table.h

//
// Created by RainSure on 2023/11/11.
//
 
#ifndef RSMESH_TABLE_H
#define RSMESH_TABLE_H
 
#include <iostream>
#include <fstream>
#include <vector>
#include <numeric>
#include "Eigen/Core"
#include "types.h"
#include "numeric/roundtrip_string.h"
#include "boost/algorithm/string.hpp"
 
namespace rsmesh {
    using tabled = Eigen::Matrix<double, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor>;
    
    inline tabled read_table(const std::string& filename, const char* delimiters = " \t,") {
        std::ifstream ifs(filename);
        if(!ifs) {
            throw std::runtime_error("Failed to open file '" + filename + "'.");
        }
        
        std::vector<double> buffer;
        std::string line;
        
        auto n_cols = index_t{0};
        auto line_no = 0;
        
        while(std::getline(ifs, line)) {
            line_no ++;
            
            if (boost::starts_with(line, "#")) {
                continue;
            }
            
            std::vector<std::string> row;
            boost::split(row, line, boost::is_any_of(delimiters));
            
            auto row_size = static_cast<index_t>(row.size());
            
            if(n_cols == 0) {
                n_cols = row_size;
            } else if(row_size != n_cols) {
                std::cerr << "Skipping line " << line_no << " with a different number of columns." << std::endl;
                continue;
            }
            
            for(const auto& cell : row) {
                buffer.push_back(numeric::to_double(boost::trim_copy(cell)));
            }
        }
        
        if(n_cols == 0) {
            throw std::runtime_error("File '" + filename + "' is empty.");
        }
        
        auto n_rows = static_cast<index_t>(buffer.size()) / n_cols;
        return tabled::Map(buffer.data(), n_rows, n_cols);
    }
 
    template<class Derived>
    void write_table(const std::string& filename, const Eigen::MatrixBase<Derived>& table, char delimiter = ' ') {
        std::ofstream ofs(filename);
        if(!ofs) {
            throw std::runtime_error("Failed to open file '" + filename + "'.");
        }
 
        auto n_cols = table.cols();
        for(auto row : table.rowwise()) {
            for(index_t i = 0; i < n_cols; i ++) {
                ofs << numeric::to_string(row(i));
                if(i != n_cols - 1) {
                    ofs << delimiter;
                }
            }
            ofs << "\n";
        }
    }
}
 
 
#endif //RSMESH_TABLE_H