string_view.cc
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1 // Copyright 2017 The Abseil Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
16 
17 #ifndef ABSL_HAVE_STD_STRING_VIEW
18 
19 #include <algorithm>
20 #include <climits>
21 #include <cstring>
22 #include <ostream>
23 
25 
26 namespace absl {
27 
28 namespace {
29 void WritePadding(std::ostream& o, size_t pad) {
30  char fill_buf[32];
31  memset(fill_buf, o.fill(), sizeof(fill_buf));
32  while (pad) {
33  size_t n = std::min(pad, sizeof(fill_buf));
34  o.write(fill_buf, n);
35  pad -= n;
36  }
37 }
38 
39 class LookupTable {
40  public:
41  // For each character in wanted, sets the index corresponding
42  // to the ASCII code of that character. This is used by
43  // the find_.*_of methods below to tell whether or not a character is in
44  // the lookup table in constant time.
45  explicit LookupTable(string_view wanted) {
46  for (char c : wanted) {
47  table_[Index(c)] = true;
48  }
49  }
50  bool operator[](char c) const { return table_[Index(c)]; }
51 
52  private:
53  static unsigned char Index(char c) { return static_cast<unsigned char>(c); }
54  bool table_[UCHAR_MAX + 1] = {};
55 };
56 
57 } // namespace
58 
59 std::ostream& operator<<(std::ostream& o, string_view piece) {
60  std::ostream::sentry sentry(o);
61  if (sentry) {
62  size_t lpad = 0;
63  size_t rpad = 0;
64  if (static_cast<size_t>(o.width()) > piece.size()) {
65  size_t pad = o.width() - piece.size();
66  if ((o.flags() & o.adjustfield) == o.left) {
67  rpad = pad;
68  } else {
69  lpad = pad;
70  }
71  }
72  if (lpad) WritePadding(o, lpad);
73  o.write(piece.data(), piece.size());
74  if (rpad) WritePadding(o, rpad);
75  o.width(0);
76  }
77  return o;
78 }
79 
81  size_type pos) const {
82  size_type ulen = length_;
83  assert(pos <= ulen);
84  size_type rlen = std::min(ulen - pos, n);
85  if (rlen > 0) {
86  const char* start = ptr_ + pos;
87  std::copy(start, start + rlen, buf);
88  }
89  return rlen;
90 }
91 
93  noexcept {
94  if (empty() || pos > length_) {
95  if (empty() && pos == 0 && s.empty()) return 0;
96  return npos;
97  }
98  const char* result =
99  strings_internal::memmatch(ptr_ + pos, length_ - pos, s.ptr_, s.length_);
100  return result ? result - ptr_ : npos;
101 }
102 
104  if (empty() || pos >= length_) {
105  return npos;
106  }
107  const char* result =
108  static_cast<const char*>(memchr(ptr_ + pos, c, length_ - pos));
109  return result != nullptr ? result - ptr_ : npos;
110 }
111 
113  noexcept {
114  if (length_ < s.length_) return npos;
115  if (s.empty()) return std::min(length_, pos);
116  const char* last = ptr_ + std::min(length_ - s.length_, pos) + s.length_;
117  const char* result = std::find_end(ptr_, last, s.ptr_, s.ptr_ + s.length_);
118  return result != last ? result - ptr_ : npos;
119 }
120 
121 // Search range is [0..pos] inclusive. If pos == npos, search everything.
123  noexcept {
124  // Note: memrchr() is not available on Windows.
125  if (empty()) return npos;
126  for (size_type i = std::min(pos, length_ - 1);; --i) {
127  if (ptr_[i] == c) {
128  return i;
129  }
130  if (i == 0) break;
131  }
132  return npos;
133 }
134 
136  size_type pos) const
137  noexcept {
138  if (empty() || s.empty()) {
139  return npos;
140  }
141  // Avoid the cost of LookupTable() for a single-character search.
142  if (s.length_ == 1) return find_first_of(s.ptr_[0], pos);
143  LookupTable tbl(s);
144  for (size_type i = pos; i < length_; ++i) {
145  if (tbl[ptr_[i]]) {
146  return i;
147  }
148  }
149  return npos;
150 }
151 
153  size_type pos) const
154  noexcept {
155  if (empty()) return npos;
156  // Avoid the cost of LookupTable() for a single-character search.
