Using a unified number converter to display short versions of numbers

src/main/java/appeng/util/ReadableNumberConverter.java

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+package appeng.util;
+
+
+/**
+ * Converter class to convert a large number into a SI system.
+ *
+ * @author thatsIch
+ * @version rv2
+ * @since rv2
+ */
+public enum ReadableNumberConverter
+{
+	INSTANCE;
+
+	/**
+	 * Defines the base for a division, non-si standard could be 1024 for kilobytes
+	 */
+	private static final int DIVISION_BASE = 1000;
+
+	/**
+	 * for lg(1000) = 3, just saves some calculation
+	 */
+	private static final double LOG_DIVISION_BASE = Math.log( DIVISION_BASE );
+
+	/**
+	 * String representation of the sorted postfixes
+	 */
+	private static final char[] ENCODED_POSTFIXES = "KMGTPE".toCharArray();
+
+	/**
+	 * if a result would be higher than this threshold,
+	 * it is pushed into the next bigger group,
+	 * so the display string is shorter
+	 */
+	private static final int SHORT_THRESHOLD = 100;
+
+	/**
+	 * Converts a number into a human readable form. It will not round the number, but floor it.
+	 *
+	 * Example: 15555L -> 15.5K
+	 *
+	 * @param number to be converted number
+	 *
+	 * @return String in SI format cut down as far as possible
+	 */
+	public String toHumanReadableForm( long number )
+	{
+		final String sign = this.getSign( number );
+		final long absNumber = Math.abs( number );
+
+		if( absNumber < DIVISION_BASE )
+			return Long.toString( absNumber );
+
+		final int exp = (int) ( Math.log( absNumber ) / LOG_DIVISION_BASE );
+		final char postFix = ENCODED_POSTFIXES[exp - 1];
+		final int result = (int) ( absNumber / Math.pow( DIVISION_BASE, exp ) );
+
+		return String.format( "%s%d%s", sign, result, postFix );
+	}
+
+	/**
+	 * Converts a number into a human readable form. It will not round the number, but floor it.
+	 * Will try to cut the number down 1 decimal earlier. This will limit the String size to 3 chars.
+	 *
+	 * Example: 900L -> 0.9K
+	 *
+	 * @param number to be converted number
+	 *
+	 * @return String in SI format cut down as far as possible
+	 */
+	public String toShortHumanReadableForm( long number )
+	{
+		final String sign = this.getSign( number );
+		final long absNumber = Math.abs( number );
+
+		if( absNumber < DIVISION_BASE )
+			return Long.toString( absNumber );
+
+		final int exp = (int) ( Math.log( absNumber ) / LOG_DIVISION_BASE );
+		final int result = (int) ( absNumber / Math.pow( DIVISION_BASE, exp ) );
+		if( result >= SHORT_THRESHOLD )
+		{
+			final int shortResult = result / SHORT_THRESHOLD;
+			final char postFix = ENCODED_POSTFIXES[exp];
+
+			return String.format( "%s.%d%s", sign, shortResult, postFix );
+		}
+		else
+		{
+			final char postFix = ENCODED_POSTFIXES[exp - 1];
+
+			return String.format( "%s%d%s", sign, result, postFix );
+		}
+	}
+
+	/**
+	 * Gets character representation of the sign of a number
+	 *
+	 * @param number maybe signed number
+	 *
+	 * @return '-' if the number is signed, else an empty character
+	 */
+	private String getSign( long number )
+	{
+		if ( number < 0 )
+		{
+			return "-";
+		}
+		else
+		{
+			return "";
+		}
+	}
+}