Reading a Float from memory

Mattzimmerer

Wow I am burning my brain right here... I'm so very close to just saying screw it and writing some sort of conversion myself. First I'd love to know if there is an existing macro to do what I want to do... I have a char array: char OutputBuffer[1024] = {0}; (huge i know, but ill lower the size later ;P) that has a byte put into it... (78 AB 45 44) is a value I had at one time... as a float it means 790.67919921875 note!: this value has been read straight from memory The problem is I cant get this DWORD into a float for the life of me... Is there any existing macro? If not throw me a bone and tell me how i might convert this into a float from scratch...

Lost User

Mattzimmerer wrote:

The problem is I cant get this DWORD into a float for the life of me...

If this is already a float (as you state) then there is nothing to do. If you mean reference it as a float then you just use the (float) cast in front of the reference. Or do I misunderstand your problem?

MVP 2010 - are they mad?

Graham Breach

I don't know about an existing macro, but this will do it:

char OutputBuffer[4] = { 0x78, 0xAB, 0x45, 0x44 };
float d = *((float*)&OutputBuffer[0]);

Luc Pattyn

Assuming your code is managed and you're in the right forum, have a look at BitConverter.ToSingle() :)

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Mattzimmerer

This worked great, thanks! Now i have a new trick lool, why didnt i think of that: cast it as a pointer of the type i know it is and then deference it =D...

dybs

One caveat to the BitConverter class is the endianness it uses is based on the architecture of the machine the program is running on. So if you're interfacing to a piece of hardware and its endianness doesn't match the endian-ness of the computer, or you're reading a binary file created on a computer with a different endianness and using BitConverter, then BitConverter will not give the correct result. Dybs

The shout of progress is not "Eureka!" it's "Strange... that's not what i expected". - peterchen

Luc Pattyn

Sure, whatever method is used, one better is aware of all applying conventions; endianness being the most relevant one here. :)

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I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.
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