How Do I read values from Binary file and Write to a new Binay file?

First off, all files are technically binary data. Some binary data is just interpreted differently depending on the context. For instance, if I have a text file that contains the word "Test", you won't find the letters 'T', 'e', 's', and 't' on your hard drive anywhere. You'll see a series of binary values corresponding to those letters depending on the encoding you use. Opening the file and treating it as text allows you to view it as text, even if it wasn't. I could open notepad, write a bunch of crap, and save it as a .dat, and it would still have the same binary data as any txt.

If the file is too fat to load all at once, you'll have to load it a chunk at a time (I suggest loading it like 1KB or so at a time, then discarding that data. I forgot how big a sector is nowadays, but that's a different story). Anyways, you could use the BinaryReader and BinaryWriter classes to make your life a tiny bit easier with this (though they're not necessary; they just make "writing binary" (I put that in quotes because, really, what else can you write to a file? Nothing. Just binary, every time).

Anyways, I'm not 100% sure I understand your question. Your "binary file", as you call it, has a bunch of binary in it, I've gathere that much (once again, I ask you, what else could it contain?). You are also saying that the binary within it should be interpreted as a very large series of short integers (ie 16-bit integers). I'm going to assume, for my solution to you, that you wish to add 10 to each short value in this file, and write the 'result' to the other file.

I really do hope this isn't homework, as I don't condone cheating, but here you go. For this example, I'm just going to read one short at a time for simplicity's sake. I suggest that you optimize it yourself (consider this my challenge to you :) ), though you don't have to, of course. Depending on the size of the file, the code I provide should be pretty slow after a certain point (then again, .NET likes to buffer file data without your knowing anyway, so it doesn't make much of a difference, if your file isn't too big...). However, the code should handle any amount of data.

Let me know if you have any questions, but as for optimizing it for you, that's up to you (unless you get it started and I see that you put some geniune effort into it. I may help you out in that case).

Hope it helps,

Nate

void RenameThisMethodRangers99()
{
//#error Ranger99: RENAME THIS METHOD. Then, remove this line.
    using (FileStream origFile = File.OpenRead("original.dat"))
    using (FileStream newFile = File.OpenWrite("newfile.dat"))
    {
        BinaryReader read = new BinaryReader(origFile);
        BinaryWriter write = new BinaryWriter(newFile);
 
        write.Write((Int16)(read.ReadInt16() + 10));
    }
}

                                              

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>> The commentary was addressing what I thought was a pretty simple question that could have been found with a simple google search.

Ehh, yes and no. Binary data scares most people, as most don't really understand it, so I guess I can't blame him. I've certainly seen much, much worse questions, oh lord... Hell, I could pick out like 40 within the first 60 questions. Anyways, most would be surprised to hear that fetching a Byte (8 bits) from RAM actually entails telling the RAM to give you 32 bits of information, padding on the extra 24 bits for you. Binary knowledge isn't common, but I suppose it isn't rare, either. .NET is one of the "languages" in which it is forgiveable to know little about deep details.

As for converting bytes to other data types, rangers99, it's extremely easy in .NET. There are a few ways to do it; however, the easiest one is to use the static class called "BitConverter" in the System namespace. For example, to convert bytes to an Int16 (aka short) using BitConverter, you call the BitConverter.ToInt16 method. You could grab a hunk of your data (an even number, probably something like 1024 bytes or some other power of 2) as a Byte array and pass it to the BitConverter.ToInt16 method with the necessary offset.

As well as using this class, you could just shift left and OR the two bytes you want to "merge" (ie ((Int16)(leftByte << 8)) | ((Int16)rightByte). I can't remember if .NET upcasts operands of bitwise operators to Int32 by default, but I'm too lazy to check, and casting them to Int16 shows your intent anyway (even if it does look a little strange).

I surely hope you're not cheating on your homework, as the number of borderline retarded programmers on the market is already astonishing. I don't know how much more if it I can take, so please, learn your profession, and learn it well. Cheating never helps ;)

Hope it helps,

Nate