* order in the case of <code>valueAt(int)<code>.
* </p>
*/
+
+/*
+ * Imported into Jalview September 2016
+ * Change log:
+ * Sep 2016 method add(int, int) added for more efficient increment of counts
+ * (a single binary search, rather than one on read and one on write)
+ */
public class SparseIntArray implements Cloneable
{
private int[] mKeys;
*
* @param key
* @oparam toAdd
+ * @return the new value of the count for the key
+ * @throw ArithmeticException if the result would exceed the maximum value of
+ * an int
*/
- public void add(int key, int toAdd)
+ public int add(int key, int toAdd)
{
+ int newValue = toAdd;
int i = ContainerHelpers.binarySearch(mKeys, mSize, key);
if (i >= 0)
{
+ checkOverflow(mValues[i], toAdd);
mValues[i] += toAdd;
+ newValue = mValues[i];
}
else
{
int n = idealIntArraySize(mSize + 1);
int[] nkeys = new int[n];
int[] nvalues = new int[n];
- // Log.e("SparseIntArray", "grow " + mKeys.length + " to " + n);
System.arraycopy(mKeys, 0, nkeys, 0, mKeys.length);
System.arraycopy(mValues, 0, nvalues, 0, mValues.length);
mKeys = nkeys;
}
if (mSize - i != 0)
{
- // Log.e("SparseIntArray", "move " + (mSize - i));
System.arraycopy(mKeys, i, mKeys, i + 1, mSize - i);
System.arraycopy(mValues, i, mValues, i + 1, mSize - i);
}
mValues[i] = toAdd;
mSize++;
}
+ return newValue;
+ }
+
+ /**
+ * Throws ArithmeticException if adding addend to value would exceed the range
+ * of int
+ *
+ * @param value
+ * @param addend
+ */
+ static void checkOverflow(int value, int addend)
+ {
+ /*
+ * test cases being careful to avoid overflow while testing!
+ */
+ if (addend > 0)
+ {
+ if (value > 0 && Integer.MAX_VALUE - value < addend)
+ {
+ throw new ArithmeticException("Integer overflow adding " + addend
+ + " to " + value);
+ }
+ }
+ else if (addend < 0)
+ {
+ if (value < 0 && Integer.MIN_VALUE - value > addend)
+ {
+ throw new ArithmeticException("Integer underflow adding " + addend
+ + " to " + value);
+ }
+ }
}
}