1 files changed, 72 insertions, 0 deletions
diff --git a/src/installer/corehost/cli/apphost/bundle/reader.h b/src/installer/corehost/cli/apphost/bundle/reader.h
new file mode 100644
index 00000000000..1824ece515a
--- /dev/null
+++ b/src/installer/corehost/cli/apphost/bundle/reader.h
@@ -0,0 +1,72 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#ifndef __READER_H__
+#define __READER_H__
+
+#include <cstdint>
+#include "pal.h"
+
+namespace bundle
+{
+    // Helper class for reading sequentially from the memory-mapped bundle file.
+    struct reader_t
+    {
+        reader_t(const int8_t* base_ptr, int64_t bound)
+            : m_base_ptr(base_ptr)
+            , m_ptr(base_ptr)
+            , m_bound(bound)
+            , m_bound_ptr(add_without_overflow(base_ptr, bound))
+        {
+        }
+
+    public:
+
+        void set_offset(int64_t offset);
+
+        operator const int8_t*() const
+        {
+            return m_ptr;
+        }
+
+        int8_t read()
+        {
+            bounds_check();
+            return *m_ptr++;
+        }
+
+        // Copy len bytes from m_ptr to dest
+        void read(void* dest, int64_t len)
+        {
+            bounds_check(len);
+            memcpy(dest, m_ptr, len);
+            m_ptr += len;
+        }
+
+        // Return a pointer to the requested bytes within the memory-mapped file.
+        // Skip over len bytes.
+        const int8_t* read_direct(int64_t len)
+        {
+            bounds_check(len);
+            const int8_t *ptr = m_ptr;
+            m_ptr += len;
+            return ptr;
+        }
+
+        size_t read_path_length();
+        void read_path_string(pal::string_t &str);
+
+    private:
+
+        void bounds_check(int64_t len = 1);
+        static const int8_t* add_without_overflow(const int8_t* ptr, int64_t len);
+
+        const int8_t* const m_base_ptr;
+        const int8_t* m_ptr;
+        const int64_t m_bound;
+        const int8_t* const m_bound_ptr;
+    };
+}
+
+#endif // __READER_H__