63 lines
1.6 KiB
JavaScript
63 lines
1.6 KiB
JavaScript
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var iconv,
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inherits = require('util').inherits,
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stream = require('stream');
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var regex = /(?:charset|encoding)\s*=\s*['"]? *([\w\-]+)/i;
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inherits(StreamDecoder, stream.Transform);
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function StreamDecoder(charset) {
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if (!(this instanceof StreamDecoder))
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return new StreamDecoder(charset);
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stream.Transform.call(this, charset);
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this.charset = charset;
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this.parsed_chunk = false;
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}
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StreamDecoder.prototype._transform = function(chunk, encoding, done) {
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// try to get charset from chunk, but just once
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if (!this.parsed_chunk && (this.charset == 'utf-8' || this.charset == 'utf8')) {
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this.parsed_chunk = true;
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var matches = regex.exec(chunk.toString());
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if (matches) {
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var found = matches[1].toLowerCase().replace('utf8', 'utf-8'); // canonicalize;
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// set charset, but only if iconv can handle it
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if (iconv.encodingExists(found)) this.charset = found;
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}
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}
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// if charset is already utf-8 or given encoding isn't supported, just pass through
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if (this.charset == 'utf-8' || !iconv.encodingExists(this.charset)) {
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this.push(chunk);
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return done();
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}
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// initialize stream decoder if not present
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var self = this;
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if (!this.decoder) {
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this.decoder = iconv.decodeStream(this.charset);
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this.decoder.on('data', function(decoded_chunk) {
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self.push(decoded_chunk);
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});
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};
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this.decoder.write(chunk);
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done();
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}
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module.exports = function(charset) {
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try {
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if (!iconv) iconv = require('iconv-lite');
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} catch(e) {
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/* iconv not found */
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}
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if (iconv)
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return new StreamDecoder(charset);
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else
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return new stream.PassThrough;
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}
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