| // Copyright 2004 The RE2 Authors. All Rights Reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in string_piece.hh. |
| |
| #include "util/string_piece.hh" |
| |
| #include <algorithm> |
| |
| #include <limits.h> |
| |
| #ifndef HAVE_ICU |
| |
| typedef StringPiece::size_type size_type; |
| |
| void StringPiece::CopyToString(std::string* target) const { |
| target->assign(ptr_, length_); |
| } |
| |
| size_type StringPiece::find(const StringPiece& s, size_type pos) const { |
| // Not sure why length_ < 0 was here since it's std::size_t. |
| if (/*length_ < 0 || */pos > static_cast<size_type>(length_)) |
| return npos; |
| |
| const char* result = std::search(ptr_ + pos, ptr_ + length_, |
| s.ptr_, s.ptr_ + s.length_); |
| const size_type xpos = result - ptr_; |
| return xpos + s.length_ <= length_ ? xpos : npos; |
| } |
| |
| size_type StringPiece::find(char c, size_type pos) const { |
| if (length_ <= 0 || pos >= static_cast<size_type>(length_)) { |
| return npos; |
| } |
| const char* result = std::find(ptr_ + pos, ptr_ + length_, c); |
| return result != ptr_ + length_ ? result - ptr_ : npos; |
| } |
| |
| size_type StringPiece::rfind(const StringPiece& s, size_type pos) const { |
| if (length_ < s.length_) return npos; |
| const size_t ulen = length_; |
| if (s.length_ == 0) return std::min(ulen, pos); |
| |
| const char* last = ptr_ + std::min(ulen - s.length_, pos) + s.length_; |
| const char* result = std::find_end(ptr_, last, s.ptr_, s.ptr_ + s.length_); |
| return result != last ? result - ptr_ : npos; |
| } |
| |
| size_type StringPiece::rfind(char c, size_type pos) const { |
| if (length_ <= 0) return npos; |
| for (int i = std::min(pos, static_cast<size_type>(length_ - 1)); |
| i >= 0; --i) { |
| if (ptr_[i] == c) { |
| return i; |
| } |
| } |
| return npos; |
| } |
| |
| // For each character in characters_wanted, sets the index corresponding |
| // to the ASCII code of that character to 1 in table. This is used by |
| // the find_.*_of methods below to tell whether or not a character is in |
| // the lookup table in constant time. |
| // The argument `table' must be an array that is large enough to hold all |
| // the possible values of an unsigned char. Thus it should be be declared |
| // as follows: |
| // bool table[UCHAR_MAX + 1] |
| static inline void BuildLookupTable(const StringPiece& characters_wanted, |
| bool* table) { |
| const size_type length = characters_wanted.length(); |
| const char* const data = characters_wanted.data(); |
| for (size_type i = 0; i < length; ++i) { |
| table[static_cast<unsigned char>(data[i])] = true; |
| } |
| } |
| |
| size_type StringPiece::find_first_of(const StringPiece& s, |
| size_type pos) const { |
| if (length_ == 0 || s.length_ == 0) |
| return npos; |
| |
| // Avoid the cost of BuildLookupTable() for a single-character search. |
| if (s.length_ == 1) |
| return find_first_of(s.ptr_[0], pos); |
| |
| bool lookup[UCHAR_MAX + 1] = { false }; |
| BuildLookupTable(s, lookup); |
| for (size_type i = pos; i < length_; ++i) { |
| if (lookup[static_cast<unsigned char>(ptr_[i])]) { |
| return i; |
| } |
| } |
| return npos; |
| } |
| |
| size_type StringPiece::find_first_not_of(const StringPiece& s, |
| size_type pos) const { |
| if (length_ == 0) |
| return npos; |
| |
| if (s.length_ == 0) |
| return 0; |
| |
| // Avoid the cost of BuildLookupTable() for a single-character search. |
| if (s.length_ == 1) |
| return find_first_not_of(s.ptr_[0], pos); |
| |
| bool lookup[UCHAR_MAX + 1] = { false }; |
| BuildLookupTable(s, lookup); |
| for (size_type i = pos; i < length_; ++i) { |
| if (!lookup[static_cast<unsigned char>(ptr_[i])]) { |
| return i; |
| } |
| } |
| return npos; |
| } |
| |
| size_type StringPiece::find_first_not_of(char c, size_type pos) const { |
| if (length_ == 0) |
| return npos; |
| |
| for (; pos < length_; ++pos) { |
| if (ptr_[pos] != c) { |
| return pos; |
| } |
| } |
| return npos; |
| } |
| |
| size_type StringPiece::find_last_of(const StringPiece& s, size_type pos) const { |
| if (length_ == 0 || s.length_ == 0) |
| return npos; |
| |
| // Avoid the cost of BuildLookupTable() for a single-character search. |
| if (s.length_ == 1) |
| return find_last_of(s.ptr_[0], pos); |
| |
| bool lookup[UCHAR_MAX + 1] = { false }; |
| BuildLookupTable(s, lookup); |
| for (size_type i = std::min(pos, length_ - 1); ; --i) { |
| if (lookup[static_cast<unsigned char>(ptr_[i])]) |
| return i; |
| if (i == 0) |
| break; |
| } |
| return npos; |
| } |
| |
| size_type StringPiece::find_last_not_of(const StringPiece& s, |
| size_type pos) const { |
| if (length_ == 0) |
| return npos; |
| |
| size_type i = std::min(pos, length_ - 1); |
| if (s.length_ == 0) |
| return i; |
| |
| // Avoid the cost of BuildLookupTable() for a single-character search. |
| if (s.length_ == 1) |
| return find_last_not_of(s.ptr_[0], pos); |
| |
| bool lookup[UCHAR_MAX + 1] = { false }; |
| BuildLookupTable(s, lookup); |
| for (; ; --i) { |
| if (!lookup[static_cast<unsigned char>(ptr_[i])]) |
| return i; |
| if (i == 0) |
| break; |
| } |
| return npos; |
| } |
| |
| size_type StringPiece::find_last_not_of(char c, size_type pos) const { |
| if (length_ == 0) |
| return npos; |
| |
| for (size_type i = std::min(pos, length_ - 1); ; --i) { |
| if (ptr_[i] != c) |
| return i; |
| if (i == 0) |
| break; |
| } |
| return npos; |
| } |
| |
| StringPiece StringPiece::substr(size_type pos, size_type n) const { |
| if (pos > length_) pos = length_; |
| if (n > length_ - pos) n = length_ - pos; |
| return StringPiece(ptr_ + pos, n); |
| } |
| |
| const size_type StringPiece::npos = size_type(-1); |
| |
| #endif // !HAVE_ICU |