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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 // Copied from strings/stringpiece.cc with modifications
5 
6 #include "base/strings/string_piece.h"
7 
8 #include <limits.h>
9 
10 #include <algorithm>
11 #include <ostream>
12 
13 #include "base/logging.h"
14 
15 namespace base {
16 namespace {
17 
18 // For each character in characters_wanted, sets the index corresponding
19 // to the ASCII code of that character to 1 in table.  This is used by
20 // the find_.*_of methods below to tell whether or not a character is in
21 // the lookup table in constant time.
22 // The argument `table' must be an array that is large enough to hold all
23 // the possible values of an unsigned char.  Thus it should be be declared
24 // as follows:
25 //   bool table[UCHAR_MAX + 1]
BuildLookupTable(const StringPiece & characters_wanted,bool * table)26 inline void BuildLookupTable(const StringPiece& characters_wanted,
27                              bool* table) {
28   const size_t length = characters_wanted.length();
29   const char* const data = characters_wanted.data();
30   for (size_t i = 0; i < length; ++i) {
31     table[static_cast<unsigned char>(data[i])] = true;
32   }
33 }
34 
35 }  // namespace
36 
37 // MSVC doesn't like complex extern templates and DLLs.
38 #if !defined(COMPILER_MSVC)
39 template class BasicStringPiece<std::string>;
40 template class BasicStringPiece<string16>;
41 #endif
42 
operator ==(const StringPiece & x,const StringPiece & y)43 bool operator==(const StringPiece& x, const StringPiece& y) {
44   if (x.size() != y.size())
45     return false;
46 
47   return StringPiece::wordmemcmp(x.data(), y.data(), x.size()) == 0;
48 }
49 
operator <<(std::ostream & o,const StringPiece & piece)50 std::ostream& operator<<(std::ostream& o, const StringPiece& piece) {
51   o.write(piece.data(), static_cast<std::streamsize>(piece.size()));
52   return o;
53 }
54 
55 namespace internal {
56 
57 template<typename STR>
CopyToStringT(const BasicStringPiece<STR> & self,STR * target)58 void CopyToStringT(const BasicStringPiece<STR>& self, STR* target) {
59   if (self.empty())
60     target->clear();
61   else
62     target->assign(self.data(), self.size());
63 }
64 
CopyToString(const StringPiece & self,std::string * target)65 void CopyToString(const StringPiece& self, std::string* target) {
66   CopyToStringT(self, target);
67 }
68 
CopyToString(const StringPiece16 & self,string16 * target)69 void CopyToString(const StringPiece16& self, string16* target) {
70   CopyToStringT(self, target);
71 }
72 
73 template<typename STR>
AppendToStringT(const BasicStringPiece<STR> & self,STR * target)74 void AppendToStringT(const BasicStringPiece<STR>& self, STR* target) {
75   if (!self.empty())
76     target->append(self.data(), self.size());
77 }
78 
AppendToString(const StringPiece & self,std::string * target)79 void AppendToString(const StringPiece& self, std::string* target) {
80   AppendToStringT(self, target);
81 }
82 
AppendToString(const StringPiece16 & self,string16 * target)83 void AppendToString(const StringPiece16& self, string16* target) {
84   AppendToStringT(self, target);
85 }
86 
87 template<typename STR>
copyT(const BasicStringPiece<STR> & self,typename STR::value_type * buf,size_t n,size_t pos)88 size_t copyT(const BasicStringPiece<STR>& self,
89              typename STR::value_type* buf,
90              size_t n,
91              size_t pos) {
92   size_t ret = std::min(self.size() - pos, n);
93   memcpy(buf, self.data() + pos, ret * sizeof(typename STR::value_type));
94   return ret;
95 }
96 
copy(const StringPiece & self,char * buf,size_t n,size_t pos)97 size_t copy(const StringPiece& self, char* buf, size_t n, size_t pos) {
98   return copyT(self, buf, n, pos);
99 }
100 
copy(const StringPiece16 & self,char16 * buf,size_t n,size_t pos)101 size_t copy(const StringPiece16& self, char16* buf, size_t n, size_t pos) {
102   return copyT(self, buf, n, pos);
103 }
104 
105 template<typename STR>
findT(const BasicStringPiece<STR> & self,const BasicStringPiece<STR> & s,size_t pos)106 size_t findT(const BasicStringPiece<STR>& self,
107              const BasicStringPiece<STR>& s,
108              size_t pos) {
109   if (pos > self.size())
110     return BasicStringPiece<STR>::npos;
111 
112   typename BasicStringPiece<STR>::const_iterator result =
113       std::search(self.begin() + pos, self.end(), s.begin(), s.end());
114   const size_t xpos =
115     static_cast<size_t>(result - self.begin());
116   return xpos + s.size() <= self.size() ? xpos : BasicStringPiece<STR>::npos;
117 }
118 
find(const StringPiece & self,const StringPiece & s,size_t pos)119 size_t find(const StringPiece& self, const StringPiece& s, size_t pos) {
120   return findT(self, s, pos);
121 }
122 
find(const StringPiece16 & self,const StringPiece16 & s,size_t pos)123 size_t find(const StringPiece16& self, const StringPiece16& s, size_t pos) {
124   return findT(self, s, pos);
125 }
126 
127 template<typename STR>
findT(const BasicStringPiece<STR> & self,typename STR::value_type c,size_t pos)128 size_t findT(const BasicStringPiece<STR>& self,
129              typename STR::value_type c,
130              size_t pos) {
131   if (pos >= self.size())
132     return BasicStringPiece<STR>::npos;
133 
134   typename BasicStringPiece<STR>::const_iterator result =
135       std::find(self.begin() + pos, self.end(), c);
136   return result != self.end() ?
