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| 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.cc with modifications |
| 5 |
| 6 #include <algorithm> |
| 7 #include <ostream> |
| 8 |
| 9 #include "base/string_piece.h" |
| 10 |
| 11 namespace base { |
| 12 |
| 13 typedef StringPiece::size_type size_type; |
| 14 |
| 15 std::ostream& operator<<(std::ostream& o, const StringPiece& piece) { |
| 16 o.write(piece.data(), static_cast<std::streamsize>(piece.size())); |
| 17 return o; |
| 18 } |
| 19 |
| 20 bool operator==(const StringPiece& x, const StringPiece& y) { |
| 21 if (x.size() != y.size()) |
| 22 return false; |
| 23 |
| 24 return StringPiece::wordmemcmp(x.data(), y.data(), x.size()) == 0; |
| 25 } |
| 26 |
| 27 void StringPiece::CopyToString(std::string* target) const { |
| 28 target->assign(!empty() ? data() : "", size()); |
| 29 } |
| 30 |
| 31 void StringPiece::AppendToString(std::string* target) const { |
| 32 if (!empty()) |
| 33 target->append(data(), size()); |
| 34 } |
| 35 |
| 36 size_type StringPiece::copy(char* buf, size_type n, size_type pos) const { |
| 37 size_type ret = std::min(length_ - pos, n); |
| 38 memcpy(buf, ptr_ + pos, ret); |
| 39 return ret; |
| 40 } |
| 41 |
| 42 size_type StringPiece::find(const StringPiece& s, size_type pos) const { |
| 43 if (pos > length_) |
| 44 return npos; |
| 45 |
| 46 const char* result = std::search(ptr_ + pos, ptr_ + length_, |
| 47 s.ptr_, s.ptr_ + s.length_); |
| 48 const size_type xpos = result - ptr_; |
| 49 return xpos + s.length_ <= length_ ? xpos : npos; |
| 50 } |
| 51 |
| 52 size_type StringPiece::find(char c, size_type pos) const { |
| 53 if (pos >= length_) |
| 54 return npos; |
| 55 |
| 56 const char* result = std::find(ptr_ + pos, ptr_ + length_, c); |
| 57 return result != ptr_ + length_ ? static_cast<size_t>(result - ptr_) : npos; |
| 58 } |
| 59 |
| 60 size_type StringPiece::rfind(const StringPiece& s, size_type pos) const { |
| 61 if (length_ < s.length_) |
| 62 return npos; |
| 63 |
| 64 if (s.empty()) |
| 65 return std::min(length_, pos); |
| 66 |
| 67 const char* last = ptr_ + std::min(length_ - s.length_, pos) + s.length_; |
| 68 const char* result = std::find_end(ptr_, last, s.ptr_, s.ptr_ + s.length_); |
| 69 return result != last ? static_cast<size_t>(result - ptr_) : npos; |
| 70 } |
| 71 |
| 72 size_type StringPiece::rfind(char c, size_type pos) const { |
| 73 if (length_ == 0) |
| 74 return npos; |
| 75 |
| 76 for (size_type i = std::min(pos, length_ - 1); ; --i) { |
| 77 if (ptr_[i] == c) |
| 78 return i; |
| 79 if (i == 0) |
| 80 break; |
| 81 } |
| 82 return npos; |
| 83 } |
| 84 |
| 85 // For each character in characters_wanted, sets the index corresponding |
| 86 // to the ASCII code of that character to 1 in table. This is used by |
| 87 // the find_.*_of methods below to tell whether or not a character is in |
| 88 // the lookup table in constant time. |
| 89 // The argument `table' must be an array that is large enough to hold all |
| 90 // the possible values of an unsigned char. Thus it should be be declared |
| 91 // as follows: |
| 92 // bool table[UCHAR_MAX + 1] |
| 93 static inline void BuildLookupTable(const StringPiece& characters_wanted, |
| 94 bool* table) { |
| 95 const size_type length = characters_wanted.length(); |
| 96 const char* const data = characters_wanted.data(); |
| 97 for (size_type i = 0; i < length; ++i) { |
| 98 table[static_cast<unsigned char>(data[i])] = true; |
| 99 } |
| 100 } |
| 101 |
| 102 size_type StringPiece::find_first_of(const StringPiece& s, |
