com.bytezone.dm3270.orders.BufferAddress Maven / Gradle / Ivy

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This is a trimmed down version of https://github.com/dmolony/dm3270 to be used as TN3270 client library

There is a newer version: 0.15-lib

package com.bytezone.dm3270.orders;

public class BufferAddress {

  public static final byte[] ADDRESS = new byte[64];
  private static int columns = 80;                          // default value

  private int location;
  private final byte b1;
  private final byte b2;

  static {
    int value = 0x40;
    int ptr = 0;

    for (int i = 0; i < 4; i++) {
      ADDRESS[ptr++] = (byte) value++;
      for (int j = 0; j < 9; j++) {
        ADDRESS[ptr++] = (byte) (value++ | 0x80);
      }
      for (int j = 0; j < 6; j++) {
        ADDRESS[ptr++] = (byte) value++;
      }
    }

    ADDRESS[33] &= 0x7F;             // = 0x61;             // was 0xE1
    ADDRESS[48] |= (byte) 0x80;      // = (byte) 0xF0;      // was 0x70
  }

  public BufferAddress(byte b1, byte b2) {
    this.b1 = b1;
    this.b2 = b2;
    int flag = b1 & 0xC0;       // top two bits

    // using 14-bit method
    if (flag == 0) {
      location = (b1 & 0x3F) << 8;
      location |= (b2 & 0xFF);
    } else {
      location = (b1 & 0x3F) << 6;
      location |= (b2 & 0x3F);
    }
  }

  public BufferAddress(int location) {
    this.location = location;
    b1 = ADDRESS[location >> 6];
    b2 = ADDRESS[location & 0x3F];
  }

  public static void setScreenWidth(int width) {
    columns = width;
  }

  public int getLocation() {
    return location;
  }

  public int packAddress(byte[] buffer, int offset) {
    buffer[offset++] = ADDRESS[location >> 6];
    buffer[offset++] = ADDRESS[location & 0x3F];

    return offset;
  }

  @Override
  public String toString() {
    return String.format("%04d %03d/%03d : %02X %02X", location, location / columns,
        location % columns, b1, b2);
  }

}