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Issue 1647803004: Move base to DEPS (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: Created 4 years, 10 months ago
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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.h with modifications
5 //
6 // A string-like object that points to a sized piece of memory.
7 //
8 // 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.
13 //
14 // 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.
21
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"
32 #include "base/containers/hash_tables.h"
33 #include "base/strings/string16.h"
34
35 namespace base {
36
37 template <typename STRING_TYPE> class BasicStringPiece;
38 typedef BasicStringPiece<std::string> StringPiece;
39 typedef BasicStringPiece<string16> StringPiece16;
40
41 // 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.
50 namespace internal {
51
52 BASE_EXPORT void CopyToString(const StringPiece& self, std::string* target);
53 BASE_EXPORT void CopyToString(const StringPiece16& self, string16* target);
54
55 BASE_EXPORT void AppendToString(const StringPiece& self, std::string* target);
56 BASE_EXPORT void AppendToString(const StringPiece16& self, string16* target);
57
58 BASE_EXPORT size_t copy(const StringPiece& self,
59 char* buf,
60 size_t n,
61 size_t pos);
62 BASE_EXPORT size_t copy(const StringPiece16& self,
63 char16* buf,
64 size_t n,
65 size_t pos);
66
67 BASE_EXPORT size_t find(const StringPiece& self,
68 const StringPiece& s,
69 size_t pos);
70 BASE_EXPORT size_t find(const StringPiece16& self,
71 const StringPiece16& s,
72 size_t pos);
73 BASE_EXPORT size_t find(const StringPiece& self,
74 char c,
75 size_t pos);
76 BASE_EXPORT size_t find(const StringPiece16& self,
77 char16 c,
78 size_t pos);
79
80 BASE_EXPORT size_t rfind(const StringPiece& self,
81 const StringPiece& s,
82 size_t pos);
83 BASE_EXPORT size_t rfind(const StringPiece16& self,
84 const StringPiece16& s,
85 size_t pos);
86 BASE_EXPORT size_t rfind(const StringPiece& self,
87 char c,
88 size_t pos);
89 BASE_EXPORT size_t rfind(const StringPiece16& self,
90 char16 c,
91 size_t pos);
92
93 BASE_EXPORT size_t find_first_of(const StringPiece& self,
94 const StringPiece& s,
95 size_t pos);
96 BASE_EXPORT size_t find_first_of(const StringPiece16& self,
97 const StringPiece16& s,
98 size_t pos);
99
100 BASE_EXPORT size_t find_first_not_of(const StringPiece& self,
101 const StringPiece& s,
102 size_t pos);
103 BASE_EXPORT size_t find_first_not_of(const StringPiece16& self,
104 const StringPiece16& s,
105 size_t pos);
106 BASE_EXPORT size_t find_first_not_of(const StringPiece& self,
107 char c,
108 size_t pos);
109 BASE_EXPORT size_t find_first_not_of(const StringPiece16& self,
110 char16 c,
111 size_t pos);
112
113 BASE_EXPORT size_t find_last_of(const StringPiece& self,
114 const StringPiece& s,
115 size_t pos);
116 BASE_EXPORT size_t find_last_of(const StringPiece16& self,
117 const StringPiece16& s,
118 size_t pos);
119 BASE_EXPORT size_t find_last_of(const StringPiece& self,
120 char c,
121 size_t pos);
122 BASE_EXPORT size_t find_last_of(const StringPiece16& self,
123 char16 c,
124 size_t pos);
125
126 BASE_EXPORT size_t find_last_not_of(const StringPiece& self,
127 const StringPiece& s,
128 size_t pos);
129 BASE_EXPORT size_t find_last_not_of(const StringPiece16& self,
130 const StringPiece16& s,
131 size_t pos);
132 BASE_EXPORT size_t find_last_not_of(const StringPiece16& self,
133 char16 c,
134 size_t pos);
135 BASE_EXPORT size_t find_last_not_of(const StringPiece& self,
136 char c,
137 size_t pos);
138
139 BASE_EXPORT StringPiece substr(const StringPiece& self,
140 size_t pos,
141 size_t n);
142 BASE_EXPORT StringPiece16 substr(const StringPiece16& self,
143 size_t pos,
144 size_t n);
145
146 } // namespace internal
147
148 // BasicStringPiece ------------------------------------------------------------
149
150 // Defines the types, methods, operators, and data members common to both
151 // StringPiece and StringPiece16. Do not refer to this class directly, but
152 // rather to BasicStringPiece, StringPiece, or StringPiece16.
