标签：eva 移动 lis generate err long byte ddb 表示
要学会位运算，首先要清楚什么是位运算？程序中的所有内容在计算机内存中都是以二进制的形式储存的（即：0或1），位运算就是直接对在内存中的二进制数的每位进行运算操作
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运算符号
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意义
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运算对象类型
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运算结果类型
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对象数
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实例
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~
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位逻辑非运算
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整型，字符型
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整型
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1
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~a
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&
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位逻辑与运算
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2
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a & b
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||
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位逻辑或运算
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2
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a | b
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||
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^
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位逻辑异或运算
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2
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a ^ b
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||
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<<
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位左移运算
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2
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a<<4
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||
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>>
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位右移运算
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2
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a>>2
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x<<1= x*2
x<<2= x*4
x<<3= x*8
x<<4= x*16
右移相当于整除. 右移一位相当于除以2;右移两位相当于除以4;右移三位相当于除以8。
x>>1= x/2
x>>2= x/4
x>>3= x/8
x>>4=x/16
位运算帮助类
using System;
using System.Linq;
namespace BitwiseDemo.Utilities
{
/// <summary>
/// 位运算校验帮助类
/// </summary>
public class BitwiseOperationHelper
{
/// <summary>
/// 验证整数是否为2的幂级
/// </summary>
/// <remarks></remarks>
/// <param name="n"></param>
/// <returns></returns>
public static bool ValidateValuePower(long n)
{
return (n & (n - 1)) == 0;
}
/// <summary>
/// 获取2的n次方值
/// </summary>
/// <param name="n">n次方值</param>
/// <returns></returns>
public static long GetValuePower(int n)
{
return (long)System.Math.Pow(2, n);
}
/// <summary>
/// 获取二进制数
/// </summary>
/// <param name="n"></param>
/// <returns></returns>
public static string GetBinaryValue(long n)
{
return Convert.ToString(n, 2);
}
/// <summary>
/// 生成位运算数值
/// </summary>
/// <param name="list">权限值</param>
/// <remarks>每个值执行或操作（value = value | n）</remarks>
/// <returns></returns>
public static long GenerateBitwise(params long[] list)
{
if (list == null)
throw new Exception("值数组不允许为空");
long value = 0;
list.ToList().ForEach(n =>
{
if (!ValidateValuePower(n))
throw new Exception($"值 {n} 为无效的值，不是2的幂级");
if (n < 0 || n > 4611686018427387904)
throw new Exception($"鉴权值 {n} 应大于 0 小于 4611686018427387904");
value |= n;
});
return value;
}
/// <summary>
/// 添加位值
/// </summary>
/// <param name="oldValue">原位数值</param>
/// <param name="value">新加入的位值</param>
/// <remarks>value = oldValue | newValue</remarks>
/// <returns></returns>
public static long AddBitwise(long oldValue, long value)
{
if (!ValidateValuePower(value))
throw new Exception($"值 {value} 为无效的值，不是2的幂级");
if (value < 0 || value > 4611686018427387904)
throw new Exception($"值 {value} 应大于 0 小于 4611686018427387904");
long returnValue = oldValue | value;
return returnValue;
}
/// <summary>
/// 移除位值
/// </summary>
/// <param name="oldValue">鉴权码</param>
/// <param name="value">权限值（2的幂级）</param>
/// <remarks>code = authCode & (~auth)</remarks>
/// <returns></returns>
public static long RemoveBitwise(long oldValue, long value)
{
if (!ValidateValuePower(value))
throw new Exception($"值 {value} 无效");
if (value < 0 || value > 4611686018427387904)
throw new Exception($"值 {value} 应在 0 与 4611686018427387904 之间");
long returnValue = oldValue & (~value);
return returnValue;
}
/// <summary>
/// 验证位值是否存在
/// </summary>
/// <param name="oldValue">原位值</param>
/// <param name="value">值（2的幂级）</param>
/// <remarks>value == (oldValue & value)</remarks>
/// <returns></returns>
public static bool ValidateBitwise(long oldValue, long value)
{
if (!ValidateValuePower(value))
throw new Exception($"值 {value} 为无效的值");
if (oldValue <= 0 || value <= 0)
return false;
return value == (oldValue & value);
}
}
}
示例：
public void ValidateBitwise()
{
#region 测试位运算
var validate = BitwiseOperationHelper.ValidateValuePower(3);
Console.WriteLine($"validate:{validate}");
//获取枚举值的幂次方
var valuePower = BitwiseOperationHelper.GetValuePower((int)UserRight.Add);
Console.WriteLine($"valuePower:{valuePower}");
//获取枚举的二进制数
var binary = BitwiseOperationHelper.GetBinaryValue(2);
Console.WriteLine($"binary:{binary}");
var binaryValue = BitwiseOperationHelper.GenerateBitwise(new long[] { (int)UserRight.Add, (int)UserRight.Update, (int)UserRight.View });
var f = BitwiseOperationHelper.ValidateBitwise(binaryValue, (int)UserRight.Delete);
var t = BitwiseOperationHelper.ValidateBitwise(binaryValue, (int)UserRight.Update);
Console.WriteLine($"f:{f},t:{t}");
#endregion
}
使用到的枚举
public enum UserRight
{
Add = 1 << 0,
Update = 1 << 1,
View = 1 << 2,
Delete = 1 << 3
}
善于总结，才能进步更快
标签：eva 移动 lis generate err long byte ddb 表示
原文地址：https://www.cnblogs.com/yuyoho/p/13185690.html
