/// <summary>
/// Gets the hash of a byte array.
/// </summary>
/// <param name="bytes">The bytes.</param>
/// <param name="seed">The seed.</param>
/// <returns>The hash.</returns>
public UInt192 GetHash(byte[] bytes, UInt192 seed)
{
Documents.UInt128 hash128 = MurmurHash3.Hash128(bytes, bytes.Length, Documents.UInt128.Create(seed.GetLow(), seed.GetMid()));
ulong hash64 = MurmurHash3.Hash64(bytes, bytes.Length, seed.GetHigh());
return(UInt192.Create(hash128.GetLow(), hash128.GetHigh(), hash64));
}
/// <summary>
/// Gets the hash of a byte array.
/// </summary>
/// <param name="bytes">The bytes.</param>
/// <param name="seed">The seed.</param>
/// <returns>The hash.</returns>
public static UInt192 GetHash(byte[] bytes, UInt192 seed)
{
// TODO: Have MurmurHash3 work on Span<T> instead.
Documents.UInt128 hash128 = Microsoft.Azure.Documents.Routing.MurmurHash3.Hash128(
bytes,
bytes.Length,
Documents.UInt128.Create(seed.GetLow(), seed.GetMid()));
ulong hash64 = Microsoft.Azure.Documents.Routing.MurmurHash3.Hash64(bytes, bytes.Length, seed.GetHigh());
return(UInt192.Create(hash128.GetLow(), hash128.GetHigh(), hash64));
}
/// <summary>
/// Adds a string to the distinct map.
/// </summary>
/// <param name="value">The string to add.</param>
/// <returns>Whether or not the value was successfully added.</returns>
private bool AddStringValue(string value)
{
bool added = false;
int utf8Length = Encoding.UTF8.GetByteCount(value);
// If you fit the string with full fidelity in 24 bytes, then you might as well just hash the string.
if (utf8Length <= UnorderdDistinctMap.UInt192Length)
{
// Zero out the array since you want all trailing bytes to be 0 for the conversions that happen next.
Array.Clear(this.utf8Buffer, 0, this.utf8Buffer.Length);
Encoding.UTF8.GetBytes(value, 0, utf8Length, this.utf8Buffer, 0);
if (utf8Length == 0)
{
added = this.AddSimpleValue(SimpleValues.EmptyString);
}
else if (utf8Length <= UnorderdDistinctMap.UIntLength)
{
uint uintValue = BitConverter.ToUInt32(this.utf8Buffer, 0);
added = this.stringsLength4.Add(uintValue);
}
else if (utf8Length <= UnorderdDistinctMap.ULongLength)
{
ulong uLongValue = BitConverter.ToUInt64(this.utf8Buffer, 0);
added = this.stringLength8.Add(uLongValue);
}
else if (utf8Length <= UnorderdDistinctMap.UInt128Length)
{
UInt128 uInt128Value = UInt128.FromByteArray(this.utf8Buffer, 0);
added = this.stringLength16.Add(uInt128Value);
}
else
{
UInt192 uInt192Value = UInt192.FromByteArray(this.utf8Buffer, 0);
added = this.stringLength24.Add(uInt192Value);
}
}
else
{
// Else the string is too large and we will just store the hash.
UInt192 uint192Value = DistinctHash.GetHash(CosmosString.Create(value));
added = this.stringLength24Plus.Add(uint192Value);
}
return(added);
}
