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[email protected]7d7b0ac2013-03-28 20:07:401// 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//
[email protected]16b200c2014-06-24 02:55:218// You can use StringPiece as a function or method parameter. A StringPiece
9// parameter can receive a double-quoted string literal argument, a "const
10// char*" argument, a string argument, or a StringPiece argument with no data
11// copying. Systematic use of StringPiece for arguments reduces data
12// copies and strlen() calls.
[email protected]7d7b0ac2013-03-28 20:07:4013//
[email protected]16b200c2014-06-24 02:55:2114// Prefer passing StringPieces by value:
15// void MyFunction(StringPiece arg);
16// If circumstances require, you may also pass by const reference:
17// void MyFunction(const StringPiece& arg); // not preferred
18// Both of these have the same lifetime semantics. Passing by value
19// generates slightly smaller code. For more discussion, Googlers can see
20// the thread go/stringpiecebyvalue on c-users.
[email protected]7d7b0ac2013-03-28 20:07:4021
22#ifndef BASE_STRINGS_STRING_PIECE_H_
23#define BASE_STRINGS_STRING_PIECE_H_
24
25#include <stddef.h>
26
27#include <iosfwd>
28#include <string>
29
30#include "base/base_export.h"
31#include "base/basictypes.h"
[email protected]14c1c232013-06-11 17:52:4432#include "base/containers/hash_tables.h"
[email protected]c851cfd2013-06-10 20:11:1433#include "base/strings/string16.h"
[email protected]7d7b0ac2013-03-28 20:07:4034
35namespace base {
36
37template <typename STRING_TYPE> class BasicStringPiece;
38typedef BasicStringPiece<std::string> StringPiece;
39typedef BasicStringPiece<string16> StringPiece16;
40
[email protected]0ecab7892014-03-11 21:15:4041// internal --------------------------------------------------------------------
42
43// Many of the StringPiece functions use different implementations for the
44// 8-bit and 16-bit versions, and we don't want lots of template expansions in
45// this (very common) header that will slow down compilation.
46//
47// So here we define overloaded functions called by the StringPiece template.
48// For those that share an implementation, the two versions will expand to a
49// template internal to the .cc file.
[email protected]7d7b0ac2013-03-28 20:07:4050namespace internal {
51
[email protected]0ecab7892014-03-11 21:15:4052BASE_EXPORT void CopyToString(const StringPiece& self, std::string* target);
53BASE_EXPORT void CopyToString(const StringPiece16& self, string16* target);
54
55BASE_EXPORT void AppendToString(const StringPiece& self, std::string* target);
56BASE_EXPORT void AppendToString(const StringPiece16& self, string16* target);
57
58BASE_EXPORT size_t copy(const StringPiece& self,
59 char* buf,
60 size_t n,
61 size_t pos);
62BASE_EXPORT size_t copy(const StringPiece16& self,
63 char16* buf,
64 size_t n,
65 size_t pos);
66
67BASE_EXPORT size_t find(const StringPiece& self,
68 const StringPiece& s,
69 size_t pos);
70BASE_EXPORT size_t find(const StringPiece16& self,
71 const StringPiece16& s,
72 size_t pos);
73BASE_EXPORT size_t find(const StringPiece& self,
74 char c,
75 size_t pos);
76BASE_EXPORT size_t find(const StringPiece16& self,
77 char16 c,
78 size_t pos);
79
80BASE_EXPORT size_t rfind(const StringPiece& self,
81 const StringPiece& s,
82 size_t pos);
83BASE_EXPORT size_t rfind(const StringPiece16& self,
84 const StringPiece16& s,
85 size_t pos);
86BASE_EXPORT size_t rfind(const StringPiece& self,
87 char c,
88 size_t pos);
89BASE_EXPORT size_t rfind(const StringPiece16& self,
