1 files changed, 167 insertions, 0 deletions
diff --git a/src/com/android/messaging/mmslib/pdu/Base64.java b/src/com/android/messaging/mmslib/pdu/Base64.java
new file mode 100644
index 0000000..2f27117
--- /dev/null
+++ b/src/com/android/messaging/mmslib/pdu/Base64.java
@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) 2007 Esmertec AG.
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.messaging.mmslib.pdu;
+
+public class Base64 {
+    /**
+     * Used to get the number of Quadruples.
+     */
+    static final int FOURBYTE = 4;
+
+    /**
+     * Byte used to pad output.
+     */
+    static final byte PAD = (byte) '=';
+
+    /**
+     * The base length.
+     */
+    static final int BASELENGTH = 255;
+
+    // Create arrays to hold the base64 characters
+    private static byte[] base64Alphabet = new byte[BASELENGTH];
+
+    // Populating the character arrays
+    static {
+        for (int i = 0; i < BASELENGTH; i++) {
+            base64Alphabet[i] = (byte) -1;
+        }
+        for (int i = 'Z'; i >= 'A'; i--) {
+            base64Alphabet[i] = (byte) (i - 'A');
+        }
+        for (int i = 'z'; i >= 'a'; i--) {
+            base64Alphabet[i] = (byte) (i - 'a' + 26);
+        }
+        for (int i = '9'; i >= '0'; i--) {
+            base64Alphabet[i] = (byte) (i - '0' + 52);
+        }
+
+        base64Alphabet['+'] = 62;
+        base64Alphabet['/'] = 63;
+    }
+
+    /**
+     * Decodes Base64 data into octects
+     *
+     * @param base64Data Byte array containing Base64 data
+     * @return Array containing decoded data.
+     */
+    public static byte[] decodeBase64(byte[] base64Data) {
+        // RFC 2045 requires that we discard ALL non-Base64 characters
+        base64Data = discardNonBase64(base64Data);
+
+        // handle the edge case, so we don't have to worry about it later
+        if (base64Data.length == 0) {
+            return new byte[0];
+        }
+
+        int numberQuadruple = base64Data.length / FOURBYTE;
+        byte decodedData[] = null;
+        byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;
+
+        // Throw away anything not in base64Data
+
+        int encodedIndex = 0;
+        int dataIndex = 0;
+        {
+            // this sizes the output array properly - rlw
+            int lastData = base64Data.length;
+            // ignore the '=' padding
+            while (base64Data[lastData - 1] == PAD) {
+                if (--lastData == 0) {
+                    return new byte[0];
+                }
+            }
+            decodedData = new byte[lastData - numberQuadruple];
+        }
+
+        for (int i = 0; i < numberQuadruple; i++) {
+            dataIndex = i * 4;
+            marker0 = base64Data[dataIndex + 2];
+            marker1 = base64Data[dataIndex + 3];
+
+            b1 = base64Alphabet[base64Data[dataIndex]];
+            b2 = base64Alphabet[base64Data[dataIndex + 1]];
+
+            if (marker0 != PAD && marker1 != PAD) {
+                //No PAD e.g 3cQl
+                b3 = base64Alphabet[marker0];
+                b4 = base64Alphabet[marker1];
+
+                decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
+                decodedData[encodedIndex + 1] =
+                        (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
+                decodedData[encodedIndex + 2] = (byte) (b3 << 6 | b4);
+            } else if (marker0 == PAD) {
+                //Two PAD e.g. 3c[Pad][Pad]
+                decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
+            } else if (marker1 == PAD) {
+                //One PAD e.g. 3cQ[Pad]
+                b3 = base64Alphabet[marker0];
+
+                decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
+                decodedData[encodedIndex + 1] =
+                        (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
+            }
+            encodedIndex += 3;
+        }
+        return decodedData;
+    }
+
+    /**
+     * Check octect wheter it is a base64 encoding.
+     *
+     * @param octect to be checked byte
+     * @return ture if it is base64 encoding, false otherwise.
+     */
+    private static boolean isBase64(byte octect) {
+        if (octect == PAD) {
+            return true;
+        } else if (base64Alphabet[octect] == -1) {
+            return false;
+        } else {
+            return true;
+        }
+    }
+
+    /**
+     * Discards any characters outside of the base64 alphabet, per
+     * the requirements on page 25 of RFC 2045 - "Any characters
+     * outside of the base64 alphabet are to be ignored in base64
+     * encoded data."
+     *
+     * @param data The base-64 encoded data to groom
+     * @return The data, less non-base64 characters (see RFC 2045).
+     */
+    static byte[] discardNonBase64(byte[] data) {
+        byte groomedData[] = new byte[data.length];
+        int bytesCopied = 0;
+
+        for (int i = 0; i < data.length; i++) {
+            if (isBase64(data[i])) {
+                groomedData[bytesCopied++] = data[i];
+            }
+        }
+
+        byte packedData[] = new byte[bytesCopied];
+
+        System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);
+
+        return packedData;
+    }
+}