/// <summary>
/// Encodes each face as a varint64 with value kNumFaces * count + face.
/// 21 faces can fit in a single byte. Varint64 is used so that 4G faces
/// can be encoded instead of just 4G / 6 = ~700M.
/// </summary>
public void Encode(Encoder encoder)
{
encoder.Ensure(Encoder.kVarintMax64);
// It isn't necessary to encode the number of faces left for the last run,
// but since this would only help if there were more than 21 faces, it will
// be a small overall savings, much smaller than the bound encoding.
encoder.PutVarUInt64((UInt64)(S2CellId.kNumFaces * (Int64)Count + Face));
System.Diagnostics.Debug.Assert(encoder.Avail() >= 0);
}
/// <summary>
/// Encodes an unsigned integer in little-endian format using "length" bytes.
/// (The client must ensure that the encoder's buffer is large enough.)
///
/// REQUIRES: T is an unsigned integer type.
/// REQUIRES: 2 <= sizeof(T) <= 8
/// REQUIRES: 0 <= length <= sizeof(T)
/// REQUIRES: value < 256 ** length
/// REQUIRES: encoder.Avail() >= length
/// </summary>
public static void EncodeUintWithLength(UInt16 value, int length, Encoder encoder)
{
System.Diagnostics.Debug.Assert(length >= 0 && length <= sizeof(UInt16));
System.Diagnostics.Debug.Assert(encoder.Avail() >= length);
while (--length >= 0)
{
encoder.Put8((byte)value);
value = (UInt16)(value >> 8);
}
System.Diagnostics.Debug.Assert(value == 0);
}