1 // Copyright (c) 2006-2008 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 18 #ifndef BASE_STRING_PIECE_H_ 19 #define BASE_STRING_PIECE_H_ 20 21 #include <algorithm> 22 #include <iosfwd> 23 #include <string> 24 25 #include "base/basictypes.h" 26 27 namespace base { 28 29 class StringPiece { 30 public: 31 typedef size_t size_type; 32 33 private: 34 const char* ptr_; 35 size_type length_; 36 37 public: 38 // We provide non-explicit singleton constructors so users can pass 39 // in a "const char*" or a "string" wherever a "StringPiece" is 40 // expected. 41 StringPiece() : ptr_(NULL), length_(0) { } 42 StringPiece(const char* str) 43 : ptr_(str), length_((str == NULL) ? 0 : strlen(str)) { } 44 StringPiece(const std::string& str) 45 : ptr_(str.data()), length_(str.size()) { } 46 StringPiece(const char* offset, size_type len) 47 : ptr_(offset), length_(len) { } 48 49 // data() may return a pointer to a buffer with embedded NULs, and the 50 // returned buffer may or may not be null terminated. Therefore it is 51 // typically a mistake to pass data() to a routine that expects a NUL 52 // terminated string. 53 const char* data() const { return ptr_; } 54 size_type size() const { return length_; } 55 size_type length() const { return length_; } 56 bool empty() const { return length_ == 0; } 57 58 void clear() { 59 ptr_ = NULL; 60 length_ = 0; 61 } 62 void set(const char* data, size_type len) { 63 ptr_ = data; 64 length_ = len; 65 } 66 void set(const char* str) { 67 ptr_ = str; 68 length_ = str ? strlen(str) : 0; 69 } 70 void set(const void* data, size_type len) { 71 ptr_ = reinterpret_cast<const char*>(data); 72 length_ = len; 73 } 74 75 char operator[](size_type i) const { return ptr_[i]; } 76 77 void remove_prefix(size_type n) { 78 ptr_ += n; 79 length_ -= n; 80 } 81 82 void remove_suffix(size_type n) { 83 length_ -= n; 84 } 85 86 int compare(const StringPiece& x) const { 87 int r = wordmemcmp(ptr_, x.ptr_, std::min(length_, x.length_)); 88 if (r == 0) { 89 if (length_ < x.length_) r = -1; 90 else if (length_ > x.length_) r = +1; 91 } 92 return r; 93 } 94 95 std::string as_string() const { 96 // std::string doesn't like to take a NULL pointer even with a 0 size. 97 return std::string(!empty() ? data() : "", size()); 98 } 99 100 void CopyToString(std::string* target) const; 101 void AppendToString(std::string* target) const; 102 103 // Does "this" start with "x" 104 bool starts_with(const StringPiece& x) const { 105 return ((length_ >= x.length_) && 106 (wordmemcmp(ptr_, x.ptr_, x.length_) == 0)); 107 } 108 109 // Does "this" end with "x" 110 bool ends_with(const StringPiece& x) const { 111 return ((length_ >= x.length_) && 112 (wordmemcmp(ptr_ + (length_-x.length_), x.ptr_, x.length_) == 0)); 113 } 114 115 // standard STL container boilerplate 116 typedef char value_type; 117 typedef const char* pointer; 118 typedef const char& reference; 119 typedef const char& const_reference; 120 typedef ptrdiff_t difference_type; 121 static const size_type npos; 122 typedef const char* const_iterator; 123 typedef const char* iterator; 124 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 125 typedef std::reverse_iterator<iterator> reverse_iterator; 126 iterator begin() const { return ptr_; } 127 iterator end() const { return ptr_ + length_; } 128 const_reverse_iterator rbegin() const { 129 return const_reverse_iterator(ptr_ + length_); 130 } 131 const_reverse_iterator rend() const { 132 return const_reverse_iterator(ptr_); 133 } 134 135 size_type max_size() const { return length_; } 136 size_type capacity() const { return length_; } 137 138 size_type copy(char* buf, size_type n, size_type pos = 0) const; 139 140 size_type find(const StringPiece& s, size_type pos = 0) const; 141 size_type find(char c, size_type pos = 0) const; 142 size_type rfind(const StringPiece& s, size_type pos = npos) const; 143 size_type rfind(char c, size_type pos = npos) const; 144 145 size_type find_first_of(const StringPiece& s, size_type pos = 0) const; 146 size_type find_first_of(char c, size_type pos = 0) const { 147 return find(c, pos); 148 } 149 size_type find_first_not_of(const StringPiece& s, size_type pos = 0) const; 150 size_type find_first_not_of(char c, size_type pos = 0) const; 151 size_type find_last_of(const StringPiece& s, size_type pos = npos) const; 152 size_type find_last_of(char c, size_type pos = npos) const { 153 return rfind(c, pos); 154 } 155 size_type find_last_not_of(const StringPiece& s, size_type pos = npos) const; 156 size_type find_last_not_of(char c, size_type pos = npos) const; 157 158 StringPiece substr(size_type pos, size_type n = npos) const; 159 160 static int wordmemcmp(const char* p, const char* p2, size_type N) { 161 return memcmp(p, p2, N); 162 } 163 }; 164 165 bool operator==(const StringPiece& x, const StringPiece& y); 166 167 inline bool operator!=(const StringPiece& x, const StringPiece& y) { 168 return !(x == y); 169 } 170 171 inline bool operator<(const StringPiece& x, const StringPiece& y) { 172 const int r = StringPiece::wordmemcmp(x.data(), y.data(), 173 std::min(x.size(), y.size())); 174 return ((r < 0) || ((r == 0) && (x.size() < y.size()))); 175 } 176 177 inline bool operator>(const StringPiece& x, const StringPiece& y) { 178 return y < x; 179 } 180 181 inline bool operator<=(const StringPiece& x, const StringPiece& y) { 182 return !(x > y); 183 } 184 185 inline bool operator>=(const StringPiece& x, const StringPiece& y) { 186 return !(x < y); 187 } 188 189 // allow StringPiece to be logged (needed for unit testing). 190 extern std::ostream& operator<<(std::ostream& o, const StringPiece& piece); 191 192 } // namespace base 193 194 #endif // BASE_STRING_PIECE_H_ 195
