Converting byte arrays (from readfile) to string

Question

So, I am using ReadFile from kernel32 for reading the file. Here is my code in reading files with the help of SetFilePointer and ReadFile.

public long ReadFileMe(IntPtr filehandle, int startpos, int length, byte[] outdata)
{
    IntPtr filea = IntPtr.Zero;
    long ntruelen = GetFileSize(filehandle, filea);
    int nRequestStart;
    uint nRequestLen;
    uint nApproxLength;
    int a = 0;
    if (ntruelen <= -1)
    {
        return -1;
    }
    else if (ntruelen == 0)
    {
        return -2;
    }

    if (startpos > ntruelen)
    {
        return -3;
    }
    else if (length <= 0)
    {
        return -5;
    }
    else if (length > ntruelen)
    {
        return -6;
    }
    else
    {
        nRequestStart = startpos;
        nRequestLen = (uint)length;

        outdata = new byte[nRequestLen - 1];

        SetFilePointer(filehandle, (nRequestStart - 1), ref a, 0);
        ReadFile(filehandle, outdata, nRequestLen, out nApproxLength, IntPtr.Zero);
        return nApproxLength; //just for telling how many bytes are read in this function
    }
}

When I used this function, it works (for another purpose) so this code is tested and works.

But the main problem is, I now need to convert the outdata on the parameter which the function puts the bytes into string.

I tried using Encoding.Unicode and so on (all UTF), but it doesn't work.

did you try this: string result = System.Text.Encoding.Default.GetString(outdata); and see whether you are able to get the output converted to string. — Saravanan
– Saravanan, Commented Dec 26, 2012 at 7:27
Without a return parameter or a reference parameter, the function will put nothing in it... — knaki02
– knaki02, Commented Dec 27, 2012 at 8:02

Ria · Accepted Answer · 2012-12-26 07:30:55Z

1

Try to use Encoding.GetString (Byte[], Int32, Int32) method. this decodes a sequence of bytes from the specified byte array into a string.

answered Dec 26, 2012 at 7:30

Ria

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akekir · Accepted Answer · 2012-12-26 09:07:24Z

1

Hmm... Encoding.Name_of_encoding.GetString must work... try smth like this:

var convertedBuffer = Encoding.Convert(
             Encoding.GetEncoding( /*name of encoding*/),Encoding.UTF8, outdata);
var str = Encoding.UTF8.GetString(convertedBuffer);

UPDATE: and what about this?:

using (var streamReader = new StreamReader(@"C:\test.txt", true))
        {
            var currentEncoding = streamReader.CurrentEncoding.EncodingName;
            Console.WriteLine(currentEncoding);
        }

edited Dec 26, 2012 at 9:07

answered Dec 26, 2012 at 7:32

akekir

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2 Comments

newbie Over a year ago

yeah. but the name of encoding is what i'm looking for >.<

newbie Over a year ago

it says that it is on unicode (UTF-8). But I did tried unicode and utf-8

knaki02 · Accepted Answer · 2012-12-26 10:11:00Z

0

You might need to add the out parameter on outdata parameter : Passing Arrays Using ref and out

public long ReadFileMe(IntPtr filehandle, int startpos, int length, out byte[] outdata)

edited Dec 26, 2012 at 10:11

answered Dec 26, 2012 at 9:51

knaki02

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