ComPackSignedExpFloat.cxx

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//--------------------------------------------------------------------------
// File and Version Information:
//      $Id: ComPackSignedExpFloat.cxx,v 1.2 2009/12/23 02:59:56 zhangy Exp $
//
// Description:
//      class ComPackExpFloat
//
// Environment:
//      Software developed for the BaBar Detector at the SLAC B-Factory.
//
// Author List:
//      Dave Brown               10/12/00
//
// Copyright Information:
//      Copyright (C) 2000 LBNL
//
// History:
//  Migration for BESIII MDC
//
//
//--------------------------------------------------------------------------
 
// #include "BaBar/BaBar.hh"
#include "MdcRecoUtil/ComPackSignedExpFloat.h"
#include <assert.h>
#include <math.h>
using std::endl;
using std::ostream;
 
ComPackSignedExpFloat::ComPackSignedExpFloat( unsigned nbits, unsigned maxexponent,
                                              double maxval, bool invert, bool center )
    : ComPackBase<double>( -maxval, maxval, nbits )
    , _packer( nbits - 1, maxexponent, invert ? maxval : 0.0, invert ? 0.0 : maxval, center )
    , _signbit( 1 << nbits - 1 )
    , _signmask( ~( 1 << nbits - 1 ) ) {
  assert( maxval > 0.0 );
}
 
ComPackSignedExpFloat::~ComPackSignedExpFloat() { ; }
 
ComPackBase<double>::StatusCode ComPackSignedExpFloat::pack( const double value,
                                                             d_ULong&     packdata ) const {
  // first, pack the absolute value
  ComPackBase<double>::StatusCode retval = _packer.pack( fabs( value ), packdata );
  if ( retval != TAG_BAD )
  {
    if ( value > 0 ) packdata &= _signmask;
    else packdata |= _signbit;
  }
  return retval;
}
 
ComPackBase<double>::StatusCode ComPackSignedExpFloat::unpack( const d_ULong packdata,
                                                               double&       value ) const {
  ComPackBase<double>::StatusCode retval = _packer.unpack( packdata, value );
  if ( value < 0 ) value = 0;
  else if ( packdata & _signbit ) value *= -1.0;
  return retval;
}
 
void ComPackSignedExpFloat::print( ostream& os ) const {
  os << "Signed exponential packer using exponential packer as follows:" << endl;
  _packer.print( os );
}