/**
* Adds an element to the end of the array.
*
* @param elem element to add
* @return self reference for convenience
*/
public ArrayBuilder append(final Value elem) {
if (inRight < Array.MAX_DIGIT) {
// just insert the element
vals[(mid + inRight) % CAP] = elem;
inRight++;
} else if (tree.isEmpty() && inLeft < Array.MAX_DIGIT) {
// move the middle to the right
mid = (mid + 1) % CAP;
vals[(mid + inRight + CAP - 1) % CAP] = elem;
inLeft++;
} else {
// push leaf node into the tree
final Value[] leaf = new Value[NODE_SIZE];
final int start = mid;
for (int i = 0; i < NODE_SIZE; i++) leaf[i] = vals[(start + i) % CAP];
tree.append(new LeafNode(leaf));
// move rest of the nodes to the right
final int rest = inRight - NODE_SIZE;
for (int i = 0; i < rest; i++) {
final int to = (mid + i) % CAP, from = (to + NODE_SIZE) % CAP;
vals[to] = vals[from];
}
// insert the element
vals[(mid + rest) % CAP] = elem;
inRight = rest + 1;
}
return this;
}
/**
* Appends the given array to this builder.
*
* @param arr array to append
* @return self reference for convenience
*/
public ArrayBuilder append(final Array arr) {
if (!(arr instanceof BigArray)) {
for (final Value val : arr.members()) append(val);
return this;
}
final BigArray big = (BigArray) arr;
final Value[] ls = big.left, rs = big.right;
final FingerTree<Value, Value> midTree = big.middle;
if (midTree.isEmpty()) {
for (final Value l : big.left) append(l);
for (final Value r : big.right) append(r);
return this;
}
// merge middle digits
if (tree.isEmpty()) {
final int k = inLeft + inRight;
final Value[] temp = new Value[k];
final int l = (mid - inLeft + CAP) % CAP, m = CAP - l;
if (k <= m) {
System.arraycopy(vals, l, temp, 0, k);
} else {
System.arraycopy(vals, l, temp, 0, m);
System.arraycopy(vals, 0, temp, m, k - m);
}
inLeft = inRight = 0;
tree.append(midTree);
for (int i = ls.length; --i >= 0; ) prepend(ls[i]);
for (int i = k; --i >= 0; ) prepend(temp[i]);
for (final Value r : rs) append(r);
return this;
}
final int inMiddle = inRight + big.left.length,
leaves = (inMiddle + Array.MAX_LEAF - 1) / Array.MAX_LEAF,
leafSize = (inMiddle + leaves - 1) / leaves;
for (int i = 0, l = 0; l < leaves; l++) {
final int inLeaf = Math.min(leafSize, inMiddle - i);
final Value[] leaf = new Value[inLeaf];
for (int p = 0; p < inLeaf; p++) {
leaf[p] = i < inRight ? vals[(mid + i) % CAP] : big.left[i - inRight];
i++;
}
tree.append(new LeafNode(leaf));
}
tree.append(big.middle);
inRight = 0;
for (final Value r : big.right) append(r);
return this;
}
/**
* Creates an {@link Array} containing the elements of this builder.
*
* @return resulting array
*/
public Array freeze() {
final int n = inLeft + inRight;
if (n == 0) return Array.empty();
final int start = (mid - inLeft + CAP) % CAP;
if (n <= Array.MAX_SMALL) {
// small int array, fill directly
final Value[] small = new Value[n];
for (int i = 0; i < n; i++) small[i] = vals[(start + i) % CAP];
return new SmallArray(small);
}
// deep array
final int a = tree.isEmpty() ? n / 2 : inLeft, b = n - a;
final Value[] ls = new Value[a], rs = new Value[b];
for (int i = 0; i < a; i++) ls[i] = vals[(start + i) % CAP];
for (int i = a; i < n; i++) rs[i - a] = vals[(start + i) % CAP];
return new BigArray(ls, tree.freeze(), rs);
}
@Override
public String toString() {
final StringBuilder sb = new StringBuilder(getClass().getSimpleName()).append('[');
if (tree.isEmpty()) {
final int n = inLeft + inRight, first = (mid - inLeft + CAP) % CAP;
if (n > 0) {
sb.append(vals[first]);
for (int i = 1; i < n; i++) sb.append(", ").append(vals[(first + i) % CAP]);
}
} else {
final int first = (mid - inLeft + CAP) % CAP;
sb.append(vals[first]);
for (int i = 1; i < inLeft; i++) sb.append(", ").append(vals[(first + i) % CAP]);
for (final Value val : tree) sb.append(", ").append(val);
for (int i = 0; i < inRight; i++) sb.append(", ").append(vals[(mid + i) % CAP]);
}
return sb.append(']').toString();
}
