public static IndexTable FromCollection(ICollection<object> items)
{
var result = new IndexTable ();
result.entries = new List<object> ();
if (items.Count <= byte.MaxValue)
result.type = Type.Tiny;
else if (items.Count <= UInt16.MaxValue)
result.type = Type.Small;
else
result.type = Type.Normal;
foreach (var value in items)
result.entries.Add (value);
return result;
}
public static IndexTable[] FromCollection(ICollection<object> items, int maxSplit)
{
if (items.Count == 0)
return null;
int bucketCount = (int)Math.Ceiling(items.Count / (float)byte.MaxValue);
if (bucketCount == 1 || bucketCount > maxSplit)
return new IndexTable[] { FromCollection (items) };
var keyList = new List<object>(items);
var result = new IndexTable[bucketCount];
for (int i = 0, k = 0; i < keyList.Count; i += byte.MaxValue, k++) {
int end = i + byte.MaxValue;
int count = Math.Min(end, keyList.Count) - i;
result[k] = FromCollection(keyList.GetRange(i, count));
}
return result;
}
private void EncodeIndexTable(IndexTable table)
{
int count = table.entries.Count;
if (count <= byte.MaxValue) {
mWriter.Write ((byte)IndexTable.Type.Tiny);
mWriter.Write((byte) count);
} else if (count <= UInt16.MaxValue) {
mWriter.Write ((byte)IndexTable.Type.Small);
mWriter.Write((UInt16) count);
} else {
mWriter.Write ((byte)IndexTable.Type.Normal);
mWriter.Write((UInt32) count);
}
foreach (var value in table.entries) {
EncodeElement (value, false);
}
}
private IndexTable ReadIndexTable()
{
uint count;
var indexType = (IndexTable.Type)mReader.ReadByte ();
switch (indexType) {
case IndexTable.Type.Tiny:
count = mReader.ReadByte();
break;
case IndexTable.Type.Small:
count = mReader.ReadUInt16();
break;
case IndexTable.Type.Normal:
count = mReader.ReadUInt32();
break;
default:
throw new Exception("Invalid index table type found");
}
var table = new IndexTable ();
table.type = indexType;
table.entries = new List<object>();
for (ulong i = 0; i < count; i++)
table.entries.Add(DecodeElement()); // XXX: do not consider nested elements
return table;
}
