// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using Microsoft.ML.Runtime;
 
namespace Microsoft.ML.Data;
 
/// <summary>
/// Base class for creating a cursor of rows that filters out some input rows.
/// </summary>
[BestFriend]
internal abstract class LinkedRowFilterCursorBase : LinkedRowRootCursorBase
{
    public override long Batch => Input.Batch;
 
    protected LinkedRowFilterCursorBase(IChannelProvider provider, DataViewRowCursor input, DataViewSchema schema, bool[] active)
        : base(provider, input, schema, active)
    {
    }
 
    public override ValueGetter<DataViewRowId> GetIdGetter()
    {
        return Input.GetIdGetter();
    }
 
    protected override bool MoveNextCore()
    {
        while (Root.MoveNext())
        {
            if (Accept())
                return true;
        }
 
        return false;
    }
 
    /// <summary>
    /// Return whether the current input row should be returned by this cursor.
    /// </summary>
    protected abstract bool Accept();
}