include/Geant4/G4SurfBits.hh

0001 //
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0025 //
0026 // G4SurfBits
0027 //
0028 // Class description:
0029 //
0030 // This class provides a simple container of bits, to be used for
0031 // optimization of tessellated surfaces (G4TessellatedSolid).
0032 // Each bit can be set and tested via the functions SetBitNumber and
0033 // TestBitNumber.
0034 // The default value of all bits is false.
0035 // The size of the container is automatically extended when a bit
0036 // number is either set or tested.  To reduce the memory size of the
0037 // container use the Compact function, this will discard the memory
0038 // occupied by the upper bits that are 0.
0039
0040 // Author: Marek Gayer (CERN), 19.10.2012 - Created and adapted from original
0041 //                                          implementation of Root/TBits class.
0042 // --------------------------------------------------------------------
0043 #ifndef G4SURFBITS_HH
0044 #define G4SURFBITS_HH
0045
0046 #include <cstring>
0047
0048 #include "G4Types.hh"
0049
0050 /**
0051  * @brief G4SurfBits provides a simple container of bits, to be used for
0052  * optimization of tessellated surfaces. The size of the container is
0053  * automatically extended when a bit number is either set or tested.
0054  */
0055
0056 class G4SurfBits
0057 {
0058   public:
0059
0060     /**
0061      * Constructor given the number of bits.
0062      *  @param[in] nbits The number of bits.
0063      */
0064     G4SurfBits(unsigned int nbits = 0);
0065
0066     /**
0067      * Destructor. Clears all allocated bits.
0068      */
0069    ~G4SurfBits();
0070
0071     /**
0072      * Copy constructor and assignment operator.
0073      */
0074     G4SurfBits(const G4SurfBits&);
0075     G4SurfBits& operator=(const G4SurfBits&);
0076
0077     /**
0078      * Methods for bit manipulation.
0079      */
0080     void ResetAllBits(G4bool value = false);  // if value=1 set all bits to 1
0081     inline void ResetBitNumber(unsigned int bitnumber);
0082     inline void SetBitNumber(unsigned int bitnumber, G4bool value = true);
0083     inline G4bool TestBitNumber(unsigned int bitnumber) const;
0084
0085     /**
0086      * Accessor operator.
0087      */
0088     inline G4bool operator[](unsigned int bitnumber) const;
0089
0090     /**
0091      * Optimized setters. Each of these will replace the contents of the
0092      * receiver with the bitvector in the parameter array. The number of bits
0093      * is changed to 'nbits'. If nbits is smaller than fNBits, the receiver
0094      * will NOT be compacted.
0095      */
0096     void set(unsigned int nbits, const char* array);
0097     void set(unsigned int nbits, const G4int* array);
0098
0099     /**
0100      * Optimized getters. Each of these will replace the contents of the
0101      * parameter array with the bits in the receiver. The parameter array must
0102      * be large enough to hold all of the bits in the receiver.
0103      * Note on semantics: any bits in the parameter array that go beyond the
0104      * number of the bits in the receiver will have an unspecified value. For
0105      * example, if calling Get(Int*) with an array of one integer and the
0106      * G4SurfBits object has less than 32 bits, then the remaining bits in the
0107      * integer will have an unspecified value.
0108      */
0109     void Get(char* array) const;
0110     void Get(G4int* array) const;
0111
0112     /**
0113      * Utilities to clear or reduce the space used.
0114      */
0115     void Clear();
0116     void Compact();               // Reduce the space used.
0117
0118     /**
0119      * Accessors.
0120      */
0121     inline unsigned int GetNbits() const { return fNBits; }
0122     inline unsigned int GetNbytes() const { return fNBytes; }
0123
0124     /**
0125      * Logging functions.
0126      */
0127     void Print() const;  // to show the list of active bits
0128     void Output(std::ostream &) const;
0129
0130   public:
0131
0132     unsigned char* fAllBits = nullptr; // [fNBytes] array of UChars
0133
0134   private:
0135
0136     void ReserveBytes(unsigned int nbytes);
0137
0138   private:
0139
0140     unsigned int fNBits;         // Highest bit set + 1
0141     unsigned int fNBytes;        // Number of UChars in fAllBits
0142 };
0143
0144 // inline functions...
0145
0146 #include "G4SurfBits.icc"
0147
0148 #endif