Do not print offset when it is used as tag's value

src/image.cpp

@@ -370,7 +370,9 @@ namespace Exiv2 {
                 // if ( offset > io.size() ) offset = 0; // Denial of service?
                 DataBuf  buf(size*count + pad+20);  // allocate a buffer
                 std::memcpy(buf.pData_,dir.pData_+8,4);  // copy dir[8:11] into buffer (short strings)
-                if ( count*size > 4 ) {            // read into buffer
+                const bool offsetIsPointer = count*size > 4;
+
+                if ( offsetIsPointer ) {         // read into buffer
                     size_t   restore = io.tell();  // save
                     io.seek(offset,BasicIo::beg);  // position
                     io.read(buf.pData_,count*size);// read
@@ -378,10 +380,14 @@ namespace Exiv2 {
                 }
 
                 if ( bPrint ) {
-                    uint32_t address = start + 2 + i*12 ;
+                    const uint32_t address = start + 2 + i*12 ;
+                    const std::string offsetString = offsetIsPointer?
+                        Internal::stringFormat("%10u", offset):
+                        "";
+
                     out << Internal::indent(depth)
-                    << Internal::stringFormat("%8u | %#06x %-25s |%10s |%9u |%10u | "
-                                              ,address,tag,tagName(tag).c_str(),typeName(type),count,offset);
+                    << Internal::stringFormat("%8u | %#06x %-25s |%10s |%9u |%10s | "
+                                              ,address,tag,tagName(tag).c_str(),typeName(type),count,offsetString.c_str());
                     if ( isShortType(type) ){
                         for ( size_t k = 0 ; k < kount ; k++ ) {
                             out << sp << byteSwap2(buf,k*size,bSwap);