1 files changed, 80 insertions, 0 deletions
diff --git a/provider_src/com/android/email/FixedLengthInputStream.java b/provider_src/com/android/email/FixedLengthInputStream.java
new file mode 100644
index 000000000..753c03181
--- /dev/null
+++ b/provider_src/com/android/email/FixedLengthInputStream.java
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2008 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.email;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * A filtering InputStream that stops allowing reads after the given length has been read. This
+ * is used to allow a client to read directly from an underlying protocol stream without reading
+ * past where the protocol handler intended the client to read. 
+ */
+public class FixedLengthInputStream extends InputStream {
+    private final InputStream mIn;
+    private final int mLength;
+    private int mCount;
+
+    public FixedLengthInputStream(InputStream in, int length) {
+        this.mIn = in;
+        this.mLength = length;
+    }
+
+    @Override
+    public int available() throws IOException {
+        return mLength - mCount;
+    }
+
+    @Override
+    public int read() throws IOException {
+        if (mCount < mLength) {
+            mCount++;
+            return mIn.read();
+        } else {
+            return -1;
+        }
+    }
+
+    @Override
+    public int read(byte[] b, int offset, int length) throws IOException {
+        if (mCount < mLength) {
+            int d = mIn.read(b, offset, Math.min(mLength - mCount, length));
+            if (d == -1) {
+                return -1;
+            } else {
+                mCount += d;
+                return d;
+            }
+        } else {
+            return -1;
+        }
+    }
+
+    @Override
+    public int read(byte[] b) throws IOException {
+        return read(b, 0, b.length);
+    }
+
+    public int getLength() {
+        return mLength;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("FixedLengthInputStream(in=%s, length=%d)", mIn.toString(), mLength);
+    }
+}