153 //
154 // This is templatized by string class type rather than character type, so
155 // BasicStringPiece<std::string> or BasicStringPiece<base::string16>.
156 template <typename STRING_TYPE> class BasicStringPiece {
157 public:
158 // Standard STL container boilerplate.
159 typedef size_t size_type;
160 typedef typename STRING_TYPE::value_type value_type;
161 typedef const value_type* pointer;
162 typedef const value_type& reference;
163 typedef const value_type& const_reference;
164 typedef ptrdiff_t difference_type;
165 typedef const value_type* const_iterator;
166 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
167
168 static const size_type npos;
169
170 public:
171 // We provide non-explicit singleton constructors so users can pass
172 // in a "const char*" or a "string" wherever a "StringPiece" is
173 // expected (likewise for char16, string16, StringPiece16).
174 BasicStringPiece() : ptr_(NULL), length_(0) {}
175 BasicStringPiece(const value_type* str)
176 : ptr_(str),
177 length_((str == NULL) ? 0 : STRING_TYPE::traits_type::length(str)) {}
178 BasicStringPiece(const STRING_TYPE& str)
179 : ptr_(str.data()), length_(str.size()) {}
180 BasicStringPiece(const value_type* offset, size_type len)
181 : ptr_(offset), length_(len) {}
182 BasicStringPiece(const typename STRING_TYPE::const_iterator& begin,
183 const typename STRING_TYPE::const_iterator& end)
184 : ptr_((end > begin) ? &(*begin) : NULL),
185 length_((end > begin) ? (size_type)(end - begin) : 0) {}
186
187 // data() may return a pointer to a buffer with embedded NULs, and the
188 // returned buffer may or may not be null terminated. Therefore it is
189 // typically a mistake to pass data() to a routine that expects a NUL
190 // terminated string.
191 const value_type* data() const { return ptr_; }
192 size_type size() const { return length_; }
193 size_type length() const { return length_; }
194 bool empty() const { return length_ == 0; }
195
196 void clear() {
197 ptr_ = NULL;
198 length_ = 0;
199 }
200 void set(const value_type* data, size_type len) {
201 ptr_ = data;
202 length_ = len;
203 }
204 void set(const value_type* str) {
205 ptr_ = str;
206 length_ = str ? STRING_TYPE::traits_type::length(str) : 0;
207 }
208
209 value_type operator[](size_type i) const { return ptr_[i]; }
210
211 void remove_prefix(size_type n) {
212 ptr_ += n;
213 length_ -= n;
214 }
215
216 void remove_suffix(size_type n) {
217 length_ -= n;
218 }
219
220 int compare(const BasicStringPiece<STRING_TYPE>& x) const {
221 int r = wordmemcmp(
222 ptr_, x.ptr_, (length_ < x.length_ ? length_ : x.length_));
223 if (r == 0) {
224 if (length_ < x.length_) r = -1;
225 else if (length_ > x.length_) r = +1;
226 }
227 return r;
228 }
229
230 STRING_TYPE as_string() const {
231 // std::string doesn't like to take a NULL pointer even with a 0 size.
