1 files changed, 66 insertions, 0 deletions
diff --git a/core/java/com/android/internal/util/SizedInputStream.java b/core/java/com/android/internal/util/SizedInputStream.java
new file mode 100644
index 0000000..00a729d
--- /dev/null
+++ b/core/java/com/android/internal/util/SizedInputStream.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2014 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.internal.util;
+
+import libcore.io.Streams;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Reads exact number of bytes from wrapped stream, returning EOF once those
+ * bytes have been read.
+ */
+public class SizedInputStream extends InputStream {
+    private final InputStream mWrapped;
+    private long mLength;
+
+    public SizedInputStream(InputStream wrapped, long length) {
+        mWrapped = wrapped;
+        mLength = length;
+    }
+
+    @Override
+    public void close() throws IOException {
+        super.close();
+        mWrapped.close();
+    }
+
+    @Override
+    public int read() throws IOException {
+        return Streams.readSingleByte(this);
+    }
+
+    @Override
+    public int read(byte[] buffer, int byteOffset, int byteCount) throws IOException {
+        if (mLength <= 0) {
+            return -1;
+        } else if (byteCount > mLength) {
+            byteCount = (int) mLength;
+        }
+
+        final int n = mWrapped.read(buffer, byteOffset, byteCount);
+        if (n == -1) {
+            if (mLength > 0) {
+                throw new IOException("Unexpected EOF; expected " + mLength + " more bytes");
+            }
+        } else {
+            mLength -= n;
+        }
+        return n;
+    }
+}