add Column#clamp

common/api/src/main/java/com/dfsek/terra/api/world/chunk/generation/util/Column.java

@@ -17,16 +17,30 @@ import com.dfsek.terra.api.world.WritableWorld;
 
 /**
  * A single vertical column of a world.
+ *
+ * <b>Due to the {@link #clamp(int, int)} method, the height of the column may not always be the same as the world! Be careful!</b>
  */
 public class Column<T extends WritableWorld> {
     private final int x;
     private final int z;
+    private final int min;
+    private final int max;
     private final T world;
     
     public Column(int x, int z, T world) {
         this.x = x;
         this.z = z;
         this.world = world;
+        this.max = world.getMaxHeight();
+        this.min = world.getMinHeight();
+    }
+    
+    public Column(int x, int z, T world, int min, int max) {
+        this.x = x;
+        this.z = z;
+        this.world = world;
+        this.max = min;
+        this.min = max;
     }
     
     public int getX() {
@@ -38,6 +52,9 @@ public class Column<T extends WritableWorld> {
     }
     
     public BlockState getBlock(int y) {
+        if(y >= max || y < min) {
+            throw new IllegalArgumentException("Y out of range [" + min + ", " + max + ")");
+        }
         return world.getBlockState(x, y, z);
     }
     
@@ -46,11 +63,11 @@ public class Column<T extends WritableWorld> {
     }
     
     public int getMinY() {
-        return world.getMinHeight();
+        return min;
     }
     
     public int getMaxY() {
-        return world.getMaxHeight();
+        return max;
     }
     
     public void forEach(IntConsumer function) {
@@ -59,6 +76,10 @@ public class Column<T extends WritableWorld> {
         }
     }
     
+    public Column<T> clamp(int min, int max) {
+        return new Column<>(x, z, world, min, max);
+    }
+    
     public BinaryColumn newBinaryColumn(IntToBooleanFunction function) {
         return new BinaryColumn(getMinY(), getMaxY(), function);
     }