/** <inheritdoc /> */
int IBinaryEqualityComparer.GetHashCode(IBinaryStream stream, int startPos, int length,
BinaryObjectSchemaHolder schema, int schemaId, Marshaller marshaller, IBinaryTypeDescriptor desc)
{
Debug.Assert(stream != null);
Debug.Assert(startPos >= 0);
Debug.Assert(length >= 0);
Debug.Assert(schema != null);
Debug.Assert(marshaller != null);
Debug.Assert(desc != null);
Validate();
stream.Flush();
// Preserve stream position.
var pos = stream.Position;
var reader = marshaller.StartUnmarshal(stream, BinaryMode.ForceBinary);
var fields = schema.GetFullSchema(schemaId);
int hash = 0;
foreach (var fieldName in FieldNames)
{
int fieldId = BinaryUtils.FieldId(desc.TypeId, fieldName, desc.NameMapper, desc.IdMapper);
int fieldHash = 0; // Null (missing) field hash code is 0.
int fieldPos;
if (fields.TryGetValue(fieldId, out fieldPos))
{
stream.Seek(startPos + fieldPos - BinaryObjectHeader.Size, SeekOrigin.Begin);
var fieldVal = reader.Deserialize <object>();
fieldHash = fieldVal != null?fieldVal.GetHashCode() : 0;
}
hash = 31 * hash + fieldHash;
}
// Restore stream position.
stream.Seek(pos, SeekOrigin.Begin);
return(hash);
}
