DO NOT MERGE: Add AUtils::isInRange, and use it to detect malformed MPEG4 nal sizes

Bug: 19641538
Change-Id: I5aae3f100846c125decc61eec7cd6563e3f33777

Conflicts:
	media/libstagefright/MPEG4Extractor.cpp

1 files changed, 45 insertions, 0 deletions

diff --git a/include/media/stagefright/foundation/AUtils.h b/include/media/stagefright/foundation/AUtils.h
new file mode 100644
index 0000000..60cb41d
--- /dev/null
+++ b/include/media/stagefright/foundation/AUtils.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright 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.
+ */
+
+#ifndef A_UTILS_H_
+
+#define A_UTILS_H_
+
+/* ============================ math templates ============================ */
+
+template<class T>
+void ENSURE_UNSIGNED_TYPE() {
+    T TYPE_MUST_BE_UNSIGNED[(T)-1 < 0 ? -1 : 0];
+}
+
+// needle is in range [hayStart, hayStart + haySize)
+template<class T, class U>
+inline static bool isInRange(const T &hayStart, const U &haySize, const T &needle) {
+    ENSURE_UNSIGNED_TYPE<U>();
+    return (T)(hayStart + haySize) >= hayStart && needle >= hayStart && (U)(needle - hayStart) < haySize;
+}
+
+// [needleStart, needleStart + needleSize) is in range [hayStart, hayStart + haySize)
+template<class T, class U>
+inline static bool isInRange(
+        const T &hayStart, const U &haySize, const T &needleStart, const U &needleSize) {
+    ENSURE_UNSIGNED_TYPE<U>();
+    return isInRange(hayStart, haySize, needleStart)
+            && (T)(needleStart + needleSize) >= needleStart
+            && (U)(needleStart + needleSize - hayStart) <= haySize;
+}
+
+#endif  // A_UTILS_H_