imported Base64

darcs-hash:20040713021323-5007d-311bd662d3919d0566031502d450e537a6269afe.gz

diff --git a/src/org/ibex/util/Base64.java b/src/org/ibex/util/Base64.java
new file mode 100644 (file)
index 0000000..d3bb10d
--- /dev/null
+++ b/src/org/ibex/util/Base64.java
@@ -0,0 +1,185 @@
+package org.ibex.util;
+
+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];
+        }
+
+        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;
+    }
+
+    private static final byte[] decodingTable;
+
+    static {
+        decodingTable = new byte[128];
+        for (int i = 'A'; i <= 'Z'; i++) decodingTable[i] = (byte)(i - 'A');
+        for (int i = 'a'; i <= 'z'; i++) decodingTable[i] = (byte)(i - 'a' + 26);
+        for (int i = '0'; i <= '9'; i++) decodingTable[i] = (byte)(i - '0' + 52);
+        decodingTable['+'] = 62;
+        decodingTable['/'] = 63;
+    }
+
+    /**
+     * decode the base 64 encoded input data.
+     *
+     * @return a byte array representing the decoded data.
+     */
+    public static byte[] decode(byte[]  data) {
+        byte[]  bytes;
+        byte    b1, b2, b3, b4;
+
+        if (data[data.length - 2] == '=') bytes = new byte[(((data.length / 4) - 1) * 3) + 1];
+        else if (data[data.length - 1] == '=') bytes = new byte[(((data.length / 4) - 1) * 3) + 2];
+        else bytes = new byte[((data.length / 4) * 3)];
+
+        for (int i = 0, j = 0; i < data.length - 4; i += 4, j += 3) {
+            b1 = decodingTable[data[i]];
+            b2 = decodingTable[data[i + 1]];
+            b3 = decodingTable[data[i + 2]];
+            b4 = decodingTable[data[i + 3]];
+            
+            bytes[j] = (byte)((b1 << 2) | (b2 >> 4));
+            bytes[j + 1] = (byte)((b2 << 4) | (b3 >> 2));
+            bytes[j + 2] = (byte)((b3 << 6) | b4);
+        }
+
+        if (data[data.length - 2] == '=') {
+            b1 = decodingTable[data[data.length - 4]];
+            b2 = decodingTable[data[data.length - 3]];
+            bytes[bytes.length - 1] = (byte)((b1 << 2) | (b2 >> 4));
+        } else if (data[data.length - 1] == '=') {
+            b1 = decodingTable[data[data.length - 4]];
+            b2 = decodingTable[data[data.length - 3]];
+            b3 = decodingTable[data[data.length - 2]];
+            bytes[bytes.length - 2] = (byte)((b1 << 2) | (b2 >> 4));
+            bytes[bytes.length - 1] = (byte)((b2 << 4) | (b3 >> 2));
+        } else {
+            b1 = decodingTable[data[data.length - 4]];
+            b2 = decodingTable[data[data.length - 3]];
+            b3 = decodingTable[data[data.length - 2]];
+            b4 = decodingTable[data[data.length - 1]];
+            bytes[bytes.length - 3] = (byte)((b1 << 2) | (b2 >> 4));
+            bytes[bytes.length - 2] = (byte)((b2 << 4) | (b3 >> 2));
+            bytes[bytes.length - 1] = (byte)((b3 << 6) | b4);
+        }
+        return bytes;
+    }
+
+    /**
+     * decode the base 64 encoded String data.
+     *
+     * @return a byte array representing the decoded data.
+     */
+    public static byte[] decode(String  data) {
+        byte[]  bytes;
+        byte    b1, b2, b3, b4;
+
+        if (data.charAt(data.length() - 2) == '=')
+            bytes = new byte[(((data.length() / 4) - 1) * 3) + 1];
+        else if (data.charAt(data.length() - 1) == '=')
+            bytes = new byte[(((data.length() / 4) - 1) * 3) + 2];
+        else
+            bytes = new byte[((data.length() / 4) * 3)];
+
+        for (int i = 0, j = 0; i < data.length() - 4; i += 4, j += 3) {
+            b1 = decodingTable[data.charAt(i)];
+            b2 = decodingTable[data.charAt(i + 1)];
+            b3 = decodingTable[data.charAt(i + 2)];
+            b4 = decodingTable[data.charAt(i + 3)];
+            
+            bytes[j] = (byte)((b1 << 2) | (b2 >> 4));
+            bytes[j + 1] = (byte)((b2 << 4) | (b3 >> 2));
+            bytes[j + 2] = (byte)((b3 << 6) | b4);
+        }
+
+        if (data.charAt(data.length() - 2) == '=') {
+            b1 = decodingTable[data.charAt(data.length() - 4)];
+            b2 = decodingTable[data.charAt(data.length() - 3)];
+            bytes[bytes.length - 1] = (byte)((b1 << 2) | (b2 >> 4));
+        } else if (data.charAt(data.length() - 1) == '=') {
+            b1 = decodingTable[data.charAt(data.length() - 4)];
+            b2 = decodingTable[data.charAt(data.length() - 3)];
+            b3 = decodingTable[data.charAt(data.length() - 2)];
+            bytes[bytes.length - 2] = (byte)((b1 << 2) | (b2 >> 4));
+            bytes[bytes.length - 1] = (byte)((b2 << 4) | (b3 >> 2));
+        } else {
+            b1 = decodingTable[data.charAt(data.length() - 4)];
+            b2 = decodingTable[data.charAt(data.length() - 3)];
+            b3 = decodingTable[data.charAt(data.length() - 2)];
+            b4 = decodingTable[data.charAt(data.length() - 1)];
+            bytes[bytes.length - 3] = (byte)((b1 << 2) | (b2 >> 4));
+            bytes[bytes.length - 2] = (byte)((b2 << 4) | (b3 >> 2));
+            bytes[bytes.length - 1] = (byte)((b3 << 6) | b4);
+        }
+        return bytes;
+    }
+}