1 // Copyright (c) 2011 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
6 // A string-like object that points to a sized piece of memory.
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.
14 // Systematic usage of StringPiece is encouraged as it will reduce unnecessary
15 // conversions from "const char*" to "string" and back again.
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.
23 #ifndef BASE_STRING_PIECE_H_
24 #define BASE_STRING_PIECE_H_
29 #include "base/base_export.h"
30 #include "base/basictypes.h"
31 #include "base/hash_tables.h"
32 #include "base/string16.h"
36 class BASE_EXPORT StringPiece {
38 // standard STL container boilerplate
39 typedef size_t size_type;
40 typedef char value_type;
41 typedef const char* pointer;
42 typedef const char& reference;
43 typedef const char& const_reference;
44 typedef ptrdiff_t difference_type;
45 typedef const char* const_iterator;
46 typedef const char* iterator;
47 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
48 typedef std::reverse_iterator<iterator> reverse_iterator;
50 static const size_type npos;
53 // We provide non-explicit singleton constructors so users can pass
54 // in a "const char*" or a "string" wherever a "StringPiece" is
56 StringPiece() : ptr_(NULL), length_(0) { }
57 StringPiece(const char* str)
58 : ptr_(str), length_((str == NULL) ? 0 : strlen(str)) { }
59 StringPiece(const std::string& str)
60 : ptr_(str.data()), length_(str.size()) { }
61 StringPiece(const char* offset, size_type len)
62 : ptr_(offset), length_(len) { }
64 // data() may return a pointer to a buffer with embedded NULs, and the
65 // returned buffer may or may not be null terminated. Therefore it is
66 // typically a mistake to pass data() to a routine that expects a NUL
68 const char* data() const { return ptr_; }
69 size_type size() const { return length_; }
70 size_type length() const { return length_; }
71 bool empty() const { return length_ == 0; }
77 void set(const char* data, size_type len) {
81 void set(const char* str) {
83 length_ = str ? strlen(str) : 0;
85 void set(const void* data, size_type len) {
86 ptr_ = reinterpret_cast<const char*>(data);
90 char operator[](size_type i) const { return ptr_[i]; }
92 void remove_prefix(size_type n) {
97 void remove_suffix(size_type n) {
101 int compare(const StringPiece& x) const {
103 ptr_, x.ptr_, (length_ < x.length_ ? length_ : x.length_));
105 if (length_ < x.length_) r = -1;
106 else if (length_ > x.length_) r = +1;
111 std::string as_string() const {
112 // std::string doesn't like to take a NULL pointer even with a 0 size.
113 return std::string(!empty() ? data() : "", size());
116 void CopyToString(std::string* target) const;
117 void AppendToString(std::string* target) const;
119 // Does "this" start with "x"
120 bool starts_with(const StringPiece& x) const {
121 return ((length_ >= x.length_) &&
122 (wordmemcmp(ptr_, x.ptr_, x.length_) == 0));
125 // Does "this" end with "x"
126 bool ends_with(const StringPiece& x) const {
127 return ((length_ >= x.length_) &&
128 (wordmemcmp(ptr_ + (length_-x.length_), x.ptr_, x.length_) == 0));
131 iterator begin() const { return ptr_; }
132 iterator end() const { return ptr_ + length_; }
133 const_reverse_iterator rbegin() const {
134 return const_reverse_iterator(ptr_ + length_);
136 const_reverse_iterator rend() const {
137 return const_reverse_iterator(ptr_);
140 size_type max_size() const { return length_; }
141 size_type capacity() const { return length_; }
143 size_type copy(char* buf, size_type n, size_type pos = 0) const;
145 size_type find(const StringPiece& s, size_type pos = 0) const;
146 size_type find(char c, size_type pos = 0) const;
147 size_type rfind(const StringPiece& s, size_type pos = npos) const;
148 size_type rfind(char c, size_type pos = npos) const;
150 size_type find_first_of(const StringPiece& s, size_type pos = 0) const;
151 size_type find_first_of(char c, size_type pos = 0) const {
154 size_type find_first_not_of(const StringPiece& s, size_type pos = 0) const;
155 size_type find_first_not_of(char c, size_type pos = 0) const;
156 size_type find_last_of(const StringPiece& s, size_type pos = npos) const;
157 size_type find_last_of(char c, size_type pos = npos) const {
158 return rfind(c, pos);
160 size_type find_last_not_of(const StringPiece& s, size_type pos = npos) const;
161 size_type find_last_not_of(char c, size_type pos = npos) const;
163 StringPiece substr(size_type pos, size_type n = npos) const;
165 static int wordmemcmp(const char* p, const char* p2, size_type N) {
166 return memcmp(p, p2, N);
174 class BASE_EXPORT StringPiece16 {
176 // standard STL container boilerplate
177 typedef size_t size_type;
178 typedef char16 value_type;
179 typedef const char16* pointer;
180 typedef const char16& reference;
181 typedef const char16& const_reference;
182 typedef ptrdiff_t difference_type;
183 typedef const char16* const_iterator;
184 typedef const char16* iterator;
185 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
186 typedef std::reverse_iterator<iterator> reverse_iterator;
189 // We provide non-explicit singleton constructors so users can pass
190 // in a "const char16*" or a "string16" wherever a "StringPiece16" is
192 StringPiece16() : ptr_(NULL), length_(0) { }
193 StringPiece16(const char16* str)
195 length_((str == NULL) ? 0 : string16::traits_type::length(str)) { }
196 StringPiece16(const string16& str)
197 : ptr_(str.data()), length_(str.size()) { }
198 StringPiece16(const char16* offset, size_type len)
199 : ptr_(offset), length_(len) { }
201 // data() may return a pointer to a buffer with embedded NULs, and the
202 // returned buffer may or may not be null terminated. Therefore it is
203 // typically a mistake to pass data() to a routine that expects a NUL
204 // terminated string.
