/// <summary>
/// This iterator provides range query support.
/// </summary>
/// <param name="startKey">Minimum inclusive key value of range.</param>
/// <param name="endKey">Maximum inclusive key value of range.</param>
/// <returns>An enumerator for all key/value pairs between startKey and endKey.</returns>
/// <remarks>
/// Neither <em>startKey</em> or <em>endKey</em> need to be present in the collection.
/// </remarks>
/// <example>
/// <code source="BtreeExamples\BtreeExample03\BtreeExample03.cs" lang="cs" />
/// </example>
public IEnumerable <KeyValuePair <TKey, TValue> > BetweenKeys(TKey startKey, TKey endKey)
{
int index;
Leaf <TKey, TValue> leaf = Find(startKey, out index);
// When the supplied start key is not be found, start with the next highest key.
if (index < 0)
{
index = ~index;
}
for (;;)
{
if (index < leaf.KeyCount)
{
if (leaf.GetKey(index).CompareTo(endKey) > 0)
{
yield break;
}
yield return(leaf.GetPair(index));
++index;
continue;
}
leaf = leaf.RightLeaf;
if (leaf == null)
{
yield break;
}
index = 0;
}
}
/// <summary>
/// This iterator provides range query support with ordered results.
/// </summary>
/// <param name="key">Minimum value of range.</param>
/// <returns>An enumerator for the collection for key values greater than or equal to <em>key</em>.</returns>
public IEnumerable <KeyValuePair <TKey, TValue> > SkipUntilKey(TKey key)
{
int index;
Leaf <TKey, TValue> leaf = Find(key, out index);
// When the supplied start key is not be found, start with the next highest key.
if (index < 0)
{
index = ~index;
}
for (;;)
{
if (index < leaf.KeyCount)
{
yield return(leaf.GetPair(index));
++index;
continue;
}
leaf = leaf.RightLeaf;
if (leaf == null)
{
yield break;
}
index = 0;
}
}
