1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Character Map Class
//
// A fast, bit-vector map for 8-bit unsigned characters.
// This class is useful for non-character purposes as well.
#ifndef ABSL_STRINGS_INTERNAL_CHAR_MAP_H_
#define ABSL_STRINGS_INTERNAL_CHAR_MAP_H_
#include <cstddef>
#include <cstdint>
#include <cstring>
#include "absl/base/macros.h"
#include "absl/base/port.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace strings_internal {
class Charmap {
public:
constexpr Charmap() : m_() {}
// Initializes with a given char*. Note that NUL is not treated as
// a terminator, but rather a char to be flicked.
Charmap(const char* str, int len) : m_() {
while (len--) SetChar(*str++);
}
// Initializes with a given char*. NUL is treated as a terminator
// and will not be in the charmap.
explicit Charmap(const char* str) : m_() {
while (*str) SetChar(*str++);
}
constexpr bool contains(unsigned char c) const {
return (m_[c / 64] >> (c % 64)) & 0x1;
}
// Returns true if and only if a character exists in both maps.
bool IntersectsWith(const Charmap& c) const {
for (size_t i = 0; i < ABSL_ARRAYSIZE(m_); ++i) {
if ((m_[i] & c.m_[i]) != 0) return true;
}
return false;
}
bool IsZero() const {
for (uint64_t c : m_) {
if (c != 0) return false;
}
return true;
}
// Containing only a single specified char.
static constexpr Charmap Char(char x) {
return Charmap(CharMaskForWord(x, 0), CharMaskForWord(x, 1),
CharMaskForWord(x, 2), CharMaskForWord(x, 3));
}
// Containing all the chars in the C-std::string 's'.
// Note that this is expensively recursive because of the C++11 constexpr
// formulation. Use only in constexpr initializers.
static constexpr Charmap FromString(const char* s) {
return *s == 0 ? Charmap() : (Char(*s) | FromString(s + 1));
}
// Containing all the chars in the closed interval [lo,hi].
static constexpr Charmap Range(char lo, char hi) {
return Charmap(RangeForWord(lo, hi, 0), RangeForWord(lo, hi, 1),
RangeForWord(lo, hi, 2), RangeForWord(lo, hi, 3));
}
friend constexpr Charmap operator&(const Charmap& a, const Charmap& b) {
return Charmap(a.m_[0] & b.m_[0], a.m_[1] & b.m_[1], a.m_[2] & b.m_[2],
a.m_[3] & b.m_[3]);
}
friend constexpr Charmap operator|(const Charmap& a, const Charmap& b) {
return Charmap(a.m_[0] | b.m_[0], a.m_[1] | b.m_[1], a.m_[2] | b.m_[2],
a.m_[3] | b.m_[3]);
}
friend constexpr Charmap operator~(const Charmap& a) {
return Charmap(~a.m_[0], ~a.m_[1], ~a.m_[2], ~a.m_[3]);
}
private:
constexpr Charmap(uint64_t b0, uint64_t b1, uint64_t b2, uint64_t b3)
: m_{b0, b1, b2, b3} {}
static constexpr uint64_t RangeForWord(unsigned char lo, unsigned char hi,
uint64_t word) {
return OpenRangeFromZeroForWord(hi + 1, word) &
~OpenRangeFromZeroForWord(lo, word);
}
// All the chars in the specified word of the range [0, upper).
static constexpr uint64_t OpenRangeFromZeroForWord(uint64_t upper,
uint64_t word) {
return (upper <= 64 * word)
? 0
: (upper >= 64 * (word + 1))
? ~static_cast<uint64_t>(0)
: (~static_cast<uint64_t>(0) >> (64 - upper % 64));
}
static constexpr uint64_t CharMaskForWord(unsigned char x, uint64_t word) {
return (x / 64 == word) ? (static_cast<uint64_t>(1) << (x % 64)) : 0;
}
private:
void SetChar(unsigned char c) {
m_[c / 64] |= static_cast<uint64_t>(1) << (c % 64);
}
uint64_t m_[4];
};
// Mirror the char-classifying predicates in <cctype>
constexpr Charmap UpperCharmap() { return Charmap::Range('A', 'Z'); }
constexpr Charmap LowerCharmap() { return Charmap::Range('a', 'z'); }
constexpr Charmap DigitCharmap() { return Charmap::Range('0', '9'); }
constexpr Charmap AlphaCharmap() { return LowerCharmap() | UpperCharmap(); }
constexpr Charmap AlnumCharmap() { return DigitCharmap() | AlphaCharmap(); }
constexpr Charmap XDigitCharmap() {
return DigitCharmap() | Charmap::Range('A', 'F') | Charmap::Range('a', 'f');
}
constexpr Charmap PrintCharmap() { return Charmap::Range(0x20, 0x7e); }
constexpr Charmap SpaceCharmap() { return Charmap::FromString("\t\n\v\f\r "); }
constexpr Charmap CntrlCharmap() {
return Charmap::Range(0, 0x7f) & ~PrintCharmap();
}
constexpr Charmap BlankCharmap() { return Charmap::FromString("\t "); }
constexpr Charmap GraphCharmap() { return PrintCharmap() & ~SpaceCharmap(); }
constexpr Charmap PunctCharmap() { return GraphCharmap() & ~AlnumCharmap(); }
} // namespace strings_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_CHAR_MAP_H_
|
