80 lines
2.4 KiB
Java
80 lines
2.4 KiB
Java
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);
|
|
}
|
|
|
|
}
|