137       static_cast<size_t>(result - self.begin()) : BasicStringPiece<STR>::npos;
138 }
139 
find(const StringPiece & self,char c,size_t pos)140 size_t find(const StringPiece& self, char c, size_t pos) {
141   return findT(self, c, pos);
142 }
143 
find(const StringPiece16 & self,char16 c,size_t pos)144 size_t find(const StringPiece16& self, char16 c, size_t pos) {
145   return findT(self, c, pos);
146 }
147 
148 template<typename STR>
rfindT(const BasicStringPiece<STR> & self,const BasicStringPiece<STR> & s,size_t pos)149 size_t rfindT(const BasicStringPiece<STR>& self,
150               const BasicStringPiece<STR>& s,
151               size_t pos) {
152   if (self.size() < s.size())
153     return BasicStringPiece<STR>::npos;
154 
155   if (s.empty())
156     return std::min(self.size(), pos);
157 
158   typename BasicStringPiece<STR>::const_iterator last =
159       self.begin() + std::min(self.size() - s.size(), pos) + s.size();
160   typename BasicStringPiece<STR>::const_iterator result =
161       std::find_end(self.begin(), last, s.begin(), s.end());
162   return result != last ?
163       static_cast<size_t>(result - self.begin()) : BasicStringPiece<STR>::npos;
164 }
165 
rfind(const StringPiece & self,const StringPiece & s,size_t pos)166 size_t rfind(const StringPiece& self, const StringPiece& s, size_t pos) {
167   return rfindT(self, s, pos);
168 }
169 
rfind(const StringPiece16 & self,const StringPiece16 & s,size_t pos)170 size_t rfind(const StringPiece16& self, const StringPiece16& s, size_t pos) {
171   return rfindT(self, s, pos);
172 }
173 
174 template<typename STR>
rfindT(const BasicStringPiece<STR> & self,typename STR::value_type c,size_t pos)175 size_t rfindT(const BasicStringPiece<STR>& self,
176               typename STR::value_type c,
177               size_t pos) {
178   if (self.size() == 0)
179     return BasicStringPiece<STR>::npos;
180 
181   for (size_t i = std::min(pos, self.size() - 1); ;
182        --i) {
183     if (self.data()[i] == c)
184       return i;
185     if (i == 0)
186       break;
187   }
188   return BasicStringPiece<STR>::npos;
189 }
190 
rfind(const StringPiece & self,char c,size_t pos)191 size_t rfind(const StringPiece& self, char c, size_t pos) {
192   return rfindT(self, c, pos);
193 }
194 
rfind(const StringPiece16 & self,char16 c,size_t pos)195 size_t rfind(const StringPiece16& self, char16 c, size_t pos) {
196   return rfindT(self, c, pos);
197 }
198 
199 // 8-bit version using lookup table.
find_first_of(const StringPiece & self,const StringPiece & s,size_t pos)200 size_t find_first_of(const StringPiece& self,
201                      const StringPiece& s,
202                      size_t pos) {
203   if (self.size() == 0 || s.size() == 0)
204     return StringPiece::npos;
205 
206   // Avoid the cost of BuildLookupTable() for a single-character search.
