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
|
// 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.
#include "absl/strings/str_split.h"
#include <algorithm>
#include <cstddef>
#include <cstdlib>
#include <cstring>
#include "absl/base/config.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/strings/string_view.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace {
// This GenericFind() template function encapsulates the finding algorithm
// shared between the ByString and ByAnyChar delimiters. The FindPolicy
// template parameter allows each delimiter to customize the actual find
// function to use and the length of the found delimiter. For example, the
// Literal delimiter will ultimately use absl::string_view::find(), and the
// AnyOf delimiter will use absl::string_view::find_first_of().
template <typename FindPolicy>
absl::string_view GenericFind(absl::string_view text,
absl::string_view delimiter, size_t pos,
FindPolicy find_policy) {
if (delimiter.empty() && text.length() > 0) {
// Special case for empty string delimiters: always return a zero-length
// absl::string_view referring to the item at position 1 past pos.
return absl::string_view(text.data() + pos + 1, 0);
}
size_t found_pos = absl::string_view::npos;
absl::string_view found(text.data() + text.size(),
0); // By default, not found
found_pos = find_policy.Find(text, delimiter, pos);
if (found_pos != absl::string_view::npos) {
found = absl::string_view(text.data() + found_pos,
find_policy.Length(delimiter));
}
return found;
}
// Finds using absl::string_view::find(), therefore the length of the found
// delimiter is delimiter.length().
struct LiteralPolicy {
static size_t Find(absl::string_view text, absl::string_view delimiter,
size_t pos) {
return text.find(delimiter, pos);
}
static size_t Length(absl::string_view delimiter) {
return delimiter.length();
}
};
// Finds using absl::string_view::find_first_of(), therefore the length of the
// found delimiter is 1.
struct AnyOfPolicy {
static size_t Find(absl::string_view text, absl::string_view delimiter,
size_t pos) {
return text.find_first_of(delimiter, pos);
}
static size_t Length(absl::string_view /* delimiter */) { return 1; }
};
} // namespace
//
// ByString
//
ByString::ByString(absl::string_view sp) : delimiter_(sp) {}
absl::string_view ByString::Find(absl::string_view text, size_t pos) const {
if (delimiter_.length() == 1) {
// Much faster to call find on a single character than on an
// absl::string_view.
size_t found_pos = text.find(delimiter_[0], pos);
if (found_pos == absl::string_view::npos)
return absl::string_view(text.data() + text.size(), 0);
return text.substr(found_pos, 1);
}
return GenericFind(text, delimiter_, pos, LiteralPolicy());
}
//
// ByChar
//
absl::string_view ByChar::Find(absl::string_view text, size_t pos) const {
size_t found_pos = text.find(c_, pos);
if (found_pos == absl::string_view::npos)
return absl::string_view(text.data() + text.size(), 0);
return text.substr(found_pos, 1);
}
//
// ByAnyChar
//
ByAnyChar::ByAnyChar(absl::string_view sp) : delimiters_(sp) {}
absl::string_view ByAnyChar::Find(absl::string_view text, size_t pos) const {
return GenericFind(text, delimiters_, pos, AnyOfPolicy());
}
//
// ByLength
//
ByLength::ByLength(ptrdiff_t length) : length_(length) {
ABSL_RAW_CHECK(length > 0, "");
}
absl::string_view ByLength::Find(absl::string_view text, size_t pos) const {
pos = std::min(pos, text.size()); // truncate `pos`
absl::string_view substr = text.substr(pos);
// If the string is shorter than the chunk size we say we
// "can't find the delimiter" so this will be the last chunk.
if (substr.length() <= static_cast<size_t>(length_))
return absl::string_view(text.data() + text.size(), 0);
return absl::string_view(substr.data() + length_, 0);
}
ABSL_NAMESPACE_END
} // namespace absl
|
