Add support for IEC and SI size units to wxFileName::GetHumanReadableSize().

Allow choosing the multiplier to use (1000 or 1024) and the names of the units
(SI or IEC). By default, still use traditional convention, i.e. multiplier of
1024 but SI unit names. This will probably need to be changed to use IEC units
in the future.

Also added unit test for this function.

Closes #10673.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63870 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/filename.cpp

@@ -2647,27 +2647,53 @@ wxULongLong wxFileName::GetSize(const wxString &filename)
 /* static */
 wxString wxFileName::GetHumanReadableSize(const wxULongLong &bs,
                                           const wxString &nullsize,
-                                          int precision)
+                                          int precision,
+                                          wxSizeConvention conv)
 {
-    static const double KILOBYTESIZE = 1024.0;
-    static const double MEGABYTESIZE = 1024.0*KILOBYTESIZE;
-    static const double GIGABYTESIZE = 1024.0*MEGABYTESIZE;
-    static const double TERABYTESIZE = 1024.0*GIGABYTESIZE;
-
-    if (bs == 0 || bs == wxInvalidSize)
+    // deal with trivial case first
+    if ( bs == 0 || bs == wxInvalidSize )
         return nullsize;
 
-    double bytesize = bs.ToDouble();
-    if (bytesize < KILOBYTESIZE)
-        return wxString::Format(_("%s B"), bs.ToString().c_str());
-    if (bytesize < MEGABYTESIZE)
-        return wxString::Format(_("%.*f kB"), precision, bytesize/KILOBYTESIZE);
-    if (bytesize < GIGABYTESIZE)
-        return wxString::Format(_("%.*f MB"), precision, bytesize/MEGABYTESIZE);
-    if (bytesize < TERABYTESIZE)
-        return wxString::Format(_("%.*f GB"), precision, bytesize/GIGABYTESIZE);
+    // depending on the convention used the multiplier may be either 1000 or
+    // 1024 and the binary infix may be empty (for "KB") or "i" (for "KiB")
+    double multiplier;
+    wxString biInfix;
 
-    return wxString::Format(_("%.*f TB"), precision, bytesize/TERABYTESIZE);
+    switch ( conv )
+    {
+        case wxSIZE_CONV_IEC:
+            biInfix = "i";
+            // fall through
+
+        case wxSIZE_CONV_TRADIONAL:
+            multiplier = 1024.;
+            break;
+
+        case wxSIZE_CONV_SI:
+            multiplier = 1000;
+            break;
+    }
+
+    const double kiloByteSize = multiplier;
+    const double megaByteSize = multiplier * kiloByteSize;
+    const double gigaByteSize = multiplier * megaByteSize;
+    const double teraByteSize = multiplier * gigaByteSize;
+
+    const double bytesize = bs.ToDouble();
+
+    wxString result;
+    if ( bytesize < kiloByteSize )
+        result.Printf("%s B", bs.ToString());
+    else if ( bytesize < megaByteSize )
+        result.Printf("%.*f K%sB", precision, bytesize/kiloByteSize, biInfix);
+    else if (bytesize < gigaByteSize)
+        result.Printf("%.*f M%sB", precision, bytesize/megaByteSize, biInfix);
+    else if (bytesize < teraByteSize)
+        result.Printf("%.*f G%sB", precision, bytesize/gigaByteSize, biInfix);
+    else
+        result.Printf("%.*f T%sB", precision, bytesize/teraByteSize, biInfix);
+
+    return result;
 }
 
 wxULongLong wxFileName::GetSize() const
@@ -2675,9 +2701,11 @@ wxULongLong wxFileName::GetSize() const
     return GetSize(GetFullPath());
 }
 
-wxString wxFileName::GetHumanReadableSize(const wxString &failmsg, int precision) const
+wxString wxFileName::GetHumanReadableSize(const wxString& failmsg,
+                                          int precision,
+                                          wxSizeConvention conv) const
 {
-    return GetHumanReadableSize(GetSize(), failmsg, precision);
+    return GetHumanReadableSize(GetSize(), failmsg, precision, conv);
 }
 
 #endif // wxUSE_LONGLONG