GRIFFIN: = (CHAR,CHAR) implementation

core/src/main/java/io/questdb/griffin/engine/functions/eq/EqCharCharFunctionFactory.java

+/*******************************************************************************
+ *    ___                  _   ____  ____
+ *   / _ \ _   _  ___  ___| |_|  _ \| __ )
+ *  | | | | | | |/ _ \/ __| __| | | |  _ \
+ *  | |_| | |_| |  __/\__ \ |_| |_| | |_) |
+ *   \__\_\\__,_|\___||___/\__|____/|____/
+ *
+ * Copyright (C) 2014-2019 Appsicle
+ *
+ * This program is free software: you can redistribute it and/or  modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ ******************************************************************************/
+
+package io.questdb.griffin.engine.functions.eq;
+
+import io.questdb.cairo.CairoConfiguration;
+import io.questdb.cairo.sql.Function;
+import io.questdb.cairo.sql.Record;
+import io.questdb.griffin.FunctionFactory;
+import io.questdb.griffin.engine.functions.BinaryFunction;
+import io.questdb.griffin.engine.functions.BooleanFunction;
+import io.questdb.std.ObjList;
+
+public class EqCharCharFunctionFactory implements FunctionFactory {
+    @Override
+    public String getSignature() {
+        return "=(AA)";
+    }
+
+    @Override
+    public Function newInstance(ObjList<Function> args, int position, CairoConfiguration configuration) {
+        // there are optimisation opportunities
+        // 1. when one of args is constant null comparison can boil down to checking
+        //    length of non-constant (must be -1)
+        // 2. when one of arguments is constant, save method call and use a field
+
+        Function chrFunc1 = args.getQuick(0);
+        Function chrFunc2 = args.getQuick(1);
+
+        return new Func(position, chrFunc1, chrFunc2);
+    }
+
+    private static class Func extends BooleanFunction implements BinaryFunction {
+
+        private final Function chrFunc1;
+        private final Function chrFunc2;
+
+        public Func(int position, Function chrFunc1, Function chrFunc2) {
+            super(position);
+            this.chrFunc1 = chrFunc1;
+            this.chrFunc2 = chrFunc2;
+        }
+
+        @Override
+        public Function getLeft() {
+            return chrFunc1;
+        }
+
+        @Override
+        public Function getRight() {
+            return chrFunc2;
+        }
+
+        @Override
+        public boolean getBool(Record rec) {
+            return chrFunc1.getChar(rec) == chrFunc2.getChar(rec);
+        }
+    }
+}

core/src/main/resources/META-INF/services/io.questdb.griffin.FunctionFactory

@@ -21,6 +21,29 @@
 #
 ################################################################################
 
+################################################################################
+#    ___                  _   ____  ____
+#   / _ \ _   _  ___  ___| |_|  _ \| __ )
+#  | | | | | | |/ _ \/ __| __| | | |  _ \
+#  | |_| | |_| |  __/\__ \ |_| |_| | |_) |
+#   \__\_\\__,_|\___||___/\__|____/|____/
+#
+# Copyright (C) 2014-2019 Appsicle
+#
+# This program is free software: you can redistribute it and/or  modify
+# it under the terms of the GNU Affero General Public License, version 3,
+# as published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+################################################################################
+
 # logical operations
 io.questdb.griffin.engine.functions.bool.OrFunctionFactory
 io.questdb.griffin.engine.functions.bool.AndFunctionFactory
@@ -35,6 +58,7 @@ io.questdb.griffin.engine.functions.eq.EqLong256FunctionFactory
 io.questdb.griffin.engine.functions.eq.EqStrCharFunctionFactory
 io.questdb.griffin.engine.functions.eq.EqSymStrFunctionFactory
 io.questdb.griffin.engine.functions.eq.EqSymCharFunctionFactory
+io.questdb.griffin.engine.functions.eq.EqCharCharFunctionFactory
 
 # '<>'
 io.questdb.griffin.engine.functions.eq.NotEqStrFunctionFactory