CODEWITHSUNDEEP
c#
Andrew
Andrew

Reputation: 9

What is the best method of concatenating a series of binary files into one file?

I have a series of PDF byte arrays in a arraylist files that i wish to concatenate into one file,
Currently when the PDF application tries to open the file is it corrupted:

foreach (byte[] array in files)
{
    using (Stream s = new MemoryStream(downloadbytes))
    {
        s.Write(array, 0, array.Length);
    }
}

downloadbytes is the resultant concatenated array of bytes below is another implementation which also failed

foreach (byte[] array in files)
{
    System.Buffer.BlockCopy(array, 0, downloadbytes, offset, array.Length);
    offset += array.Length;
}

any pointers?

Upvotes: 0

Views: 2434

Answers (5)

etc
etc

Reputation: 630

You will likely need to use a PDF library to concatenate the files. Take a look at iTextSharp.

Upvotes: 2

code4life
code4life

Reputation: 15794

You can't just merge the bytes together - you need a 3rd party library, for instance PDFSharp. PDFSharp has a tutorial on merging documents:

http://www.pdfsharp.net/wiki/CombineDocuments-sample.ashx

Upvotes: 1

Tim Lloyd
Tim Lloyd

Reputation: 38434

You will need to use a PDF handling tool to do this job as PDF files cannot be simply concatenated to form a single PDF. PDF files follow a specification, you can't just join them together. Think about XML, you cannot just join XML files together to form a single XML file.

Upvotes: 1

Jon Skeet
Jon Skeet

Reputation: 1500425

If you've got byte arrays, you can just write them directly:

using (Stream output = File.OpenWrite("output.pdf"))
{
    foreach (byte[] array in files)
    {
        output.Write(array, 0, array.Length);
    }
}

That will effectively concatenate the byte arrays... but if each byte array represents an individual, complete PDF file you shouldn't expect the result of the concatenation to be a single valid PDF file. Combining PDFs isn't just a case of writing one after the other. You'll need to use a PDF library (e.g. iText) to do that.

To put it another way: what do you get if you build 5 two-bedroom houses next to each other? Not a ten-bedroom mansion...

Upvotes: 2

Darin Dimitrov
Darin Dimitrov

Reputation: 1038780

using (var result = File.OpenWrite("result.bin"))
{
    foreach (byte[] array in files)
    {
        result.Write(array, 0, array.Length);
    }
}

Also you talk about PDFs. Don't expect that if you have a series of PDF files and concatenate the binaries you will receive a valid PDF file by just adding the bytes. If this is what you want you may take a look at iTextSharp which allows you to concatenate PDFs.

Upvotes: 1

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