//------------------------------------------------------------------------------
// <copyright file="SmiGettersStream.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
// <owner current="true" primary="true">[....]</owner>
// <owner current="true" primary="false">[....]</owner>
//------------------------------------------------------------------------------

namespace Microsoft.SqlServer.Server {
    using System;
    using System.Data.Common;
    using System.Data.SqlClient;
    using System.IO;
    using System.Diagnostics;

    internal class SmiGettersStream : Stream {

        private SmiEventSink_Default    _sink;
        private ITypedGettersV3         _getters;
        private int                     _ordinal;
        private long                    _readPosition;
        private SmiMetaData             _metaData;

        internal SmiGettersStream( SmiEventSink_Default sink, ITypedGettersV3 getters, int ordinal, SmiMetaData metaData ) {
            Debug.Assert( null != sink );
            Debug.Assert( null != getters );
            Debug.Assert( 0 <= ordinal );
            Debug.Assert( null != metaData );

            _sink = sink;
            _getters = getters;
            _ordinal = ordinal;
            _readPosition = 0;
            _metaData = metaData;
        }

        public override bool CanRead {
            get {
                return true;
            }
        }

        // If CanSeek is false, Position, Seek, Length, and SetLength should throw.
        public override bool CanSeek {
            get {
                return false;
            }
        }

        public override bool CanWrite {
            get {
                return false;
            }
        }

        public override long Length {
            get {
                return ValueUtilsSmi.GetBytesInternal( _sink, _getters, _ordinal, _metaData, 0, null, 0, 0, false );
            }
        }

        public override long Position {
            get {
                return _readPosition;
            }
            set {
                throw SQL.StreamSeekNotSupported();
            }
        }

        public override void Flush() {
            throw SQL.StreamWriteNotSupported();
        }

        public override long Seek(long offset, SeekOrigin origin) {
            throw SQL.StreamSeekNotSupported();
        }

        public override void SetLength(long value) {
            throw SQL.StreamWriteNotSupported();
        }

        public override int Read( byte[] buffer, int offset, int count ) {
            long bytesRead = ValueUtilsSmi.GetBytesInternal( _sink, _getters, _ordinal, _metaData, _readPosition, buffer, offset, count, false );
            _readPosition += bytesRead;

            return checked( (int) bytesRead );
        }

        public override void Write( byte[] buffer, int offset, int count ) {
            throw SQL.StreamWriteNotSupported();
        }
    }

}