SysexBuilder.java

package com.bitwig.extension.api.util.midi;

import java.nio.charset.StandardCharsets;
import java.util.Arrays;

public class SysexBuilder
{
   private final static int MAX_LENGTH = 512;

   public static SysexBuilder fromHex(final String hexString)
   {
      return new SysexBuilder().addHex(hexString);
   }

   public SysexBuilder addByte(int value)
   {
      mData[mLength++] = (byte) (value & 0x7f);
      return this;
   }

   public SysexBuilder addString(final String string, final int length)
   {
      byte[] ascii = string.getBytes(StandardCharsets.US_ASCII);

      for(int i=0; i<length; i++)
      {
         if (i < ascii.length)
         {
            mData[mLength++] = ascii[i];
         }
         else
         {
            mData[mLength++] = 32;
         }
      }

      return this;
   }

   public SysexBuilder add(final byte[] bytes)
   {
      for (int i = 0; i < bytes.length; i++)
      {
         mData[mLength++] = bytes[i];
      }

      return this;
   }

   public SysexBuilder addHex(final String hex)
   {
      String sysexMessage = hex.replace(" ", "");
      sysexMessage = sysexMessage.toUpperCase();

      if ((sysexMessage.length() & 1) != 0)
      {
         throw new IllegalArgumentException("Invalid sysex string");
      }

      final int bytes = sysexMessage.length() / 2;

      for(int i=0; i<bytes; i++)
      {
         mData[mLength++] = Integer.valueOf(sysexMessage.substring(i*2, i*2+2), 16).byteValue();
      }

      return this;
   }

   public byte[] terminate()
   {
      addByte(0x7f);
      return array();
   }

   public byte[] array()
   {
      return Arrays.copyOfRange(mData, 0, mLength);
   }

   private byte[] mData = new byte[MAX_LENGTH];
   private int mLength;
}