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 Functions to read and write numbers and strings as bytes.

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

 */

/** @module byteData */

import endianness from 'endianness';

import {pack as packUTF8, unpack as unpackUTF8} from 'utf8-buffer';

import NumberBuffer from './lib/number-buffer.js';

import {validateIsNumber} from './lib/validation.js';

/**

 * Throw a value error.

 * @throws {Error} A Error with a message based on the input params.

 */

/**

 * Read a string of UTF-8 characters from a byte buffer.

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

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

 * @param {number=} end The buffer index to stop reading, non inclusive.

 *   Assumes buffer length if undefined.

 * @return {string}

 */

export function unpackString(buffer, index=0, end=buffer.length) {

  return unpackUTF8(buffer, index, end);

}

/**

 * Write a string of UTF-8 characters as a byte buffer.

 * @param {string} str The string to pack.

 * @return {!Array<number>} The UTF-8 string bytes.

 */ 

export function packString(str) {

  /** @type {!Array<number>} */

  let buffer = [];

  packUTF8(str, buffer, 0);

  return buffer;

}

/**

 * Write a string of UTF-8 characters to a byte buffer.

 * @param {string} str The string to pack.

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

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

 *   Assumes zero if undefined.

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

 */

export function packStringTo(str, buffer, index=0) {

  return packUTF8(str, buffer, index);

}

// Numbers

/**

 * Pack a array of numbers to a byte buffer.

 * All other packing functions are interfaces to this function.

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

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

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

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

 *   Assumes zero if undefined.

 * @return {number} The next index to write.

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

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

 */

export function packArrayTo(values, theType, buffer, index=0) {

  theType = theType || {};

  /** @type {NumberBuffer} */

  let packer = new NumberBuffer(theType.bits, theType.fp, theType.signed);

  /** @type {number} */

  let i = 0;

  /** @type {number} */

  let start = index;

  try {

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

      validateIsNumber(values[i]);

      index = packer.pack(buffer, values[i], index);

    }

    if (theType.be) {

      endianness(buffer, packer.offset, start, index);

    }

  } catch (e) {

    throwValueError_(e, values[i], i, theType.fp);

  }

  return index;

}

/**

 * Unpack a array of numbers to a typed array.

 * All other unpacking functions are interfaces to this function.

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

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

 * @param {!TypedArray|!Array<number>} output The output array.

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

 *   Assumes zero if undefined.

 * @param {number=} end The buffer index to stop reading.

 *   Assumes the buffer length if undefined.

 * @param {boolean=} safe If set to false, extra bytes in the end of

 *   the array are ignored and input buffers with insufficient bytes will

 *   write nothing to the output array. If safe is set to true the function

 *   will throw a 'Bad buffer length' error. Defaults to false.

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

 * @throws {Error} On overflow

 */

export function unpackArrayTo(

    buffer, theType, output, start=0, end=buffer.length, safe=false) {

  theType = theType || {};

  /** @type {NumberBuffer} */

  let packer = new NumberBuffer(

    theType.bits, theType.fp, theType.signed);

  let offset = packer.offset;

  /** @type {number} */

  let extra = (end - start) % offset;

  if (safe && (extra || buffer.length < offset)) {

    throw new Error('Bad buffer length');

  }

  end -= extra;

  /** @type {number} */

  let index = 0;

  try {

    if (theType.be) {

      endianness(buffer, offset, start, end);

    }

    for (let j = start; j < end; j += offset, index++) {

      output[index] = packer.unpack(buffer, j);

    }

    if (theType.be) {

      endianness(buffer, offset, start, end);

    }

  } catch (e) {

    throw new Error(e.message + ' at output index ' + index);

  }

}

/**

 * Pack a number as a byte buffer.

 * @param {number} value The number.

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

 * @return {!Array<number>} The packed value.

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

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

 */

export function pack(value, theType) {

  /** @type {!Array<number>} */

  let output = [];

  packTo(value, theType, output);

  return output;

}

/**

 * Pack a number to a byte buffer.

 * @param {number} 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. Assumes 0 if undefined.

 * @return {number} The next index to write.

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

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

 */

export function packTo(value, theType, buffer, index=0) {

  return packArrayTo([value], theType, buffer, index);

}

/**

 * Pack an array of numbers as a byte buffer.

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

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

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

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

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

 */

export function packArray(values, theType) {

  /** @type {!Array<number>} */

  let output = [];

  packArrayTo(values, theType, output);

  return output;

}

/**

 * Unpack a number from a byte buffer.

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

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

 * @param {number=} index The buffer index to read. Assumes zero if undefined.

 * @return {number}

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

 * @throws {Error} On bad buffer length.

 * @throws {Error} On overflow

 */

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

  return unpackArray(

    buffer, theType, index, index + Math.ceil(theType.bits / 8), true)[0];

}

/**

 * Unpack an array of numbers from a byte buffer.

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

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

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

 *   Assumes zero if undefined.

 * @param {number=} end The buffer index to stop reading.

 *   Assumes the buffer length if undefined.

 * @param {boolean=} safe If set to false, extra bytes in the end of

 *   the array are ignored and input buffers with insufficient bytes will

 *   output a empty array. If safe is set to true the function

 *   will throw a 'Bad buffer length' error. Defaults to false.

 * @return {!Array<number>}

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

 * @throws {Error} On overflow

 */

export function unpackArray(

    buffer, theType, start=0, end=buffer.length, safe=false) {

  /** @type {!Array<number>} */

  let output = [];

  unpackArrayTo(buffer, theType, output, start, end, safe);

  return output;

}