'use strict'
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const { createWriteStream } = require('fs')
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/**
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* @typedef {object} HexDumpParams
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* @property {Buffer} buffer The buffer instance to serialize into a hex dump.
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* @property {string} [prefix=''] A string to prefix each byte with, e.g.
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* `0x`.
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* @property {string} [separator=''] A string to separate each byte with, e.g.
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* `, '.
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* @property {string[]} [wrapCharacters=[]] A set of characters to wrap the
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* output with. For example, `wrapCharacters=['[', ']']` will start the hex
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* dump with `[` and end it with `]`.
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* @property {number} [width=10] How many bytes to write per line.
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* @property {WriteStream | string} [destination=process.stdout] Where to
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* write the serialized data. If a string is provided, it is assumed to be
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* the path to a file. This file will be completely overwritten.
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* @property {boolean} [closeDestination=false] Indicates whether the
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* `destination` should be closed when done. This _should_ be `true` when the
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* passed in `destination` is a stream that you control. If a string path is
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* supplied for the `destination`, this will automatically be handled.
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*/
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// We'd like to put this coverage directive after the doc block,
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// but that confuses doc tooling (e.g. WebStorm).
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/* istanbul ignore next: defaults don't need 100% coverage */
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/**
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* Given a buffer of bytes, generate a hex dump that can be loaded later
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* or viewed in a hex editor (e.g. [Hex Fiend](https://hexfiend.com)).
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*
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* @param {HexDumpParams} params
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*
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* @throws When the destination cannot be accessed.
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*/
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module.exports = function bufferToHexDump ({
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buffer,
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prefix = '',
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separator = '',
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wrapCharacters = [],
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width = 10,
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destination = process.stdout,
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closeDestination = false
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}) {
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let closeStream = closeDestination
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if (typeof destination === 'string') {
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destination = createWriteStream(destination)
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closeStream = true
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}
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if (wrapCharacters[0]) {
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destination.write(wrapCharacters[0])
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}
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for (const [i, byte] of buffer.entries()) {
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const outByte = Number(byte).toString(16).padStart(2, '0')
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destination.write(prefix + outByte)
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if (i !== buffer.byteLength - 1) {
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destination.write(separator)
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}
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if ((i + 1) % width === 0) {
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destination.write('\n')
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}
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}
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if (wrapCharacters[1]) {
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destination.write(wrapCharacters[1])
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}
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/* istanbul ignore else */
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if (closeStream === true) {
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destination.end()
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}
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}
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