| Geant4 Cross Reference |
1 //
2 // ********************************************************************
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4 // * *
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24 // ********************************************************************
25 //
26 // G4SurfBits
27 //
28 // Class description:
29 //
30 // This class provides a simple container of bits, to be used for
31 // optimization of tessellated surfaces (G4TessellatedSolid).
32 // Each bit can be set and tested via the functions SetBitNumber and
33 // TestBitNumber.
34 // The default value of all bits is false.
35 // The size of the container is automatically extended when a bit
36 // number is either set or tested. To reduce the memory size of the
37 // container use the Compact function, this will discard the memory
38 // occupied by the upper bits that are 0.
39
40 // 19.10.12 - Marek Gayer, created and adapted from original implementation
41 // of Root's TBits class by P.Canal
42 // --------------------------------------------------------------------
43 #ifndef G4SURFBITS_HH
44 #define G4SURFBITS_HH
45
46 #include <cstring>
47
48 #include "G4Types.hh"
49
50 class G4SurfBits
51 {
52 public:
53
54 G4SurfBits(unsigned int nbits = 0);
55 G4SurfBits(const G4SurfBits&);
56 G4SurfBits& operator=(const G4SurfBits&);
57 ~G4SurfBits();
58
59 //----- Bit manipulation
60 void ResetAllBits(G4bool value = false); // if value=1 set all bits to 1
61 void ResetBitNumber(unsigned int bitnumber);
62 void SetBitNumber(unsigned int bitnumber, G4bool value = true);
63 G4bool TestBitNumber(unsigned int bitnumber) const;
64
65 //----- Accessors and operator
66 G4bool operator[](unsigned int bitnumber) const;
67
68 //----- Optimized setters
69 // Each of these will replace the contents of the receiver with the
70 // bitvector in the parameter array. The number of bits is changed
71 // to nbits. If nbits is smaller than fNBits, the receiver will NOT
72 // be compacted.
73 void set(unsigned int nbits, const char* array);
74 void set(unsigned int nbits, const G4int* array);
75
76 //----- Optimized getters
77 // Each of these will replace the contents of the parameter array with the
78 // bits in the receiver. The parameter array must be large enough to hold
79 // all of the bits in the receiver.
80 // Note on semantics: any bits in the parameter array that go beyond the
81 // number of the bits in the receiver will have an unspecified value. For
82 // example, if you call Get(Int*) with an array of one integer and the
83 // G4SurfBits object has less than 32 bits, then the remaining bits in the
84 // integer will have an unspecified value.
85 void Get(char* array) const;
86 void Get(G4int* array) const;
87
88 //----- Utilities
89 void Clear();
90 void Compact(); // Reduce the space used.
91
92 unsigned int GetNbits() const { return fNBits; }
93 unsigned int GetNbytes() const { return fNBytes; }
94
95 void Print() const; // to show the list of active bits
96 void Output(std::ostream &) const;
97
98 protected:
99
100 void ReserveBytes(unsigned int nbytes);
101
102 public:
103
104 unsigned char* fAllBits = nullptr; // [fNBytes] array of UChars
105
106 protected:
107
108 unsigned int fNBits; // Highest bit set + 1
109 unsigned int fNBytes; // Number of UChars in fAllBits
110 };
111
112 // inline functions...
113
114 inline void G4SurfBits::SetBitNumber(unsigned int bitnumber, G4bool value)
115 {
116 // set bit number 'bitnumber' to be value
117
118 if (bitnumber >= fNBits)
119 {
120 unsigned int new_size = (bitnumber/8) + 1;
121 if (new_size > fNBytes)
122 {
123 if (new_size < 100 * 1024 * 1024) new_size *= 2;
124 unsigned char *old_location = fAllBits;
125 fAllBits = new unsigned char[new_size];
126 std::memcpy(fAllBits,old_location,fNBytes);
127 std::memset(fAllBits+fNBytes ,0, new_size-fNBytes);
128 fNBytes = new_size;
129 delete [] old_location;
130 }
131 fNBits = bitnumber+1;
132 }
133 unsigned int loc = bitnumber/8;
134 unsigned char bit = bitnumber%8;
135 if (value)
136 fAllBits[loc] |= (1<<bit);
137 else
138 fAllBits[loc] &= (0xFF ^ (1<<bit));
139 }
140
141 inline G4bool G4SurfBits::TestBitNumber(unsigned int bitnumber) const
142 {
143 // Return the current value of the bit
144
145 if (bitnumber >= fNBits) return false;
146 unsigned int loc = bitnumber/8;
147 unsigned char value = fAllBits[loc];
148 unsigned char bit = bitnumber%8;
149 G4bool result = (value & (1<<bit)) != 0;
150 return result;
151 // short: return 0 != (fAllBits[bitnumber/8] & (1<< (bitnumber%8)));
152 }
153
154 inline void G4SurfBits::ResetBitNumber(unsigned int bitnumber)
155 {
156 SetBitNumber(bitnumber,false);
157 }
158
159 inline G4bool G4SurfBits::operator[](unsigned int bitnumber) const
160 {
161 return TestBitNumber(bitnumber);
162 }
163
164 #endif
165