2 files changed, 66 insertions, 3 deletions
diff --git a/utils/helpers/bmp.hpp b/utils/helpers/bmp.hpp
new file mode 100644
index 0000000..dc3cdac
--- /dev/null
+++ b/utils/helpers/bmp.hpp
@@ -0,0 +1,51 @@
+// Copyright (c) 2016 Egor Tensin <Egor.Tensin@gmail.com>
+// This file is part of the "AES tools" project.
+// For details, see https://github.com/egor-tensin/aes-tools.
+// Distributed under the MIT License.
+
+#include <Windows.h>
+
+#include <cstddef>
+#include <cstring>
+
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace bmp
+{
+    class BmpFile
+    {
+    public:
+        BmpFile(std::vector<char>&& buffer)
+            : buffer{std::move(buffer)}
+            , header_size{extract_pixels_offset()}
+        { }
+
+        const void* get_buffer() const { return buffer.data(); }
+
+        std::size_t get_size() const { return buffer.size(); }
+
+        std::size_t get_header_size() const { return header_size; }
+
+        const void* get_pixels() const { return buffer.data() + get_header_size(); }
+
+        std::size_t get_pixels_size() const { return get_size() - get_header_size(); }
+
+        void replace_pixels(std::vector<unsigned char>&& pixels)
+        {
+            buffer.resize(get_header_size() + pixels.size());
+            std::memcpy(buffer.data() + get_header_size(), pixels.data(), pixels.size());
+        }
+
+    private:
+        std::size_t extract_pixels_offset() const
+        {
+            const auto header = reinterpret_cast<const BITMAPFILEHEADER*>(get_buffer());
+            return header->bfOffBits;
+        }
+
+        std::vector<char> buffer;
+        std::size_t header_size;
+    };
+}
diff --git a/utils/helpers/file.hpp b/utils/helpers/file.hpp
index a327c35..febe98f 100644
--- a/utils/helpers/file.hpp
+++ b/utils/helpers/file.hpp
@@ -3,10 +3,12 @@
 // For details, see https://github.com/egor-tensin/aes-tools.
 // Distributed under the MIT License.
 
+#include <cassert>
 #include <cstddef>
 
 #include <fstream>
 #include <iterator>
+#include <limits>
 #include <string>
 #include <vector>
 
@@ -17,7 +19,9 @@ namespace file
         std::ifstream ifs;
         ifs.exceptions(std::ifstream::badbit | std::ifstream::failbit);
         ifs.open(path, std::ifstream::binary | std::ifstream::ate);
-        return ifs.tellg();
+        const auto size = static_cast<std::streamoff>(ifs.tellg());
+        assert(size <= static_cast<std::streamoff>(std::numeric_limits<std::size_t>::max()));
+        return static_cast<std::size_t>(size);
     }
 
     inline std::vector<char> read_file(const std::string& path)
@@ -38,11 +42,19 @@ namespace file
 
     inline void write_file(
         const std::string& path,
-        const std::vector<unsigned char>& src)
+        const void* buffer,
+        const std::size_t size)
     {
         std::ofstream ofs;
         ofs.exceptions(std::ofstream::badbit | std::ofstream::failbit);
         ofs.open(path, std::ofstream::binary);
-        ofs.write(reinterpret_cast<const char*>(src.data()), src.size());
+        ofs.write(reinterpret_cast<const char*>(buffer), size);
+    }
+
+    inline void write_file(
+        const std::string& path,
+        const std::vector<unsigned char>& src)
+    {
+        write_file(path, src.data(), src.size());
     }
 }