string_view_vector.h

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#ifndef GRAPHSCOPE_UTILS_STRING_VIEW_VECTOR_H_
#define GRAPHSCOPE_UTILS_STRING_VIEW_VECTOR_H_
 
#include <stdlib.h>
#include <string.h>
 
#include <string_view>
#include <vector>
 
namespace gs {
 
class StringViewVector {
 public:
 StringViewVector() { offsets_.push_back(0); }
 ~StringViewVector() {}
 
 void push_back(const std::string_view& val) {
 size_t old_size = buffer_.size();
 buffer_.resize(old_size + val.size());
 memcpy(&buffer_[old_size], val.data(), val.size());
 offsets_.push_back(buffer_.size());
 }
 
 void emplace_back(const std::string_view& val) {
 size_t old_size = buffer_.size();
 buffer_.resize(old_size + val.size());
 memcpy(&buffer_[old_size], val.data(), val.size());
 offsets_.push_back(buffer_.size());
 }
 
 size_t size() const {
 assert(offsets_.size() > 0);
 return offsets_.size() - 1;
 }
 
 std::string_view operator[](size_t index) const {
 size_t from = offsets_[index];
 size_t len = offsets_[index + 1] - from;
 return std::string_view(&buffer_[from], len);
 }
 
 std::vector<char>& content_buffer() { return buffer_; }
 
 const std::vector<char>& content_buffer() const { return buffer_; }
 
 std::vector<size_t>& offset_buffer() { return offsets_; }
 
 const std::vector<size_t>& offset_buffer() const { return offsets_; }
 
 void clear() {
 buffer_.clear();
 offsets_.clear();
 offsets_.push_back(0);
 }
 
 void swap(StringViewVector& rhs) {
 buffer_.swap(rhs.buffer_);
 offsets_.swap(rhs.offsets_);
 }
 
 private:
 std::vector<char> buffer_;
 std::vector<size_t> offsets_;
};
 
} // namespace gs
 
#endif // GRAPHSCOPE_UTILS_STRING_VIEW_VECTOR_H_