rochars / byte-data

 * byte-data: Pack and unpack binary data.

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

 *

 * Copyright (c) 2017-2018 Rafael da Silva Rocha.

 *

 * 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.

 *

 */

/**

 * @fileoverview The byte-data API.

 */

/** @module byteData */

import Integer from './lib/integer.js';

import endianness from 'endianness';

export {default as types} from './lib/types.js';

/**

 * Pack a number or a string as a byte buffer.

 * @param {number|string} value The value.

 * @param {!Object} theType The type definition.

 * @return {!Array<number>}

 * @throws {Error} If the type definition is not valid.

 * @throws {Error} If the value is not valid.

 */

export function pack(value, theType) {

  setUp_(theType);

  return toBytes_([value], theType);

}

/**

 * Pack an array of numbers or strings to a byte buffer.

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

 * @param {!Object} theType The type definition.

 * @return {!Array<number>}

 * @throws {Error} If the type definition is not valid.

 * @throws {Error} If any of the values are not valid.

 */

export function packArray(values, theType) {

  setUp_(theType);

  return toBytes_(values, theType);

}

/**

 * Pack a number or a string to a existing byte buffer.

 * @param {number|string} value The value.

 * @param {!Object} theType The type definition.

 * @param {!Uint8Array|!Array<number>} buffer The output buffer.

 * @param {number} index The buffer index to write.

 * @return {number} The next index to start writing.

 * @throws {Error} If the type definition is not valid.

 * @throws {Error} If the value is not valid.

 */

export function packTo(value, theType, buffer, index) {

  setUp_(theType);

  let validate = validateNotNull_;

  if (theType['char']) {

    validate = validateString_;

  }

  return writeBytes_(value,

    theType,

    buffer,

    index,

    index + theType['offset'],

    validate,

    theType['be']);

}

/**

 * Pack a array of numbers or strings to a existing byte buffer.

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

 * @param {!Object} theType The type definition.

 * @param {!Uint8Array|!Array<number>} buffer The output buffer.

 * @param {number} index The buffer index to write.

 * @return {number} The next index to start writing.

 * @throws {Error} If the type definition is not valid.

 * @throws {Error} If the value is not valid.

 */

export function packArrayTo(values, theType, buffer, index) {

  setUp_(theType);

  let validate = validateNotNull_;

  if (theType['char']) {

    validate = validateString_;

  }

  let be = theType['be'];

  let offset = theType['offset'];

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

    index = writeBytes_(

      values[i],

      theType,

      buffer,

      index,

      index + offset,

      validate, be);

  }

  return index;

}

/**

 * Unpack a number or a string from a byte buffer.

 * @param {!Array<number>|!Uint8Array} buffer The byte buffer.

 * @param {!Object} theType The type definition.

 * @return {number|string}

 * @throws {Error} If the type definition is not valid

 */

export function unpack(buffer, theType) {

  setUp_(theType);

  let values = fromBytes_(

    buffer.slice(0, theType['offset']), theType);

  return values[0];

}

/**

 * Unpack an array of numbers or strings from a byte buffer.

 * @param {!Array<number>|!Uint8Array} buffer The byte buffer.

 * @param {!Object} theType The type definition.

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

 * @throws {Error} If the type definition is not valid.

 */

export function unpackArray(buffer, theType) {

  setUp_(theType);

  return fromBytes_(buffer, theType);

}

/**

 * Unpack a number or a string from a byte buffer index.

 * @param {!Array<number>|!Uint8Array} buffer The byte buffer.

 * @param {!Object} theType The type definition.

 * @param {number=} index The buffer index to read.

 * @return {number|string}

 * @throws {Error} If the type definition is not valid

 */

export function unpackFrom(buffer, theType, index=0) {

  setUp_(theType);

  return readBytes_(buffer, theType, index);

}

/**

 * Unpack a array of numbers strings from a byte buffer index.

 * @param {!Array<number>|!Uint8Array} buffer The byte buffer.

 * @param {!Object} theType The type definition.

 * @param {number=} start The start index. Assumes 0.

