add hll_create2 scalar function

AggregateFunctions/Base.cpp

@@ -264,8 +264,25 @@ void* HllAggregateFunctionBase::getAggregateState(void* state, char* aggPtr) {
     return (void*)hll;
 }
 
+void* createHll() {
+    return new SerializedHyperLogLog(10, false);   
+}
+
+void deleteHll(void* hll) {
+    delete (SerializedHyperLogLog*)hll;  
+}
+
+void addItemToHll(void* hll, const VString& item) {
+    SerializedHyperLogLog* phll = (SerializedHyperLogLog*)hll;
+    phll->add(item.data(), item.length());
+}
+
+void getHllString(void* hll, VString& result) {
+    updateStringFromHll(result, (SerializedHyperLogLog*)hll);
+}
+
 void* SimpleHllAggregateFunctionBase::createHll() {
-    return new SerializedHyperLogLog(10, false);
+    return ::createHll();
 }
 
 void* SimpleHllAggregateFunctionBase::createLegacyHll() {

ScalarFunctions/HllCreate2.cpp

@@ -0,0 +1,98 @@
+/* Copyright (c) 2005 - 2012 Vertica, an HP company -*- C++ -*- */
+/* 
+ *
+ * Description: Example User Defined Scalar Function: Add 2 ints
+ *
+ * Create Date: Apr 29, 2011
+ */
+#include "Vertica.h"
+
+using namespace Vertica;
+
+int resultLength();
+void* createHll();
+void deleteHll(void* hll);
+void addItemToHll(void* hll, const VString& item);
+void getHllString(void* hll, VString& result);
+
+class exception;
+
+/*
+ * This is a simple function that adds two integers and returns the result
+ */
+class HllCreate2 : public ScalarFunction
+{
+public:
+
+    /*
+     * This method processes a block of rows in a single invocation.
+     *
+     * The inputs are retrieved via argReader
+     * The outputs are returned via resWriter
+     */
+    virtual void processBlock(ServerInterface &srvInterface,
+                              BlockReader &argReader,
+                              BlockWriter &resWriter)
+    {
+        try {
+          // Basic error checking
+          const SizedColumnTypes& typeMetadata = argReader.getTypeMetaData();
+          for(unsigned int i = 0; i < typeMetadata.getColumnCount(); i++) {
+            if (!typeMetadata.getColumnType(i).isVarchar()){
+              vt_report_error(0, "Function only accept arguments of type varchar");
+            }
+          }
+
+            // While we have inputs to process
+            do {
+              void* hll = createHll();
+
+              for(unsigned int i = 0; i < argReader.getNumCols(); i++) {
+                const VString& item = argReader.getStringRef(i);
+
+                addItemToHll(hll, item);
+              }
+
+              getHllString(hll, resWriter.getStringRef());
+              deleteHll(hll);
+
+              resWriter.next();
+            } while (argReader.next());
+        } catch(std::exception& e) {
+            // Standard exception. Quit.
+            vt_report_error(0, "Exception while processing block: [%s]", e.what());
+        }
+    }
+};
+
+class HllCreate2Factory : public ScalarFunctionFactory
+{
+protected:
+    int mMaxResultLength;
+
+public:
+
+    HllCreate2Factory() {
+        mMaxResultLength = resultLength();
+    }
+
+    // return an instance of Add2Ints to perform the actual addition.
+    virtual ScalarFunction *createScalarFunction(ServerInterface &interface)
+    { return vt_createFuncObject<HllCreate2>(interface.allocator); }
+
+    virtual void getPrototype(ServerInterface &interface,
+                              ColumnTypes &argTypes,
+                              ColumnTypes &returnType)
+    {
+        argTypes.addAny();
+        returnType.addVarchar();
+    }
+
+    virtual void getReturnType(ServerInterface &srvfloaterface, 
+                               const SizedColumnTypes &inputTypes, 
+                               SizedColumnTypes &outputTypes) {
+        outputTypes.addVarchar(mMaxResultLength);
+    }
+};
+
+RegisterFactory(HllCreate2Factory);

sql/udf.sql

@@ -6,4 +6,5 @@ Create or replace aggregate function HLL_CREATE_LEGACY as language 'C++' NAME 'H
 Create or replace aggregate function HLL_MERGE as language 'C++' NAME 'HllMergeFactory' Library libverticahll;
 Create or replace aggregate function HLL_MERGE_COMPUTE as language 'C++' NAME 'HllMergeComputeFactory' Library libverticahll;
 Create or replace function HLL_MERGE2 as language 'C++' NAME 'HllMerge2Factory' Library libverticahll;
-Create or replace function HLL_CONVERT_TO_LATEST as language 'C++' NAME 'HllConvertToLatestFactory' Library libverticahll NOT FENCED;
+Create or replace function HLL_CONVERT_TO_LATEST as language 'C++' NAME 'HllConvertToLatestFactory' Library libverticahll NOT FENCED;
+Create or replace function HLL_CREATE2 as language 'C++' NAME 'HllCreate2Factory' Library libverticahll NOT FENCED;