Merge pull request #34 from amelsmajic/master

Option to throw exception when duplicate fields in section

README.md

@@ -69,6 +69,21 @@ int main()
 }
 ```
 
+When duplicate fields are decoded the previous value is simply overwritten by default. You can disallow duplicate fields from being overwritten by using the ```allowOverwriteDuplicateFields(false)``` function. If you do this, an exception will be thrown if a duplicate field is found inside a section.
+
+```cpp
+#include <inicpp.h>
+
+int main()
+{
+    // load an ini file
+    ini::IniFile myIni;
+    myIni.allowOverwriteDuplicateFields(false);
+    // throws an exception if the ini file has duplicate fields
+    myIni.load("some/ini/path");
+}
+```
+
 Sections and fields can be accessed using the index operator ```[]```.
 The values can be converted to various native types:
 

include/inicpp.h

@@ -419,6 +419,7 @@ namespace ini
         char esc_ = '\\';
         std::vector<std::string> commentPrefixes_ = { "#" , ";" };
         bool multiLineValues_ = false;
+        bool overwriteDuplicateFields_ = true;
 
         void eraseComment(const std::string &commentPrefix,
             std::string &str,
@@ -581,6 +582,16 @@ namespace ini
             multiLineValues_ = enable;
         }
 
+        /** Sets whether or not overwriting duplicate fields is allowed.
+          * If overwriting duplicate fields is not allowed,
+          * an exception is thrown when a duplicate field is found inside a section.
+          * Default is true.
+          * @param allowed Is overwriting duplicate fields allowed or not? */
+        void allowOverwriteDuplicateFields(bool allowed)
+        {
+            overwriteDuplicateFields_ = allowed;
+        }
+
         /** Tries to decode a ini file from the given input stream.
           * @param is input stream from which data should be read. */
         void decode(std::istream &is)
@@ -670,6 +681,13 @@ namespace ini
                         // retrieve field name and value
                         std::string name = line.substr(0, pos);
                         trim(name);
+                        if (!overwriteDuplicateFields_ && currentSection->count(name) != 0)
+                        {
+                            std::stringstream ss;
+                            ss << "l." << lineNo
+                               << ": ini parsing failed, duplicate field found";
+                            throw std::logic_error(ss.str());
+                        }
                         std::string value = line.substr(pos + 1, std::string::npos);
                         trim(value);
                         (*currentSection)[name] = value;

test/test_inifile.cpp

@@ -67,6 +67,17 @@ TEST_CASE("parse section with duplicate field", "IniFile")
     REQUIRE(inif["Foo"]["bar"].as<std::string>() == "world");
 }
 
+TEST_CASE("parse section with duplicate field and overwriteDuplicateFields_ set to true", "IniFile")
+{
+    ini::IniFile inif;
+    inif.allowOverwriteDuplicateFields(true);
+    inif.decode("[Foo]\nbar=hello\nbar=world");
+
+    REQUIRE(inif.size() == 1);
+    REQUIRE(inif["Foo"].size() == 1);
+    REQUIRE(inif["Foo"]["bar"].as<std::string>() == "world");
+}
+
 TEST_CASE("parse field as bool", "IniFile")
 {
     std::istringstream ss("[Foo]\nbar1=true\nbar2=false\nbar3=tRuE");
@@ -865,3 +876,10 @@ TEST_CASE("spaces are not taken into account in sections", "IniFile")
 
     REQUIRE(inif.find("Foo") != inif.end());
 }
+
+TEST_CASE("parse section with duplicate field and overwriteDuplicateFields_ set to false", "IniFile")
+{
+    ini::IniFile inif;
+    inif.allowOverwriteDuplicateFields(false);
+    REQUIRE_THROWS(inif.decode("[Foo]\nbar=hello\nbar=world"));
+}