157  if (s.length_ == 1) return find_first_not_of(s.ptr_[0], pos);
158  LookupTable tbl(s);
159  for (size_type i = pos; i < length_; ++i) {
160  if (!tbl[ptr_[i]]) {
161  return i;
162  }
163  }
164  return npos;
165 }
166 
168  size_type pos) const
169  noexcept {
170  if (empty()) return npos;
171  for (; pos < length_; ++pos) {
172  if (ptr_[pos] != c) {
173  return pos;
174  }
175  }
176  return npos;
177 }
178 
180  size_type pos) const noexcept {
181  if (empty() || s.empty()) return npos;
182  // Avoid the cost of LookupTable() for a single-character search.
183  if (s.length_ == 1) return find_last_of(s.ptr_[0], pos);
184  LookupTable tbl(s);
185  for (size_type i = std::min(pos, length_ - 1);; --i) {
186  if (tbl[ptr_[i]]) {
187  return i;
188  }
189  if (i == 0) break;
190  }
191  return npos;
192 }
193 
195  size_type pos) const
196  noexcept {
197  if (empty()) return npos;
198  size_type i = std::min(pos, length_ - 1);
199  if (s.empty()) return i;
200  // Avoid the cost of LookupTable() for a single-character search.
201  if (s.length_ == 1) return find_last_not_of(s.ptr_[0], pos);
202  LookupTable tbl(s);
203  for (;; --i) {
204  if (!tbl[ptr_[i]]) {
205  return i;
206  }
207  if (i == 0) break;
208  }
209  return npos;
210 }
211 
213  size_type pos) const
214  noexcept {
215  if (empty()) return npos;
216  size_type i = std::min(pos, length_ - 1);
217  for (;; --i) {
218  if (ptr_[i] != c) {
219  return i;
220  }
221  if (i == 0) break;
222  }
223  return npos;
224 }
225 
226 // MSVC has non-standard behavior that implicitly creates definitions for static
227 // const members. These implicit definitions conflict with explicit out-of-class
228 // member definitions that are required by the C++ standard, resulting in
229 // LNK1169 "multiply defined" errors at link time. __declspec(selectany) asks
230 // MSVC to choose only one definition for the symbol it decorates. See details
231 // at https://msdn.microsoft.com/en-us/library/34h23df8(v=vs.100).aspx
232 #ifdef _MSC_VER
233 #define ABSL_STRING_VIEW_SELECTANY __declspec(selectany)
234 #else
235 #define ABSL_STRING_VIEW_SELECTANY
236 #endif
237 
242 
243 } // namespace absl
244 
245 #endif // ABSL_HAVE_STD_STRING_VIEW
std::string * ptr_
static constexpr size_type kMaxSize
Definition: string_view.h:491
size_type find(string_view s, size_type pos=0) const noexcept
Definition: string_view.cc:92
static constexpr size_type npos
Definition: string_view.h:159
#define ABSL_STRING_VIEW_SELECTANY
Definition: string_view.cc:235
bool table_[UCHAR_MAX+1]
Definition: string_view.cc:54
std::ostream & operator<<(std::ostream &os, absl::LogSeverity s)
Definition: log_severity.cc:21
char buf[N]
Definition: algorithm.h:29
constexpr size_type size() const noexcept
Definition: string_view.h:260
size_type rfind(string_view s, size_type pos=npos) const noexcept
Definition: string_view.cc:112
size_type find_last_of(string_view s, size_type pos=npos) const noexcept
Definition: string_view.cc:179
UnboundConversion o
Definition: parser_test.cc:86
size_type find_last_not_of(string_view s, size_type pos=npos) const noexcept
Definition: string_view.cc:194
size_type find_first_not_of(string_view s, size_type pos=0) const noexcept
Definition: string_view.cc:152
constexpr const_pointer data() const noexcept
Definition: string_view.h:302
size_type find_first_of(string_view s, size_type pos=0) const noexcept
Definition: string_view.cc:135
const char * memmatch(const char *phaystack, size_t haylen, const char *pneedle, size_t neelen)
Definition: memutil.cc:88
size_type copy(char *buf, size_type n, size_type pos=0) const
Definition: string_view.cc:80


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autogenerated on Tue Jun 18 2019 19:44:37