207   if (s.size() == 1)
208     return find(self, s.data()[0], pos);
209 
210   bool lookup[UCHAR_MAX + 1] = { false };
211   BuildLookupTable(s, lookup);
212   for (size_t i = pos; i < self.size(); ++i) {
213     if (lookup[static_cast<unsigned char>(self.data()[i])]) {
214       return i;
215     }
216   }
217   return StringPiece::npos;
218 }
219 
220 // 16-bit brute force version.
find_first_of(const StringPiece16 & self,const StringPiece16 & s,size_t pos)221 size_t find_first_of(const StringPiece16& self,
222                      const StringPiece16& s,
223                      size_t pos) {
224   StringPiece16::const_iterator found =
225       std::find_first_of(self.begin() + pos, self.end(), s.begin(), s.end());
226   if (found == self.end())
227     return StringPiece16::npos;
228   return found - self.begin();
229 }
230 
231 // 8-bit version using lookup table.
find_first_not_of(const StringPiece & self,const StringPiece & s,size_t pos)232 size_t find_first_not_of(const StringPiece& self,
233                          const StringPiece& s,
234                          size_t pos) {
235   if (self.size() == 0)
236     return StringPiece::npos;
237 
238   if (s.size() == 0)
239     return 0;
240 
241   // Avoid the cost of BuildLookupTable() for a single-character search.
242   if (s.size() == 1)
243     return find_first_not_of(self, s.data()[0], pos);
244 
245   bool lookup[UCHAR_MAX + 1] = { false };
246   BuildLookupTable(s, lookup);
247   for (size_t i = pos; i < self.size(); ++i) {
248     if (!lookup[static_cast<unsigned char>(self.data()[i])]) {
249       return i;
250     }
251   }
252   return StringPiece::npos;
253 }
254 
255 // 16-bit brute-force version.
find_first_not_of(const StringPiece16 & self,const StringPiece16 & s,size_t pos)256 BASE_EXPORT size_t find_first_not_of(const StringPiece16& self,
257                                      const StringPiece16& s,
258                                      size_t pos) {
259   if (self.size() == 0)
260     return StringPiece16::npos;
261 
262   for (size_t self_i = pos; self_i < self.size(); ++self_i) {
263     bool found = false;
264     for (size_t s_i = 0; s_i < s.size(); ++s_i) {
265       if (self[self_i] == s[s_i]) {
266         found = true;
267         break;
268       }
269     }
270     if (!found)
271       return self_i;
272   }
273   return StringPiece16::npos;
274 }
275 
276 template<typename STR>
find_first_not_ofT(const BasicStringPiece<STR> & self,typename STR::value_type c,size_t pos)277 size_t find_first_not_ofT(const BasicStringPiece<STR>& self,
278                           typename STR::value_type c,
279                           size_t pos) {
280   if (self.size() == 0)
281     return BasicStringPiece<STR>::npos;
282 
283   for (; pos < self.size(); ++pos) {
284     if (self.data()[pos] != c) {
285       return pos;
286     }
287   }
288   return BasicStringPiece<STR>::npos;
289 }
290 
find_first_not_of(const StringPiece & self,char c,size_t pos)291 size_t find_first_not_of(const StringPiece& self,
292                          char c,
293                          size_t pos) {
294   return find_first_not_ofT(self, c, pos);
295 }
296 
find_first_not_of(const StringPiece16 & self,char16 c,size_t pos)297 size_t find_first_not_of(const StringPiece16& self,
298                          char16 c,
299                          size_t pos) {
300   return find_first_not_ofT(self, c, pos);
301 }
302 
303 // 8-bit version using lookup table.
find_last_of(const StringPiece & self,const StringPiece & s,size_t pos)304 size_t find_last_of(const StringPiece& self, const StringPiece& s, size_t pos) {
305   if (self.size() == 0 || s.size() == 0)
306     return StringPiece::npos;
307 
308   // Avoid the cost of BuildLookupTable() for a single-character search.
309   if (s.size() == 1)
310     return rfind(self, s.data()[0], pos);
311 
312   bool lookup[UCHAR_MAX + 1] = { false };
313   BuildLookupTable(s, lookup);
314   for (size_t i = std::min(pos, self.size() - 1); ; --i) {
315     if (lookup[static_cast<unsigned char>(self.data()[i])])
316       return i;
317     if (i == 0)
318       break;
319   }
320   return StringPiece::npos;
321 }
322 
323 // 16-bit brute-force version.
find_last_of(const StringPiece16 & self,const StringPiece16 & s,size_t pos)324 size_t find_last_of(const StringPiece16& self,
325                     const StringPiece16& s,
326                     size_t pos) {
327   if (self.size() == 0)
328     return StringPiece16::npos;
329 
330   for (size_t self_i = std::min(pos, self.size() - 1); ;
331        --self_i) {
332     for (size_t s_i = 0; s_i < s.size(); s_i++) {
333       if (self.data()[self_i] == s[s_i])
334         return self_i;
335     }
336     if (self_i == 0)
337       break;
338   }
339   return StringPiece16::npos;
340 }
341 
342 // 8-bit version using lookup table.
