Base64 Encoding in UnrealScript

Our example demonstrates base64 encoding and decoding in UnrealScript. UnrealScript doesn’t have built-in support for base64, so we’ll implement basic encoding and decoding functions.

class Base64Example extends Object;

var string Base64Chars;

function Init()
{
    Base64Chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
}

function string EncodeBase64(string Data)
{
    local int i, j, Remainder;
    local string Result;
    local array<int> Bytes;

    for (i = 0; i < Len(Data); i++)
    {
        Bytes[i] = Asc(Mid(Data, i, 1));
    }

    for (i = 0; i < Bytes.Length; i += 3)
    {
        Result $= Mid(Base64Chars, (Bytes[i] >> 2) & 0x3F, 1);
        if (i + 1 < Bytes.Length)
        {
            Result $= Mid(Base64Chars, ((Bytes[i] & 0x3) << 4) | ((Bytes[i+1] >> 4) & 0xF), 1);
            if (i + 2 < Bytes.Length)
            {
                Result $= Mid(Base64Chars, ((Bytes[i+1] & 0xF) << 2) | ((Bytes[i+2] >> 6) & 0x3), 1);
                Result $= Mid(Base64Chars, Bytes[i+2] & 0x3F, 1);
            }
            else
            {
                Result $= Mid(Base64Chars, (Bytes[i+1] & 0xF) << 2, 1);
                Result $= "=";
            }
        }
        else
        {
            Result $= Mid(Base64Chars, (Bytes[i] & 0x3) << 4, 1);
            Result $= "==";
        }
    }

    return Result;
}

function string DecodeBase64(string EncodedData)
{
    local int i, j, Value;
    local string Result;
    local array<int> Bytes;

    for (i = 0; i < Len(EncodedData); i++)
    {
        if (Mid(EncodedData, i, 1) == "=")
            break;
        j = InStr(Base64Chars, Mid(EncodedData, i, 1));
        if (j != -1)
            Bytes[Bytes.Length] = j;
    }

    for (i = 0; i < Bytes.Length; i += 4)
    {
        Value = (Bytes[i] << 18) | (Bytes[i+1] << 12) | (Bytes[i+2] << 6) | Bytes[i+3];
        Result $= Chr((Value >> 16) & 0xFF);
        if (i + 2 < Bytes.Length)
            Result $= Chr((Value >> 8) & 0xFF);
        if (i + 3 < Bytes.Length)
            Result $= Chr(Value & 0xFF);
    }

    return Result;
}

function Example()
{
    local string Data, EncodedData, DecodedData;

    Init();

    // Here's the string we'll encode/decode
    Data = "abc123!?$*&()'-=@~";

    // Encode the string
    EncodedData = EncodeBase64(Data);
    `log("Encoded: " $ EncodedData);

    // Decode the string
    DecodedData = DecodeBase64(EncodedData);
    `log("Decoded: " $ DecodedData);
}

In this example, we’ve implemented basic Base64 encoding and decoding functions. UnrealScript doesn’t have built-in Base64 support, so we’ve created our own implementation.

The EncodeBase64 function takes a string and returns its Base64 encoded version. The DecodeBase64 function does the reverse, taking a Base64 encoded string and returning the original data.

To use these functions:

First, call the Init function to set up the Base64 character set.
Then you can use EncodeBase64 to encode a string and DecodeBase64 to decode it.

The Example function demonstrates how to use these functions. It encodes a sample string, prints the encoded version, then decodes it back and prints the result.

Note that this is a basic implementation and may not handle all edge cases or be optimized for performance. In a real game scenario, you might want to use a more robust, tested library if available, or further optimize this code for your specific needs.

To run this code, you would typically include it in an UnrealScript class in your Unreal Engine project and call the Example function from appropriate game logic.

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Base64 Encoding in UnrealScript