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/* |
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* to-bytes: bytes to numbers and strings. |
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* Copyright (c) 2017 Rafael da Silva Rocha. |
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* https://github.com/rochars/byte-data |
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*/ |
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const intBits = require("int-bits"); |
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const pad = require("../src/byte-padding.js"); |
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const endianness = require("endianness"); |
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const writer = require("../src/write-bytes.js"); |
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const bitDepths = require("../src/bit-depth.js"); |
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/** |
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* Turn numbers and strings to bytes. |
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* @param {!Array<number>|number|string} values The data. |
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* @param {number} bitDepth The bit depth of the data. |
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* Possible values are 1, 2, 4, 8, 16, 24, 32, 40, 48 or 64. |
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* @param {Object} options The options: |
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* - "float": True for floating point numbers. Default is false. |
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* This option is available for 16, 32 and 64-bit numbers. |
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* - "base": The base of the output. Default is 10. Can be 2, 10 or 16. |
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* - "char": If the bytes represent a string. Default is false. |
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* - "be": If the values are big endian. Default is false (little endian). |
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* - "buffer": If the bytes should be returned as a Uint8Array. |
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* Default is false (bytes are returned as a regular array). |
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* @return {!Array<number>|Uint8Array} the data as a byte buffer. |
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*/ |
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function toBytes(values, bitDepth, options={}) { |
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if (!options.char && typeof values != "string") { |
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values = turnToArray(values); |
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} |
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let base = 10; |
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if ("base" in options) { |
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base = options.base; |
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} |
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let bytes = writeBytes(values, options.char, options.float, bitDepth); |
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makeBigEndian(bytes, options.be, bitDepth); |
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outputToBase(bytes, bitDepth, base); |
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if (options.buffer) { |
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bytes = new Uint8Array(bytes); |
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} |
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return bytes; |
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} |
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/** |
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* Make a single value an array in case it is not. |
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* @param {!Array<number>|number|string} values The value or values. |
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* @return {!Array<number>} |
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*/ |
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function turnToArray(values) { |
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if (!Array.isArray(values)) { |
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values = [values]; |
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} |
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return values; |
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} |
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/** |
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* Turn the output to the correct base. |
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* @param {!Array<number>} bytes The bytes. |
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* @param {number} bitDepth The bit depth of the data. |
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* @param {number} base The desired base for the output data. |
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*/ |
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function outputToBase(bytes, bitDepth, base) { |
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if (bitDepth == 4) { |
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bytesToBase(bytes, base, pad.paddingNibble); |
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} else if (bitDepth == 2) { |
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bytesToBase(bytes, base, pad.paddingCrumb); |
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} else if(bitDepth == 1) { |
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bytesToBase(bytes, base, function(){}); |
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}else { |
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bytesToBase(bytes, base); |
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} |
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} |
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/** |
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* Write values as bytes. |
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* @param {!Array<number>|number|string} values The data. |
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* @param {boolean} isChar True if it is a string. |
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* @param {boolean} isFloat True if it is a IEEE floating point number. |
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* @param {number} bitDepth The bitDepth of the data. |
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* @return {!Array<number>} the bytes. |
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*/ |
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function writeBytes(values, isChar, isFloat, bitDepth) { |
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let bitWriter; |
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if (isChar) { |
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bitWriter = writer.writeString; |
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} else { |
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bitWriter = writer['write' + bitDepth + 'Bit' + (isFloat ? "Float" : "")]; |
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} |
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let i = 0; |
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let j = 0; |
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let len = values.length; |
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let bytes = []; |
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while (i < len) { |
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j = bitWriter(bytes, values, i, j); |
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i++; |
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} |
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return bytes; |
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} |
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/** |
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* Write values as bytes. |
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* @param {!Array<number>} bytes The values. |
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* @param {boolean} isBigEndian True if the bytes should be big endian. |
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* @param {number} bitDepth The bitDepth of the data. |
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*/ |
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function makeBigEndian(bytes, isBigEndian, bitDepth) { |
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if (isBigEndian) { |
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endianness.endianness(bytes, bitDepths.BitDepthOffsets[bitDepth]); |
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} |
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} |
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/** |
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* Turn bytes to base. |
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* @param {!Array<string>|!Array<number>} bytes The bytes. |
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* @param {number} base The base. |
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* @param {Function} padFunction The function to use for padding. |
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*/ |
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function bytesToBase(bytes, base, padFunction=pad.padding) { |
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if (base != 10) { |
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let i = 0; |
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let len = bytes.length; |
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while (i < len) { |
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bytes[i] = bytes[i].toString(base); |
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padFunction(bytes, base, i); |
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i++; |
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} |
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} |
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} |
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module.exports.toBytes = toBytes; |
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rochars /
byte-data
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