1 files changed, 19 insertions, 7 deletions

diff --git a/apps/SoilMoistureIo.h b/apps/SoilMoistureIo.h
index aff7c85..4edf4f4 100644
--- a/apps/SoilMoistureIo.h
+++ b/apps/SoilMoistureIo.h
@@ -34,7 +34,7 @@ public:
         return entries.end();
     }
 
-    string& operator[](string key) {
+    string &operator[](string key) {
         return entries[key];
     }
 
@@ -49,34 +49,46 @@ public:
 
 class CsvSampleOutputStream : public SampleOutputStream {
 public:
-    CsvSampleOutputStream(ostream& stream, vector<string> fields);
+    CsvSampleOutputStream(ostream &stream);
+
+    CsvSampleOutputStream(ostream &stream, vector<string> fields);
 
     void write(Sample values);
 
 private:
-    ostream& stream;
+    void writeHeader();
+
+    ostream &stream;
+    bool headerWritten;
+    bool filterFields;
     vector<string> fields;
 };
 
 class JsonSampleOutputStream : public SampleOutputStream {
 public:
-    JsonSampleOutputStream(ostream& stream, vector<string> fields);
+    JsonSampleOutputStream(ostream &stream);
+
+    JsonSampleOutputStream(ostream &stream, vector<string> fields);
 
     void write(Sample values);
 
 private:
-    ostream& stream;
+    ostream &stream;
+    bool filterFields;
     vector<string> fields;
 };
 
 class SqlSampleOutputStream : public SampleOutputStream {
 public:
-    SqlSampleOutputStream(ostream& stream, vector<string> fields);
+    SqlSampleOutputStream(ostream &stream);
+
+    SqlSampleOutputStream(ostream &stream, vector<string> fields);
 
     void write(Sample values);
 
 private:
-    ostream& stream;
+    ostream &stream;
+    bool filterFields;
     vector<string> fields;
 };