/**
 * END USER LICENSE AGREEMENT (“EULA”)
 *
 * READ THIS AGREEMENT CAREFULLY (date: 9/13/2011):
 * http://www.akiban.com/licensing/20110913
 *
 * BY INSTALLING OR USING ALL OR ANY PORTION OF THE SOFTWARE, YOU ARE ACCEPTING
 * ALL OF THE TERMS AND CONDITIONS OF THIS AGREEMENT. YOU AGREE THAT THIS
 * AGREEMENT IS ENFORCEABLE LIKE ANY WRITTEN AGREEMENT SIGNED BY YOU.
 *
 * IF YOU HAVE PAID A LICENSE FEE FOR USE OF THE SOFTWARE AND DO NOT AGREE TO
 * THESE TERMS, YOU MAY RETURN THE SOFTWARE FOR A FULL REFUND PROVIDED YOU (A) DO
 * NOT USE THE SOFTWARE AND (B) RETURN THE SOFTWARE WITHIN THIRTY (30) DAYS OF
 * YOUR INITIAL PURCHASE.
 *
 * IF YOU WISH TO USE THE SOFTWARE AS AN EMPLOYEE, CONTRACTOR, OR AGENT OF A
 * CORPORATION, PARTNERSHIP OR SIMILAR ENTITY, THEN YOU MUST BE AUTHORIZED TO SIGN
 * FOR AND BIND THE ENTITY IN ORDER TO ACCEPT THE TERMS OF THIS AGREEMENT. THE
 * LICENSES GRANTED UNDER THIS AGREEMENT ARE EXPRESSLY CONDITIONED UPON ACCEPTANCE
 * BY SUCH AUTHORIZED PERSONNEL.
 *
 * IF YOU HAVE ENTERED INTO A SEPARATE WRITTEN LICENSE AGREEMENT WITH AKIBAN FOR
 * USE OF THE SOFTWARE, THE TERMS AND CONDITIONS OF SUCH OTHER AGREEMENT SHALL
 * PREVAIL OVER ANY CONFLICTING TERMS OR CONDITIONS IN THIS AGREEMENT.
 */

package com.akiban.server.types3.mcompat.mfuncs;

import com.akiban.server.types3.LazyList;
import com.akiban.server.types3.TExecutionContext;
import com.akiban.server.types3.TOverload;
import com.akiban.server.types3.TOverloadResult;
import com.akiban.server.types3.mcompat.mtypes.MNumeric;
import com.akiban.server.types3.mcompat.mtypes.MString;
import com.akiban.server.types3.pvalue.PValueSource;
import com.akiban.server.types3.pvalue.PValueTarget;
import com.akiban.server.types3.texpressions.TInputSetBuilder;
import com.akiban.server.types3.texpressions.TOverloadBase;

public class MChar extends TOverloadBase
{

    public static final TOverload INSTANCE = new MChar();
    
    private MChar(){}
    
    @Override
    protected void buildInputSets(TInputSetBuilder builder)
    {
        builder.vararg(MNumeric.BIGINT);
    }

    @Override
    protected void doEvaluate(TExecutionContext context, LazyList<? extends PValueSource> inputs, PValueTarget output)
    {
        // length of the varbin string
        int length = 0;
        
        // legnth of each sub string
        int lengths[] = new int[inputs.size()];
        
        int n = 0;
        for(PValueSource num : inputs)
            length += lengths[n++] = (int)(Math.log(num.getInt64()) / DIV + 1);
        
        byte ret[] = new byte[length];
        
        int pos = 0;
        for (n = 0; n < lengths.length; ++n)
            parse(inputs.get(n).getInt64(), ret, pos += lengths[n]);
        
        output.putBytes(ret);
    }

    @Override
    public String overloadName()
    {
        return "CHAR";
    }

    @Override
    public TOverloadResult resultType()
    {
        // TODO: calculate the length of varbinary
        return TOverloadResult.fixed(MString.VARBINARY.instance());
    }
    
    private static final long MASK = 0xff;
    private static final double DIV = Math.log(256);
    
    /**
     * TODO: byte is too small ==> causes overflow, but this is what underlies VARBINARY
     * @param num
     * 
     */
    static void parse(long num, byte[] ret, int limit)
    {
        int n = limit -1;
        
        while (num > 0)
        {
            ret[n--] = (byte)(num & MASK);
            num >>= 8;
        }
    }
}

@@ -2471,22 +2471,18 @@
 %5D = 
-(int)(Math.log
+byteLength
 (num
@@ -2497,29 +2497,10 @@
 4())
- / DIV + 1);%0A        
+;%0A
 %0A   
@@ -2535,24 +2535,16 @@
 ength%5D;%0A
-        
 %0A       
@@ -3087,24 +3087,185 @@
 (256);%0A    %0A
+    private static int byteLength(long num)%0A    %7B%0A        return num %3C 255 %0A                    ? 1%0A                    : (int)(Math.log(num) / DIV + 1); %0A    %7D%0A
     /**%0A    

clean up