lakebane/src/engine/util/ByteUtils.java

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//      Magicbane Emulator Project © 2013 - 2022
//                www.magicbane.com


package engine.util;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

public abstract class ByteUtils {

    private ByteUtils() {
    }

    public static byte[] switchByteArrayEndianness(byte[] in) {
        int size = in.length;

        byte[] out = new byte[size];

        for (int i = 0; i < size; ++i) {
            out[size - i - 1] = in[i];
        }
        return out;
    }

    /*
     * Converts a single byte to a hex StringBuffer
     */
    public static void byteToStringHex(byte b, StringBuffer buf) {
        char[] hexChars = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
                'A', 'B', 'C', 'D', 'E', 'F'};
        int high = ((b & 0xf0) >> 4);
        int low = (b & 0x0f);
        buf.append(hexChars[high]);
        buf.append(hexChars[low]);
    }

    /*
     * Converts a single byte to a hex String
     */
    public static String byteToStringHex(byte b) {
        StringBuffer sb = new StringBuffer();
        byteToStringHex(b, sb);
        return sb.toString();
    }

    /*
     * Converts a byte array to hex String
     */
    public static String byteArrayToStringHex(byte[] block) {
        StringBuffer buf = new StringBuffer();
        int len = block.length;

        for (int i = 0; i < len; i++) {
            ByteUtils.byteToStringHex(block[i], buf);
            if (i < len - 1) {
                buf.append(':');
            }
        }
        return buf.toString();
    }

    /*
     * Converts a single byte to a hex StringBuffer
     */
    public static void byteToSafeStringHex(byte b, StringBuffer buf) {
        char[] hexChars = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
                'a', 'b', 'c', 'd', 'e', 'f'};
        int high = ((b & 0xf0) >> 4);
        int low = (b & 0x0f);
        buf.append(hexChars[high]);
        buf.append(hexChars[low]);
    }

    /*
     * Converts a single byte to a hex String
     */
    public static String byteToSafeStringHex(byte b) {
        StringBuffer sb = new StringBuffer();
        byteToSafeStringHex(b, sb);
        return sb.toString();
    }

    /*
     * Converts a byte array to hex String
     */
    public static String byteArrayToSafeStringHex(byte[] block) {
        StringBuffer buf = new StringBuffer();

        int len = block.length;

        for (int i = 0; i < len; i++) {
            ByteUtils.byteToSafeStringHex(block[i], buf);
        }
        return buf.toString();
    }

    /*
     * Converts a hex string to Byte Array
     */
    public static byte[] stringHexToByteArray(String hex) {
        int length = hex.length();
        char[] hexchar = hex.toCharArray();
        byte[] ret = new byte[length / 2];
        int i1 = 0;

        for (int i = 0; i < length - 1; i += 2) {
            ret[i1] = (byte) (Character.digit(hexchar[i], 16) * 16 + Character
                    .digit(hexchar[i + 1], 16));
            i1++;
        }

        return ret;
    }

    /*
     * Converts a hex string formatted by our byteToStringHex to a byte array
     * returns null if passed a null string
     */
    public static byte[] formattedStringHexToByteArray(String hex) {
        if (hex == null) {
            return null;
        }

        String tmpString = hex.replaceAll(":", "");
        int length = tmpString.length();
        char[] hexchar = tmpString.toCharArray();
        byte[] ret = new byte[length / 2];
        int i1 = 0;

        for (int i = 0; i < length - 1; i += 2) {
            ret[i1] = (byte) (Character.digit(hexchar[i], 16) * 16 + Character
                    .digit(hexchar[i + 1], 16));
            i1++;
        }

        return ret;
    }

    public static byte[] compress(final byte[] in) throws IOException {
        final ByteArrayOutputStream out = new ByteArrayOutputStream();
        final GZIPOutputStream gzOs = new GZIPOutputStream(out);
        gzOs.write(in);
        gzOs.close();
        return out.toByteArray();
    }

    public static byte[] decompress(final byte[] in) throws IOException {
        final ByteArrayOutputStream out = new ByteArrayOutputStream();
        final GZIPInputStream gzIs = new GZIPInputStream(new ByteArrayInputStream(in));
        final byte[] buffer = new byte[512];
        int lastRead = 0;

        lastRead = gzIs.read(buffer);
        while (lastRead > 0) {
            out.write(buffer, 0, lastRead);
            lastRead = gzIs.read(buffer);
        }
        gzIs.close();
        return out.toByteArray();
    }

}