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.h with modifications 5 // 6 // A string-like object that points to a sized piece of memory. 7 // 8 // Functions or methods may use const StringPiece& parameters to accept either 9 // a "const char*" or a "string" value that will be implicitly converted to 10 // a StringPiece. The implicit conversion means that it is often appropriate 11 // to include this .h file in other files rather than forward-declaring 12 // StringPiece as would be appropriate for most other Google classes. 13 // 14 // Systematic usage of StringPiece is encouraged as it will reduce unnecessary 15 // conversions from "const char*" to "string" and back again. 16 // 17 // StringPiece16 is similar to StringPiece but for base::string16 instead of 18 // std::string. We do not define as large of a subset of the STL functions 19 // from basic_string as in StringPiece, but this can be changed if these 20 // functions (find, find_first_of, etc.) are found to be useful in this context. 21 // 22 23 #ifndef BASE_STRINGS_STRING_PIECE_H_ 24 #define BASE_STRINGS_STRING_PIECE_H_ 25 26 #include <stddef.h> 27 28 #include <iosfwd> 29 #include <string> 30 31 #include "base/base_export.h" 32 #include "base/basictypes.h" 33 #include "base/containers/hash_tables.h" 34 #include "base/strings/string16.h" 35 36 namespace base { 37 38 template <typename STRING_TYPE> class BasicStringPiece; 39 typedef BasicStringPiece<std::string> StringPiece; 40 typedef BasicStringPiece<string16> StringPiece16; 41 42 // internal -------------------------------------------------------------------- 43 44 // Many of the StringPiece functions use different implementations for the 45 // 8-bit and 16-bit versions, and we don't want lots of template expansions in 46 // this (very common) header that will slow down compilation. 47 // 48 // So here we define overloaded functions called by the StringPiece template. 49 // For those that share an implementation, the two versions will expand to a 50 // template internal to the .cc file. 51 namespace internal { 52 53 BASE_EXPORT void CopyToString(const StringPiece& self, std::string* target); 54 BASE_EXPORT void CopyToString(const StringPiece16& self, string16* target); 55 56 BASE_EXPORT void AppendToString(const StringPiece& self, std::string* target); 57 BASE_EXPORT void AppendToString(const StringPiece16& self, string16* target); 58 59 BASE_EXPORT size_t copy(const StringPiece& self, 60 char* buf, 61 size_t n, 62 size_t pos); 63 BASE_EXPORT size_t copy(const StringPiece16& self, 64 char16* buf, 65 size_t n, 66 size_t pos); 67 68 BASE_EXPORT size_t find(const StringPiece& self, 69 const StringPiece& s, 70 size_t pos); 71 BASE_EXPORT size_t find(const StringPiece16& self, 72 const StringPiece16& s, 73 size_t pos); 74 BASE_EXPORT size_t find(const StringPiece& self, 75 char c, 76 size_t pos); 77 BASE_EXPORT size_t find(const StringPiece16& self, 78 char16 c, 79 size_t pos); 80 81 BASE_EXPORT size_t rfind(const StringPiece& self, 82 const StringPiece& s, 83 size_t pos); 84 BASE_EXPORT size_t rfind(const StringPiece16& self, 85 const StringPiece16& s, 86 size_t pos); 87 BASE_EXPORT size_t rfind(const StringPiece& self, 88 char c, 89 size_t pos); 90 BASE_EXPORT size_t rfind(const StringPiece16& self, 91 char16 c, 92 size_t pos); 93 94 BASE_EXPORT size_t find_first_of(const StringPiece& self, 95 const StringPiece& s, 96 size_t pos); 97 BASE_EXPORT size_t find_first_of(const StringPiece16& self, 98 const StringPiece16& s, 99 size_t pos); 100 101 BASE_EXPORT size_t find_first_not_of(const StringPiece& self, 102 const StringPiece& s, 103 size_t pos); 104 BASE_EXPORT size_t find_first_not_of(const StringPiece16& self, 105 const StringPiece16& s, 106 size_t pos); 107 BASE_EXPORT size_t find_first_not_of(const StringPiece& self, 108 char c, 109 size_t pos); 110 BASE_EXPORT size_t find_first_not_of(const StringPiece16& self, 111 char16 c, 112 size_t pos); 113 114 BASE_EXPORT size_t find_last_of(const