1 /*
2 Copyright 2015 Esri
3
4 Licensed under the Apache License, Version 2.0 (the "License");
5 you may not use this file except in compliance with the License.
6 You may obtain a copy of the License at
7
8 http://www.apache.org/licenses/LICENSE-2.0
9
10 Unless required by applicable law or agreed to in writing, software
11 distributed under the License is distributed on an "AS IS" BASIS,
12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 See the License for the specific language governing permissions and
14 limitations under the License.
15
16 A local copy of the license and additional notices are located with the
17 source distribution at:
18
19 http://github.com/Esri/lerc/
20
21 Contributors: Thomas Maurer
22 */
23
24 #include "Defines.h"
25 #include "BitMask.h"
26 #include <cstring>
27
28 USING_NAMESPACE_LERC
29
30 // -------------------------------------------------------------------------- ;
31
BitMask(const BitMask & src)32 BitMask::BitMask(const BitMask& src) : m_pBits(nullptr)
33 {
34 SetSize(src.m_nCols, src.m_nRows);
35 if (m_pBits && src.m_pBits)
36 memcpy(m_pBits, src.m_pBits, Size());
37 }
38
39 // -------------------------------------------------------------------------- ;
40
operator =(const BitMask & src)41 BitMask& BitMask::operator= (const BitMask& src)
42 {
43 if (this == &src) return *this;
44
45 SetSize(src.m_nCols, src.m_nRows);
46 if (m_pBits && src.m_pBits)
47 memcpy(m_pBits, src.m_pBits, Size());
48
49 return *this;
50 }
51
52 // -------------------------------------------------------------------------- ;
53
SetAllValid() const54 void BitMask::SetAllValid() const
55 {
56 memset(m_pBits, 255, Size());
57 }
58
SetAllInvalid() const59 void BitMask::SetAllInvalid() const
60 {
61 memset(m_pBits, 0, Size());
62 }
63
64 // -------------------------------------------------------------------------- ;
65
SetSize(int nCols,int nRows)66 bool BitMask::SetSize(int nCols, int nRows)
67 {
68 if (nCols != m_nCols || nRows != m_nRows)
69 {
70 Clear();
71 m_pBits = new Byte[(nCols * nRows + 7) >> 3];
72 m_nCols = nCols;
73 m_nRows = nRows;
74 }
75 return m_pBits != nullptr;
76 }
77
78 // -------------------------------------------------------------------------- ;
79
CountValidBits() const80 int BitMask::CountValidBits() const
81 {
82 const Byte numBitsHB[16] = {0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4};
83 const Byte* ptr = m_pBits;
84 int sum = 0;
85 int i = Size();
86 while (i--)
87 {
88 sum += numBitsHB[*ptr & 15] + numBitsHB[*ptr >> 4];
89 ptr++;
90 }
91
92 // subtract undefined bits potentially contained in the last byte
93 for (int k = m_nCols * m_nRows; k < Size() * 8; k++)
94 if (IsValid(k))
95 sum--;
96
97 return sum;
98 }
99
100 // -------------------------------------------------------------------------- ;
101
Clear()102 void BitMask::Clear()
103 {
104 delete[] m_pBits;
105 m_pBits = nullptr;
106 m_nCols = 0;
107 m_nRows = 0;
108 }
109
110 // -------------------------------------------------------------------------- ;
111
112