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 * Copyright (c) 2013, Salesforce.com, Inc.
 * All rights reserved.
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 * modification, are permitted provided that the following conditions are met:
 * 
 *     Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
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 *     this list of conditions and the following disclaimer in the documentation
 *     and/or other materials provided with the distribution.
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 *     be used to endorse or promote products derived from this software without 
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 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE 
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package com.salesforce.phoenix.expression.function;

import java.sql.SQLException;
import java.util.*;

import org.apache.hadoop.hbase.io.ImmutableBytesWritable;

import com.salesforce.phoenix.expression.Expression;
import com.salesforce.phoenix.parse.FunctionParseNode.Argument;
import com.salesforce.phoenix.parse.FunctionParseNode.BuiltInFunction;
import com.salesforce.phoenix.schema.PDataType;
import com.salesforce.phoenix.schema.tuple.Tuple;
import com.salesforce.phoenix.util.ByteUtil;


/**
 * 
 * Implementation of the RTrim(<string>) build-in function. It removes from the right end of
 * <string> space character and other function bytes in single byte utf8 characters set 
 * 
 * @author zhuang
 * @since 0.1
 */
@BuiltInFunction(name=RTrimFunction.NAME, args={
    @Argument(allowedTypes={PDataType.VARCHAR})})
public class RTrimFunction extends ScalarFunction {
    public static final String NAME = "RTRIM";
    private static final byte SPACE_UTF8 = (byte) 0x20;
    private static final byte SINGLE_BYTE_MASK = (byte) 0x80;

    private Integer maxLength;

    public RTrimFunction() { }

    public RTrimFunction(List<Expression> children) throws SQLException {
        super(children);
        if (getStringExpression().getDataType().isFixedWidth()) {
            maxLength = getStringExpression().getMaxLength();
        }
    }

    private Expression getStringExpression() {
        return children.get(0);
    }

    @Override
    public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
        // Starting from the end of the byte, look for all single bytes at the end of the string
        // that is below SPACE_UTF8 (space and control characters) or above (control chars).
        if (!getStringExpression().evaluate(tuple, ptr)) {
            return false;
        }
        if (ptr.getLength() == 0) {
            ptr.set(ByteUtil.EMPTY_BYTE_ARRAY);
            return true;
        }
        byte[] string = ptr.get();
        int offset = ptr.getOffset();
        int length = ptr.getLength();
        int i = offset + length - 1;
        for ( ; i >= offset; i--) {
            if ((string[i] & SINGLE_BYTE_MASK) == 0 && SPACE_UTF8 < string[i] && string[i] != 0x7f) {
                break;
            }
        }
        if (i == offset - 1) {
            ptr.set(ByteUtil.EMPTY_BYTE_ARRAY);
            return true;
        }
        ptr.set(string, offset, i - offset + 1);
        return true;
    }

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

    @Override
    public KeyFormationDirective getKeyFormationDirective() {
        return KeyFormationDirective.TRAVERSE_AND_LEAVE;
    }

    @Override
    public Integer getMaxLength() {
        return maxLength;
    }

    @Override
    public PDataType getDataType() {
        return PDataType.VARCHAR;
    }

    @Override
    public String getName() {
        return NAME;
    }

}

@@ -4253,35 +4253,36 @@
 %0A        return 
-tru
+fals
 e;%0A    %7D%0A%0A    @O

improve trim test