/*
* 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
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.facebook.presto.operator.scalar;
import com.facebook.presto.spi.PrestoException;
import com.facebook.presto.spi.function.Description;
import com.facebook.presto.spi.function.ScalarFunction;
import com.facebook.presto.spi.function.SqlType;
import com.facebook.presto.spi.type.StandardTypes;
import static com.facebook.presto.spi.StandardErrorCode.INVALID_FUNCTION_ARGUMENT;
public final class BitwiseFunctions
{
private BitwiseFunctions() {}
@Description("count number of set bits in 2's complement representation")
@ScalarFunction
@SqlType(StandardTypes.BIGINT)
public static long bitCount(@SqlType(StandardTypes.BIGINT) long num, @SqlType(StandardTypes.BIGINT) long bits)
{
if (bits == 64) {
return Long.bitCount(num);
}
if (bits <= 1 || bits > 64) {
throw new PrestoException(INVALID_FUNCTION_ARGUMENT, "Bits specified in bit_count must be between 2 and 64, got " + bits);
}
long lowBitsMask = (1 << (bits - 1)) - 1; // set the least (bits - 1) bits
if (num > lowBitsMask || num < ~lowBitsMask) {
throw new PrestoException(INVALID_FUNCTION_ARGUMENT, "Number must be representable with the bits specified. " + num + " can not be represented with " + bits + " bits");
}
long mask = lowBitsMask | 0x8000_0000_0000_0000L; // set the least (bits - 1) bits and the sign bit
return Long.bitCount(num & mask);
}
@Description("bitwise NOT in 2's complement arithmetic")
@ScalarFunction
@SqlType(StandardTypes.BIGINT)
public static long bitwiseNot(@SqlType(StandardTypes.BIGINT) long num)
{
return ~num;
}
@Description("bitwise AND in 2's complement arithmetic")
@ScalarFunction
@SqlType(StandardTypes.BIGINT)
public static long bitwiseAnd(@SqlType(StandardTypes.BIGINT) long left, @SqlType(StandardTypes.BIGINT) long right)
{
return left & right;
}
@Description("bitwise OR in 2's complement arithmetic")
@ScalarFunction
@SqlType(StandardTypes.BIGINT)
public static long bitwiseOr(@SqlType(StandardTypes.BIGINT) long left, @SqlType(StandardTypes.BIGINT) long right)
{
return left | right;
}
@Description("bitwise XOR in 2's complement arithmetic")
@ScalarFunction
@SqlType(StandardTypes.BIGINT)
public static long bitwiseXor(@SqlType(StandardTypes.BIGINT) long left, @SqlType(StandardTypes.BIGINT) long right)
{
return left ^ right;
}
}