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