1 files changed, 32 insertions, 0 deletions
diff --git a/fpdfsdk/cpdfsdk_memoryaccess.cpp b/fpdfsdk/cpdfsdk_memoryaccess.cpp
new file mode 100644
index 0000000000..2a5b7aed00
--- /dev/null
+++ b/fpdfsdk/cpdfsdk_memoryaccess.cpp
@@ -0,0 +1,32 @@
+// Copyright 2018 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#include "fpdfsdk/cpdfsdk_memoryaccess.h"
+
+CPDFSDK_MemoryAccess::CPDFSDK_MemoryAccess(const uint8_t* pBuf,
+                                           FX_FILESIZE size)
+    : m_pBuf(pBuf), m_size(size) {}
+
+CPDFSDK_MemoryAccess::~CPDFSDK_MemoryAccess() = default;
+
+FX_FILESIZE CPDFSDK_MemoryAccess::GetSize() {
+  return m_size;
+}
+
+bool CPDFSDK_MemoryAccess::ReadBlock(void* buffer,
+                                     FX_FILESIZE offset,
+                                     size_t size) {
+  if (offset < 0)
+    return false;
+
+  FX_SAFE_FILESIZE newPos = pdfium::base::checked_cast<FX_FILESIZE>(size);
+  newPos += offset;
+  if (!newPos.IsValid() || newPos.ValueOrDie() > m_size)
+    return false;
+
+  memcpy(buffer, m_pBuf + offset, size);
+  return true;
+}