+// DynamicMMap::Grow - Grow the mmap /*{{{*/
+// ---------------------------------------------------------------------
+/* This method is a wrapper around different methods to (try to) grow
+ a mmap (or our char[]-fallback). Encounterable environments:
+ 1. Moveable + !Fallback + linux -> mremap with MREMAP_MAYMOVE
+ 2. Moveable + !Fallback + !linux -> not possible (forbidden by constructor)
+ 3. Moveable + Fallback -> realloc
+ 4. !Moveable + !Fallback + linux -> mremap alone - which will fail in 99,9%
+ 5. !Moveable + !Fallback + !linux -> not possible (forbidden by constructor)
+ 6. !Moveable + Fallback -> not possible
+ [ While Moveable and Fallback stands for the equally named flags and
+ "linux" indicates a linux kernel instead of a freebsd kernel. ]
+ So what you can see here is, that a MMAP which want to be growable need
+ to be moveable to have a real chance but that this method will at least try
+ the nearly impossible 4 to grow it before it finally give up: Never say never. */
+bool DynamicMMap::Grow() {
+ if (Limit != 0 && WorkSpace >= Limit)
+ return _error->Error(_("The size of a MMap has already reached the defined limit of %lu bytes,"
+ "abort the try to grow the MMap."), Limit);
+
+ unsigned long const newSize = WorkSpace + 1024*1024;
+
+ if(Fd != 0) {
+ Fd->Seek(newSize - 1);
+ char C = 0;
+ Fd->Write(&C,sizeof(C));
+ }
+ if ((Flags & Fallback) != Fallback) {
+#if defined(_POSIX_MAPPED_FILES) && defined(__linux__)
+ #ifdef MREMAP_MAYMOVE
+ if ((Flags & Moveable) == Moveable)
+ Base = mremap(Base, WorkSpace, newSize, MREMAP_MAYMOVE);
+ else
+ #endif
+ Base = mremap(Base, WorkSpace, newSize, 0);
+
+ if(Base == MAP_FAILED)
+ return false;
+#else
+ return false;
+#endif
+ } else {
+ if ((Flags & Moveable) != Moveable)
+ return false;
+
+ Base = realloc(Base, newSize);
+ if (Base == NULL)
+ return false;
+ }
+
+ WorkSpace = newSize;
+ return true;
+}
+ /*}}}*/