Java kodlarını Php ye çevirme

import java.security.MessageDigest;
import java.nio.charset.Charset;

public class checksumGenerator {
    public static void main(String[] args) {
        StringBuilder stringBuilder = new StringBuilder();
        String encodedstr = encodeFile("upload.jpg");
        stringBuilder.append(get());
        stringBuilder.append("|");
        stringBuilder.append("nick");
        stringBuilder.append("|");
        stringBuilder.append("password");
        stringBuilder.append("|");
        stringBuilder.append("to");
        stringBuilder.append("|");
        stringBuilder.append("source");
        stringBuilder.append("|");
        stringBuilder.append(encodedstr);
        String checksum = set(stringBuilder.toString(), false);
        System.out.println(checksum);
    }
    public static String encodeFile(String filename) {
        File file = new File(filename);
        String res = "";
        try {
            int k = (int) file.length();
            int j = k;
            if (k > 1000) {
                j = 1000;
            }
            byte[] arrayOfByte = new byte[j];
            try {
                BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(file));
                bufferedInputStream.read(arrayOfByte, 0, j);
                bufferedInputStream.close();
                res = Base64.encodeToString(arrayOfByte);
            }
        }
        return res;
    }
    public static String get() {
        String str = "";
        for (int i = 65; i <= 90; i++) {
            StringBuilder stringBuilder = new StringBuilder();
            stringBuilder.append(str);
            stringBuilder.append((char)((i - 1) * 256 % 25 + 97));
            str = stringBuilder.toString();
        }
        return set(str, true);
    }

    public static String set(String var1, boolean var2) {
        byte[] arrayOfByte = null;
        StringBuffer stringBuffer = new StringBuffer();
        try {
            MessageDigest messageDigest = MessageDigest.getInstance("SHA-256");
            messageDigest.reset();
            Charset charset = Charset.forName("UTF-8");
            arrayOfByte = var1.getBytes(charset);
            arrayOfByte = messageDigest.digest(arrayOfByte);
        } catch (Exception e) {
            // Always must return something
        }
        int j = arrayOfByte.length;
        int i = 0;
        while (i < j) {
            String str = Integer.toString((arrayOfByte[i] & 0xFF) + 256);
            if (str != null) {
                str = str.substring(1);
                stringBuffer.append(str);
                i++;
                continue;
            }
        }
        if (var2) {
            String str = stringBuffer.toString();
            if (str != null) {
                str = str.toUpperCase();
                str = str.replace("C", "I");
                return str;
            }
        }
        String str1 = stringBuffer.toString();
        return str1;
    }
}