Can't read a file with null bytes?

Question

Hey guys I'm trying to read this file that has null bytes ( 00 hex ) sort of like padding. Every time I try to read the text it stops at the first null byte ( 00 hex ) does anybody know how to get around this?

Do you try to load this file as a text-file? If your file contains 0x0s, you have to read it in binary mode. — HCL, May 05 '11 at 19:15
Can you post your code to read the file? It sounds like it is being interpreted as a string ( where 0x00 signifies the end of the string ). — IanNorton, May 05 '11 at 19:16
@IanNorton Yes this is what I have been doing. If i read it in binary how can i convert it to a string with out it ending like that? — user556396, May 05 '11 at 19:17
the 0 byte is internal the end of a string. You will have to find a different method of reading. You can read text file if you know the length. — Roger Far, May 05 '11 at 19:18

score 2 · Accepted Answer · edited May 23 '17 at 12:16

2

You will have to read it as binary data and then few instructions at this link to handle your byte data. Removing trailing nulls from byte array in C#

edited May 23 '17 at 12:16

Community

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answered May 05 '11 at 19:20

Priyank

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Thanks, I just tested it and it seemed to work after removing all the nulls. – user556396 May 05 '11 at 19:26

score 1 · Answer 2 · answered May 05 '11 at 19:17

1

Use File.ReadAllBytes Method.

answered May 05 '11 at 19:17

Timofey Stolbov

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Now if i do this how could I use something like split on it seeing as it is not a string? – user556396 May 05 '11 at 19:19

Developer63 · Answer 3 · 2016-06-20T17:22:16.860

Here is an example, using FileReadAllBytes, of reading an otherwise "text" file that contains hex 00 nulls as well as other special characters.

Background: The old Borland Database Engine from Paradox and Delphi days has a config file, named either IDAPI.CFG or IDAPI32.CFG. The file is mostly normal text, but also contains the ASCII characters 0 (null) through 4. I needed to read this file to determine the current value of the "NET DIR" setting, and skip over the nulls.

The approach: 1) Read the file as a stream of bytes, in one big (or small) gulp into a byte array. The important statement is byte[filecontents] = File.ReadAllBytes(fileName).

2) Read and process each character in the byte array. For each character... * If null, ignore it * If other selected character, (ASCII 01 thru 04) either ignore it or transform to a different character representing its function, e.g., NewLine or equals sign. * If other (e.g. displayable) ASCII character, transform the byte back into a character form and append to an output stringbuilder. The line of code that does this is textOut.Append((char)fileByte)

        private string GetBDEConfigText(string fileName)
    {
        StringBuilder textOut = new StringBuilder();
        byte[] fileContents = File.ReadAllBytes(fileName);
        foreach (byte fileByte in fileContents)
        {
            switch (fileByte)
            {
                case 0:
                    {
                        // Leave unchanged, strip out binary character
                        break;
                    }
                case 1:
                    {
                        // Leave unchanged, strip out binary character
                        break;
                    }
                case 2:
                    {
                        break;
                    }
                case 3:
                    {
                        textOut.Append(Environment.NewLine);
                        break;
                    }
                case 4:
                    {
                        textOut.Append('=');
                        break;
                    }
                default:
                    {
                        textOut.Append((char)fileByte);
                        break;
                    }
            }
        }
        return textOut.ToString();
    }

Can't read a file with null bytes?

3 Answers3