StringPiece& self, 115 const StringPiece& s, 116 size_t pos); 117 BASE_EXPORT size_t find_last_of(const StringPiece16& self, 118 const StringPiece16& s, 119 size_t pos); 120 BASE_EXPORT size_t find_last_of(const StringPiece& self, 121 char c, 122 size_t pos); 123 BASE_EXPORT size_t find_last_of(const StringPiece16& self, 124 char16 c, 125 size_t pos); 126 127 BASE_EXPORT size_t find_last_not_of(const StringPiece& self, 128 const StringPiece& s, 129 size_t pos); 130 BASE_EXPORT size_t find_last_not_of(const StringPiece16& self, 131 const StringPiece16& s, 132 size_t pos); 133 BASE_EXPORT size_t find_last_not_of(const StringPiece16& self, 134 char16 c, 135 size_t pos); 136 BASE_EXPORT size_t find_last_not_of(const StringPiece& self, 137 char c, 138 size_t pos); 139 140 BASE_EXPORT StringPiece substr(const StringPiece& self, 141 size_t pos, 142 size_t n); 143 BASE_EXPORT StringPiece16 substr(const StringPiece16& self, 144 size_t pos, 145 size_t n); 146 147 } // namespace internal 148 149 // BasicStringPiece ------------------------------------------------------------ 150 151 // Defines the types, methods, operators, and data members common to both 152 // StringPiece and StringPiece16. Do not refer to this class directly, but 153 // rather to BasicStringPiece, StringPiece, or StringPiece16. 154 // 155 // This is templatized by string class type rather than character type, so 156 // BasicStringPiece<std::string> or BasicStringPiece<base::string16>. 157 template <typename STRING_TYPE> class BasicStringPiece { 158 public: 159 // Standard STL container boilerplate. 160 typedef size_t size_type; 161 typedef typename STRING_TYPE::value_type value_type; 162 typedef const value_type* pointer; 163 typedef const value_type& reference; 164 typedef const value_type& const_reference; 165 typedef ptrdiff_t difference_type; 166 typedef const value_type* const_iterator; 167 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 168 169 static const size_type npos; 170 171 public: 172 // We provide non-explicit singleton constructors so users can pass 173 // in a "const char*" or a "string" wherever a "StringPiece" is 174 // expected (likewise for char16, string16, StringPiece16). 175 BasicStringPiece() : ptr_(NULL), length_(0) {} 176 BasicStringPiece(const value_type* str) 177 : ptr_(str), 178 length_((str == NULL) ? 0 : STRING_TYPE::traits_type::length(str)) {} 179 BasicStringPiece(const STRING_TYPE& str) 180 : ptr_(str.data()), length_(str.size()) {} 181 BasicStringPiece(const value_type* offset, size_type len) 182 : ptr_(offset), length_(len) {} 183 BasicStringPiece(const typename STRING_TYPE::const_iterator& begin, 184 const typename STRING_TYPE::const_iterator& end) 185 : ptr_((end > begin) ? &(*begin) : NULL), 186 length_((end > begin) ? (size_type)(end - begin) : 0) {} 187 188 // data() may return a pointer to a buffer with embedded NULs, and the 189 // returned buffer may or may not be null terminated. Therefore it is 190 // typically a mistake to pass data() to a routine that expects a NUL 191 // terminated string. 192 const value_type* data() const { return ptr_; } 193 size_type size() const { return length_; } 194 size_type length() const { return length_; } 195 bool empty() const { return length_ == 0; } 196 197 void clear() { 198 ptr_ = NULL; 199 length_ = 0; 200 } 201 void set(const value_type* data, size_type len) { 202 ptr_ = data; 203 length_ = len; 204 } 205 void set(const value_type* str) { 206 ptr_ = str; 207 length_ = str ? STRING_TYPE::traits_type::length(str) : 0; 208 } 209 210 value_type operator[](size_type i) const { return ptr_[i]; } 211 212 void remove_prefix(size_type n) { 213 ptr_ += n; 214 length_ -= n; 215 } 216 217 void remove_suffix(size_type n) { 218 length_ -= n; 219 } 220 221 int compare(const BasicStringPiece<STRING_TYPE>& x) const { 222 int r = wordmemcmp( 223 ptr_, x.ptr_, (length_ < x.length_ ? length_ : x.length_)); 224 if (r == 0) { 225 if (length_ < x.length_) r = -1; 226 else if (length_ > x.length_) r = +1; 227 } 228 return r; 229 } 230 231 STRING_TYPE as_string() const { 232 // std::string doesn't like to take a NULL pointer even with a 0 size. 233 return empty() ? STRING_TYPE() : STRING_TYPE(data(), size()); 234 } 235 236 const_iterator begin() const { return ptr_; } 237 const_iterator end() const { return ptr_ + length_; } 238 const_reverse_iterator rbegin() const { 239 return const_reverse_iterator(ptr_ + length_); 240 } 241 const_reverse_iterator rend() const { 242 return const_reverse_iterator(ptr_); 243 } 244 245 size_type max_size() const { return length_; } 246 size_type capacity() const { return length_; } 247 248 static int wordmemcmp(const value_type* p, 249 const value_type* p2, 250 size_type N) { 251 return STRING_TYPE::traits_type::compare(p, p2, N); 252 } 253 254 // Sets the value of the given string target type to be the current string. 255 // This saves a temporary over doing |a = b.as_string()| 256 void CopyToString(STRING_TYPE* target) const { 257 internal::CopyToString(*this, target); 258 } 259 260 void AppendToString(STRING_TYPE* target) const { 261 internal::AppendToString(*this, target); 262 } 263 264 size_type copy(value_type* buf, size_type n, size_type pos = 0) const { 265 return internal::copy(*this, buf, n, pos); 266 } 267 268 // Does "this" start with "x" 269 bool starts_with(const BasicStringPiece& x) const { 270 return ((this->length_ >= x.length_) && 271 (wordmemcmp(this->ptr_, x.ptr_, x.length_) == 0)); 272 } 273 274 // Does "this" end with "x" 275 bool ends_with(const BasicStringPiece& x) const { 276 return ((this->length_ >= x.length_) && 277 (wordmemcmp(this->ptr_ + (this->length_-x.length_), 278 x.ptr_, x.length_) == 0)); 279 } 280 281 // find: Search for a character or substring at a given offset. 282 size_type find(const BasicStringPiece<STRING_TYPE>& s, 283 size_type pos = 0) const { 284 return internal::find(*this, s, pos); 285 } 286 size_type find(value_type c, size_type pos = 0) const { 287 return internal::find(*this, c, pos); 288 } 289 290 // rfind: Reverse find. 291 size_type rfind(const BasicStringPiece& s, 292 size_type pos = BasicStringPiece::npos) const { 293 return internal::rfind(*this, s, pos); 294 } 295 size_type rfind(value_type c, size_type pos = BasicStringPiece::npos) const { 296 return internal::rfind(*this, c, pos); 297 } 298 299 // find_first_of: Find the first occurence of one of a set of characters. 300 size_type find_first_of(const BasicStringPiece& s, 301 size_type pos = 0) const { 302 return internal::find_first_of(*this, s, pos); 303 } 304 size_type find_first_of(value_type c, size_type pos = 0) const { 305 return find(c, pos); 306 } 307 308 // find_first_not_of: Find the first occurence not of a set of characters. 309 size_type find_first_not_of(const BasicStringPiece& s, 310 size_type pos = 0) const { 311 return internal::find_first_not_of(*this, s, pos); 312 } 313 size_type find_first_not_of(value_type c, size_type pos = 0) const { 314 return internal::find_first_not_of(*this, c, pos); 315 } 316 317 // find_last_of: Find the last occurence of one of a set of characters. 318 size_type find_last_of(const BasicStringPiece& s, 319 size_type pos = BasicStringPiece::npos) const { 320 return internal::find_last_of(*this, s, pos); 321 } 322 size_type find_last_of(value_type c, 323 size_type pos = BasicStringPiece::npos) const { 324 return rfind(c, pos); 325 } 326 327 // find_last_not_of: Find the last occurence not of a set of characters. 328 size_type find_last_not_of(const BasicStringPiece& s, 329 size_type pos = BasicStringPiece::npos) const { 330 return internal::find_last_not_of(*this, s, pos); 331 } 332 size_type find_last_not_of(value_type c, 333 size_type pos = BasicStringPiece::npos) const { 334 return internal::find_last_not_of(*this, c, pos); 335 } 336 337 // substr. 