c# memcmp图像比较错误

本文关键字：错误 比较 图像 memcmp | 更新日期: 2023-09-27 18:04:10

我尝试使用memcmp方法比较2个小块图像。我可以比较两个大小相等的位图来确定它们是否相同的最快方法是什么?我试着在我的项目中实现这个:

private void Form1_Load(object sender, EventArgs e)
{
    Bitmap prev, curr;
    prev = (Bitmap) Image.FromFile(@"C:'Users'Public'Desktop'b.png");

    curr = (Bitmap)Image.FromFile(@"C:'Users'Public'Desktop'b.png");
    MessageBox.Show(CompareMemCmp(prev, curr).ToString());
}

这是方法-

[DllImport("msvcrt.dll")]
private static extern int memcmp(IntPtr b1, IntPtr b2, long count);
public static bool CompareMemCmp(Bitmap b1, Bitmap b2)
{
    if ((b1 == null) != (b2 == null)) return false;
    if (b1.Size != b2.Size) return false;
    var bd1 = b1.LockBits(new Rectangle(new Point(0, 0), b1.Size), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
    var bd2 = b2.LockBits(new Rectangle(new Point(0, 0), b2.Size), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
    try
    {
        IntPtr bd1scan0 = bd1.Scan0;
        IntPtr bd2scan0 = bd2.Scan0;
        int stride = bd1.Stride;
        int len = stride * b1.Height;
        return memcmp(bd1scan0, bd2scan0, len) == 0;
    }
    finally
    {
        b1.UnlockBits(bd1);
        b2.UnlockBits(bd2);
    }
}

和我得到这个错误时调用memcmp函数

A call to PInvoke function 'WindowsFormsApplication1!WindowsFormsApplication1.Form1::memcmp' has unbalanced the stack. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature.

知道为什么会这样吗?我都是根据那个答案做的

c# memcmp图像比较错误

正确的签名是:

[DllImport("msvcrt.dll", CallingConvention=CallingConvention.Cdecl)]
static extern int memcmp(IntPtr b1, IntPtr b2, IntPtr count);

因为在C语言中，count是size_t，所以它可以是32位或64位，这取决于程序是在32位还是64位运行。

然后使用:

return memcmp(bd1scan0, bd2scan0, (IntPtr)len) == 0;
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