introducing getULongLong()

include/exiv2/types.hpp

@@ -266,6 +266,8 @@ namespace Exiv2 {
     EXIV2API uint16_t getUShort(const byte* buf, ByteOrder byteOrder);
     //! Read a 4 byte unsigned long value from the data buffer
     EXIV2API uint32_t getULong(const byte* buf, ByteOrder byteOrder);
+    //! Read a 8 byte unsigned long value from the data buffer
+    EXIV2API uint64_t getULongLong(const byte* buf, ByteOrder byteOrder);
     //! Read an 8 byte unsigned rational value from the data buffer
     EXIV2API URational getURational(const byte* buf, ByteOrder byteOrder);
     //! Read a 2 byte signed short value from the data buffer

src/types.cpp

@@ -252,6 +252,22 @@ namespace Exiv2 {
         }
     }
 
+    uint64_t getULongLong(const byte* buf, ByteOrder byteOrder)
+    {
+        if (byteOrder == littleEndian) {
+            return   (uint64_t)buf[7] << 56 | (uint64_t)buf[6] << 48
+                   | (uint64_t)buf[5] << 40 | (uint64_t)buf[4] << 32
+                   | (uint64_t)buf[3] << 24 | (uint64_t)buf[2] << 16
+                   | (uint64_t)buf[1] <<  8 | (uint64_t)buf[0];
+        }
+        else {
+            return   (uint64_t)buf[0] << 56 | (uint64_t)buf[1] << 48
+                   | (uint64_t)buf[2] << 40 | (uint64_t)buf[3] << 32
+                   | (uint64_t)buf[4] << 24 | (uint64_t)buf[5] << 16
+                   | (uint64_t)buf[6] <<  8 | (uint64_t)buf[7];
+        }
+    }
+
     URational getURational(const byte* buf, ByteOrder byteOrder)
     {
         uint32_t nominator = getULong(buf, byteOrder);