Passed
Branch riff-file (a0264a)
by Rafael S.
03:11
created

dw-channel-mask.js ➔ dwChannelMask   B

Complexity

Conditions 6

Size

Total Lines 21
Code Lines 13

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
eloc 13
dl 0
loc 21
rs 8.6666
c 0
b 0
f 0
cc 6
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/*
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 * Copyright (c) 2017-2019 Rafael da Silva Rocha.
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 *
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 * Permission is hereby granted, free of charge, to any person obtaining
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 * a copy of this software and associated documentation files (the
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 * "Software"), to deal in the Software without restriction, including
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 * without limitation the rights to use, copy, modify, merge, publish,
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 * distribute, sublicense, and/or sell copies of the Software, and to
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 * permit persons to whom the Software is furnished to do so, subject to
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 * the following conditions:
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 *
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 * The above copyright notice and this permission notice shall be
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 * included in all copies or substantial portions of the Software.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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 *
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 */
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/**
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 * @fileoverview The dwChannelMask function.
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 * @see https://github.com/rochars/wavefile
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 */
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/**
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 * Return the value for dwChannelMask according to the number of channels.
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 * @param {number} numChannels the number of channels.
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 * @return {number} the dwChannelMask value.
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 * @private
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 */
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export default function dwChannelMask(numChannels) {
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  /** @type {number} */
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  let dwChannelMask = 0;
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  // mono = FC
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  if (numChannels === 1) {
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    dwChannelMask = 0x4;
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  // stereo = FL, FR
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  } else if (numChannels === 2) {
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    dwChannelMask = 0x3;
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  // quad = FL, FR, BL, BR
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  } else if (numChannels === 4) {
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    dwChannelMask = 0x33;
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  // 5.1 = FL, FR, FC, LF, BL, BR
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  } else if (numChannels === 6) {
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    dwChannelMask = 0x3F;
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  // 7.1 = FL, FR, FC, LF, BL, BR, SL, SR
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  } else if (numChannels === 8) {
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    dwChannelMask = 0x63F;
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  }
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  return dwChannelMask;
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}
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