85 lines
2.1 KiB
JavaScript
85 lines
2.1 KiB
JavaScript
function getEncoding(buf) {
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const lowerCase = 3;
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const upperCase = 1;
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const codePage = {
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'k': 'koi8-r',
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'w': 'Windows-1251',
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'd': 'cp866',
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'i': 'ISO-8859-5',
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'm': 'maccyrillic',
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};
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let charsets = {
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'k': 0,
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'w': 0,
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'd': 0,
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'i': 0,
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'm': 0
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};
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const len = buf.length;
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const blockSize = (len > 5*3000 ? 3000 : len);
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let counter = 0;
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let i = 0;
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while (i < len) {
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const char = buf[i];
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i++;
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//non-russian characters
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if (char < 128 || char > 256)
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continue;
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//CP866
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if ((char > 159 && char < 176) || (char > 223 && char < 242)) charsets['d'] += lowerCase;
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if ((char > 127 && char < 160)) charsets['d'] += upperCase;
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//KOI8-R
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if ((char > 191 && char < 223)) charsets['k'] += lowerCase;
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if ((char > 222 && char < 256)) charsets['k'] += upperCase;
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//WIN-1251
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if (char > 223 && char < 256) charsets['w'] += lowerCase;
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if (char > 191 && char < 224) charsets['w'] += upperCase;
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//MAC
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if (char > 221 && char < 255) charsets['m'] += lowerCase;
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if (char > 127 && char < 160) charsets['m'] += upperCase;
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//ISO-8859-5
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if (char > 207 && char < 240) charsets['i'] += lowerCase;
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if (char > 175 && char < 208) charsets['i'] += upperCase;
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counter++;
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if (counter > blockSize) {
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counter = 0;
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i += Math.round(len/2 - 2*blockSize);
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}
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}
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let sorted = Object.keys(charsets).map(function(key) {
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return { codePage: codePage[key], c: charsets[key] };
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});
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sorted.sort((a, b) => b.c - a.c);
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if (sorted[0].c > 0)
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return sorted[0].codePage;
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else
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return 'ISO-8859-5';
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}
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function checkIfText(buf) {
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let spaceCount = 0;
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for (let i = 0; i < buf.length; i++) {
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if (buf[i] == 32)
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spaceCount++;
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}
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const freq = spaceCount/(buf.length + 1);
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return (freq > 0.1);
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}
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module.exports = {
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getEncoding,
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checkIfText,
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} |