

 */

function packArray(values, type, base=10) {

    let theType = getArrayType(type, base);

    return toBytes.toBytes(values, theType.bits, theType);

}

/**

 * 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) {

    let theType = getArrayType(type, base);

    return fromBytes.fromBytes(buffer, theType.bits, theType);

}

/**

 * Make the type a single value type on the specified base.

 * @param {Object} type One of the available types.

 * @param {number} base The base of the input.

 * @return {Object}

 */

function getSingleType(type, base) {

    let theType = Object.assign({}, type);

    theType.base = base;

    theType.single = true;

    return theType;

}

/**

 * Make the type a array with the specified base.

 * @param {Object} type One of the available types.

 * @param {number} base The base of the input.

 * @return {Object}

 */

function getArrayType(type, base) {

    let theType = Object.assign({}, type);

    theType.base = base;

    theType.single = false;

    return theType;

}

/**

 * Make a single value an array in case it is not.

 * If the value is a string it stays a string.

 * @param {!Array<number>|number|string} values The value or values.

 * @return {!Array<number>|string}

 */

// interface

module.exports.pack = pack;

module.exports.unpack = unpack;

module.exports.packArray = packArray;

module.exports.unpackArray = unpackArray;

// types

module.exports.chr = {"bits": 8, "char": true, "single": true};

module.exports.bool = {"bits": 1, "single": true};

module.exports.int2 = {"bits": 2, "signed": true, "single": true};

module.exports.uInt2 = {"bits": 2, "single": true};

module.exports.int4 = {"bits": 4, "signed": true, "single": true};

module.exports.uInt4 = {"bits": 4, "single": true};

module.exports.int8 = {"bits": 8, "signed": true, "single": true};

module.exports.uInt8 = {"bits": 8, "single": true};

module.exports.int16  = {"bits": 16, "signed": true, "single": true};

module.exports.uInt16 = {"bits": 16, "single": true};

module.exports.float16 = {"bits": 16, "float": true, "single": true};

module.exports.int24 = {"bits": 24, "signed": true, "single": true};

module.exports.uInt24 = {"bits": 24, "single": true};

module.exports.int32 = {"bits": 32, "signed": true, "single": true};

module.exports.uInt32 = {"bits": 32, "single": true};

module.exports.float32 = {"bits": 32, "float": true, "single": true};

module.exports.int40 = {"bits": 40, "signed": true, "single": true};

module.exports.uInt40 = {"bits": 40, "single": true};

module.exports.int48 = {"bits": 48, "signed": true, "single": true};

module.exports.uInt48 = {"bits": 48, "single": true};

module.exports.float64 = {"bits": 64, "float": true, "single": true};

module.exports.findString = findString;

module.exports.toBytes = toBytes.toBytes;

module.exports.fromBytes = fromBytes.fromBytes;

module.exports.packBooleans = bitPacker.packBooleans;

module.exports.unpackBooleans = bitPacker.unpackBooleans;

module.exports.packCrumbs = bitPacker.packCrumbs;

module.exports.unpackCrumbs = bitPacker.unpackCrumbs;

module.exports.packNibbles = bitPacker.packNibbles;

module.exports.unpackNibbles = bitPacker.unpackNibbles;

module.exports.BitDepthOffsets = bitDepth.BitDepthOffsets;

module.exports.BitDepthMaxValues = bitDepth.BitDepthMaxValues;