Reduce a bit the code bloat in hot paths/small functions

There is no need to bloat hot/small functions with
a ton of function calls and involving locales
for simple error messages.

apps/openmw/mwworld/esmstore.cpp

@@ -199,9 +199,7 @@ void ESMStore::load(ESM::ESMReader &esm, Loading::Listener* listener)
                 esm.skipRecord();
             }
             else {
-                std::stringstream error;
-                error << "Unknown record: " << n.toString();
-                throw std::runtime_error(error.str());
+                throw std::runtime_error("Unknown record: " + n.toString());
             }
         } else {
             RecordId id = it->second->load(esm);

components/esm/esmreader.cpp

@@ -135,11 +135,8 @@ void ESMReader::getHExact(void*p, int size)
 {
     getSubHeader();
     if (size != static_cast<int> (mCtx.leftSub))
-    {
-        std::stringstream error;
-        error << "getHExact(): size mismatch (requested " << size << ", got " << mCtx.leftSub << ")";
-        fail(error.str());
-    }
+        fail("Size mismatch, requested " + std::to_string(size) + " but got "
+                + std::to_string(mCtx.leftSub));
     getExact(p, size);
 }
 

components/esm/esmreader.hpp

@@ -135,9 +135,9 @@ public:
       getSubHeader();
       if (mCtx.leftSub != sizeof(X))
       {
-          std::stringstream error;
-          error << "getHT(): subrecord size mismatch (requested " << sizeof(X) << ", got " << mCtx.leftSub << ")";
-          fail(error.str());
+          fail("getHT(): subrecord size mismatch,requested "
+                  + std::to_string(sizeof(X)) + ", got"
+                      + std::to_string(mCtx.leftSub));
       }
       getT(x);
   }

components/files/lowlevelfile.cpp

@@ -65,31 +65,23 @@ size_t LowLevelFile::size ()
     long oldPosition = ftell (mHandle);
     if (oldPosition == -1)
     {
-        std::ostringstream os;
-        os << "An ftell() call failed: " << strerror(errno);
-        throw std::runtime_error (os.str ());
+        throw std::runtime_error ("An ftell() call failed: " + std::string(strerror(errno)));
     }
 
     if (fseek (mHandle, 0, SEEK_END) != 0)
     {
-        std::ostringstream os;
-        os << "An fseek() call failed: " << strerror(errno);
-        throw std::runtime_error (os.str ());
+        throw std::runtime_error ("An fseek() call failed: " + std::string(strerror(errno)));
     }
 
     long size = ftell (mHandle);
     if (size == -1)
     {
-        std::ostringstream os;
-        os << "An ftell() call failed: " << strerror(errno);
-        throw std::runtime_error (os.str ());
+        throw std::runtime_error ("An ftell() call failed: " + std::string(strerror(errno)));
     }
 
     if (fseek (mHandle, oldPosition, SEEK_SET) != 0)
     {
-        std::ostringstream os;
-        os << "An fseek() call failed: " << strerror(errno);
-        throw std::runtime_error (os.str ());
+        throw std::runtime_error ("An fseek() call failed: " + std::string(strerror(errno)));
     }
 
     return size_t (size);
@@ -101,9 +93,7 @@ void LowLevelFile::seek (size_t position)
 
     if (fseek (mHandle, position, SEEK_SET) != 0)
     {
-        std::ostringstream os;
-        os << "An fseek() call failed: " << strerror(errno);
-        throw std::runtime_error (os.str ());
+        throw std::runtime_error ("An fseek() call failed: " + std::string(strerror(errno)));
     }
 }
 
@@ -114,9 +104,7 @@ size_t LowLevelFile::tell ()
     long position = ftell (mHandle);
     if (position == -1)
     {
-        std::ostringstream os;
-        os << "An ftell() call failed: " << strerror(errno);
-        throw std::runtime_error (os.str ());
+        throw std::runtime_error ("An ftell() call failed: " + std::string(strerror(errno)));
     }
 
     return size_t (position);
@@ -193,25 +181,19 @@ size_t LowLevelFile::size ()
 
     if (oldPosition == size_t (-1))
     {
-        std::ostringstream os;
-        os << "An lseek() call failed: " << strerror(errno);
-        throw std::runtime_error (os.str ());
+        throw std::runtime_error ("An lseek() call failed: " + std::string(strerror(errno)));
     }
 
     size_t size = ::lseek (mHandle, 0, SEEK_END);
 
     if (size == size_t (-1))
     {
-        std::ostringstream os;
-        os << "An lseek() call failed: " << strerror(errno);
-        throw std::runtime_error (os.str ());
+        throw std::runtime_error ("An lseek() call failed: " + std::string(strerror(errno)));
     }
 
     if (lseek (mHandle, oldPosition, SEEK_SET) == -1)
     {
-        std::ostringstream os;
-        os << "An lseek() call failed: " << strerror(errno);
-        throw std::runtime_error (os.str ());
+        throw std::runtime_error ("An lseek() call failed: " + std::string(strerror(errno)));
     }
 
     return size;
@@ -223,9 +205,7 @@ void LowLevelFile::seek (size_t position)
 
     if (::lseek (mHandle, position, SEEK_SET) == -1)
     {
-        std::ostringstream os;
-        os << "An lseek() call failed: " << strerror(errno);
-        throw std::runtime_error (os.str ());
+        throw std::runtime_error ("An lseek() call failed: " + std::string(strerror(errno)));
     }
 }
 
@@ -237,9 +217,7 @@ size_t LowLevelFile::tell ()
 
     if (position == size_t (-1))
     {
-        std::ostringstream os;
-        os << "An lseek() call failed: " << strerror(errno);
-        throw std::runtime_error (os.str ());
+        throw std::runtime_error("An lseek() call failed: " + std::string(strerror(errno)));
     }
 
     return position;