 * @param {?number=} end The end index. Assumes the array length.

 * @return {!Array<number>}

 * @throws {Error} If the type definition is not valid

 */

export function unpackArrayFrom(buffer, theType, start=0, end=null) {

  setUp_(theType);

  if (theType['be']) {

    endianness(buffer, theType['offset']);

  }

  let len = end || buffer.length;

  let values = [];

  for (let i=start; i<len; i+=theType['offset']) {

    values.push(reader_(buffer, i));

  }

  if (theType['be']) {

    endianness(buffer, theType['offset']);

  }

  return values;

}

/**

 * @type {!Int8Array}

 * @private

 */

const int8_ = new Int8Array(8);

/**

 * @type {!Uint32Array}

 * @private

 */

const ui32_ = new Uint32Array(int8_.buffer);

/**

 * @type {!Float32Array}

 * @private

 */

const f32_ = new Float32Array(int8_.buffer);

/**

 * @type {!Float64Array}

 * @private

 */

const f64_ = new Float64Array(int8_.buffer);

/**

 * @type {Function}

 * @private

 */

let reader_;

/**

 * @type {Function}

 * @private

 */

let writer_;

/**

 * @type {Object}

 * @private

 */

let gInt_ = {};

/**

 * Turn a byte buffer into what the bytes represent.

 * @param {!Array<number|string>|!Uint8Array} buffer An array of bytes.

 * @param {!Object} theType The type definition.

 * @return {number}

 * @private

 */

function readBytes_(buffer, theType, start) {

  if (theType['be']) {

    endianness(buffer, theType['offset'], start, start + theType['offset']);

  }

  let value = reader_(buffer, start);

  if (theType['be']) {

    endianness(buffer, theType['offset'], start, start + theType['offset']);

  }

  return value;

}

/**

 * Turn a byte buffer into what the bytes represent.

 * @param {!Array<number|string>|!Uint8Array} buffer An array of bytes.

 * @param {!Object} theType The type definition.

 * @return {!Array<number>}

 * @private

 */

function fromBytes_(buffer, theType) {

  if (theType['be']) {

    endianness(buffer, theType['offset']);

  }

  let len = buffer.length;

  let values = [];

  len = len - (theType['offset'] - 1);

  for (let i=0; i<len; i+=theType['offset']) {

    values.push(reader_(buffer, i));

  }

  return values;

}

/**

 * Turn numbers and strings to bytes.

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

 * @param {!Object} theType The type definition.

 * @return {!Array<number|string>} the data as a byte buffer.

 * @private

 */

function toBytes_(values, theType) {

  let j = 0;

  let bytes = [];

  let len = values.length;

  let validate = validateNotNull_;

  if (theType['char']) {

    validate = validateString_;

  }

  for(let i=0; i < len; i++) {

    validate(values[i], theType);

    j = writer_(bytes, values[i], j);

  }

  if (theType['be']) {

    endianness(bytes, theType['offset']);

  }

  return bytes;

}

/**

 * Turn numbers and strings to bytes.

 * @param {number|string} value The value to be packed.

 * @param {!Object} theType The type definition.

 * @param {!Uint8Array|!Array<number>} buffer The buffer to write the bytes to.

 * @param {number} index The index to start writing.

 * @param {number} len The end index.

 * @param {!Function} validate The function used to validate input.

 * @param {boolean} be True if big-endian.

 * @return {number} the new index to be written.

 * @private

 */

function writeBytes_(value, theType, buffer, index, len, validate, be) {

  while (index < len) {

    validate(value, theType);

    index = writer_(buffer, value, index);

  }

  if (be) {

    endianness(

      buffer, theType['offset'], index - theType['offset'], index);

  }

  return index;

}

/**

 * Read int values from bytes.

 * @param {!Array<number>|!Uint8Array} bytes An array of bytes.

 * @param {number} i The index to read.

 * @return {number}

 * @private

 */

function readInt_(bytes, i) {

  return gInt_.read(bytes, i);

}

/**

 * Read 1 16-bit float from bytes.

