Arrays.cs :  » PDF » iTextSharp » Org » BouncyCastle » Utilities » C# / CSharp Open Source

using System;
using System.Text;

namespace Org.BouncyCastle.Utilities{

    /// <summary> General array utilities.</summary>
    public sealed class Arrays
    {
        private Arrays()
        {
        }

    public static bool AreEqual(
      bool[]  a,
      bool[]  b)
    {
      if (a == b)
        return true;

      if (a == null || b == null)
        return false;

      int i = a.Length;
      if (i != b.Length)
        return false;
      while (i != 0)
      {
        --i;
        if (a[i] != b[i])
          return false;
      }
      return true;
    }

        /// <summary>
        /// Are two arrays equal.
        /// </summary>
        /// <param name="a">Left side.</param>
        /// <param name="b">Right side.</param>
        /// <returns>True if equal.</returns>
        public static bool AreEqual(
      byte[]  a,
      byte[]  b)
        {
      if (a == b)
        return true;

      if (a == null || b == null)
        return false;

      return HaveSameContents(a, b);
    }

    [Obsolete("Use 'AreEqual' method instead")]
    public static bool AreSame(
      byte[]  a,
      byte[]  b)
    {
      return AreEqual(a, b);
    }

    /// <summary>
    /// A constant time equals comparison - does not terminate early if
    /// test will fail.
    /// </summary>
    /// <param name="a">first array</param>
    /// <param name="b">second array</param>
    /// <returns>true if arrays equal, false otherwise.</returns>
    public static bool ConstantTimeAreEqual(
      byte[]  a,
      byte[]  b)
    {
      int i = a.Length;
      if (i != b.Length)
        return false;
      int cmp = 0;
      while (i != 0)
      {
        --i;
        cmp |= (a[i] ^ b[i]);
      }
      return cmp == 0;
    }

    public static bool AreEqual(
      int[]  a,
      int[]  b)
    {
      if (a == b)
        return true;

      if (a == null || b == null)
        return false;

      return HaveSameContents(a, b);
    }

    private static bool HaveSameContents(
      byte[]  a,
      byte[]  b)
    {
      int i = a.Length;
      if (i != b.Length)
        return false;
      while (i != 0)
      {
        --i;
        if (a[i] != b[i])
          return false;
      }
      return true;
    }

    private static bool HaveSameContents(
      int[]  a,
      int[]  b)
    {
      int i = a.Length;
      if (i != b.Length)
        return false;
      while (i != 0)
      {
        --i;
        if (a[i] != b[i])
          return false;
      }
      return true;
    }

    public static string ToString(
      object[] a)
    {
      StringBuilder sb = new StringBuilder('[');
      if (a.Length > 0)
      {
        sb.Append(a[0]);
        for (int index = 1; index < a.Length; ++index)
        {
          sb.Append(", ").Append(a[index]);
        }
      }
      sb.Append(']');
      return sb.ToString();
    }

    public static int GetHashCode(
      byte[] data)
    {
      if (data == null)
      {
        return 0;
      }

      int i = data.Length;
      int hc = i + 1;

      while (--i >= 0)
      {
        hc *= 257;
        hc ^= data[i];
      }

      return hc;
    }

    public static byte[] Clone(
      byte[] data)
    {
      return data == null ? null : (byte[]) data.Clone();
    }

    public static int[] Clone(
      int[] data)
    {
      return data == null ? null : (int[]) data.Clone();
    }
  }
}