io.questdb.griffin.engine.functions.rnd.RndFloatCFunctionFactory Maven / Gradle / Ivy
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* Copyright (c) 2014-2019 Appsicle
* Copyright (c) 2019-2020 QuestDB
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
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package io.questdb.griffin.engine.functions.rnd;
import io.questdb.cairo.CairoConfiguration;
import io.questdb.cairo.sql.Function;
import io.questdb.cairo.sql.Record;
import io.questdb.cairo.sql.SymbolTableSource;
import io.questdb.griffin.FunctionFactory;
import io.questdb.griffin.SqlException;
import io.questdb.griffin.SqlExecutionContext;
import io.questdb.griffin.engine.functions.FloatFunction;
import io.questdb.std.ObjList;
import io.questdb.std.Rnd;
public class RndFloatCFunctionFactory implements FunctionFactory {
@Override
public String getSignature() {
return "rnd_float(i)";
}
@Override
public Function newInstance(ObjList args, int position, CairoConfiguration configuration, SqlExecutionContext sqlExecutionContext) throws SqlException {
int nanRate = args.getQuick(0).getInt(null);
if (nanRate < 0) {
throw SqlException.$(args.getQuick(0).getPosition(), "invalid NaN rate");
}
return new RndFunction(position, nanRate);
}
private static class RndFunction extends FloatFunction implements Function {
private final int nanRate;
private Rnd rnd;
public RndFunction(int position, int nanRate) {
super(position);
this.nanRate = nanRate + 1;
}
@Override
public float getFloat(Record rec) {
if ((rnd.nextInt() % nanRate) == 1) {
return Float.NaN;
}
return rnd.nextFloat();
}
@Override
public void init(SymbolTableSource symbolTableSource, SqlExecutionContext executionContext) {
this.rnd = executionContext.getRandom();
}
}
}