 * Thanks https://stackoverflow.com/a/8796597

 * @param {!Array<number>|!Uint8Array} bytes An array of bytes.

 * @param {number} i The index to read.

 * @return {number}

 * @private

 */

function read16F_(bytes, i) {

  let int = gInt_.read(bytes, i);

  let exponent = (int & 0x7C00) >> 10;

  let fraction = int & 0x03FF;

  let floatValue;

  if (exponent) {

    floatValue =  Math.pow(2, exponent - 15) * (1 + fraction / 0x400);

  } else {

    floatValue = 6.103515625e-5 * (fraction / 0x400);

  }

  return floatValue * (int >> 15 ? -1 : 1);

}

/**

 * Read 1 32-bit float from bytes.

 * @param {!Array<number>|!Uint8Array} bytes An array of bytes.

 * @param {number} i The index to read.

 * @return {number}

 * @private

 */

function read32F_(bytes, i) {

  ui32_[0] = gInt_.read(bytes, i);

  return f32_[0];

}

/**

 * Read 1 64-bit float from bytes.

 * Thanks https://gist.github.com/kg/2192799

 * @param {!Array<number>|!Uint8Array} bytes An array of bytes.

 * @param {number} i The index to read.

 * @return {number}

 * @private

 */

function read64F_(bytes, i) {

  ui32_[0] = gInt_.read(bytes, i);

  ui32_[1] = gInt_.read(bytes, i + 4);

  return f64_[0];

}

/**

 * Read 1 char from bytes.

 * @param {!Array<number>|!Uint8Array} bytes An array of bytes.

 * @param {number} i The index to read.

 * @return {string}

 * @private

 */

function readChar_(bytes, i) {

  let chrs = '';

  for(let j=0; j < gInt_.offset; j++) {

    chrs += String.fromCharCode(bytes[i+j]);

  }

  return chrs;

}

/**

 * Write a integer value to a byte buffer.

 * @param {!Array<number>|!Uint8Array} bytes An array of bytes.

 * @param {number} number The number to write as bytes.

 * @param {number} j The index being written in the byte buffer.

 * @return {!number} The next index to write on the byte buffer.

 * @private

 */

function writeInt_(bytes, number, j) {

  return gInt_.write(bytes, number, j);

}

/**

 * Write one 16-bit float as a binary value.

 * @param {!Array<number>|!Uint8Array} bytes An array of bytes.

 * @param {number} number The number to write as bytes.

 * @param {number} j The index being written in the byte buffer.

 * @return {number} The next index to write on the byte buffer.

 * @private

 */

function write16F_(bytes, number, j) {

  f32_[0] = number;

  let x = ui32_[0];

  let bits = (x >> 16) & 0x8000;

  let m = (x >> 12) & 0x07ff;

  let e = (x >> 23) & 0xff;

  if (e >= 103) {

    bits |= ((e - 112) << 10) | (m >> 1);

    bits += m & 1;

  }

  bytes[j++] = bits & 0xFF;

  bytes[j++] = bits >>> 8 & 0xFF;

  return j;

}

/**

 * Write one 32-bit float as a binary value.

 * @param {!Array<number>|!Uint8Array} bytes An array of bytes.

 * @param {number} number The number to write as bytes.

 * @param {number} j The index being written in the byte buffer.

 * @return {number} The next index to write on the byte buffer.

 * @private

 */

function write32F_(bytes, number, j) {

  f32_[0] = number;

  return gInt_.write(bytes, ui32_[0], j);

}

/**

 * Write one 64-bit float as a binary value.

 * @param {!Array<number>|!Uint8Array} bytes An array of bytes.

 * @param {number} number The number to write as bytes.

 * @param {number} j The index being written in the byte buffer.

 */

function write64F_(bytes, number, j) {

  f64_[0] = number;

  j = gInt_.write(bytes, ui32_[0], j);

  return gInt_.write(bytes, ui32_[1], j);

}

/**

 * Write one char as a byte.

 * @param {!Array<number>|!Uint8Array} bytes An array of bytes.

 * @param {string} str The string to write as bytes.