90 char16 c,
91 size_t pos);
92
93BASE_EXPORT size_t find_first_of(const StringPiece& self,
94 const StringPiece& s,
95 size_t pos);
96BASE_EXPORT size_t find_first_of(const StringPiece16& self,
97 const StringPiece16& s,
98 size_t pos);
99
100BASE_EXPORT size_t find_first_not_of(const StringPiece& self,
101 const StringPiece& s,
102 size_t pos);
103BASE_EXPORT size_t find_first_not_of(const StringPiece16& self,
104 const StringPiece16& s,
105 size_t pos);
106BASE_EXPORT size_t find_first_not_of(const StringPiece& self,
107 char c,
108 size_t pos);
109BASE_EXPORT size_t find_first_not_of(const StringPiece16& self,
110 char16 c,
111 size_t pos);
112
113BASE_EXPORT size_t find_last_of(const StringPiece& self,
114 const StringPiece& s,
115 size_t pos);
116BASE_EXPORT size_t find_last_of(const StringPiece16& self,
117 const StringPiece16& s,
118 size_t pos);
119BASE_EXPORT size_t find_last_of(const StringPiece& self,
120 char c,
121 size_t pos);
122BASE_EXPORT size_t find_last_of(const StringPiece16& self,
123 char16 c,
124 size_t pos);
125
126BASE_EXPORT size_t find_last_not_of(const StringPiece& self,
127 const StringPiece& s,
128 size_t pos);
129BASE_EXPORT size_t find_last_not_of(const StringPiece16& self,
130 const StringPiece16& s,
131 size_t pos);
132BASE_EXPORT size_t find_last_not_of(const StringPiece16& self,
133 char16 c,
134 size_t pos);
135BASE_EXPORT size_t find_last_not_of(const StringPiece& self,
136 char c,
137 size_t pos);
138
139BASE_EXPORT StringPiece substr(const StringPiece& self,
140 size_t pos,
141 size_t n);
142BASE_EXPORT StringPiece16 substr(const StringPiece16& self,
143 size_t pos,
144 size_t n);
145
brettwf22866d2015-07-27 22:22:26146#if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
147// Asserts that begin <= end to catch some errors with iterator usage.
148BASE_EXPORT void AssertIteratorsInOrder(std::string::const_iterator begin,
149 std::string::const_iterator end);
150BASE_EXPORT void AssertIteratorsInOrder(string16::const_iterator begin,
151 string16::const_iterator end);
152#endif
153
[email protected]0ecab7892014-03-11 21:15:40154} // namespace internal
155
156// BasicStringPiece ------------------------------------------------------------
157
[email protected]7d7b0ac2013-03-28 20:07:40158// Defines the types, methods, operators, and data members common to both
159// StringPiece and StringPiece16. Do not refer to this class directly, but
160// rather to BasicStringPiece, StringPiece, or StringPiece16.
[email protected]0ecab7892014-03-11 21:15:40161//
162// This is templatized by string class type rather than character type, so
163// BasicStringPiece<std::string> or BasicStringPiece<base::string16>.
164template <typename STRING_TYPE> class BasicStringPiece {
[email protected]7d7b0ac2013-03-28 20:07:40165 public:
[email protected]0ecab7892014-03-11 21:15:40166 // Standard STL container boilerplate.
[email protected]7d7b0ac2013-03-28 20:07:40167 typedef size_t size_type;
168 typedef typename STRING_TYPE::value_type value_type;
169 typedef const value_type* pointer;
170 typedef const value_type& reference;
171 typedef const value_type& const_reference;
172 typedef ptrdiff_t difference_type;
173 typedef const value_type* const_iterator;
174 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
175
176 static const size_type npos;
177
178 public:
179 // We provide non-explicit singleton constructors so users can pass
180 // in a "const char*" or a "string" wherever a "StringPiece" is
181 // expected (likewise for char16, string16, StringPiece16).
