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.

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

 */

/** @module byteData */

import endianness from './lib/endianness.js';

import {reader_, setUp_, writeBytes_,

  fromBytes_, toBytes_} from './lib/packer.js';

// Strings

/**

 * Read a string from a byte buffer.

 * @param {!Uint8Array} bytes A byte buffer.

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

 * @param {?number=} len The number of bytes to read.

 * @return {string}

 */

export function unpackString(bytes, index=0, len=null) {

  let chrs = '';

  len = len || bytes.length - index;

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

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

  }

  return chrs;

}

/**

 * Write a string as a byte buffer.

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

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

 */

export function packString(str) {

  let bytes = [];

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

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

  }

  return bytes;

}

/**

 * Write a string to a byte buffer.

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

 * @param {!Uint8Array} bytes A byte buffer.

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

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

 */

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

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

    bytes[index] = str.charCodeAt(i);

    index++;

  }

  return index;

}

// Numbers

/**

 * 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) {

  setUp_(theType);

  return toBytes_([value], theType);

}

/**

 * Pack an array of numbers as a byte buffer.

 * @param {!Array<number>} 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) {

  setUp_(theType);

  return toBytes_(values, theType);

}

/**

 * Pack a number to a byte buffer.

 * @param {number} value The value.

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

 * @param {!Uint8Array} buffer The output buffer.

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

 * @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) {

  setUp_(theType);

  return writeBytes_(value,

    theType,

    buffer,

    index,

    index + theType.offset,

    validateNotUndefined,

    theType.be);

}

/**

 * Pack a array of numbers to a byte buffer.

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

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

 * @param {!Uint8Array} buffer The output buffer.

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

 * @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) {

  setUp_(theType);

  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,

      validateNotUndefined,

      be);

  }

  return index;

}

/**

 * Unpack a number from a byte buffer.

 * @param {!Uint8Array} buffer The byte buffer.

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

 * @return {number}

 * @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 from a byte buffer.

 * @param {!Uint8Array} buffer The byte buffer.

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

 * @return {!Array<number>}

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

 */

export function unpackArray(buffer, theType) {

  setUp_(theType);

  return fromBytes_(buffer, theType);

}

/**

 * Unpack a number from a byte buffer by index.

 * @param {!Uint8Array} buffer The byte buffer.

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

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

 * @return {number}

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

 */

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

  setUp_(theType);

  if (theType.be) {

    endianness(buffer, theType.offset, index, index + theType.offset);

  }

  let value = reader_(buffer, index);

  if (theType.be) {

    endianness(buffer, theType.offset, index, index + theType.offset);

  }

  return value;

}

/**

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

 * @param {!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 buffer 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;

}

/**

 * Unpack a array of numbers to a typed array.

 * @param {!Uint8Array} buffer The byte buffer.

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

 * @param {!TypedArray} output The output array.

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

 */

export function unpackArrayTo(buffer, theType, output) {

  setUp_(theType);

  if (theType.be) {

    endianness(buffer, theType.offset);

  }

  let len = buffer.length;

  let outputIndex = 0;

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

    output.set([reader_(buffer, i)], outputIndex);

    outputIndex++;

  }

  if (theType.be) {

    endianness(buffer, theType.offset);

  }

}