优化

schangxiang@126.com

2025-09-19 0821aa23eabe557c0d9ef5dbe6989c68be35d1fe

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'use strict';
 
module.exports = SliceStream;
 
var Transform = require('readable-stream/transform');
var inherits = require("util").inherits;
 
inherits(SliceStream, Transform);
 
function SliceStream(opts, sliceFn) {
  if (!(this instanceof SliceStream)) {
    return new SliceStream(opts, sliceFn);
  }
 
  this._opts = opts;
  this._accumulatedLength = 0;
  this.sliceFn = sliceFn;
 
  Transform.call(this);
}
 
SliceStream.prototype._transform = function (chunk, encoding, callback) {
  this._accumulatedLength += chunk.length;
 
  if (this._accumulatedLength >= this._opts.length) {
    //todo handle more than one slice in a stream
    var offset = chunk.length - (this._accumulatedLength - this._opts.length);
    this.sliceFn(chunk.slice(0, offset), true, chunk.slice(offset));
    callback();
  } else {
    this.sliceFn(chunk);
    callback();
  }
};