-public class Base64
-{
- private static final byte[] encodingTable =
- {
- (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
- (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
- (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U',
- (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
- (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
- (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
- (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u',
- (byte)'v',
- (byte)'w', (byte)'x', (byte)'y', (byte)'z',
- (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6',
- (byte)'7', (byte)'8', (byte)'9',
- (byte)'+', (byte)'/'
- };
-
- /**
- * encode the input data producong a base 64 encoded byte array.
- *
- * @return a byte array containing the base 64 encoded data.
- */
- public static byte[] encode(
- byte[] data)
- {
- byte[] bytes;
-
- int modulus = data.length % 3;
- if (modulus == 0)
- {
- bytes = new byte[4 * data.length / 3];
- }
- else
- {
- bytes = new byte[4 * ((data.length / 3) + 1)];
- }
-
- int dataLength = (data.length - modulus);
- int a1, a2, a3;
- for (int i = 0, j = 0; i < dataLength; i += 3, j += 4)
- {
- a1 = data[i] & 0xff;
- a2 = data[i + 1] & 0xff;
- a3 = data[i + 2] & 0xff;
-
- bytes[j] = encodingTable[(a1 >>> 2) & 0x3f];
- bytes[j + 1] = encodingTable[((a1 << 4) | (a2 >>> 4)) & 0x3f];
- bytes[j + 2] = encodingTable[((a2 << 2) | (a3 >>> 6)) & 0x3f];
- bytes[j + 3] = encodingTable[a3 & 0x3f];
- }
-
- /*
- * process the tail end.
- */
- int b1, b2, b3;
- int d1, d2;
-
- switch (modulus)
- {
- case 0: /* nothing left to do */
- break;
- case 1:
- d1 = data[data.length - 1] & 0xff;
- b1 = (d1 >>> 2) & 0x3f;
- b2 = (d1 << 4) & 0x3f;
-
- bytes[bytes.length - 4] = encodingTable[b1];
- bytes[bytes.length - 3] = encodingTable[b2];
- bytes[bytes.length - 2] = (byte)'=';
- bytes[bytes.length - 1] = (byte)'=';
- break;
- case 2:
- d1 = data[data.length - 2] & 0xff;
- d2 = data[data.length - 1] & 0xff;
-
- b1 = (d1 >>> 2) & 0x3f;
- b2 = ((d1 << 4) | (d2 >>> 4)) & 0x3f;
- b3 = (d2 << 2) & 0x3f;
-
- bytes[bytes.length - 4] = encodingTable[b1];
- bytes[bytes.length - 3] = encodingTable[b2];
- bytes[bytes.length - 2] = encodingTable[b3];
- bytes[bytes.length - 1] = (byte)'=';
- break;
- }
-
- return bytes;
+import java.io.UnsupportedEncodingException;
+
+public final class Base64 {
+ private Base64() { /* can't be instansiated */ }
+
+ private static final char encodeMap[] = {
+ 'A','B','C','D','E','F','G','H',
+ 'I','J','K','L','M','N','O','P',
+ 'Q','R','S','T','U','V','W','X',
+ 'Y','Z','a','b','c','d','e','f',
+ 'g','h','i','j','k','l','m','n',
+ 'o','p','q','r','s','t','u','v',
+ 'w','x','y','z','0','1','2','3',
+ '4','5','6','7','8','9','+','/'
+ };
+
+ private static final int decodeMap[] = {
+ -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+ -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+ -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63,
+ 52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-2,-1,-1,
+ -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,
+ 15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,
+ -1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,
+ 41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1
+ };
+
+ public static void main(String[] args){
+ if(args.length == 2 && args[0].equals("encode"))
+ System.out.println(encode(args[1].getBytes()));
+ else if(args.length == 2 && args[0].equals("decode"))
+ System.out.println(new String(decode(args[1])));
+ else {
+ System.out.println("Usage: Base64 {encode,decode} text");
+ System.exit(1);