232 return empty() ? STRING_TYPE() : STRING_TYPE(data(), size());
233 }
234
235 const_iterator begin() const { return ptr_; }
236 const_iterator end() const { return ptr_ + length_; }
237 const_reverse_iterator rbegin() const {
238 return const_reverse_iterator(ptr_ + length_);
239 }
240 const_reverse_iterator rend() const {
241 return const_reverse_iterator(ptr_);
242 }
243
244 size_type max_size() const { return length_; }
245 size_type capacity() const { return length_; }
246
247 static int wordmemcmp(const value_type* p,
248 const value_type* p2,
249 size_type N) {
250 return STRING_TYPE::traits_type::compare(p, p2, N);
251 }
252
253 // Sets the value of the given string target type to be the current string.
254 // This saves a temporary over doing |a = b.as_string()|
255 void CopyToString(STRING_TYPE* target) const {
256 internal::CopyToString(*this, target);
257 }
258
259 void AppendToString(STRING_TYPE* target) const {
260 internal::AppendToString(*this, target);
261 }
262
263 size_type copy(value_type* buf, size_type n, size_type pos = 0) const {
264 return internal::copy(*this, buf, n, pos);
265 }
266
267 // Does "this" start with "x"
268 bool starts_with(const BasicStringPiece& x) const {
269 return ((this->length_ >= x.length_) &&
270 (wordmemcmp(this->ptr_, x.ptr_, x.length_) == 0));
271 }
272
273 // Does "this" end with "x"
274 bool ends_with(const BasicStringPiece& x) const {
275 return ((this->length_ >= x.length_) &&
276 (wordmemcmp(this->ptr_ + (this->length_-x.length_),
277 x.ptr_, x.length_) == 0));
278 }
279
280 // find: Search for a character or substring at a given offset.
281 size_type find(const BasicStringPiece<STRING_TYPE>& s,
282 size_type pos = 0) const {
283 return internal::find(*this, s, pos);
284 }
285 size_type find(value_type c, size_type pos = 0) const {
286 return internal::find(*this, c, pos);
287 }
288
289 // rfind: Reverse find.
290 size_type rfind(const BasicStringPiece& s,
291 size_type pos = BasicStringPiece::npos) const {
292 return internal::rfind(*this, s, pos);
293 }
294 size_type rfind(value_type c, size_type pos = BasicStringPiece::npos) const {
295 return internal::rfind(*this, c, pos);
296 }
297
298 // find_first_of: Find the first occurence of one of a set of characters.
299 size_type find_first_of(const BasicStringPiece& s,
300 size_type pos = 0) const {
301 return internal::find_first_of(*this, s, pos);
302 }
303 size_type find_first_of(value_type c, size_type pos = 0) const {
304 return find(c, pos);
305 }
306
307 // find_first_not_of: Find the first occurence not of a set of characters.
308 size_type find_first_not_of(const BasicStringPiece& s,
309 size_type pos = 0) const {
310 return internal::find_first_not_of(*this, s, pos);
311 }
312 size_type find_first_not_of(value_type c, size_type pos = 0) const {
313 return internal::find_first_not_of(*this, c, pos);
314 }
315
316 // find_last_of: Find the last occurence of one of a set of characters.
317 size_type find_last_of(const BasicStringPiece& s,
318 size_type pos = BasicStringPiece::npos) const {
319 return internal::find_last_of(*this, s, pos);
320 }
321 size_type find_last_of(value_type c,
322 size_type pos = BasicStringPiece::npos) const {
323 return rfind(c, pos);
324 }
325
326 // find_last_not_of: Find the last occurence not of a set of characters.
327 size_type find_last_not_of(const BasicStringPiece& s,
328 size_type pos = BasicStringPiece::npos) const {
329 return internal::find_last_not_of(*this, s, pos);
330 }
331 size_type find_last_not_of(value_type c,
332 size_type pos = BasicStringPiece::npos) const {
333 return internal::find_last_not_of(*this, c, pos);
334 }
335
336 // substr.