find_last_not_of(const StringPiece & self,const StringPiece & s,size_t pos)343 size_t find_last_not_of(const StringPiece& self,
344                         const StringPiece& s,
345                         size_t pos) {
346   if (self.size() == 0)
347     return StringPiece::npos;
348 
349   size_t i = std::min(pos, self.size() - 1);
350   if (s.size() == 0)
351     return i;
352 
353   // Avoid the cost of BuildLookupTable() for a single-character search.
354   if (s.size() == 1)
355     return find_last_not_of(self, s.data()[0], pos);
356 
357   bool lookup[UCHAR_MAX + 1] = { false };
358   BuildLookupTable(s, lookup);
359   for (; ; --i) {
360     if (!lookup[static_cast<unsigned char>(self.data()[i])])
361       return i;
362     if (i == 0)
363       break;
364   }
365   return StringPiece::npos;
366 }
367 
368 // 16-bit brute-force version.
find_last_not_of(const StringPiece16 & self,const StringPiece16 & s,size_t pos)369 size_t find_last_not_of(const StringPiece16& self,
370                         const StringPiece16& s,
371                         size_t pos) {
372   if (self.size() == 0)
373     return StringPiece::npos;
374 
375   for (size_t self_i = std::min(pos, self.size() - 1); ; --self_i) {
376     bool found = false;
377     for (size_t s_i = 0; s_i < s.size(); s_i++) {
378       if (self.data()[self_i] == s[s_i]) {
379         found = true;
380         break;
381       }
382     }
383     if (!found)
384       return self_i;
385     if (self_i == 0)
386       break;
387   }
388   return StringPiece16::npos;
389 }
390 
391 template<typename STR>
find_last_not_ofT(const BasicStringPiece<STR> & self,typename STR::value_type c,size_t pos)392 size_t find_last_not_ofT(const BasicStringPiece<STR>& self,
393                          typename STR::value_type c,
394                          size_t pos) {
395   if (self.size() == 0)
396     return BasicStringPiece<STR>::npos;
397 
398   for (size_t i = std::min(pos, self.size() - 1); ; --i) {
399     if (self.data()[i] != c)
400       return i;
401     if (i == 0)
402       break;
403   }
404   return BasicStringPiece<STR>::npos;
405 }
406 
find_last_not_of(const StringPiece & self,char c,size_t pos)407 size_t find_last_not_of(const StringPiece& self,
408                         char c,
409                         size_t pos) {
410   return find_last_not_ofT(self, c, pos);
411 }
412 
find_last_not_of(const StringPiece16 & self,char16 c,size_t pos)413 size_t find_last_not_of(const StringPiece16& self,
414                         char16 c,
415                         size_t pos) {
416   return find_last_not_ofT(self, c, pos);
417 }
418 
419 template<typename STR>
substrT(const BasicStringPiece<STR> & self,size_t pos,size_t n)420 BasicStringPiece<STR> substrT(const BasicStringPiece<STR>& self,
421                               size_t pos,
422                               size_t n) {
423   if (pos > self.size()) pos = self.size();
424   if (n > self.size() - pos) n = self.size() - pos;
425   return BasicStringPiece<STR>(self.data() + pos, n);
426 }
427 
substr(const StringPiece & self,size_t pos,size_t n)428 StringPiece substr(const StringPiece& self,
429                    size_t pos,
430                    size_t n) {
431   return substrT(self, pos, n);
432 }
433 
substr(const StringPiece16 & self,size_t pos,size_t n)434 StringPiece16 substr(const StringPiece16& self,
435                      size_t pos,
436                      size_t n) {
437   return substrT(self, pos, n);
438 }
439 
440 #if DCHECK_IS_ON()
AssertIteratorsInOrder(std::string::const_iterator begin,std::string::const_iterator end)441 void AssertIteratorsInOrder(std::string::const_iterator begin,
442                             std::string::const_iterator end) {
443   DCHECK(begin <= end) << "StringPiece iterators swapped or invalid.";
444 }
AssertIteratorsInOrder(string16::const_iterator begin,string16::const_iterator end)445 void AssertIteratorsInOrder(string16::const_iterator begin,
446                             string16::const_iterator end) {
447   DCHECK(begin <= end) << "StringPiece iterators swapped or invalid.";
448 }
449 #endif
450 
451 }  // namespace internal
452 }  // namespace base
453