1 files changed, 101 insertions, 0 deletions
diff --git a/media/libaom/src/third_party/libyuv/source/mjpeg_validate.cc b/media/libaom/src/third_party/libyuv/source/mjpeg_validate.cc
new file mode 100644
index 000000000..8edfbe1e7
--- /dev/null
+++ b/media/libaom/src/third_party/libyuv/source/mjpeg_validate.cc
@@ -0,0 +1,101 @@
+/*
+ *  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"
+
+#include <string.h>  // For memchr.
+
+#ifdef __cplusplus
+namespace libyuv {
+extern "C" {
+#endif
+
+// Enable this to try scasb implementation.
+// #define ENABLE_SCASB 1
+
+#ifdef ENABLE_SCASB
+
+// Multiple of 1.
+__declspec(naked)
+const uint8* ScanRow_ERMS(const uint8* src, uint32 val, int count) {
+  __asm {
+    mov        edx, edi
+    mov        edi, [esp + 4]   // src
+    mov        eax, [esp + 8]   // val
+    mov        ecx, [esp + 12]  // count
+    repne scasb
+    jne        sr99
+    mov        eax, edi
+    sub        eax, 1
+    mov        edi, edx
+    ret
+
+  sr99:
+    mov        eax, 0
+    mov        edi, edx
+    ret
+  }
+}
+#endif
+
+// Helper function to scan for EOI marker.
+static LIBYUV_BOOL ScanEOI(const uint8* sample, size_t sample_size) {
+  const uint8* end = sample + sample_size - 1;
+  const uint8* it = sample;
+  for (;;) {
+#ifdef ENABLE_SCASB
+    it = ScanRow_ERMS(it, 0xff, end - it);
+#else
+    it = static_cast<const uint8*>(memchr(it, 0xff, end - it));
+#endif
+    if (it == NULL) {
+      break;
+    }
+    if (it[1] == 0xd9) {
+      return LIBYUV_TRUE;  // Success: Valid jpeg.
+    }
+    ++it;  // Skip over current 0xff.
+  }
+  // ERROR: Invalid jpeg end code not found. Size sample_size
+  return LIBYUV_FALSE;
+}
+
+// Helper function to validate the jpeg appears intact.
+LIBYUV_BOOL ValidateJpeg(const uint8* sample, size_t sample_size) {
+  const size_t kBackSearchSize = 1024;
+  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;
+  }
+  // Step over SOI marker.
+  sample += 2;
+  sample_size -= 2;
+
+  // Look for the End Of Image (EOI) marker in the end kilobyte of the buffer.
+  if (sample_size > kBackSearchSize) {
+    if (ScanEOI(sample + sample_size - kBackSearchSize, kBackSearchSize)) {
+      return LIBYUV_TRUE;  // Success: Valid jpeg.
+    }
+    // Reduce search size for forward search.
+    sample_size = sample_size - kBackSearchSize + 1;
+  }
+  return ScanEOI(sample, sample_size);
+
+}
+
+#ifdef __cplusplus
+}  // extern "C"
+}  // namespace libyuv
+#endif
+