51 lines
1.3 KiB
JavaScript
51 lines
1.3 KiB
JavaScript
'use strict';
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const Iconv = require('iconv-lite');
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const { createLRU } = require('lru.min');
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const decoderCache = createLRU({
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max: 500,
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});
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exports.decode = function (buffer, encoding, start, end, options) {
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if (Buffer.isEncoding(encoding)) {
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return buffer.toString(encoding, start, end);
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}
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// Optimize for common case: encoding="short_string", options=undefined.
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let decoder;
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if (!options) {
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decoder = decoderCache.get(encoding);
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if (!decoder) {
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decoder = Iconv.getDecoder(encoding);
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decoderCache.set(encoding, decoder);
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}
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} else {
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const decoderArgs = { encoding, options };
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const decoderKey = JSON.stringify(decoderArgs);
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decoder = decoderCache.get(decoderKey);
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if (!decoder) {
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decoder = Iconv.getDecoder(decoderArgs.encoding, decoderArgs.options);
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decoderCache.set(decoderKey, decoder);
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}
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}
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const res = decoder.write(buffer.slice(start, end));
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const trail = decoder.end();
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return trail ? res + trail : res;
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};
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exports.encode = function (string, encoding, options) {
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if (Buffer.isEncoding(encoding)) {
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return Buffer.from(string, encoding);
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}
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const encoder = Iconv.getEncoder(encoding, options || {});
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const res = encoder.write(string);
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const trail = encoder.end();
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return trail && trail.length > 0 ? Buffer.concat([res, trail]) : res;
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};
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