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/* |
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* Copyright (c) 2017-2018 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 A function to swap endianness in byte buffers. |
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* @see https://github.com/rochars/endianness |
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*/ |
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/** |
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* @module endianness |
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*/ |
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/** |
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* Swap the byte ordering in a buffer. The buffer is modified in place. |
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* @param {!Array<number|string>|!Uint8Array} bytes The bytes. |
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* @param {number} offset The byte offset. |
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* @param {number=} index The start index. Assumes 0. |
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* @param {?number=} end The end index. Assumes the buffer length. |
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* @throws {Error} If the buffer length is not valid. |
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*/ |
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export default function endianness(bytes, offset, index=0, end=null) { |
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let len = end || bytes.length; |
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let limit = parseInt(offset / 2, 10); |
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if (len % offset) { |
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throw new Error("Bad buffer length."); |
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} |
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while (index < len) { |
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swap(bytes, offset, index, limit); |
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index += offset; |
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} |
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} |
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/** |
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* Swap the byte order of a value in a buffer. The buffer is modified in place. |
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* @param {!Array<number|string>|!Uint8Array} bytes The bytes. |
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* @param {number} offset The byte offset. |
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* @param {number} index The start index. |
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* @private |
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*/ |
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function swap(bytes, offset, index, limit) { |
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let x = 0; |
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let y = offset - 1; |
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while(x < limit) { |
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let theByte = bytes[index + x]; |
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bytes[index + x] = bytes[index + y]; |
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bytes[index + y] = theByte; |
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x++; |
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y--; |
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} |
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} |
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rochars /
endianness
