Add Settings class for reading config files

CMakeLists.txt

@@ -231,6 +231,7 @@ set(mapper_SRCS
 	TileGenerator.cpp
 	ZlibDecompressor.cpp
 	Color.cpp
+	Settings.cpp
 	BlockPos.cpp
 	mapper.cpp
 )

Settings.cpp

@@ -0,0 +1,82 @@
+
+#include "Settings.h"
+
+static std::string trim(const std::string s)
+{
+    size_t start = s.find_first_not_of(" \t\r\n");
+    size_t end = s.find_last_not_of(" \t\r\n");
+    return s.substr(start, (end-start+1));
+}
+
+Settings::Settings(std::string filename, std::string msgName)
+	:  m_filename(filename),
+	   m_messageName(msgName)
+{
+	if (m_messageName == "")
+		m_messageName = m_filename;
+	m_file.open(m_filename.c_str(), std::ifstream::in);
+	if (!m_file.is_open())
+		throw std::runtime_error(std::string("Failed to open file '") + m_messageName + "'");
+}
+
+Settings::~Settings(void)
+{
+	m_file.close();
+}
+
+std::string Settings::get(std::string key)
+{
+	std::string value;
+	if (getGeneric(key, &value))
+		return value;
+	else
+		throw std::runtime_error(std::string("Failed to read key '") + key + "' from file '" + m_messageName + "'");
+}
+
+std::string Settings::get(std::string key, std::string defaultValue)
+{
+	std::string value;
+	if (getGeneric(key, &value))
+		return value;
+	else
+		return defaultValue;
+}
+
+bool Settings::getGeneric(std::string key, std::string *pvalue)
+{
+	std::string line;
+	int linenr = 0;
+	bool found = false;
+	m_file.clear();
+	m_file.seekg(0);
+	for (std::getline(m_file,line); m_file.good(); std::getline(m_file,line)) {
+		linenr++;
+		std::istringstream iline;
+		iline.str(line);
+		iline >> std::skipws;
+		std::string variable;
+		std::string eq;
+		iline >> variable;
+		if (variable != key)
+			continue;
+		found = true;
+		iline >> eq;
+		if (m_file.fail() || eq != "=") {
+			std::ostringstream oss;
+			oss << "Error parsing '" << key << "' in file " << m_messageName << " at line " << linenr << " (missing '=')";
+			throw std::runtime_error(oss.str());
+		}
+		if (pvalue) {
+			std::string value;
+			iline >> value;
+			if (m_file.fail()) {
+				std::ostringstream oss;
+				oss << "Error parsing value for '" << key << "' in file " << m_messageName << " at line " << linenr;
+				throw std::runtime_error(oss.str());
+			}
+			*pvalue = trim(value);
+		}
+	}
+	return found;
+}
+

Settings.h

@@ -0,0 +1,25 @@
+
+#ifndef _SETTINGS_H_
+#define _SETTINGS_H_
+
+#include <stdexcept>
+#include <sstream>
+#include <fstream>
+
+class Settings {
+public:
+	Settings(std::string filename, std::string msgName = "");
+	~Settings(void);
+	std::string get(std::string key);
+	std::string get(std::string key, std::string defaultValue);
+	bool check(std::string key) { return getGeneric(key); }
+	bool check(std::string key, std::string &value) { return getGeneric(key, &value); }
+private:
+	std::string m_filename;
+	std::string m_messageName;
+	std::ifstream m_file;
+
+	bool getGeneric(std::string key, std::string *pvalue = NULL);
+};
+
+#endif // _SETTINGS_H_