added binary stl file size check after ascii check

src/OpenMesh/Core/IO/reader/STLReader.cc

@@ -478,9 +478,39 @@ check_stl_type(const std::string& _filename) const
    {
      return STLA;
    }
+   ifs.close();
 
-  //if the file does not start with solid it is STLB
-  return STLB;
+   //if the file does not start with solid it is probably STLB
+   //check the file size to verify it.
+
+   //open the file
+   FILE* in = fopen(_filename.c_str(), "rb");
+   if (!in) return NONE;
+
+   // determine endian mode
+   union { unsigned int i; unsigned char c[4]; } endian_test;
+   endian_test.i = 1;
+   bool swapFlag = (endian_test.c[3] == 1);
+
+
+   // read number of triangles
+   char dummy[100];
+   fread(dummy, 1, 80, in);
+   size_t nT = read_int(in, swapFlag);
+
+
+   // compute file size from nT
+   size_t binary_size = 84 + nT*50;
+
+   // get actual file size
+   size_t file_size(0);
+   rewind(in);
+   while (!feof(in))
+     file_size += fread(dummy, 1, 100, in);
+   fclose(in);
+
+   // if sizes match -> it's STLB
+      return (binary_size == file_size ? STLB : NONE);
 }