| 103 size_type pos) const { |
| 104 if (length_ == 0 || s.length_ == 0) |
| 105 return npos; |
| 106 |
| 107 // Avoid the cost of BuildLookupTable() for a single-character search. |
| 108 if (s.length_ == 1) |
| 109 return find_first_of(s.ptr_[0], pos); |
| 110 |
| 111 bool lookup[UCHAR_MAX + 1] = { false }; |
| 112 BuildLookupTable(s, lookup); |
| 113 for (size_type i = pos; i < length_; ++i) { |
| 114 if (lookup[static_cast<unsigned char>(ptr_[i])]) { |
| 115 return i; |
| 116 } |
| 117 } |
| 118 return npos; |
| 119 } |
| 120 |
| 121 size_type StringPiece::find_first_not_of(const StringPiece& s, |
| 122 size_type pos) const { |
| 123 if (length_ == 0) |
| 124 return npos; |
| 125 |
| 126 if (s.length_ == 0) |
| 127 return 0; |
| 128 |
| 129 // Avoid the cost of BuildLookupTable() for a single-character search. |
| 130 if (s.length_ == 1) |
| 131 return find_first_not_of(s.ptr_[0], pos); |
| 132 |
| 133 bool lookup[UCHAR_MAX + 1] = { false }; |
| 134 BuildLookupTable(s, lookup); |
| 135 for (size_type i = pos; i < length_; ++i) { |
| 136 if (!lookup[static_cast<unsigned char>(ptr_[i])]) { |
| 137 return i; |
| 138 } |
| 139 } |
| 140 return npos; |
| 141 } |
| 142 |
| 143 size_type StringPiece::find_first_not_of(char c, size_type pos) const { |
| 144 if (length_ == 0) |
| 145 return npos; |
| 146 |
| 147 for (; pos < length_; ++pos) { |
| 148 if (ptr_[pos] != c) { |
| 149 return pos; |
| 150 } |
| 151 } |
| 152 return npos; |
| 153 } |
| 154 |
| 155 size_type StringPiece::find_last_of(const StringPiece& s, size_type pos) const { |
| 156 if (length_ == 0 || s.length_ == 0) |
| 157 return npos; |
| 158 |
| 159 // Avoid the cost of BuildLookupTable() for a single-character search. |
| 160 if (s.length_ == 1) |
| 161 return find_last_of(s.ptr_[0], pos); |
| 162 |
| 163 bool lookup[UCHAR_MAX + 1] = { false }; |
| 164 BuildLookupTable(s, lookup); |
| 165 for (size_type i = std::min(pos, length_ - 1); ; --i) { |
| 166 if (lookup[static_cast<unsigned char>(ptr_[i])]) |
| 167 return i; |
| 168 if (i == 0) |
| 169 break; |
| 170 } |
| 171 return npos; |
| 172 } |
| 173 |
| 174 size_type StringPiece::find_last_not_of(const StringPiece& s, |
| 175 size_type pos) const { |
| 176 if (length_ == 0) |
| 177 return npos; |
| 178 |
| 179 size_type i = std::min(pos, length_ - 1); |
| 180 if (s.length_ == 0) |
| 181 return i; |
| 182 |
| 183 // Avoid the cost of BuildLookupTable() for a single-character search. |
| 184 if (s.length_ == 1) |
| 185 return find_last_not_of(s.ptr_[0], pos); |
| 186 |
| 187 bool lookup[UCHAR_MAX + 1] = { false }; |
| 188 BuildLookupTable(s, lookup); |
| 189 for (; ; --i) { |
| 190 if (!lookup[static_cast<unsigned char>(ptr_[i])]) |
| 191 return i; |
| 192 if (i == 0) |
| 193 break; |
| 194 } |
| 195 return npos; |
| 196 } |
| 197 |
| 198 size_type StringPiece::find_last_not_of(char c, size_type pos) const { |
| 199 if (length_ == 0) |
| 200 return npos; |
| 201 |
| 202 for (size_type i = std::min(pos, length_ - 1); ; --i) { |
| 203 if (ptr_[i] != c) |
| 204 return i; |
| 205 if (i == 0) |
| 206 break; |
| 207 } |
| 208 return npos; |
| 209 } |
| 210 |
| 211 StringPiece StringPiece::substr(size_type pos, size_type n) const { |
| 212 if (pos > length_) pos = length_; |
| 213 if (n > length_ - pos) n = length_ - pos; |
| 214 return StringPiece(ptr_ + pos, n); |
| 215 } |
| 216 |
| 217 const StringPiece::size_type StringPiece::npos = size_type(-1); |
| 218 |
| 219 } // namespace base |
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