C# 检查两个字节数组的相等性
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Checking equality for two byte arrays
提问by Masriyah
I am checking the equality of two byte arrays, and I wanted some help because what I have returns false even though the arrays should be equal.
我正在检查两个字节数组的相等性，我需要一些帮助，因为即使数组应该相等，我也返回 false。
Within my debug I could see both of a1 and b1 are equal, but it is not going inside the while loop to increment i.
在我的调试中，我可以看到 a1 和 b1 相等，但它不会进入 while 循环以增加 i。
public bool Equality(byte[] a1, byte[] b1)
{
int i;
bool bEqual;
if (a1.Length == b1.Length)
{
i = 0;
while ((i < a1.Length) && (a1[i]==b1[i]))
{
i++;
}
if (i == a1.Length)
{
bEqual = true;
}
}
return bEqual;
}
This always returns false: (a1[i]==b1[i]).
这总是返回 false: (a1[i]==b1[i])。
采纳答案by p.s.w.g
You need to add a return value somewhere. This should work:
您需要在某处添加一个返回值。这应该有效：
public bool Equality(byte[] a1, byte[] b1)
{
int i;
if (a1.Length == b1.Length)
{
i = 0;
while (i < a1.Length && (a1[i]==b1[i])) //Earlier it was a1[i]!=b1[i]
{
i++;
}
if (i == a1.Length)
{
return true;
}
}
return false;
}
But this is much simpler:
但这要简单得多：
return a1.SequenceEqual(b1);
Alternatively, you could use IStructuralEquatablefrom .NET 4:
或者，您可以IStructuralEquatable从 .NET 4使用：
return ((IStructuralEquatable)a1).Equals(b1, StructuralComparisons.StructuralEqualityComparer)
If performance is a concern, I'd recommend rewriting your code to use the Binaryclass, which is specifically optimized for this kind of use case:
如果性能是一个问题，我建议重写您的代码以使用Binary该类，该类专门针对此类用例进行了优化：
public bool Equality(Binary a1, Binary b1)
{
return a1.Equals(b1);
}
A quick benchmark on my machine gives the following stats:
我的机器上的快速基准测试给出了以下统计数据：
Method Min Max Avg
binary equal: 0.868 3.076 0.933 (best)
for loop: 2.636 10.004 3.065
sequence equal: 8.940 30.124 10.258
structure equal: 155.644 381.052 170.693
Download this LINQPad fileto run the benchmark yourself.
下载此 LINQPad 文件以自己运行基准测试。
回答by Moop
This should work:
这应该有效：
public bool Equality(byte[] a1, byte[] b1)
{
if(a1 == null || b1 == null)
return false;
int length = a1.Length;
if(b1.Length != length)
return false;
while(length >0) {
length--;
if(a1[length] != b1[length])
return false;
}
return true;
}
回答by Sam I am says Reinstate Monica
You should add some return statements:
您应该添加一些返回语句：
public bool Equality(byte[] a1, byte[] b1)
{
int i = 0;
if (a1.Length == b1.Length)
{
while ((i < a1.Length) && (a1[i]==b1[i]))
{
i++;
}
}
return i == a1.Length;
}
Or, better yet
或者，更好
public bool Equality(byte[] a1, byte[] b1)
{
if(a1.Length != b1.Length)
{
return false;
}
for (int i = 0; i < a1.Length; i++)
{
if (a1[i] != b1[i])
{
return false;
}
}
return true;
}
回答by Magnus
To check equality you can just write:
要检查相等性，您可以只写：
var areEqual = a1.SequenceEqual(b1);
回答by Haney
I'd recommend some short-circuiting to make things a bit simpler, and use of object.ReferenceEqualsto short-circuit for cases when the arrays are the same reference (a1 = b1):
我建议使用一些短路来使事情变得更简单，并object.ReferenceEquals在数组具有相同引用 ( a1 = b1) 的情况下使用来短路：
public bool Equality(byte[] a1, byte[] b1)
{
// If not same length, done
if (a1.Length != b1.Length)
{
return false;
}
// If they are the same object, done
if (object.ReferenceEquals(a1,b1))
{
return true;
}
// Loop all values and compare
for (int i = 0; i < a1.Length; i++)
{
if (a1[i] != b1[i])
{
return false;
}
}
// If we got here, equal
return true;
}
