base/strings/string_piece.cc

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