eistype: add exceptions, add function to load eis spectrum from disk

eisgenerator/eistype.h

@@ -8,6 +8,7 @@ typedef double fvalue;
 
 namespace eis
 {
+
 class DataPoint
 {
 public:
@@ -109,8 +110,34 @@ public:
 	static std::vector<Range> rangesFromParamString(const std::string& paramStr, size_t count);
 };
 
+class parse_errror: public std::exception
+{
+	std::string whatStr;
+public:
+	parse_errror(const std::string& whatIn): whatStr(whatIn)
+	{}
+	virtual const char* what() const noexcept override
+	{
+		return whatStr.c_str();
+	}
+};
+
+class file_error: public std::exception
+{
+	std::string whatStr;
+public:
+	file_error(const std::string& whatIn): whatStr(whatIn)
+	{}
+	virtual const char* what() const noexcept override
+	{
+		return whatStr.c_str();
+	}
+};
+
 bool saveToDisk(const std::vector<DataPoint>& data, const std::string& fileName, std::string headStr = "");
 
+std::pair<std::vector<DataPoint>, std::string> loadFromDisk(const std::string& fileName);
+
 fvalue eisDistance(const std::vector<eis::DataPoint>& a, const std::vector<eis::DataPoint>& b);
 
 fvalue eisNyquistDistance(const std::vector<eis::DataPoint>& a, const std::vector<eis::DataPoint>& b);

eistype.cpp

@@ -19,8 +19,8 @@ bool eis::saveToDisk(const std::vector<DataPoint>& data, const std::string& file
 	}
 
 	if(!headStr.empty())
-		file<<headStr<<'\n';
-	file<<"omega,real,im\n";
+		file<<headStr;
+	file<<"\nomega,real,im\n";
 
 	for(const eis::DataPoint& point : data)
 		file<<point.omega<<','<<point.im.real()<<','<<point.im.imag()<<'\n';
@@ -28,6 +28,34 @@ bool eis::saveToDisk(const std::vector<DataPoint>& data, const std::string& file
 	return true;
 }
 
+std::pair<std::vector<DataPoint>, std::string> eis::loadFromDisk(const std::string& fileName)
+{
+	std::fstream file;
+	file.open(fileName, std::ios_base::in);
+	if(!file.is_open())
+		throw file_error("can not open " + fileName + " for reading\n");
+
+	std::pair<std::vector<DataPoint>, std::string> out;
+
+	std::getline(file, out.second);
+
+	std::string line;
+	std::getline(file, line);
+	while(file.good())
+	{
+		std::getline(file, line);
+		if(line.empty() || line[0] == '#')
+			continue;
+		std::vector<std::string> tokens = tokenize(line, ',');
+		if(tokens.size() != 3)
+			throw file_error("invalid line in " + fileName + ": " + line);
+		out.first.push_back(DataPoint({std::stod(tokens[1]), std::stod(tokens[2])}, std::stod(tokens[0])));
+	}
+
+	file.close();
+	return out;
+}
+
 void eis::Range::print(int level) const
 {
 	Log(static_cast<Log::Level>(level))<<"Range "<<start<<'-'<<end<<' '<<count<<" steps"<<(log ? " Log" : "");