计算大文件MD5SUM在C＃ [英] Computing MD5SUM of large files in C#

问题描述

我使用下面的代码来计算文件的MD5SUM -

I am using following code to compute MD5SUM of a file -

byte[] b = System.IO.File.ReadAllBytes(file);
string sum = BitConverter.ToString(new MD5CryptoServiceProvider().ComputeHash(b));

这正常工作正常，但如果我遇到一个大文件（〜1GB） - 例如一个ISO镜像或DVD的VOB文件 - 我得到一个内存异常

This works fine normally, but if I encounter a large file (~1GB) - e.g. an iso image or a DVD VOB file - I get an Out of Memory exception.

不过，我能计算出MD5SUM在Cygwin中为同一个文件中有关10secs

Though, I am able to compute the MD5SUM in cygwin for the same file in about 10secs.

请建议我怎么能得到这个在我的程序的大文件的工作。

Please suggest how can I get this to work for big files in my program.

感谢

推荐答案

我建议使用另一种方法：

I suggest using the alternate method:

MD5CryptoServiceProvider.ComputeHash(Stream)

和只是通过输入流中打开你的文件。这种方法几乎肯定会的不的在一气呵成在内存中读取整个文件。

and just pass in an input stream opened on your file. This method will almost certainly not read in the whole file in memory in one go.

我还要指出，在MD5的大多数实现它的可以添加字节[] 数据放入摘要函数在一个时间块，然后要求在年底的哈希值。

I would also note that in most implementations of MD5 it's possible to add byte[] data into the digest function a chunk at a time, and then ask for the hash at the end.

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