Compressor.h

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
 
/*
 *  Compressor.h
 *  Compressor
 *
 *  Created by Ilija Vukotic on 05/07/07.
 *  <ivukotic@cern.ch>
 *
 */
 
 
#ifndef CXXUTILS_COMPRESSOR_H
#define CXXUTILS_COMPRESSOR_H
 
// TO DO :
// add double to int compressor
// enable 32 bit "compression"
// should be smart enough to call compression to short when 16 bits required. or maybe people should be aware that 16 bits is faster than 17?
 
#include <vector>
#include <iostream>
 
class Compressor{
 
public:
    Compressor(){
        m_sign=false;
        m_bits=16;
                m_bitStrip = false;
    }
    ~Compressor() = default;
    
    void setNrBits(int bits){
        m_bits=bits;
        m_bitStrip=true; // will be used to disable compression (already programmed for compressor but not decompressor.)
        if (bits<12){
            std::cout<<"WARNING -> Too large compression requested. Will leave 12 bits instead!"<<std::endl;
            m_bits=12;
        }
        else if(bits>=32 || bits==0){
            std::cout<<"WARNING -> Compression to "<<bits<<" bits is not possible. Compressing to 31 bits !"<<std::endl;
            m_bits=31;
        }
    }
    
    void setIgnoreSign(){m_sign=true;}
 
    // standard compression 32 to 16 bits - precision is better than 0.4%
    void reduceToUS(const std::vector<float> &vf, std::vector<unsigned short> &vi);
    
    // standard uncompression from 16 bits to 32
    void expandFromUStoFloat(const std::vector<unsigned short> &vi, std::vector<float>&vf);
    
    //------------
    
    // compression with variable sign, range and precision
    void reduce(const std::vector<float> & vf, std::vector<unsigned int> &vi);
    
    // uncompression with variable sign,range and precision
    void  expandToFloat(const std::vector<unsigned int> & vc, std::vector<float> & vf);
    
private:
    int  m_bits;
    bool m_sign;
    bool m_bitStrip;
};
 
#endif // not CXXUTILS_COMPRESSOR_H