Added fromNumeral method

Auxilor · Jan 10, 2021 · db9c60c · db9c60c
1 parent a34b36d
commit db9c60c
Showing 1 changed file with 25 additions and 0 deletions.
diff --git a/src/main/java/com/willfp/eco/util/NumberUtils.java b/src/main/java/com/willfp/eco/util/NumberUtils.java
@@ -1,5 +1,6 @@
 package com.willfp.eco.util;
 
+import com.sun.javaws.exceptions.InvalidArgumentException;
 import lombok.experimental.UtilityClass;
 
 import java.text.DecimalFormat;
@@ -85,6 +86,30 @@ public String toNumeral(final int number) {
         }
     }
 
+    /**
+     * Get number from roman numeral.
+     *
+     * @param numeral The numeral to convert.
+     * @return The number, converted from a roman numeral.
+     */
+    public static int fromNumeral(String numeral) {
+        if (numeral.isEmpty()) return 0;
+        if (numeral.startsWith("M")) return 1000 + fromNumeral(numeral.substring(1));
+        if (numeral.startsWith("CM")) return 900 + fromNumeral(numeral.substring(2));
+        if (numeral.startsWith("D")) return 500 + fromNumeral(numeral.substring(1));
+        if (numeral.startsWith("CD")) return 400 + fromNumeral(numeral.substring(2));
+        if (numeral.startsWith("C")) return 100 + fromNumeral(numeral.substring(1));
+        if (numeral.startsWith("XC")) return 90 + fromNumeral(numeral.substring(2));
+        if (numeral.startsWith("L")) return 50 + fromNumeral(numeral.substring(1));
+        if (numeral.startsWith("XL")) return 40 + fromNumeral(numeral.substring(2));
+        if (numeral.startsWith("X")) return 10 + fromNumeral(numeral.substring(1));
+        if (numeral.startsWith("IX")) return 9 + fromNumeral(numeral.substring(2));
+        if (numeral.startsWith("V")) return 5 + fromNumeral(numeral.substring(1));
+        if (numeral.startsWith("IV")) return 4 + fromNumeral(numeral.substring(2));
+        if (numeral.startsWith("I")) return 1 + fromNumeral(numeral.substring(1));
+        throw new IllegalArgumentException("Number is invalid!");
+    }
+
     /**
      * Generate random integer in range.
      *