 * @param {number} j The index being written in the byte buffer.

 * @return {number} The next index to write on the byte buffer.

 * @private

 */

function writeChar_(bytes, str, j) {

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

    bytes[j++] = str.charCodeAt(i);

  }

  return j;

}

/**

 * Set the function to unpack the data.

 * @param {!Object} theType The type definition.

 * @private

 */

function setReader(theType) {

  if (theType['float']) {

    if (theType['bits'] == 16) {

      reader_ = read16F_;

    } else if(theType['bits'] == 32) {

      reader_ = read32F_;

    } else if(theType['bits'] == 64) {

      reader_ = read64F_;

    }

  } else if (theType['char']) {

    reader_ = readChar_;

  } else {

    reader_ = readInt_;

  }

}

/**

 * Set the function to pack the data.

 * @param {!Object} theType The type definition.

 * @private

 */

function setWriter(theType) {

  if (theType['float']) {

    if (theType['bits'] == 16) {

      writer_ = write16F_;

    } else if(theType['bits'] == 32) {

      writer_ = write32F_;

    } else if(theType['bits'] == 64) {

      writer_ = write64F_;

    }

  } else if (theType['char']) {

    writer_ = writeChar_;

  } else {

    writer_ = writeInt_;

  }   

}

/**

 * Validate the type and set up the packing/unpacking functions.

 * @param {!Object} theType The type definition.

 * @throws {Error} If the type definition is not valid.

 * @private

 */

function setUp_(theType) {

  validateType_(theType);

  theType['offset'] = theType['bits'] < 8 ? 1 : Math.ceil(theType['bits'] / 8);

  setReader(theType);

  setWriter(theType);

  if (!theType['char']) {

    gInt_ = new Integer(

      theType['bits'] == 64 ? 32 : theType['bits'],

      theType['float'] ? false : theType['signed']);

  } else {

    // Workaround; should not use Integer when type['char']

    gInt_.offset = theType['bits'] < 8 ? 1 : Math.ceil(theType['bits'] / 8);

  }

}

/**

 * Validate the type definition.

 * @param {!Object} theType The type definition.

 * @throws {Error} If the type definition is not valid.

 * @private

 */

function validateType_(theType) {

  if (!theType) {

    throw new Error('Undefined type.');

  }

  if (theType['float']) {

    validateFloatType_(theType);

  } else {

    if (theType['char']) {

      validateCharType_(theType);

    } else {

      validateIntType_(theType);

    }

  }

}

/**

 * Validate the type definition of floating point numbers.

 * @param {!Object} theType The type definition.

 * @throws {Error} If the type definition is not valid.

 * @private

 */

function validateFloatType_(theType) {

  if ([16,32,64].indexOf(theType['bits']) == -1) {

    throw new Error('Not a supported float type.');

  }

}

/**

 * Validate the type definition of char and strings.

 * @param {!Object} theType The type definition.

 * @throws {Error} If the type definition is not valid.

 * @private

 */

function validateCharType_(theType) {

  if (theType['bits'] < 8 || theType['bits'] % 2) {

    throw new Error('Wrong offset for type char.');

  }

}

/**

 * Validate the type definition of integers.

 * @param {!Object} theType The type definition.

 * @throws {Error} If the type definition is not valid.

 * @private

 */

function validateIntType_(theType) {

  if (theType['bits'] < 1 || theType['bits'] > 53) {

    throw new Error('Not a supported type.');

  }

}

/**

 * Validate strings with bad length.

 * @param {string|number} value The string to validate.

 * @param {!Object} theType The type definition.

 * @private

 */

function validateString_(value, theType) {

  validateNotNull_(value);

  if (value.length > theType['offset']) {

    throw new Error('String is bigger than its type definition.');

  } else if (value.length < theType['offset']) {

    throw new Error('String is smaller than its type definition.');

  }

}

/**

 * Validate that the value is not null.

 * @param {string|number} value The value.

 * @private

 */

function validateNotNull_(value) {

  if (value === null || value === undefined) {

    throw new Error('Cannot pack null or undefined values.');

  }

}