Fast Copy\Cast of an array

[Gilad Kapelushnik]

Hi I need to convert a ushort[] to byte[]. if this was C I wouldn't be asking but I wonder how to do this most efficient (new array + for) in C# Gilad. Ofcource the other way around is a must...

[Guffa]

Try the Array.Copy method: byte[] newArray = new byte[original.Length]; Array.Copy(original, newArray, original.Length); --- b { font-weight: normal; }

[leppie]

go unsafe and do it like C xacc-ide 0.0.15 now with C#, MSIL, C, XML, ASP.NET, Nemerle, MyXaml and HLSL coloring - Screenshots

[leppie]

Guffa wrote: Try I suggest you try it... You did not read the question correctly. xacc-ide 0.0.15 now with C#, MSIL, C, XML, ASP.NET, Nemerle, MyXaml and HLSL coloring - Screenshots

[Guffa]

In what way didn't I read the question correctly? I tried it, and the result is that it can't be copied that way. The probable reason is that you might lose data as an ushort can not safely be converted to a byte. Copying a byte array to a ushort array works fine, though. You have to loop through the array yourself and convert each value, and handle possible data loss in the conversion. One way is to simply use the lower eight bits of the value and discard the higher eight bits. --- b { font-weight: normal; }

[Anonymous]

I guess this is the only way... If I have an array of ushort[] and I want to "cast" (not copy) it into an array of byte[] then how do I do this: ushort[] A = new ushort[10] byte[] B; unsafe{ fixed(A){ // ??? // } } now I would like to access the first byte of the first (MSB) ushort in the array through B. what do i need to do after the "fixed" statment ? thanks. Gilad.

[leppie]

Anonymous wrote: I want to "cast" (not copy) it into an array of byte[] Just like C, you cant cast to a "fixedsized" array. So you either have ushort[] and go to byte* or have byte[] and go to ushort*. Two array references cannot manage an array differently.

ushort[] A = new ushort[10];
unsafe{
fixed(ushort* a = A){
byte* b = (byte*) a;
for (int i = 0; i < A.Length*2; i++)
{
process(b[i]);
}
}}

xacc-ide 0.0.15 now with C#, MSIL, C, XML, ASP.NET, Nemerle, MyXaml and HLSL coloring - Screenshots