1 files changed, 153 insertions, 0 deletions
diff --git a/core/java/android/util/base64/Base64OutputStream.java b/core/java/android/util/base64/Base64OutputStream.java
new file mode 100644
index 0000000..126bde4
--- /dev/null
+++ b/core/java/android/util/base64/Base64OutputStream.java
@@ -0,0 +1,153 @@
+/*
+ * Copyright (C) 2010 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 android.util.base64;
+
+import java.io.FilterOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+
+/**
+ * An OutputStream that does either Base64 encoding or decoding on the
+ * data written to it, writing the resulting data to another
+ * OutputStream.
+ */
+public class Base64OutputStream extends FilterOutputStream {
+    private final boolean encode;
+    private final Base64.EncoderState estate;
+    private final Base64.DecoderState dstate;
+    private final int flags;
+
+    private byte[] buffer = null;
+    private int bpos = 0;
+
+    private static byte[] EMPTY = new byte[0];
+
+    /**
+     * Performs Base64 encoding on the data written to the stream,
+     * writing the encoded data to another OutputStream.
+     *
+     * @param out the OutputStream to write the encoded data to
+     * @param flags bit flags for controlling the encoder; see the
+     *        constants in {@link Base64}
+     */
+    public Base64OutputStream(OutputStream out, int flags) {
+        this(out, flags, true);
+    }
+
+    /**
+     * Performs Base64 encoding or decoding on the data written to the
+     * stream, writing the encoded/decoded data to another
+     * OutputStream.
+     *
+     * @param out the OutputStream to write the encoded data to
+     * @param flags bit flags for controlling the encoder; see the
+     *        constants in {@link Base64}
+     * @param encode true to encode, false to decode
+     */
+    public Base64OutputStream(OutputStream out, int flags, boolean encode) {
+        super(out);
+        this.flags = flags;
+        this.encode = encode;
+        if (encode) {
+            estate = new Base64.EncoderState(flags, null);
+            dstate = null;
+        } else {
+            estate = null;
+            dstate = new Base64.DecoderState(flags, null);
+        }
+    }
+
+    public void write(int b) throws IOException {
+        // To avoid invoking the encoder/decoder routines for single
+        // bytes, we buffer up calls to write(int) in an internal
+        // byte array to transform them into writes of decently-sized
+        // arrays.
+
+        if (buffer == null) {
+            buffer = new byte[1024];
+        }
+        if (bpos >= buffer.length) {
+            // internal buffer full; write it out.
+            internalWrite(buffer, 0, bpos, false);
+            bpos = 0;
+        }
+        buffer[bpos++] = (byte) b;
+    }
+
+    /**
+     * Flush any buffered data from calls to write(int).  Needed
+     * before doing a write(byte[], int, int) or a close().
+     */
+    private void flushBuffer() throws IOException {
+        if (bpos > 0) {
+            internalWrite(buffer, 0, bpos, false);
+            bpos = 0;
+        }
+    }
+
+    public void write(byte[] b, int off, int len) throws IOException {
+        if (len <= 0) return;
+        flushBuffer();
+        internalWrite(b, off, len, false);
+    }
+
+    public void close() throws IOException {
+        flushBuffer();
+        internalWrite(EMPTY, 0, 0, true);
+        if ((flags & Base64.NO_CLOSE) == 0) {
+            out.close();
+        } else {
+            out.flush();
+        }
+    }
+
+    /**
+     * Write the given bytes to the encoder/decoder.
+     *
+     * @param finish true if this is the last batch of input, to cause
+     *        encoder/decoder state to be finalized.
+     */
+    private void internalWrite(byte[] b, int off, int len, boolean finish) throws IOException {
+        if (encode) {
+            // len*8/5+10 is an overestimate of the most bytes the
+            // encoder can produce for len bytes of input.
+            estate.output = embiggen(estate.output, len*8/5+10);
+            Base64.encodeInternal(b, off, len, estate, finish);
+            out.write(estate.output, 0, estate.op);
+        } else {
+            // len*3/4+10 is an overestimate of the most bytes the
+            // decoder can produce for len bytes of input.
+            dstate.output = embiggen(dstate.output, len*3/4+10);
+            if (!Base64.decodeInternal(b, off, len, dstate, finish)) {
+                throw new IOException("bad base-64");
+            }
+            out.write(dstate.output, 0, dstate.op);
+        }
+    }
+
+    /**
+     * If b.length is at least len, return b.  Otherwise return a new
+     * byte array of length len.
+     */
+    private byte[] embiggen(byte[] b, int len) {
+        if (b == null || b.length < len) {
+            return new byte[len];
+        } else {
+            return b;
+        }
+    }
+}