From b6e79357de3cd436a017ba29938f8526d951279a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Walenciak?= <Kicer86@gmail.com>
Date: Wed, 20 Sep 2017 21:23:35 +0200
Subject: [PATCH] Adding 8-byte swap functions + consts

---
 include/exiv2/image.hpp | 10 ++++++----
 src/image.cpp           | 31 +++++++++++++++++++++++++++----
 2 files changed, 33 insertions(+), 8 deletions(-)

diff --git a/include/exiv2/image.hpp b/include/exiv2/image.hpp
index 47e31f14..1d7c4c25 100644
--- a/include/exiv2/image.hpp
+++ b/include/exiv2/image.hpp
@@ -353,10 +353,12 @@ namespace Exiv2 {
         bool isPrintXMP(uint16_t type, Exiv2::PrintStructureOption option);
         bool isPrintICC(uint16_t type, Exiv2::PrintStructureOption option);
 
-        uint32_t byteSwap(uint32_t value,bool bSwap);
-        uint16_t byteSwap(uint16_t value,bool bSwap);
-        uint16_t byteSwap2(DataBuf& buf,size_t offset,bool bSwap);
-        uint32_t byteSwap4(DataBuf& buf,size_t offset,bool bSwap);
+        uint64_t byteSwap(uint64_t value,bool bSwap) const;
+        uint32_t byteSwap(uint32_t value,bool bSwap) const;
+        uint16_t byteSwap(uint16_t value,bool bSwap) const;
+        uint16_t byteSwap2(const DataBuf& buf,size_t offset,bool bSwap) const;
+        uint32_t byteSwap4(const DataBuf& buf,size_t offset,bool bSwap) const;
+        uint64_t byteSwap8(const DataBuf& buf,size_t offset,bool bSwap) const;
 
         //@}
 
diff --git a/src/image.cpp b/src/image.cpp
index c8259708..ea78911b 100644
--- a/src/image.cpp
+++ b/src/image.cpp
@@ -244,7 +244,19 @@ namespace Exiv2 {
     }
     bool Image::isLittleEndianPlatform() { return !isBigEndianPlatform(); }
 
-    uint32_t Image::byteSwap(uint32_t value,bool bSwap)
+    uint64_t Image::byteSwap(uint64_t value,bool bSwap) const
+    {
+        uint64_t result = 0;
+        byte* source_value = reinterpret_cast<byte *>(&value);
+        byte* destination_value = reinterpret_cast<byte *>(&result);
+
+        for (int i = 0; i < 8; i++)
+            destination_value[i] = source_value[8 - i - 1];
+
+        return bSwap ? result : value;
+    }
+
+    uint32_t Image::byteSwap(uint32_t value,bool bSwap) const
     {
         uint32_t result = 0;
         result |= (value & 0x000000FF) << 24;
@@ -254,7 +266,7 @@ namespace Exiv2 {
         return bSwap ? result : value;
     }
 
-    uint16_t Image::byteSwap(uint16_t value,bool bSwap)
+    uint16_t Image::byteSwap(uint16_t value,bool bSwap) const
     {
         uint16_t result = 0;
         result |= (value & 0x00FF) << 8;
@@ -262,7 +274,7 @@ namespace Exiv2 {
         return bSwap ? result : value;
     }
 
-    uint16_t Image::byteSwap2(DataBuf& buf,size_t offset,bool bSwap)
+    uint16_t Image::byteSwap2(const DataBuf& buf,size_t offset,bool bSwap) const
     {
         uint16_t v;
         char*    p = (char*) &v;
@@ -271,7 +283,7 @@ namespace Exiv2 {
         return Image::byteSwap(v,bSwap);
     }
 
-    uint32_t Image::byteSwap4(DataBuf& buf,size_t offset,bool bSwap)
+    uint32_t Image::byteSwap4(const DataBuf& buf,size_t offset,bool bSwap) const
     {
         uint32_t v;
         char*    p = (char*) &v;
@@ -282,6 +294,17 @@ namespace Exiv2 {
         return Image::byteSwap(v,bSwap);
     }
 
+    uint64_t Image::byteSwap8(const DataBuf& buf,size_t offset,bool bSwap) const
+    {
+        uint64_t v;
+        byte*    p = reinterpret_cast<byte *>(&v);
+
+        for(int i = 0; i < 8; i++)
+            p[i] = buf.pData_[offset + i];
+
+        return Image::byteSwap(v,bSwap);
+    }
+
     const char* Image::typeName(uint16_t tag) const
     {
         //! List of TIFF image tags