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jooooooooota
Asked: 2020-07-04 03:02:52 +0800 CST 2020-07-04 03:02:52 +0800 CST

Encode in base 64 C# file

  • 772

Hello I am encoding a file in base 64 in c#, but for large files it doesn't work anymore.

char[] base64 = new char[miArchivo.Length];
Convert.ToBase64CharArray(miArchivo, 0, miArchivo.Length, base64, 0);
return Encoding.ASCII.GetBytes(base64);

I have tried with MemoryStreambut it has not worked, the problem is in the size of the char[] that in base64 occupies more I think.

c#

2 Answers

  1. Best Answer

    Every 3 bytes become 4 characters, because only 7 bits of each character are used to encode information. The destination array must be at least that size.

    Also note that if there are any more bytes because the size is not a multiple of 3, 4 more bytes are needed. That is, for 5 input bytes you will need 8 output, just as if they were 6.

    • 1

  2. You are missing to consider the size of the char type.

                var binaryData = File.ReadAllBytes("black-stormtrooper-64.png");

            long tamañoChar = sizeof(char);
            long arrayLength = binaryData.Length * tamañoChar;

            /*Normalizo en caso de que no termine de completar el tamaño.*/
            if (arrayLength % tamañoChar != 0)
            {
                arrayLength += tamañoChar - arrayLength % tamañoChar;
            }

            char[] base64CharArray = new char[arrayLength];

            Convert.ToBase64CharArray(binaryData, 0, binaryData.Length, base64CharArray, 0);
            var res = Encoding.ASCII.GetBytes(base64CharArray);

    As an alternative to your code you can do:

    var binaryData = File.ReadAllBytes("black-stormtrooper-64.png");
string base64String = Convert.ToBase64String(binaryData);
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