Read an array of structs in C#

Hi,

I've seen here , and also googling for "marshal" several ways to convert a byte array to a struct.

But what I'm looking for is if there is a way to read an array of structs from a file (ok, whatever memory input) in one step?

I mean, load an array of structs from file normally takes more CPU time (a read per field using a BinaryReader) than IO time. Is there any workaround?

I'm trying to load about 400K structs from a file as fast as possible.

Thanks

pablo

From stackoverflow

• Following URL may be of interest to you.

  http://www.codeproject.com/KB/files/fastbinaryfileinput.aspx

  Or otherwise I think of pseudo code like the following:

  readbinarydata in a single shot and convert back to structure..

  public struct YourStruct {

  public int First;

  public long Second;

  public double Third;

  }

  static unsafe byte[] YourStructToBytes( YourStruct s[], int arrayLen )

  {

  byte[] arr = new byte[ sizeof(YourStruct) * arrayLen ];

  fixed( byte* parr = arr )

  { * ( (YourStruct * )parr) = s; }

  return arr;

  }

  static unsafe YourStruct[] BytesToYourStruct( byte[] arr, int arrayLen ) {

  if( arr.Length < (sizeof(YourStruct)*arrayLen) )

  throw new ArgumentException();

  YourStruct s[];

  fixed( byte* parr = arr )

  { s = * ((YourStruct * )parr); }

  return s;

  }

  Now you can read bytearray from the file in a single shot and convert back to strucure using BytesToYourStruct

  Hope you can implement this idea and check...

• I found a potential solution at this site - http://www.eggheadcafe.com/software/aspnet/32846931/writingreading-an-array.aspx

  It says basically to use Binary Formatter like this:

  FileStream fs = new FileStream("DataFile.dat", FileMode.Create); BinaryFormatter formatter = new BinaryFormatter(); formatter.Serialize(fs, somestruct);

  I also found two questions from this site - http://stackoverflow.com/questions/2871/reading-a-c-c-data-structure-in-c-from-a-byte-array and http://stackoverflow.com/questions/31854/how-to-marshal-an-array-of-structs-net-c-c

  I haven't done this before, being a C# .NET beginner myself. I hope this solution helps.

  batbrat : Sorry pablo, I had computer trouble yesterday. So I couldn't follow up. I am not sure how to achieve what you want. All the best with that.

  batbrat : I hope you find out. If you do, please post an answer here. Thanks.