338 BasicStringPiece substr(size_type pos, 339 size_type n = BasicStringPiece::npos) const { 340 return internal::substr(*this, pos, n); 341 } 342 343 protected: 344 const value_type* ptr_; 345 size_type length_; 346 }; 347 348 template <typename STRING_TYPE> 349 const typename BasicStringPiece<STRING_TYPE>::size_type 350 BasicStringPiece<STRING_TYPE>::npos = 351 typename BasicStringPiece<STRING_TYPE>::size_type(-1); 352 353 // MSVC doesn't like complex extern templates and DLLs. 354 #if !defined(COMPILER_MSVC) 355 extern template class BASE_EXPORT BasicStringPiece<std::string>; 356 extern template class BASE_EXPORT BasicStringPiece<string16>; 357 #endif 358 359 // StingPiece operators -------------------------------------------------------- 360 361 BASE_EXPORT bool operator==(const StringPiece& x, const StringPiece& y); 362 363 inline bool operator!=(const StringPiece& x, const StringPiece& y) { 364 return !(x == y); 365 } 366 367 inline bool operator<(const StringPiece& x, const StringPiece& y) { 368 const int r = StringPiece::wordmemcmp( 369 x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size())); 370 return ((r < 0) || ((r == 0) && (x.size() < y.size()))); 371 } 372 373 inline bool operator>(const StringPiece& x, const StringPiece& y) { 374 return y < x; 375 } 376 377 inline bool operator<=(const StringPiece& x, const StringPiece& y) { 378 return !(x > y); 379 } 380 381 inline bool operator>=(const StringPiece& x, const StringPiece& y) { 382 return !(x < y); 383 } 384 385 // StringPiece16 operators ----------------------------------------------------- 386 387 inline bool operator==(const StringPiece16& x, const StringPiece16& y) { 388 if (x.size() != y.size()) 389 return false; 390 391 return StringPiece16::wordmemcmp(x.data(), y.data(), x.size()) == 0; 392 } 393 394 inline bool operator!=(const StringPiece16& x, const StringPiece16& y) { 395 return !(x == y); 396 } 397 398 inline bool operator<(const StringPiece16& x, const StringPiece16& y) { 399 const int r = StringPiece16::wordmemcmp( 400 x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size())); 401 return ((r < 0) || ((r == 0) && (x.size() < y.size()))); 402 } 403 404 inline bool operator>(const StringPiece16& x, const StringPiece16& y) { 405 return y < x; 406 } 407 408 inline bool operator<=(const StringPiece16& x, const StringPiece16& y) { 409 return !(x > y); 410 } 411 412 inline bool operator>=(const StringPiece16& x, const StringPiece16& y) { 413 return !(x < y); 414 } 415 416 BASE_EXPORT std::ostream& operator<<(std::ostream& o, 417 const StringPiece& piece); 418 419 } // namespace base 420 421 // Hashing --------------------------------------------------------------------- 422 423 // We provide appropriate hash functions so StringPiece and StringPiece16 can 424 // be used as keys in hash sets and maps. 425 426 // This hash function is copied from base/containers/hash_tables.h. We don't 427 // use the ones already defined for string and string16 directly because it 428 // would require the string constructors to be called, which we don't want. 429 #define HASH_STRING_PIECE(StringPieceType, string_piece) \ 430 std::size_t result = 0; \ 431 for (StringPieceType::const_iterator i = string_piece.begin(); \ 432 i != string_piece.end(); ++i) \ 433 result = (result * 131) + *i; \ 434 return result; \ 435 436 namespace BASE_HASH_NAMESPACE { 437 #if defined(COMPILER_GCC) 438 439 template<> 440 struct hash<base::StringPiece> { 441 std::size_t operator()(const base::StringPiece& sp) const { 442 HASH_STRING_PIECE(base::StringPiece, sp); 443 } 444 }; 445 template<> 446 struct hash<base::StringPiece16> { 447 std::size_t operator()(const base::StringPiece16& sp16) const { 448 HASH_STRING_PIECE(base::StringPiece16, sp16); 449 } 450 }; 451 452 #elif defined(COMPILER_MSVC) 453 454 inline size_t hash_value(const base::StringPiece& sp) { 455 HASH_STRING_PIECE(base::StringPiece, sp); 456 } 457 inline size_t hash_value(const base::StringPiece16& sp16) { 458 HASH_STRING_PIECE(base::StringPiece16, sp16); 459 } 460 461 #endif // COMPILER 462 463 } // namespace BASE_HASH_NAMESPACE 464 465 #endif // BASE_STRINGS_STRING_PIECE_H_ 466
