/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
<@pp.dropOutputFile />
<#list cast.types as type>
<#if type.major == "DecimalSparseDecimalDense">
<@pp.changeOutputFile name="/org/apache/drill/exec/expr/fn/impl/gcast/Cast${type.from}${type.to}.java" />
<#include "/@includes/license.ftl" />
package org.apache.drill.exec.expr.fn.impl.gcast;
<#include "/@includes/vv_imports.ftl" />
import org.apache.drill.exec.expr.DrillSimpleFunc;
import org.apache.drill.exec.expr.annotations.FunctionTemplate;
import org.apache.drill.exec.expr.annotations.FunctionTemplate.NullHandling;
import org.apache.drill.exec.expr.annotations.Output;
import org.apache.drill.exec.expr.annotations.Param;
import org.apache.drill.exec.expr.holders.*;
import org.apache.drill.exec.record.RecordBatch;
import org.apache.drill.exec.expr.annotations.Workspace;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.DrillBuf;
import java.nio.ByteBuffer;
/*
* This class is generated using freemarker and the ${.template_name} template.
*/
@SuppressWarnings("unused")
@FunctionTemplate(name = "cast${type.to?upper_case}",
scope = FunctionTemplate.FunctionScope.SIMPLE,
returnType = FunctionTemplate.ReturnType.DECIMAL_CAST,
nulls = NullHandling.NULL_IF_NULL)
public class Cast${type.from}${type.to} implements DrillSimpleFunc{
@Param ${type.from}Holder in;
@Inject DrillBuf buffer;
@Param BigIntHolder precision;
@Param BigIntHolder scale;
@Output ${type.to}Holder out;
public void setup() {
int size = (${type.arraySize} * (org.apache.drill.exec.util.DecimalUtility.INTEGER_SIZE));
buffer = buffer.reallocIfNeeded(size);
}
public void eval() {
out.buffer = buffer;
out.start = 0;
// Re initialize the buffer everytime
for (int i = 0; i < ${type.arraySize}; i++) {
out.setInteger(i, 0, out.start, out.buffer);
}
out.scale = (int) scale.value;
out.precision = (int) precision.value;
/* Before converting from a sparse representation to a dense representation
* we need to convert it to an intermediate representation. In the sparse
* representation we separate out the scale and the integer part of the decimal
* and pad the scale part with additional zeroes for ease of performing arithmetic
* operations. In the intermediate representation we strip out the extra zeroes and
* combine the scale and integer part.
*/
int[] intermediate = new int[in.nDecimalDigits - 1];
int index = in.nDecimalDigits - 1;
int actualDigits;
if (in.scale > 0 && (actualDigits = (in.scale % org.apache.drill.exec.util.DecimalUtility.MAX_DIGITS)) > 0) {
int paddedDigits = org.apache.drill.exec.util.DecimalUtility.MAX_DIGITS - actualDigits;
int paddedMask = (int) Math.pow(10, paddedDigits);
/* We have a scale that does not completely occupy a decimal
* digit, so we have padded zeroes to it for ease of arithmetic
* Truncate the extra zeroes added and move the digits to the right
*/
int temp = (in.getInteger(index, in.start, in.buffer)/paddedMask);
index--;
while(index >= 0) {
int transferDigits = (in.getInteger(index, in.start, in.buffer) % (paddedMask));
intermediate[index] = (int) (temp + (Math.pow(10, actualDigits) * transferDigits));
temp = (in.getInteger(index, in.start, in.buffer)/(paddedMask));
index--;
}
} else {
/* If the scale does not exist or it perfectly fits within a decimal digit
* then we have padded no zeroes, which means there can atmost be only 38 digits, which
* need only 5 decimal digit to be stored, simply copy over the integers
*/
for (int i = 1; i < in.nDecimalDigits; i++)
intermediate[i - 1] = in.getInteger(i, in.start, in.buffer);
}
/* Now we have an intermediate representation in the array intermediate[]
* Every number in the intermediate representation is base 1 billion number
* To represent it we require only 30 bits, but every integer has 32 bits.
* By shifting the bits around we can utilize the extra two bits on every
* number and create a dense representation
*/
/* Allocate a byte array */
int size = (((intermediate.length - 1) * org.apache.drill.exec.util.DecimalUtility.INTEGER_SIZE) + 1);
byte[] intermediateBytes = new byte[size];
java.nio.ByteBuffer wrapper = java.nio.ByteBuffer.wrap(intermediateBytes);
wrapper.put((byte) intermediate[0]);
for (int i = 1; i < intermediate.length; i++) {
wrapper.put(java.nio.ByteBuffer.allocate(org.apache.drill.exec.util.DecimalUtility.INTEGER_SIZE).putInt(intermediate[i]).array());
}
final int[] mask = {0x03, 0x0F, 0x3F, 0xFF};
int maskIndex = 0;
int shiftOrder = 2;
// Start just after the last integer and shift bits to the right
index = size - (org.apache.drill.exec.util.DecimalUtility.INTEGER_SIZE+ 1);
while (index >= 0) {
/* get the last bits that need to shifted to the next byte */
byte shiftBits = (byte) ((intermediateBytes[index] & mask[maskIndex]) << (8 - shiftOrder));
int shiftOrder1 = ((index % org.apache.drill.exec.util.DecimalUtility.INTEGER_SIZE) == 0) ? shiftOrder - 2 : shiftOrder;
/* transfer the bits from the left to the right */
intermediateBytes[index + 1] = (byte) (((intermediateBytes[index + 1] & 0xFF) >>> (shiftOrder1)) | shiftBits);
index--;
if ((index % org.apache.drill.exec.util.DecimalUtility.INTEGER_SIZE) == 0) {
/* We are on a border */
shiftOrder += 2;
maskIndex++;
}
}
<#if (type.from == "Decimal28Sparse") && (type.to == "Decimal38Dense")>
/* Decimal38Dense representation has four bytes more than that needed to
* represent Decimal28Dense. So our first four bytes are empty in that scenario
*/
int dstIndex = 4;
<#else>
int dstIndex = 0;
</#if>
// Set the bytes in the buffer
out.buffer.setBytes(dstIndex, intermediateBytes, 1, (size - 1));
out.setSign(in.getSign(in.start, in.buffer), out.start, out.buffer);
}
}
</#if>
</#list>