1 files changed, 80 insertions, 0 deletions
diff --git a/java/com/android/voicemailomtp/mail/PeekableInputStream.java b/java/com/android/voicemailomtp/mail/PeekableInputStream.java
new file mode 100644
index 000000000..c1181d189
--- /dev/null
+++ b/java/com/android/voicemailomtp/mail/PeekableInputStream.java
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2015 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.voicemailomtp.mail;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * A filtering InputStream that allows single byte "peeks" without consuming the byte. The
+ * client of this stream can call peek() to see the next available byte in the stream
+ * and a subsequent read will still return the peeked byte.
+ */
+public class PeekableInputStream extends InputStream {
+    private final InputStream mIn;
+    private boolean mPeeked;
+    private int mPeekedByte;
+
+    public PeekableInputStream(InputStream in) {
+        this.mIn = in;
+    }
+
+    @Override
+    public int read() throws IOException {
+        if (!mPeeked) {
+            return mIn.read();
+        } else {
+            mPeeked = false;
+            return mPeekedByte;
+        }
+    }
+
+    public int peek() throws IOException {
+        if (!mPeeked) {
+            mPeekedByte = read();
+            mPeeked = true;
+        }
+        return mPeekedByte;
+    }
+
+    @Override
+    public int read(byte[] b, int offset, int length) throws IOException {
+        if (!mPeeked) {
+            return mIn.read(b, offset, length);
+        } else {
+            b[0] = (byte)mPeekedByte;
+            mPeeked = false;
+            int r = mIn.read(b, offset + 1, length - 1);
+            if (r == -1) {
+                return 1;
+            } else {
+                return r + 1;
+            }
+        }
+    }
+
+    @Override
+    public int read(byte[] b) throws IOException {
+        return read(b, 0, b.length);
+    }
+
+    @Override
+    public String toString() {
+        return String.format("PeekableInputStream(in=%s, peeked=%b, peekedByte=%d)",
+                mIn.toString(), mPeeked, mPeekedByte);
+    }
+}
+\ No newline at end of file