118 lines
2.5 KiB
JavaScript
118 lines
2.5 KiB
JavaScript
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var fs = require('fs');
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var utf8 = require('./encoding/utf8'),
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unicode = require('./encoding/unicode'),
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mbcs = require('./encoding/mbcs'),
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sbcs = require('./encoding/sbcs'),
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iso2022 = require('./encoding/iso2022');
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var self = this;
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var recognisers = [
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new utf8,
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new unicode.UTF_16BE,
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new unicode.UTF_16LE,
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new unicode.UTF_32BE,
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new unicode.UTF_32LE,
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new mbcs.sjis,
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new mbcs.big5,
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new mbcs.euc_jp,
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new mbcs.euc_kr,
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new mbcs.gb_18030,
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new iso2022.ISO_2022_JP,
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new iso2022.ISO_2022_KR,
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new iso2022.ISO_2022_CN,
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new sbcs.ISO_8859_1,
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new sbcs.ISO_8859_2,
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new sbcs.ISO_8859_5,
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new sbcs.ISO_8859_6,
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new sbcs.ISO_8859_7,
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new sbcs.ISO_8859_8,
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new sbcs.ISO_8859_9,
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new sbcs.windows_1251,
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new sbcs.windows_1256,
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new sbcs.KOI8_R
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];
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module.exports.detect = function(buffer) {
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// Tally up the byte occurence statistics.
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var fByteStats = [];
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for (var i = 0; i < 256; i++)
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fByteStats[i] = 0;
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for (var i = buffer.length - 1; i >= 0; i--)
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fByteStats[buffer[i] & 0x00ff]++;
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var fC1Bytes = false;
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for (var i = 0x80; i <= 0x9F; i += 1) {
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if (fByteStats[i] != 0) {
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fC1Bytes = true;
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break;
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}
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}
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var context = {
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fByteStats: fByteStats,
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fC1Bytes: fC1Bytes,
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fRawInput: buffer,
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fRawLength: buffer.length,
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fInputBytes: buffer,
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fInputLen: buffer.length
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};
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var match = recognisers.map(function(rec) {
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return rec.match(context);
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}).filter(function(match) {
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return !!match;
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}).sort(function(a, b) {
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return a.confidence - b.confidence;
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}).pop();
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return match ? match.name : null;
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};
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module.exports.detectFile = function(filepath, opts, cb) {
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if (typeof opts === 'function') {
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cb = opts;
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opts = undefined;
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}
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var fd;
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var handler = function(err, buffer) {
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if (fd) {
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fs.closeSync(fd);
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}
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if (err) return cb(err, null);
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cb(null, self.detect(buffer));
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};
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if (opts && opts.sampleSize) {
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fd = fs.openSync(filepath, 'r'),
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sample = new Buffer(opts.sampleSize);
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fs.read(fd, sample, 0, opts.sampleSize, null, function(err) {
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handler(err, sample);
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});
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return;
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}
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fs.readFile(filepath, handler);
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};
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module.exports.detectFileSync = function(filepath, opts) {
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if (opts && opts.sampleSize) {
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var fd = fs.openSync(filepath, 'r'),
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sample = new Buffer(opts.sampleSize);
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fs.readSync(fd, sample, 0, opts.sampleSize);
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fs.closeSync(fd);
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return self.detect(sample);
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}
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return self.detect(fs.readFileSync(filepath));
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};
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