deep-c-rsc/mudclient204-threadless/Buffer.java

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2021-07-18 22:51:38 -04:00
import java.math.BigInteger;
public class Buffer {
/*static CRC32 unusedCRC = new CRC32();
private static int unusedArray[] = {
0, 1, 3, 7, 15, 31, 63, 127, 255, 511,
1023, 2047, 4095, 8191, 16383, 32767, 65535, 0x1ffff, 0x3ffff, 0x7ffff,
0xfffff, 0x1fffff, 0x3fffff, 0x7fffff, 0xffffff, 0x1ffffff, 0x3ffffff, 0x7ffffff, 0xfffffff, 0x1fffffff,
0x3fffffff, 0x7fffffff, -1
};*/
public byte buffer[];
public int offset;
public Buffer(byte buff[]) {
buffer = buff;
offset = 0;
}
public void putByte(int i) {
buffer[offset++] = (byte) i;
}
public void putInt(int i) {
buffer[offset++] = (byte) (i >> 24);
buffer[offset++] = (byte) (i >> 16);
buffer[offset++] = (byte) (i >> 8);
buffer[offset++] = (byte) i;
}
public void putString(String s) {
//s.getBytes(0, s.length(), buffer, offset);
System.arraycopy(s.getBytes(), 0, buffer, offset, s.length());
offset += s.length();
buffer[offset++] = 10; // null terminate
}
public void putBytes(byte src[], int srcPos, int len) {
//for (int k = srcPos; k < srcPos + len; k++)
// buffer[offset++] = src[k];
System.arraycopy(src, srcPos, buffer, offset, len);
offset += len;
}
public int getUnsignedByte() {
return buffer[offset++] & 0xff;
}
public int getUnsignedShort() {
offset += 2;
return ((buffer[offset - 2] & 0xff) << 8) + (buffer[offset - 1] & 0xff);
}
public int getUnsignedInt() {
offset += 4;
return ((buffer[offset - 4] & 0xff) << 24) + ((buffer[offset - 3] & 0xff) << 16) + ((buffer[offset - 2] & 0xff) << 8) + (buffer[offset - 1] & 0xff);
}
public void getBytes(byte dest[], int destPos, int len) {
//for (int k = destPos; k < destPos + len; k++)
// dest[k] = buffer[offset++];
System.arraycopy(buffer, offset, dest, destPos, len);
offset += len;
}
public void encrypt(BigInteger exponent, BigInteger modulus) {
int i = offset;
offset = 0;
byte buf[] = new byte[i];
getBytes(buf, 0, i);
BigInteger biginteger2 = new BigInteger(buf);
BigInteger biginteger3 = biginteger2.modPow(exponent, modulus);
byte abyte1[] = biginteger3.toByteArray();
offset = 0;
putByte(abyte1.length);
putBytes(abyte1, 0, abyte1.length);
}
}