the begginning

utils/udfsdk/udfmysql.cpp

@@ -0,0 +1,179 @@
+#include <cmath>
+#include <iostream>
+#include <sstream>
+using namespace std;
+
+#include "idb_mysql.h"
+
+namespace {
+inline double cvtArgToDouble(int t, const char* v)
+{
+	double d = 0.0;
+	switch (t)
+	{
+	case INT_RESULT:
+		d = (double)(*((long long*)v));
+		break;
+	case REAL_RESULT:
+		d = *((double*)v);
+		break;
+	case DECIMAL_RESULT:
+	case STRING_RESULT:
+		d = strtod(v, 0);
+		break;
+	case ROW_RESULT:
+		break;
+	}
+	return d;
+}
+inline long long cvtArgToInt(int t, const char* v)
+{
+	long long ll = 0;
+	switch (t)
+	{
+	case INT_RESULT:
+		ll = *((long long*)v);
+		break;
+	case REAL_RESULT:
+		ll = (long long)(*((double*)v));
+		break;
+	case DECIMAL_RESULT:
+	case STRING_RESULT:
+		ll = strtoll(v, 0, 0);
+		break;
+	case ROW_RESULT:
+		break;
+	}
+	return ll;
+}
+inline string cvtArgToString(int t, const char* v)
+{
+	string str;
+	switch (t)
+	{
+	case INT_RESULT:
+	{
+		long long ll;
+		ll = *((long long*)v);
+		ostringstream oss;
+		oss << ll;
+		str = oss.str();
+		break;
+	}
+	case REAL_RESULT:
+	{
+		double d;
+		d = *((double*)v);
+		ostringstream oss;
+		oss << d;
+		str = oss.str();
+		break;
+	}
+	case DECIMAL_RESULT:
+	case STRING_RESULT:
+		str = v;
+		break;
+	case ROW_RESULT:
+		break;
+	}
+	return str;
+}
+}
+
+/****************************************************************************
+ * UDF function interface for MySQL connector to recognize is defined in
+ * this section. MySQL's UDF function creation guideline needs to be followed.
+ *
+ * Three interface need to be defined on the connector for each UDF function.
+ *
+ * XXX_init: To allocate the necessary memory for the UDF function and validate
+ *           the input.
+ * XXX_deinit: To clean up the memory.
+ * XXX: The function implementation.
+ * Detailed instruction can be found at MySQL source directory:
+ * ~/sql/udf_example.cc.
+ *
+ * Please note that the implementation of the function defined on the connector
+ * will only be called when all the input arguments are constant. e.g., 
+ * idb_add(2,3). That way, the function does not run in a distributed fashion 
+ * and could be slow. If there is a need for the UDF function to run with
+ * pure constant input, then one needs to put a implementation in the XXX
+ * body, which is very similar to the ones in getXXXval API. If there's no
+ * such need for a given UDF, then the XXX interface can just return a dummy
+ * result because this function will never be called.
+ */
+extern "C"
+{
+/**
+ * IDB_ADD connector stub
+ */
+#ifdef _MSC_VER
+__declspec(dllexport)
+#endif
+my_bool idb_add_init(UDF_INIT* initid, UDF_ARGS* args, char* message)
+{
+	if (args->arg_count != 2)
+	{
+		strcpy(message,"idb_add() requires two argument");
+		return 1;
+	}
+
+	return 0;
+}
+
+#ifdef _MSC_VER
+__declspec(dllexport)
+#endif
+void idb_add_deinit(UDF_INIT* initid)
+{
+}
+
+#ifdef _MSC_VER
+__declspec(dllexport)
+#endif
+double idb_add(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error)
+{
+	double op1, op2;
+
+	op1 = cvtArgToDouble(args->arg_type[0], args->args[0]);
+	op2 = cvtArgToDouble(args->arg_type[1], args->args[1]);
+
+	return op1+op2;
+}
+
+/**
+ * IDB_ISNULL connector stub
+ */
+ 
+#ifdef _MSC_VER
+__declspec(dllexport)
+#endif
+my_bool idb_isnull_init(UDF_INIT* initid, UDF_ARGS* args, char* message)
+{
+	if (args->arg_count != 1)
+	{
+		strcpy(message,"idb_isnull() requires one argument");
+		return 1;
+	}
+
+	return 0;
+}
+
+#ifdef _MSC_VER
+__declspec(dllexport)
+#endif
+void idb_isnull_deinit(UDF_INIT* initid)
+{
+}	
+
+#ifdef _MSC_VER
+__declspec(dllexport)
+#endif
+long long idb_isnull(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error)
+{
+	return 0;
+}
+
+}
+// vim:ts=4 sw=4:
+