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string-decoder.js
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88 lines (78 loc) · 2.21 KB
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'use strict';
const common = require('../common.js');
const StringDecoder = require('string_decoder').StringDecoder;
const assert = require('node:assert');
const bench = common.createBenchmark(main, {
encoding: ['ascii', 'utf8', 'base64-utf8', 'base64-ascii', 'utf16le'],
inLen: [32, 128, 1024],
chunkLen: [16, 256, 1024],
n: [25e5],
});
const UTF8_ALPHA = 'Blåbærsyltetøy';
const ASC_ALPHA = 'Blueberry jam';
const UTF16_BUF = Buffer.from('Blåbærsyltetøy', 'utf16le');
function main({ encoding, inLen, chunkLen, n }) {
let alpha;
let buf;
const chunks = [];
let str = '';
const isBase64 = (encoding === 'base64-ascii' || encoding === 'base64-utf8');
if (encoding === 'ascii' || encoding === 'base64-ascii')
alpha = ASC_ALPHA;
else if (encoding === 'utf8' || encoding === 'base64-utf8')
alpha = UTF8_ALPHA;
else if (encoding === 'utf16le') {
buf = UTF16_BUF;
str = Buffer.alloc(0);
} else
throw new Error('Bad encoding');
const sd = new StringDecoder(isBase64 ? 'base64' : encoding);
for (let i = 0; i < inLen; ++i) {
if (i > 0 && (i % chunkLen) === 0 && !isBase64) {
if (alpha) {
chunks.push(Buffer.from(str, encoding));
str = '';
} else {
chunks.push(str);
str = Buffer.alloc(0);
}
}
if (alpha)
str += alpha[i % alpha.length];
else {
let start = i;
let end = i + 2;
if (i % 2 !== 0) {
++start;
++end;
}
str = Buffer.concat([
str,
buf.slice(start % buf.length, end % buf.length),
]);
}
}
if (!alpha) {
if (str.length > 0)
chunks.push(str);
} else if (str.length > 0 && !isBase64)
chunks.push(Buffer.from(str, encoding));
if (isBase64) {
str = Buffer.from(str, 'utf8').toString('base64');
while (str.length > 0) {
const len = Math.min(chunkLen, str.length);
chunks.push(Buffer.from(str.substring(0, len), 'utf8'));
str = str.substring(len);
}
}
const nChunks = chunks.length;
let avoidDeadCode;
bench.start();
for (let i = 0; i < n; ++i) {
avoidDeadCode = '';
for (let j = 0; j < nChunks; ++j)
avoidDeadCode += sd.write(chunks[j]);
}
bench.end(n);
assert.ok(avoidDeadCode);
}