//-----------------------------------------------------------------------
// <copyright file="jet_recpos.cs" company="Microsoft Corporation">
//     Copyright (c) Microsoft Corporation.
// </copyright>
//-----------------------------------------------------------------------

namespace Microsoft.Isam.Esent.Interop
{
    using System;
    using System.Diagnostics;
    using System.Diagnostics.CodeAnalysis;
    using System.Globalization;
    using System.Runtime.InteropServices;

    /// <summary>
    /// The native version of the JET_RETINFO structure.
    /// </summary>
    [StructLayout(LayoutKind.Sequential)]
    [SuppressMessage("Microsoft.StyleCop.CSharp.NamingRules",
        "SA1305:FieldNamesMustNotUseHungarianNotation",
        Justification = "This should match the unmanaged API, which isn't capitalized.")]
    [SuppressMessage(
        "Microsoft.StyleCop.CSharp.NamingRules",
        "SA1307:AccessibleFieldsMustBeginWithUpperCaseLetter",
        Justification = "This should match the unmanaged API, which isn't capitalized.")]
    internal struct NATIVE_RECPOS
    {
        /// <summary>
        /// Size of NATIVE_RECPOS structures.
        /// </summary>
        public static readonly int Size = Marshal.SizeOf(typeof(NATIVE_RECPOS));

        /// <summary>
        /// Size of this structure.
        /// </summary>
        public uint cbStruct;

        /// <summary>
        /// Approximate number of index entries less than the key.
        /// </summary>
        public uint centriesLT;

        /// <summary>
        /// Approximate number of entries in the index range.
        /// </summary>
        public uint centriesInRange;

        /// <summary>
        /// Approximate number of entries in the index.
        /// </summary>
        public uint centriesTotal;
    }

    /// <summary>
    /// Represents a fractional position within an index. This is used by JetGotoPosition
    /// and JetGetRecordPosition.
    /// </summary>
    [SuppressMessage(
        "Microsoft.StyleCop.CSharp.NamingRules",
        "SA1300:ElementMustBeginWithUpperCaseLetter",
        Justification = "This should match the unmanaged API, which isn't capitalized.")]
    [Serializable]
    public sealed class JET_RECPOS : IContentEquatable<JET_RECPOS>, IDeepCloneable<JET_RECPOS>
    {
        /// <summary>
        /// The number of entries before the key.
        /// </summary>
        private long entriesBeforeKey;

        /// <summary>
        /// Total number of entries.
        /// </summary>
        private long totalEntries;

        /// <summary>
        /// Gets or sets the approximate number of index entries less than the key.
        /// </summary>
        public long centriesLT
        {
            [DebuggerStepThrough]
            get { return this.entriesBeforeKey; }
            set { this.entriesBeforeKey = value; }
        }

        /// <summary>
        /// Gets or sets the approximate number of entries in the index.
        /// </summary>
        public long centriesTotal
        {
            [DebuggerStepThrough]
            get { return this.totalEntries; }
            set { this.totalEntries = value; }
        }

        /// <summary>
        /// Returns a deep copy of the object.
        /// </summary>
        /// <returns>A deep copy of the object.</returns>
        public JET_RECPOS DeepClone()
        {
            return (JET_RECPOS)this.MemberwiseClone();
        }

        /// <summary>
        /// Generate a string representation of the instance.
        /// </summary>
        /// <returns>The structure as a string.</returns>
        public override string ToString()
        {
            return string.Format(CultureInfo.InvariantCulture, "JET_RECPOS({0}/{1})", this.entriesBeforeKey, this.totalEntries);
        }

        /// <summary>
        /// Returns a value indicating whether this instance is equal
        /// to another instance.
        /// </summary>
        /// <param name="other">An instance to compare with this instance.</param>
        /// <returns>True if the two instances are equal.</returns>
        public bool ContentEquals(JET_RECPOS other)
        {
            if (null == other)
            {
                return false;
            }

            return this.entriesBeforeKey == other.entriesBeforeKey && this.totalEntries == other.totalEntries;
        }

        /// <summary>
        /// Get a NATIVE_RECPOS structure representing the object.
        /// </summary>
        /// <returns>A NATIVE_RECPOS whose members match the class.</returns>
        internal NATIVE_RECPOS GetNativeRecpos()
        {
            var recpos = new NATIVE_RECPOS();
            recpos.cbStruct = checked((uint)NATIVE_RECPOS.Size);
            recpos.centriesLT = checked((uint)this.centriesLT);
            recpos.centriesTotal = checked((uint)this.centriesTotal);
            return recpos;
        }

        /// <summary>
        /// Sets the fields of the object from a NATIVE_RECPOS structure.
        /// </summary>
        /// <param name="value">The NATIVE_RECPOS which will be used to set the fields.</param>
        internal void SetFromNativeRecpos(NATIVE_RECPOS value)
        {
            this.centriesLT = checked((int)value.centriesLT);
            this.centriesTotal = checked((int)value.centriesTotal);
        }
    }
}