[email protected]0ecab7892014-03-11 21:15:40182 BasicStringPiece() : ptr_(NULL), length_(0) {}
183 BasicStringPiece(const value_type* str)
[email protected]7d7b0ac2013-03-28 20:07:40184 : ptr_(str),
185 length_((str == NULL) ? 0 : STRING_TYPE::traits_type::length(str)) {}
[email protected]0ecab7892014-03-11 21:15:40186 BasicStringPiece(const STRING_TYPE& str)
[email protected]7d7b0ac2013-03-28 20:07:40187 : ptr_(str.data()), length_(str.size()) {}
[email protected]0ecab7892014-03-11 21:15:40188 BasicStringPiece(const value_type* offset, size_type len)
[email protected]7d7b0ac2013-03-28 20:07:40189 : ptr_(offset), length_(len) {}
[email protected]0ecab7892014-03-11 21:15:40190 BasicStringPiece(const typename STRING_TYPE::const_iterator& begin,
brettwf22866d2015-07-27 22:22:26191 const typename STRING_TYPE::const_iterator& end) {
192#if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
193 // This assertion is done out-of-line to avoid bringing in logging.h and
194 // instantiating logging macros for every instantiation.
195 internal::AssertIteratorsInOrder(begin, end);
196#endif
197 length_ = static_cast<size_t>(std::distance(begin, end));
198
199 // The length test before assignment is to avoid dereferencing an iterator
200 // that may point to the end() of a string.
201 ptr_ = length_ > 0 ? &*begin : nullptr;
202 }
[email protected]7d7b0ac2013-03-28 20:07:40203
204 // data() may return a pointer to a buffer with embedded NULs, and the
205 // returned buffer may or may not be null terminated. Therefore it is
206 // typically a mistake to pass data() to a routine that expects a NUL
207 // terminated string.
208 const value_type* data() const { return ptr_; }
209 size_type size() const { return length_; }
210 size_type length() const { return length_; }
211 bool empty() const { return length_ == 0; }
212
213 void clear() {
214 ptr_ = NULL;
215 length_ = 0;
216 }
217 void set(const value_type* data, size_type len) {
218 ptr_ = data;
219 length_ = len;
220 }
221 void set(const value_type* str) {
222 ptr_ = str;
223 length_ = str ? STRING_TYPE::traits_type::length(str) : 0;
224 }
225
226 value_type operator[](size_type i) const { return ptr_[i]; }
227
228 void remove_prefix(size_type n) {
229 ptr_ += n;
230 length_ -= n;
231 }
232
233 void remove_suffix(size_type n) {
234 length_ -= n;
235 }
236
237 int compare(const BasicStringPiece<STRING_TYPE>& x) const {
238 int r = wordmemcmp(
239 ptr_, x.ptr_, (length_ < x.length_ ? length_ : x.length_));
240 if (r == 0) {
241 if (length_ < x.length_) r = -1;
242 else if (length_ > x.length_) r = +1;
243 }
244 return r;
245 }
246
247 STRING_TYPE as_string() const {
248 // std::string doesn't like to take a NULL pointer even with a 0 size.
249 return empty() ? STRING_TYPE() : STRING_TYPE(data(), size());
250 }
251
252 const_iterator begin() const { return ptr_; }
253 const_iterator end() const { return ptr_ + length_; }
254 const_reverse_iterator rbegin() const {
255 return const_reverse_iterator(ptr_ + length_);
256 }
257 const_reverse_iterator rend() const {
258 return const_reverse_iterator(ptr_);
259 }
260
261 size_type max_size() const { return length_; }
262 size_type capacity() const { return length_; }
263
264 static int wordmemcmp(const value_type* p,
265 const value_type* p2,
266 size_type N) {
267 return STRING_TYPE::traits_type::compare(p, p2, N);
268 }
269
[email protected]0ecab7892014-03-11 21:15:40270 // Sets the value of the given string target type to be the current string.
