| // Copyright 2004 and onwards Google Inc. |
| // |
| // |
| |
| #include "kudu/gutil/strings/stringpiece.h" |
| |
| #include <algorithm> |
| #include <climits> |
| #include <cstring> |
| #include <string> |
| |
| #include <glog/logging.h> |
| |
| #include "kudu/gutil/hash/legacy_hash.h" |
| #include "kudu/gutil/stl_util.h" |
| #include "kudu/gutil/strings/memutil.h" |
| |
| using std::min; |
| using std::string; |
| |
| namespace std { |
| size_t hash<StringPiece>::operator()(StringPiece s) const { |
| return HashTo32(s.data(), s.size()); |
| } |
| } // namespace std |
| |
| std::ostream& operator<<(std::ostream& o, StringPiece piece) { |
| o.write(piece.data(), piece.size()); |
| return o; |
| } |
| |
| StringPiece::StringPiece(StringPiece x, int pos) |
| : ptr_(x.ptr_ + pos), length_(x.length_ - pos) { |
| DCHECK_LE(0, pos); |
| DCHECK_LE(pos, x.length_); |
| } |
| |
| StringPiece::StringPiece(StringPiece x, int pos, int len) |
| : ptr_(x.ptr_ + pos), length_(min(len, x.length_ - pos)) { |
| DCHECK_LE(0, pos); |
| DCHECK_LE(pos, x.length_); |
| DCHECK_GE(len, 0); |
| } |
| |
| void StringPiece::CopyToString(string* target) const { |
| STLAssignToString(target, ptr_, length_); |
| } |
| |
| void StringPiece::AppendToString(string* target) const { |
| STLAppendToString(target, ptr_, length_); |
| } |
| |
| int StringPiece::copy(char* buf, size_type n, size_type pos) const { |
| int ret = min(length_ - pos, n); |
| memcpy(buf, ptr_ + pos, ret); |
| return ret; |
| } |
| |
| bool StringPiece::contains(StringPiece s) const { |
| return find(s, 0) != npos; |
| } |
| |
| int StringPiece::find(StringPiece s, size_type pos) const { |
| if (length_ <= 0 || pos > static_cast<size_type>(length_)) { |
| if (length_ == 0 && pos == 0 && s.length_ == 0) return 0; |
| return npos; |
| } |
| const char *result = memmatch(ptr_ + pos, length_ - pos, |
| s.ptr_, s.length_); |
| return result ? result - ptr_ : npos; |
| } |
| |
| int StringPiece::find(char c, size_type pos) const { |
| if (length_ <= 0 || pos >= static_cast<size_type>(length_)) { |
| return npos; |
| } |
| const char* result = static_cast<const char*>( |
| memchr(ptr_ + pos, c, length_ - pos)); |
| return result != nullptr ? result - ptr_ : npos; |
| } |
| |
| int StringPiece::rfind(StringPiece s, size_type pos) const { |
| if (length_ < s.length_) return npos; |
| const size_t ulen = length_; |
| if (s.length_ == 0) return min(ulen, pos); |
| |
| const char* last = ptr_ + 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; |
| } |
| |
| // Search range is [0..pos] inclusive. If pos == npos, search everything. |
| int StringPiece::rfind(char c, size_type pos) const { |
| // Note: memrchr() is not available on Windows. |
| if (length_ <= 0) return npos; |
| for (int i = 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(StringPiece characters_wanted, |
| bool* table) { |
| const int length = characters_wanted.length(); |
| const char* const data = characters_wanted.data(); |
| for (int i = 0; i < length; ++i) { |
| table[static_cast<unsigned char>(data[i])] = true; |
| } |
| } |
| |
| int StringPiece::find_first_of(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 (int i = pos; i < length_; ++i) { |
| if (lookup[static_cast<unsigned char>(ptr_[i])]) { |
| return i; |
| } |
| } |
| return npos; |
| } |
| |
| int StringPiece::find_first_not_of(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 (int i = pos; i < length_; ++i) { |
| if (!lookup[static_cast<unsigned char>(ptr_[i])]) { |
| return i; |
| } |
| } |
| return npos; |
| } |
| |
| int StringPiece::find_first_not_of(char c, size_type pos) const { |
| if (length_ <= 0) return npos; |
| |
| for (; pos < static_cast<size_type>(length_); ++pos) { |
| if (ptr_[pos] != c) { |
| return pos; |
| } |
| } |
| return npos; |
| } |
| |
| int StringPiece::find_last_of(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 (int i = min(pos, static_cast<size_type>(length_ - 1)); |
| i >= 0; --i) { |
| if (lookup[static_cast<unsigned char>(ptr_[i])]) { |
| return i; |
| } |
| } |
| return npos; |
| } |
| |
| int StringPiece::find_last_not_of(StringPiece s, size_type pos) const { |
| if (length_ <= 0) return npos; |
| |
| int i = min(pos, static_cast<size_type>(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 >= 0; --i) { |
| if (!lookup[static_cast<unsigned char>(ptr_[i])]) { |
| return i; |
| } |
| } |
| return npos; |
| } |
| |
| int StringPiece::find_last_not_of(char c, size_type pos) const { |
| if (length_ <= 0) return npos; |
| |
| for (int i = min(pos, static_cast<size_type>(length_ - 1)); |
| i >= 0; --i) { |
| if (ptr_[i] != c) { |
| return i; |
| } |
| } |
| 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 StringPiece::size_type StringPiece::npos = size_type(-1); |