windows: disk{available,capacity}: 4x faster with .NET

Author: scivision

+stdlib/disk_available.m

@@ -1,5 +1,5 @@
 %% DISK_AVAILABLE disk available space (bytes)
-% requires: mex or java
+% optional: mex
 %
 % example:  stdlib.disk_available('/')
 %
@@ -10,10 +10,12 @@
   d {mustBeTextScalar}
 end
 
-f = javaFileObject(d).getUsableSpace();
-
-f = uint64(f);
-
+if ispc()
+  % 4x faster than Java
+  f = System.IO.DriveInfo(d).AvailableFreeSpace();
+else
+  f = javaFileObject(d).getUsableSpace();
+  f = uint64(f);
 end
 
 %!assert (disk_available('.') > 0)

+stdlib/disk_capacity.m

@@ -1,5 +1,5 @@
 %% DISK_CAPACITY disk total capacity (bytes)
-% requires: mex or java
+% optional: mex
 %
 % example:  stdlib.disk_capacity('/')
 
@@ -8,9 +8,13 @@
   d {mustBeTextScalar}
 end
 
-f = javaFileObject(d).getTotalSpace();
-
-f = uint64(f);
+if ispc()
+  % 4x faster than Java
+  f = System.IO.DriveInfo(d).TotalSize();
+else
+  f = javaFileObject(d).getTotalSpace();
+  f = uint64(f);
+end
 
 end