Arrays.java

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package sec.sun.awt.geom;

/**
 *
 * @author Michael Deutch An inexpensive hack to the Arrays class so that we can
 * sort the curves. Instead of using a comparator object we are using a specific
 * instance of its compare method as required for adding Areas.
 */
public class Arrays {

    private static final int INSERTIONSORT_THRESHOLD = 7;

    public static void sort(Object[] a) {
        Object[] aux = new Object[a.length];
        int n = a.length;
        //for(int j=0;j<a.length;j++)
        for (int j = 0; j < n; j++) {
            aux[j] = a[j];
        }

        mergeSort(aux, a, 0, a.length, 0);
    }

    private static void swap(Object[] x, int a, int b) {
        Object t = x[a];
        x[a] = x[b];
        x[b] = t;
    }

    private static int compare(Object o1, Object o2) {
        CurveObject c1 = ((Edge) o1).getCurve();
        CurveObject c2 = ((Edge) o2).getCurve();
        double v1, v2;
        if ((v1 = c1.getYTop()) == (v2 = c2.getYTop())) {
            if ((v1 = c1.getXTop()) == (v2 = c2.getXTop())) {
                return 0;
            }
        }
        if (v1 < v2) {
            return -1;
        }
        return 1;
    }

    private static void mergeSort(Object[] src,
            Object[] dest,
            int low, int high, int off) {
        //Comparator c) {
        int length = high - low;

        // Insertion sort on smallest arrays
        if (length < INSERTIONSORT_THRESHOLD) {
            for (int i = low; i < high; i++) {
                for (int j = i; j > low && compare(dest[j - 1], dest[j]) > 0; j--) {
                    swap(dest, j, j - 1);
                }
            }
            return;
        }

        // Recursively sort halves of dest into src
        int destLow = low;
        int destHigh = high;
        low += off;
        high += off;
        int mid = (low + high) >>> 1;
        //mergeSort(dest, src, low, mid, -off, c);
        //mergeSort(dest, src, mid, high, -off, c);
        mergeSort(dest, src, low, mid, -off);
        mergeSort(dest, src, mid, high, -off);

        // If list is already sorted, just copy from src to dest.  This is an
        // optimization that results in faster sorts for nearly ordered lists.
        if (compare(src[mid - 1], src[mid]) <= 0) {
            System.arraycopy(src, low, dest, destLow, length);
           //arraycopy(src, low, dest, destLow, length);
            //return;
        }

        // Merge sorted halves (now in src) into dest
        for (int i = destLow, p = low, q = mid; i < destHigh; i++) {
            if (q >= high || p < mid && compare(src[p], src[q]) <= 0) {
                dest[i] = src[p++];
            } else {
                dest[i] = src[q++];
            }
        }
    }

    /**
     * @param src the source array.
     * @param srcPos starting position in the source array.
     * @param dest the destination array.
     * @param destPos starting position in the destination data.
     * @param length the number of array elements to be copied.
     * @exception IndexOutOfBoundsException if copying would cause access of
     * data outside array bounds.
     * @exception ArrayStoreException if an element in the <code>src</code>
     * array could not be stored into the <code>dest</code> array because of a
     * type mismatch.
     * @exception NullPointerException if either <code>src</code> or
     * <code>dest</code> is <code>null</code>.
     */
    public static void arraycopy(Object[] src, int srcPos,
            Object[] dest, int destPos,
            int length) {
        //int j=0;
        for (int j = 0; j < length; j++) {
            dest[j + destPos] = src[srcPos + j];
        }
    }

}