twitst4tz

twitter statistics web application
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streams.js (3387B)

      1 "use strict";
      2 
      3 var Buffer = require("buffer").Buffer,
      4     Transform = require("stream").Transform;
      5 
      6 
      7 // == Exports ==================================================================
      8 module.exports = function(iconv) {
      9     
     10     // Additional Public API.
     11     iconv.encodeStream = function encodeStream(encoding, options) {
     12         return new IconvLiteEncoderStream(iconv.getEncoder(encoding, options), options);
     13     }
     14 
     15     iconv.decodeStream = function decodeStream(encoding, options) {
     16         return new IconvLiteDecoderStream(iconv.getDecoder(encoding, options), options);
     17     }
     18 
     19     iconv.supportsStreams = true;
     20 
     21 
     22     // Not published yet.
     23     iconv.IconvLiteEncoderStream = IconvLiteEncoderStream;
     24     iconv.IconvLiteDecoderStream = IconvLiteDecoderStream;
     25     iconv._collect = IconvLiteDecoderStream.prototype.collect;
     26 };
     27 
     28 
     29 // == Encoder stream =======================================================
     30 function IconvLiteEncoderStream(conv, options) {
     31     this.conv = conv;
     32     options = options || {};
     33     options.decodeStrings = false; // We accept only strings, so we don't need to decode them.
     34     Transform.call(this, options);
     35 }
     36 
     37 IconvLiteEncoderStream.prototype = Object.create(Transform.prototype, {
     38     constructor: { value: IconvLiteEncoderStream }
     39 });
     40 
     41 IconvLiteEncoderStream.prototype._transform = function(chunk, encoding, done) {
     42     if (typeof chunk != 'string')
     43         return done(new Error("Iconv encoding stream needs strings as its input."));
     44     try {
     45         var res = this.conv.write(chunk);
     46         if (res && res.length) this.push(res);
     47         done();
     48     }
     49     catch (e) {
     50         done(e);
     51     }
     52 }
     53 
     54 IconvLiteEncoderStream.prototype._flush = function(done) {
     55     try {
     56         var res = this.conv.end();
     57         if (res && res.length) this.push(res);
     58         done();
     59     }
     60     catch (e) {
     61         done(e);
     62     }
     63 }
     64 
     65 IconvLiteEncoderStream.prototype.collect = function(cb) {
     66     var chunks = [];
     67     this.on('error', cb);
     68     this.on('data', function(chunk) { chunks.push(chunk); });
     69     this.on('end', function() {
     70         cb(null, Buffer.concat(chunks));
     71     });
     72     return this;
     73 }
     74 
     75 
     76 // == Decoder stream =======================================================
     77 function IconvLiteDecoderStream(conv, options) {
     78     this.conv = conv;
     79     options = options || {};
     80     options.encoding = this.encoding = 'utf8'; // We output strings.
     81     Transform.call(this, options);
     82 }
     83 
     84 IconvLiteDecoderStream.prototype = Object.create(Transform.prototype, {
     85     constructor: { value: IconvLiteDecoderStream }
     86 });
     87 
     88 IconvLiteDecoderStream.prototype._transform = function(chunk, encoding, done) {
     89     if (!Buffer.isBuffer(chunk))
     90         return done(new Error("Iconv decoding stream needs buffers as its input."));
     91     try {
     92         var res = this.conv.write(chunk);
     93         if (res && res.length) this.push(res, this.encoding);
     94         done();
     95     }
     96     catch (e) {
     97         done(e);
     98     }
     99 }
    100 
    101 IconvLiteDecoderStream.prototype._flush = function(done) {
    102     try {
    103         var res = this.conv.end();
    104         if (res && res.length) this.push(res, this.encoding);                
    105         done();
    106     }
    107     catch (e) {
    108         done(e);
    109     }
    110 }
    111 
    112 IconvLiteDecoderStream.prototype.collect = function(cb) {
    113     var res = '';
    114     this.on('error', cb);
    115     this.on('data', function(chunk) { res += chunk; });
    116     this.on('end', function() {
    117         cb(null, res);
    118     });
    119     return this;
    120 }
    121