271 // This saves a temporary over doing |a = b.as_string()|
272 void CopyToString(STRING_TYPE* target) const {
273 internal::CopyToString(*this, target);
274 }
275
276 void AppendToString(STRING_TYPE* target) const {
277 internal::AppendToString(*this, target);
278 }
279
280 size_type copy(value_type* buf, size_type n, size_type pos = 0) const {
281 return internal::copy(*this, buf, n, pos);
282 }
283
284 // Does "this" start with "x"
285 bool starts_with(const BasicStringPiece& x) const {
286 return ((this->length_ >= x.length_) &&
287 (wordmemcmp(this->ptr_, x.ptr_, x.length_) == 0));
288 }
289
290 // Does "this" end with "x"
291 bool ends_with(const BasicStringPiece& x) const {
292 return ((this->length_ >= x.length_) &&
293 (wordmemcmp(this->ptr_ + (this->length_-x.length_),
294 x.ptr_, x.length_) == 0));
295 }
296
297 // find: Search for a character or substring at a given offset.
298 size_type find(const BasicStringPiece<STRING_TYPE>& s,
299 size_type pos = 0) const {
300 return internal::find(*this, s, pos);
301 }
302 size_type find(value_type c, size_type pos = 0) const {
303 return internal::find(*this, c, pos);
304 }
305
306 // rfind: Reverse find.
307 size_type rfind(const BasicStringPiece& s,
308 size_type pos = BasicStringPiece::npos) const {
309 return internal::rfind(*this, s, pos);
310 }
311 size_type rfind(value_type c, size_type pos = BasicStringPiece::npos) const {
312 return internal::rfind(*this, c, pos);
313 }
314
315 // find_first_of: Find the first occurence of one of a set of characters.
316 size_type find_first_of(const BasicStringPiece& s,
317 size_type pos = 0) const {
318 return internal::find_first_of(*this, s, pos);
319 }
320 size_type find_first_of(value_type c, size_type pos = 0) const {
321 return find(c, pos);
322 }
323
324 // find_first_not_of: Find the first occurence not of a set of characters.
325 size_type find_first_not_of(const BasicStringPiece& s,
326 size_type pos = 0) const {
327 return internal::find_first_not_of(*this, s, pos);
328 }
329 size_type find_first_not_of(value_type c, size_type pos = 0) const {
330 return internal::find_first_not_of(*this, c, pos);
331 }
332
333 // find_last_of: Find the last occurence of one of a set of characters.
334 size_type find_last_of(const BasicStringPiece& s,
335 size_type pos = BasicStringPiece::npos) const {
336 return internal::find_last_of(*this, s, pos);
337 }
338 size_type find_last_of(value_type c,
339 size_type pos = BasicStringPiece::npos) const {
340 return rfind(c, pos);
341 }
342
343 // find_last_not_of: Find the last occurence not of a set of characters.
344 size_type find_last_not_of(const BasicStringPiece& s,
345 size_type pos = BasicStringPiece::npos) const {
346 return internal::find_last_not_of(*this, s, pos);
347 }
348 size_type find_last_not_of(value_type c,
349 size_type pos = BasicStringPiece::npos) const {
350 return internal::find_last_not_of(*this, c, pos);
351 }
352
353 // substr.
354 BasicStringPiece substr(size_type pos,
355 size_type n = BasicStringPiece::npos) const {
356 return internal::substr(*this, pos, n);
357 }
358
[email protected]7d7b0ac2013-03-28 20:07:40359 protected:
360 const value_type* ptr_;
361 size_type length_;
362};
363
364template <typename STRING_TYPE>
[email protected]0ecab7892014-03-11 21:15:40365const typename BasicStringPiece<STRING_TYPE>::size_type
366BasicStringPiece<STRING_TYPE>::npos =
367 typename BasicStringPiece<STRING_TYPE>::size_type(-1);
[email protected]7d7b0ac2013-03-28 20:07:40368
369// MSVC doesn't like complex extern templates and DLLs.