337 BasicStringPiece substr(size_type pos,
338 size_type n = BasicStringPiece::npos) const {
339 return internal::substr(*this, pos, n);
340 }
341
342 protected:
343 const value_type* ptr_;
344 size_type length_;
345 };
346
347 template <typename STRING_TYPE>
348 const typename BasicStringPiece<STRING_TYPE>::size_type
349 BasicStringPiece<STRING_TYPE>::npos =
350 typename BasicStringPiece<STRING_TYPE>::size_type(-1);
351
352 // MSVC doesn't like complex extern templates and DLLs.
353 #if !defined(COMPILER_MSVC)
354 extern template class BASE_EXPORT BasicStringPiece<std::string>;
355 extern template class BASE_EXPORT BasicStringPiece<string16>;
356 #endif
357
358 // StingPiece operators --------------------------------------------------------
359
360 BASE_EXPORT bool operator==(const StringPiece& x, const StringPiece& y);
361
362 inline bool operator!=(const StringPiece& x, const StringPiece& y) {
363 return !(x == y);
364 }
365
366 inline bool operator<(const StringPiece& x, const StringPiece& y) {
367 const int r = StringPiece::wordmemcmp(
368 x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size()));
369 return ((r < 0) || ((r == 0) && (x.size() < y.size())));
370 }
371
372 inline bool operator>(const StringPiece& x, const StringPiece& y) {
373 return y < x;
374 }
375
376 inline bool operator<=(const StringPiece& x, const StringPiece& y) {
377 return !(x > y);
378 }
379
380 inline bool operator>=(const StringPiece& x, const StringPiece& y) {
381 return !(x < y);
382 }
383
384 // StringPiece16 operators -----------------------------------------------------
385
386 inline bool operator==(const StringPiece16& x, const StringPiece16& y) {
387 if (x.size() != y.size())
388 return false;
389
390 return StringPiece16::wordmemcmp(x.data(), y.data(), x.size()) == 0;
391 }
392
393 inline bool operator!=(const StringPiece16& x, const StringPiece16& y) {
394 return !(x == y);
395 }
396
397 inline bool operator<(const StringPiece16& x, const StringPiece16& y) {
398 const int r = StringPiece16::wordmemcmp(
399 x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size()));
400 return ((r < 0) || ((r == 0) && (x.size() < y.size())));
401 }
402
403 inline bool operator>(const StringPiece16& x, const StringPiece16& y) {
404 return y < x;
405 }
406
407 inline bool operator<=(const StringPiece16& x, const StringPiece16& y) {
408 return !(x > y);
409 }
410
411 inline bool operator>=(const StringPiece16& x, const StringPiece16& y) {
412 return !(x < y);
413 }
414
415 BASE_EXPORT std::ostream& operator<<(std::ostream& o,
416 const StringPiece& piece);
417
418 } // namespace base
419
420 // Hashing ---------------------------------------------------------------------
421
422 // We provide appropriate hash functions so StringPiece and StringPiece16 can
423 // be used as keys in hash sets and maps.
424
425 // This hash function is copied from base/containers/hash_tables.h. We don't
426 // use the ones already defined for string and string16 directly because it
427 // would require the string constructors to be called, which we don't want.
428 #define HASH_STRING_PIECE(StringPieceType, string_piece) \
429 std::size_t result = 0; \
430 for (StringPieceType::const_iterator i = string_piece.begin(); \
431 i != string_piece.end(); ++i) \
432 result = (result * 131) + *i; \
433 return result; \
434
435 namespace BASE_HASH_NAMESPACE {
436
437 template<>
438 struct hash<base::StringPiece> {
439 std::size_t operator()(const base::StringPiece& sp) const {
440 HASH_STRING_PIECE(base::StringPiece, sp);
441 }
442 };
443 template<>
444 struct hash<base::StringPiece16> {
445 std::size_t operator()(const base::StringPiece16& sp16) const {
446 HASH_STRING_PIECE(base::StringPiece16, sp16);
447 }
448 };
449
450 } // namespace BASE_HASH_NAMESPACE
451
452 #endif // BASE_STRINGS_STRING_PIECE_H_
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