.NET中基本数据类型的GetHashCode

最新推荐文章于 2025-08-01 09:37:21 发布

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本文详细介绍了C#中各种基本数据类型如Boolean、Byte、SByte等的GetHashCode方法的具体实现方式，通过这些方法可以了解不同类型如何计算其哈希值。

Boolean型：

    public override int GetHashCode()
    {
      return !this ? 0 : 1;
    }

Byte型：

    public override int GetHashCode()
    {
      return (int) this;
    }

SByte型：

    public override int GetHashCode()
    {
      return (int) this ^ (int) (this >> 32);
    }

Char型：

    public override int GetHashCode()
    {
      return (int) this | (int) this << 16;
    }

Double型：

    public override unsafe int GetHashCode()
    {
      double num1 = this;
      if (num1 == 0.0)
        return 0;
      long num2 = *(long*) &num1;
      return (int) num2 ^ (int) (num2 >> 32);
    }

Int16型：

    public override int GetHashCode()
    {
      return (int) (ushort) this | (int) this << 16;
    }

Int32型：

    public override int GetHashCode()
    {
      return this;
    }

Int64型：

    public override int GetHashCode()
    {
      return (int) this ^ (int) (this >> 32);
    }

String型：

public override unsafe int GetHashCode()
    {
      if (HashHelpers.s_UseRandomizedStringHashing)
        return string.InternalMarvin32HashString(this, this.Length, 0L);
      fixed (char* chPtr = this)
      {
        int num1 = 352654597;
        int num2 = num1;
        int* numPtr = (int*) chPtr;
        int length = this.Length;
        while (length > 2)
        {
          num1 = (num1 << 5) + num1 + (num1 >> 27) ^ *numPtr;
          num2 = (num2 << 5) + num2 + (num2 >> 27) ^ numPtr[1];
          numPtr += 2;
          length -= 4;
        }
        if (length > 0)
          num1 = (num1 << 5) + num1 + (num1 >> 27) ^ *numPtr;
        return num1 + num2 * 1566083941;
      }
    }