/src/gdal/port/cpl_mask.h
Line | Count | Source (jump to first uncovered line) |
1 | | /********************************************************************** |
2 | | * |
3 | | * Name: cpl_mask.h |
4 | | * Project: CPL - Common Portability Library |
5 | | * Purpose: Bitmask manipulation functions |
6 | | * Author: Daniel Baston, dbaston@gmail.com |
7 | | * |
8 | | ********************************************************************** |
9 | | * Copyright (c) 2022, ISciences LLC |
10 | | * |
11 | | * SPDX-License-Identifier: MIT |
12 | | ****************************************************************************/ |
13 | | |
14 | | #ifndef CPL_MASK_H_INCLUDED |
15 | | #define CPL_MASK_H_INCLUDED |
16 | | |
17 | | #include "cpl_port.h" |
18 | | #include "cpl_vsi.h" |
19 | | |
20 | | #ifdef __cplusplus |
21 | | |
22 | | #include <cstring> |
23 | | |
24 | | /** |
25 | | * Allocates a buffer to store a given number of bits |
26 | | * |
27 | | * @param size number of bits |
28 | | * @param default_value initial value of bits |
29 | | */ |
30 | | inline GUInt32 *CPLMaskCreate(std::size_t size, bool default_value) |
31 | 0 | { |
32 | 0 | std::size_t nBytes = (size + 31) / 8; |
33 | 0 | void *buf = VSI_MALLOC_VERBOSE(nBytes); |
34 | 0 | if (buf == nullptr) |
35 | 0 | { |
36 | 0 | return nullptr; |
37 | 0 | } |
38 | 0 | std::memset(buf, default_value ? 0xff : 0, nBytes); |
39 | 0 | return static_cast<GUInt32 *>(buf); |
40 | 0 | } |
41 | | |
42 | | /** |
43 | | * Get the value of a bit |
44 | | * |
45 | | * @param mask bit mask |
46 | | * @param i index of bit |
47 | | * @return `true` if bit is set |
48 | | */ |
49 | | inline bool CPLMaskGet(GUInt32 *mask, std::size_t i) |
50 | 0 | { |
51 | 0 | return mask[i >> 5] & (0x01 << (i & 0x1f)); |
52 | 0 | } |
53 | | |
54 | | /** |
55 | | * Clear the value of a bit (set to false) |
56 | | * |
57 | | * @param mask bit mask |
58 | | * @param i index of bit to clear |
59 | | */ |
60 | | inline void CPLMaskClear(GUInt32 *mask, std::size_t i) |
61 | 0 | { |
62 | 0 | mask[i >> 5] &= ~(0x01 << (i & 0x1f)); |
63 | 0 | } |
64 | | |
65 | | /** |
66 | | * Clear all bits in a mask |
67 | | * |
68 | | * @param mask bit mask |
69 | | * @param size number of bits in mask |
70 | | */ |
71 | | inline void CPLMaskClearAll(GUInt32 *mask, std::size_t size) |
72 | 0 | { |
73 | 0 | auto nBytes = (size + 31) / 8; |
74 | 0 | std::memset(mask, 0, nBytes); |
75 | 0 | } |
76 | | |
77 | | /** |
78 | | * Set the value of a bit to true |
79 | | * |
80 | | * @param mask bit mask |
81 | | * @param i index of bit to set |
82 | | */ |
83 | | inline void CPLMaskSet(GUInt32 *mask, std::size_t i) |
84 | 0 | { |
85 | 0 | mask[i >> 5] |= (0x01 << (i & 0x1f)); |
86 | 0 | } |
87 | | |
88 | | /** |
89 | | * Set all bits in a mask |
90 | | * |
91 | | * @param mask bit mask |
92 | | * @param size number of bits in mask |
93 | | */ |
94 | | inline void CPLMaskSetAll(GUInt32 *mask, std::size_t size) |
95 | 0 | { |
96 | 0 | auto nBytes = (size + 31) / 8; |
97 | 0 | std::memset(mask, 0xff, nBytes); |
98 | 0 | } |
99 | | |
100 | | /** |
101 | | * Set a mask to true wherever a second mask is true |
102 | | * |
103 | | * @param mask1 destination mask |
104 | | * @param mask2 source mask |
105 | | * @param n number of bits in masks (must be same) |
106 | | */ |
107 | | inline void CPLMaskMerge(GUInt32 *mask1, GUInt32 *mask2, std::size_t n) |
108 | 0 | { |
109 | 0 | std::size_t nBytes = (n + 31) / 8; |
110 | 0 | std::size_t nIter = nBytes / 4; |
111 | 0 | for (std::size_t i = 0; i < nIter; i++) |
112 | 0 | { |
113 | 0 | mask1[i] |= mask2[i]; |
114 | 0 | } |
115 | 0 | } |
116 | | |
117 | | #endif // __cplusplus |
118 | | |
119 | | #endif // CPL_MASK_H |