66 lines
1.1 KiB
JavaScript
66 lines
1.1 KiB
JavaScript
'use strict'
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const wout = (s) => {
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process.stdout.write(s)
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}
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const padStr = (s, len, ch) => {
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ch = ch || ' '
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while (s.length < len) {
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s = ch + s
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}
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return s
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}
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const hexDigit = (n, len) => {
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return padStr(n.toString(16), len || 2, '0')
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}
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const printableCh = (c) => {
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// [space to '~')
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if (c > 0x20 && c <= 0x7e) {
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return String.fromCharCode(c)
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} else {
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return '.'
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}
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}
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const hexdump = (buf, len) => {
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len = len || buf.length
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const maxline = 16
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let ascii = new Array(maxline)
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let i
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for (i = 0; i < len; i++) {
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if (i % maxline === 0) {
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if (i > 0) {
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wout(' ' + ascii.join(''))
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wout('\n')
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}
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wout(hexDigit(i, 4) + ': ')
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}
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// output the hex digit
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wout(hexDigit(buf[i]))
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wout(' ')
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ascii[i % maxline] = printableCh(buf[i])
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}
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if (i % maxline !== 0) {
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let diff = maxline - (i % maxline)
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wout(' '.repeat(diff))
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}
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wout(' ' + ascii.slice(0, (i % maxline)).join('') + '\n')
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}
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/*
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let buf = Buffer.alloc(500)
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for (let i = 0; i < buf.length; i++) {
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buf[i] = i & 0xff
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}
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hexdump(buf)
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*/
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module.exports = hexdump
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