io.questdb.griffin.engine.functions.eq.EqDoubleFunctionFactory Maven / Gradle / Ivy

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 *  Copyright (c) 2019-2022 QuestDB
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package io.questdb.griffin.engine.functions.eq;

import io.questdb.cairo.CairoConfiguration;
import io.questdb.cairo.ColumnType;
import io.questdb.cairo.sql.Function;
import io.questdb.cairo.sql.Record;
import io.questdb.griffin.FunctionFactory;
import io.questdb.griffin.SqlExecutionContext;
import io.questdb.griffin.engine.functions.BinaryFunction;
import io.questdb.griffin.engine.functions.NegatableBooleanFunction;
import io.questdb.griffin.engine.functions.UnaryFunction;
import io.questdb.std.IntList;
import io.questdb.std.Numbers;
import io.questdb.std.ObjList;

public class EqDoubleFunctionFactory implements FunctionFactory {
    @Override
    public String getSignature() {
        return "=(DD)";
    }

    @Override
    public boolean isBoolean() {
        return true;
    }

    @Override
    public Function newInstance(int position, ObjList args, IntList argPositions, CairoConfiguration configuration, SqlExecutionContext sqlExecutionContext) {
        // this is probably a special case factory
        // NaN is always a double, so this could lead comparisons of all primitive types
        // to NaN route to this factory. Obviously comparing naively will not work
        // We have to check arg types and when NaN is present we would generate special case
        // functions for NaN checks.

        Function left = args.getQuick(0);
        Function right = args.getQuick(1);

        int leftType = left.getType();
        int rightType = right.getType();

        if (isNullConstant(left, leftType)) {
            return dispatchUnaryFunc(right, rightType);
        }
        if (isNullConstant(right, rightType)) {
            return dispatchUnaryFunc(left, leftType);
        }
        return new Func(args.getQuick(0), args.getQuick(1));
    }

    private static boolean isNullConstant(Function operand, int operandType) {
        return operand.isConstant() &&
                (ColumnType.isDouble(operandType) && Double.isNaN(operand.getDouble(null))
                        ||
                        operandType == ColumnType.NULL);
    }

    private static Function dispatchUnaryFunc(Function operand, int operandType) {
        switch (ColumnType.tagOf(operandType)) {
            case ColumnType.INT:
                return new FuncIntIsNaN(operand);
            case ColumnType.LONG:
                return new FuncLongIsNaN(operand);
            case ColumnType.DATE:
                return new FuncDateIsNaN(operand);
            case ColumnType.TIMESTAMP:
                return new FuncTimestampIsNaN(operand);
            case ColumnType.FLOAT:
                return new FuncFloatIsNaN(operand);
            default:
                // double
                return new FuncDoubleIsNaN(operand);
        }
    }

    protected static class Func extends NegatableBooleanFunction implements BinaryFunction {
        // This function class uses both subtraction and equality to judge whether two parameters
        // are equal because subtraction is to prevent the judging mistakes with different
        // precision, and equality is for the comparison of Infinity. In java,
        // Infinity - Infinity = NaN, so it won't satisfy the subtraction situation. But
        // Infinity = Infinity, so use equality could solve this problem.

        protected final Function left;
        protected final Function right;

        public Func(Function left, Function right) {
            this.left = left;
            this.right = right;
        }

        @Override
        public boolean getBool(Record rec) {
            final double l = left.getDouble(rec);
            final double r = right.getDouble(rec);
            return negated != (l != l && r != r || Math.abs(l - r) < 0.0000000001 || l == r);
        }

        @Override
        public Function getLeft() {
            return left;
        }

        @Override
        public Function getRight() {
            return right;
        }
    }

    protected static class FuncIntIsNaN extends NegatableBooleanFunction implements UnaryFunction {
        protected final Function arg;

        public FuncIntIsNaN(Function arg) {
            this.arg = arg;
        }

        @Override
        public boolean getBool(Record rec) {
            return negated != (arg.getInt(rec) == Numbers.INT_NaN);
        }

        @Override
        public Function getArg() {
            return arg;
        }
    }

    protected static class FuncLongIsNaN extends NegatableBooleanFunction implements UnaryFunction {
        protected final Function arg;

        public FuncLongIsNaN(Function arg) {
            this.arg = arg;
        }

        @Override
        public boolean getBool(Record rec) {
            return negated != (arg.getLong(rec) == Numbers.LONG_NaN);
        }

        @Override
        public Function getArg() {
            return arg;
        }
    }

    protected static class FuncDateIsNaN extends NegatableBooleanFunction implements UnaryFunction {
        protected final Function arg;

        public FuncDateIsNaN(Function arg) {
            this.arg = arg;
        }

        @Override
        public boolean getBool(Record rec) {
            return negated != (arg.getDate(rec) == Numbers.LONG_NaN);
        }

        @Override
        public Function getArg() {
            return arg;
        }
    }

    protected static class FuncTimestampIsNaN extends NegatableBooleanFunction implements UnaryFunction {
        protected final Function arg;

        public FuncTimestampIsNaN(Function arg) {
            this.arg = arg;
        }

        @Override
        public boolean getBool(Record rec) {
            return negated != (arg.getTimestamp(rec) == Numbers.LONG_NaN);
        }

        @Override
        public Function getArg() {
            return arg;
        }
    }

    protected static class FuncFloatIsNaN extends NegatableBooleanFunction implements UnaryFunction {
        protected final Function arg;

        public FuncFloatIsNaN(Function arg) {
            this.arg = arg;
        }

        @Override
        public boolean getBool(Record rec) {
            return negated != (Float.isNaN(arg.getFloat(rec)));
        }

        @Override
        public Function getArg() {
            return arg;
        }
    }

    protected static class FuncDoubleIsNaN extends NegatableBooleanFunction implements UnaryFunction {
        protected final Function arg;

        public FuncDoubleIsNaN(Function arg) {
            this.arg = arg;
        }

        @Override
        public boolean getBool(Record rec) {
            return negated != (Double.isNaN(arg.getDouble(rec)));
        }

        @Override
        public Function getArg() {
            return arg;
        }
    }
}