Howto convert a byte array to double array.

[kevinniu]

Hi everyone,

In c#, what is the fastest way(include unsafe) to

convert a array of bytes(which really contains the

bytes of a double array) to a arry of double.

thanks

kn

[Jon Skeet [C# MVP]]

kevinniu <ke******@hotma il.com> wrote:

In c#, what is the fastest way(include unsafe) to
convert a array of bytes(which really contains the
bytes of a double array) to a arry of double.

Try Buffer.BlockCop y - that should be pretty fast.

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Nadav]

if you want to prvent the copying use mixed mode C++, using unmanaged C++ you can get a void* pointer to the managed buffer, then you can do with it whatever you want...

Mixed mode C++ array manipulation ( access a System::Byte array as an 'unsigned short' array):
virtual int ManipArray(Syst em::Byte btArray __gc[])
{
int i = 0;
BYTE __pin *pbtArray = &btArray[0];
unsigned short *uiArray = (unsigned short*)pbtArray ;
for(i; i < btArray->Length/2; i++)
uiArray[i] <<= 1;
return 0;
}

--
Nadav
http://www.ddevel.com
"kevinniu" wrote:

Hi everyone,

In c#, what is the fastest way(include unsafe) to

convert a array of bytes(which really contains the

bytes of a double array) to a arry of double.

thanks

kn

[Lin Liang]

Nadav,

Thanks for the reply.

Is it possible to use unsafe code in C# to get the same result?

You know I am programming in C# and I am not familiar with mixed C++.

Any idea?

Regards

kevin

"Nadav" <Na***@discussi ons.microsoft.c om> wrote in message
news:98******** *************** ***********@mic rosoft.com...

if you want to prvent the copying use mixed mode C++, using unmanaged C++ you can get a void* pointer to the managed buffer, then you can do with it
whatever you want...
Mixed mode C++ array manipulation ( access a System::Byte array as an 'unsigned short' array): virtual int ManipArray(Syst em::Byte btArray __gc[])
{
int i = 0;
BYTE __pin *pbtArray = &btArray[0];
unsigned short *uiArray = (unsigned short*)pbtArray ;
for(i; i < btArray->Length/2; i++)
uiArray[i] <<= 1;
return 0;
}

--
Nadav
http://www.ddevel.com
"kevinniu" wrote:

Hi everyone,

In c#, what is the fastest way(include unsafe) to

convert a array of bytes(which really contains the

bytes of a double array) to a arry of double.

thanks

kn

[Lin Liang]

Jon,

Thanks for your reply.

I have tried with the BlockCopy, as I have a lot of data,

I really need to speed thing up..

Any other ways to improve the performance?

Best Regards

Kevin

"Jon Skeet [C# MVP]" <sk***@pobox.co m> wrote in message
news:MP******** *************** @msnews.microso ft.com...

kevinniu <ke******@hotma il.com> wrote:

In c#, what is the fastest way(include unsafe) to
convert a array of bytes(which really contains the
bytes of a double array) to a arry of double.

Try Buffer.BlockCop y - that should be pretty fast.

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Jon Skeet [C# MVP]]

Lin Liang <l.******@pgrad .unimelb.edu.au > wrote:

Is it possible to use unsafe code in C# to get the same result?

You know I am programming in C# and I am not familiar with mixed C++.

Any idea?

I should think you could just use unsafe code and write almost exactly
the same code in C#. See a tutorial on unsafe code for more
information.

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too