205 const char16* data() const { return ptr_; }
206 size_type size() const { return length_; }
207 size_type length() const { return length_; }
208 bool empty() const { return length_ == 0; }
214 void set(const char16* data, size_type len) {
218 void set(const char16* str) {
220 length_ = str ? string16::traits_type::length(str) : 0;
223 char16 operator[](size_type i) const { return ptr_[i]; }
225 string16 as_string16() const {
226 // StringPiece claims that this is bad when data() is NULL, but unittesting
227 // seems to say otherwise.
228 return string16(data(), size());
231 iterator begin() const { return ptr_; }
232 iterator end() const { return ptr_ + length_; }
233 const_reverse_iterator rbegin() const {
234 return const_reverse_iterator(ptr_ + length_);
236 const_reverse_iterator rend() const {
237 return const_reverse_iterator(ptr_);
240 size_type max_size() const { return length_; }
241 size_type capacity() const { return length_; }
243 static int wordmemcmp(const char16* p, const char16* p2, size_type N) {
244 return string16::traits_type::compare(p, p2, N);
252 BASE_EXPORT bool operator==(const StringPiece& x, const StringPiece& y);
254 inline bool operator!=(const StringPiece& x, const StringPiece& y) {
258 inline bool operator<(const StringPiece& x, const StringPiece& y) {
259 const int r = StringPiece::wordmemcmp(
260 x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size()));
261 return ((r < 0) || ((r == 0) && (x.size() < y.size())));
264 inline bool operator>(const StringPiece& x, const StringPiece& y) {
268 inline bool operator<=(const StringPiece& x, const StringPiece& y) {
272 inline bool operator>=(const StringPiece& x, const StringPiece& y) {
276 inline bool operator==(const StringPiece16& x, const StringPiece16& y) {
277 if (x.size() != y.size())
280 return StringPiece16::wordmemcmp(x.data(), y.data(), x.size()) == 0;
283 inline bool operator!=(const StringPiece16& x, const StringPiece16& y) {
287 inline bool operator<(const StringPiece16& x, const StringPiece16& y) {
288 const int r = StringPiece16::wordmemcmp(
289 x.data(), y.data(), (x.size() < y.size() ? x.size() : y.size()));
290 return ((r < 0) || ((r == 0) && (x.size() < y.size())));
293 inline bool operator>(const StringPiece16& x, const StringPiece16& y) {
297 inline bool operator<=(const StringPiece16& x, const StringPiece16& y) {
301 inline bool operator>=(const StringPiece16& x, const StringPiece16& y) {
307 // We provide appropriate hash functions so StringPiece and StringPiece16 can
308 // be used as keys in hash sets and maps.
310 // This hash function is copied from base/hash_tables.h. We don't use the
311 // ones already defined for string and string16 directly because it would
312 // require the string constructors to be called, which we don't want.
313 #define HASH_STRING_PIECE(StringPieceType, string_piece) \
314 std::size_t result = 0; \
315 for (StringPieceType::const_iterator i = string_piece.begin(); \
316 i != string_piece.end(); ++i) \
317 result = (result * 131) + *i; \
320 namespace BASE_HASH_NAMESPACE {
321 #if defined(COMPILER_GCC)
324 struct hash<base::StringPiece> {
325 std::size_t operator()(const base::StringPiece& sp) const {
326 HASH_STRING_PIECE(base::StringPiece, sp);
330 struct hash<base::StringPiece16> {
331 std::size_t operator()(const base::StringPiece16& sp16) const {
332 HASH_STRING_PIECE(base::StringPiece16, sp16);
336 #elif defined(COMPILER_MSVC)
338 inline size_t hash_value(const base::StringPiece& sp) {
339 HASH_STRING_PIECE(base::StringPiece, sp);
341 inline size_t hash_value(const base::StringPiece16& sp16) {
342 HASH_STRING_PIECE(base::StringPiece16, sp16);
347 } // namespace BASE_HASH_NAMESPACE
349 #endif // BASE_STRING_PIECE_H_