libvpx: Pull from upstream

source/libvpx/third_party/libyuv/source/mjpeg_validate.cc

Index: source/libvpx/third_party/libyuv/source/mjpeg_validate.cc
===================================================================
--- source/libvpx/third_party/libyuv/source/mjpeg_validate.cc	(revision 0)
+++ source/libvpx/third_party/libyuv/source/mjpeg_validate.cc	(revision 0)
@@ -0,0 +1,47 @@
+/*
+ *  Copyright 2012 The LibYuv Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS. All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "libyuv/mjpeg_decoder.h"
+
+#ifdef __cplusplus
+namespace libyuv {
+extern "C" {
+#endif
+
+// Helper function to validate the jpeg appears intact.
+// TODO(fbarchard): Optimize case where SOI is found but EOI is not.
+LIBYUV_BOOL ValidateJpeg(const uint8* sample, size_t sample_size) {
+  size_t i;
+  if (sample_size < 64) {
+    // ERROR: Invalid jpeg size: sample_size
+    return LIBYUV_FALSE;
+  }
+  if (sample[0] != 0xff || sample[1] != 0xd8) {  // Start Of Image
+    // ERROR: Invalid jpeg initial start code
+    return LIBYUV_FALSE;
+  }
+  for (i = sample_size - 2; i > 1;) {
+    if (sample[i] != 0xd9) {
+      if (sample[i] == 0xff && sample[i + 1] == 0xd9) {  // End Of Image
+        return LIBYUV_TRUE;  // Success: Valid jpeg.
+      }
+      --i;
+    }
+    --i;
+  }
+  // ERROR: Invalid jpeg end code not found. Size sample_size
+  return LIBYUV_FALSE;
+}
+
+#ifdef __cplusplus
+}  // extern "C"
+}  // namespace libyuv
+#endif
+