#ifndef __ZLibStats_h_
#define __ZLibStats_h_

#include "ThreadMonitor.h"


/////////////////////////////////////////////////////////////////////
// ZLibStats
//
// Keep track of our compression results in the log file via
// ThreadMonitor.
//
// This records how many bytes have gone through and what the
// compression rate is.
/////////////////////////////////////////////////////////////////////

class ZLibStats : private ThreadMonitor::Extra
{
private:
  static ZLibStats *instance()
  {
    static __thread ZLibStats *_instance = new ZLibStats();
    return _instance;
  }
  int64_t _beforeCompression;
  int64_t _afterCompression;
  int64_t _beforeDecompression;
  int64_t _afterDecompression;

  ZLibStats() : _beforeCompression(0),
		_afterCompression(0), 
		_beforeDecompression(0), 
		_afterDecompression(0) 
  { ThreadMonitor::find().add(this); }

  // ThreadMonitor::Extra
  virtual std::string getInfoForThreadMonitor()
  {
    TclList result;
    if (_beforeCompression || _afterCompression)
    {
      result<<"zlib compression"<<_beforeCompression<<_afterCompression;
      if (_afterCompression == 0)
	// Something compressed to nothing.  That's possible if we don't
	// call flush right before doing these statistics.  It's possible that
	// some bytes are hiding in a zlib buffer somewhere.
	result<<"100%";
      else
	// 0% means no change.  99% means 99% disappeared and 1% is left.
	// -1% means the result is 1% *larger* than the input.  This is
	// consistent with the way that zip and gzip normally display the
	// same statistics.
	result<<(dtoa((_beforeCompression - _afterCompression) * 100.0 
		      / _beforeCompression, 4) + '%');
    }
    if (_beforeDecompression || _afterDecompression)
    { // Use the same output format for compression and decompression.  A
      // larger percent means better compression.  If one program is
      // compressing data, and another program is decompressing the same data,
      // they should both display the same number.
      result<<"zlib decompression"<<_afterDecompression<<_beforeDecompression;
      if (_beforeDecompression == 0)
	result<<"100%";
      else
	result<<(dtoa((_afterDecompression - _beforeDecompression) * 100.0
                      / _afterDecompression, 4) + '%');
    }
    _beforeCompression = 0;
    _afterCompression = 0;
    _beforeDecompression = 0;
    _afterDecompression = 0;
    return result;
  }

public:

  // Each time you call deflate(), call this function with the size of the
  // input in bytes.
  static void beforeCompression(int64_t bytes)
  { instance()->_beforeCompression += bytes; }

  // Each time you call deflate(), call this function with the size of the
  // output in bytes.
  static void afterCompression(int64_t bytes)
  { instance()->_afterCompression += bytes; }

  // Each time you call inflate(), call this function with the size of the
  // input in bytes.
  static void beforeDecompression(int64_t bytes)
  { instance()->_beforeDecompression += bytes; }

  // Each time you call inflate(), call this function with the size of the
  // output in bytes.
  static void afterDecompression(int64_t bytes)
  { instance()->_afterDecompression += bytes; }
  
};


#endif