370#if !defined(COMPILER_MSVC)
[email protected]0ecab7892014-03-11 21:15:40371extern template class BASE_EXPORT BasicStringPiece<std::string>;
[email protected]50bc27c2014-03-07 01:45:03372extern template class BASE_EXPORT BasicStringPiece<string16>;
373#endif
[email protected]51cb94c2014-03-06 17:54:33374
[email protected]0ecab7892014-03-11 21:15:40375// StingPiece operators --------------------------------------------------------
376
[email protected]7d7b0ac2013-03-28 20:07:40377BASE_EXPORT bool operator==(const StringPiece& x, const StringPiece& y);
378
379inline bool operator!=(const StringPiece& x, const StringPiece& y) {
380 return !(x == y);
381}
382
383inline bool operator<(const StringPiece& x, const StringPiece& y) {
384 const int r = StringPiece::wordmemcmp(
385 x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size()));
386 return ((r < 0) || ((r == 0) && (x.size() < y.size())));
387}
388
389inline bool operator>(const StringPiece& x, const StringPiece& y) {
390 return y < x;
391}
392
393inline bool operator<=(const StringPiece& x, const StringPiece& y) {
394 return !(x > y);
395}
396
397inline bool operator>=(const StringPiece& x, const StringPiece& y) {
398 return !(x < y);
399}
400
[email protected]0ecab7892014-03-11 21:15:40401// StringPiece16 operators -----------------------------------------------------
402
[email protected]7d7b0ac2013-03-28 20:07:40403inline bool operator==(const StringPiece16& x, const StringPiece16& y) {
404 if (x.size() != y.size())
405 return false;
406
407 return StringPiece16::wordmemcmp(x.data(), y.data(), x.size()) == 0;
408}
409
410inline bool operator!=(const StringPiece16& x, const StringPiece16& y) {
411 return !(x == y);
412}
413
414inline bool operator<(const StringPiece16& x, const StringPiece16& y) {
415 const int r = StringPiece16::wordmemcmp(
416 x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size()));
417 return ((r < 0) || ((r == 0) && (x.size() < y.size())));
418}
419
420inline bool operator>(const StringPiece16& x, const StringPiece16& y) {
421 return y < x;
422}
423
424inline bool operator<=(const StringPiece16& x, const StringPiece16& y) {
425 return !(x > y);
426}
427
428inline bool operator>=(const StringPiece16& x, const StringPiece16& y) {
429 return !(x < y);
430}
431
432BASE_EXPORT std::ostream& operator<<(std::ostream& o,
433 const StringPiece& piece);
434
435} // namespace base
436
[email protected]0ecab7892014-03-11 21:15:40437// Hashing ---------------------------------------------------------------------
438
[email protected]7d7b0ac2013-03-28 20:07:40439// We provide appropriate hash functions so StringPiece and StringPiece16 can
440// be used as keys in hash sets and maps.
441
[email protected]14c1c232013-06-11 17:52:44442// This hash function is copied from base/containers/hash_tables.h. We don't
443// use the ones already defined for string and string16 directly because it
444// would require the string constructors to be called, which we don't want.
[email protected]7d7b0ac2013-03-28 20:07:40445#define HASH_STRING_PIECE(StringPieceType, string_piece) \
446 std::size_t result = 0; \
447 for (StringPieceType::const_iterator i = string_piece.begin(); \
448 i != string_piece.end(); ++i) \
449 result = (result * 131) + *i; \
450 return result; \
451
452namespace BASE_HASH_NAMESPACE {
[email protected]7d7b0ac2013-03-28 20:07:40453
454template<>
455struct hash<base::StringPiece> {
456 std::size_t operator()(const base::StringPiece& sp) const {
457 HASH_STRING_PIECE(base::StringPiece, sp);
458 }
459};
460template<>
461struct hash<base::StringPiece16> {
462 std::size_t operator()(const base::StringPiece16& sp16) const {
463 HASH_STRING_PIECE(base::StringPiece16, sp16);
464 }
465};
466
[email protected]7d7b0ac2013-03-28 20:07:40467} // namespace BASE_HASH_NAMESPACE
468
469#endif // BASE_STRINGS_STRING_PIECE_H_