| /* |
| * 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. |
| */ |
| package org.apache.drill.exec.expr.fn.impl; |
| |
| import org.apache.drill.exec.expr.DrillSimpleFunc; |
| import org.apache.drill.exec.expr.annotations.FunctionTemplate; |
| import org.apache.drill.exec.expr.annotations.Output; |
| import org.apache.drill.exec.expr.annotations.Param; |
| import org.apache.drill.exec.expr.holders.BigIntHolder; |
| import org.apache.drill.exec.expr.holders.VarBinaryHolder; |
| |
| public class ByteArrayFunctions { |
| private ByteArrayFunctions() { |
| } |
| |
| // TODO: implement optional length parameter |
| /** |
| * Evaluate a substring expression for a given value; specifying the start |
| * position, and optionally the end position. |
| * |
| * - If the start position is negative, start from abs(start) characters from |
| * the end of the buffer. |
| * |
| * - If no length is specified, continue to the end of the string. |
| * |
| * - If the substring expression's length exceeds the value's upward bound, the |
| * value's length will be used. |
| * |
| * - If the substring is invalid, return an empty string. |
| */ |
| @FunctionTemplate(names = {"bytesubstring", "byte_substr"}, |
| scope = FunctionTemplate.FunctionScope.SIMPLE, |
| nulls = FunctionTemplate.NullHandling.NULL_IF_NULL, |
| outputWidthCalculatorType = FunctionTemplate.OutputWidthCalculatorType.CUSTOM_CLONE_DEFAULT) |
| public static class ByteSubstring implements DrillSimpleFunc { |
| |
| @Param VarBinaryHolder in; |
| @Param BigIntHolder offset; |
| @Param BigIntHolder length; |
| @Output VarBinaryHolder out; |
| |
| @Override |
| public void setup() { } |
| |
| @Override |
| public void eval() { |
| out.buffer = in.buffer; |
| |
| // handle invalid values; e.g. SUBSTRING(value, 0, x) or SUBSTRING(value, x, 0) |
| if (offset.value == 0 || length.value <= 0) { |
| out.start = 0; |
| out.end = 0; |
| } else { |
| // handle negative and positive offset values |
| if (offset.value < 0) { |
| out.start = in.end + (int)offset.value; |
| } else { |
| out.start = in.start + (int)offset.value - 1; |
| } |
| // calculate end position from length and truncate to upper value bounds |
| if (out.start + length.value > in.end) { |
| out.end = in.end; |
| } else { |
| out.end = out.start + (int)length.value; |
| } |
| } |
| } |
| } |
| |
| @FunctionTemplate( |
| name = "length", |
| scope = FunctionTemplate.FunctionScope.SIMPLE, |
| nulls = FunctionTemplate.NullHandling.NULL_IF_NULL |
| ) |
| public static class ByteArrLength implements DrillSimpleFunc { |
| @Param VarBinaryHolder input; |
| @Output BigIntHolder out; |
| |
| @Override |
| public void setup() {} |
| |
| @Override |
| public void eval() { |
| out.value = input.end - input.start; |
| } |
| } |
| } |