1 files changed, 66 insertions, 0 deletions
diff --git a/eclipse/plugins/com.android.ide.eclipse.gldebugger/src/com/android/ide/eclipse/gltrace/TraceFileReader.java b/eclipse/plugins/com.android.ide.eclipse.gldebugger/src/com/android/ide/eclipse/gltrace/TraceFileReader.java
new file mode 100644
index 000000000..76b32b099
--- /dev/null
+++ b/eclipse/plugins/com.android.ide.eclipse.gldebugger/src/com/android/ide/eclipse/gltrace/TraceFileReader.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2011 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.ide.eclipse.gltrace;
+
+import com.android.ide.eclipse.gltrace.GLProtoBuf.GLMessage;
+import com.google.protobuf.InvalidProtocolBufferException;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+
+public class TraceFileReader {
+    /** Maximum size for a protocol buffer message.
+     * The message size is dominated by the size of the compressed framebuffer.
+     * Currently, we assume that the maximum is for a 1080p display. Since the buffers compress
+     * well, we should probably never get close to this.
+     */
+    private static final int MAX_PROTOBUF_SIZE = 1920 * 1080 * 100;
+
+    /**
+     * Obtain the next protobuf message in this file.
+     * @param file file to read from
+     * @param offset offset to start reading from
+     * @return protobuf message at given offset
+     * @throws IOException in case of file I/O errors
+     * @throws InvalidProtocolBufferException if protobuf is not well formed
+     */
+    public GLMessage getMessageAtOffset(RandomAccessFile file, long offset) throws IOException {
+        int len;
+        byte[] b;
+        try {
+            if (offset != -1) {
+                file.seek(offset);
+            }
+
+            len = file.readInt();
+            if (len > MAX_PROTOBUF_SIZE) {
+                String msg = String.format(
+                        "Unexpectedly large (%d bytes) protocol buffer message encountered.",
+                        len);
+                throw new InvalidProtocolBufferException(msg);
+            }
+
+            b = new byte[len];
+            file.readFully(b);
+        } catch (EOFException e) {
+            return null;
+        }
+
+        return GLMessage.parseFrom(b);
+    }
+}