MB2WC/WC2MB are not pure virtual any longer, implement them in terms of To/FromWChar()

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@38542 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/strconv.h

@@ -35,6 +35,12 @@
 // wxMBConv (abstract base class for conversions)
 // ----------------------------------------------------------------------------
 
+// When deriving a new class from wxMBConv you must reimplement ToWChar() and
+// FromWChar() methods which are not pure virtual only for historical reasons,
+// don't let the fact that the existing classes implement MB2WC/WC2MB() instead
+// confuse you.
+//
+// And you might need to override GetMBNulLen() as well.
 class WXDLLIMPEXP_BASE wxMBConv
 {
 public:
@@ -137,8 +143,8 @@ public:
     // Note that outLen is the length of the output buffer, not the length of
     // the input (which is always supposed to be terminated by one or more
     // NULs, as appropriate for the encoding)!
-    virtual size_t MB2WC(wchar_t *out, const char *in, size_t outLen) const = 0;
+    virtual size_t MB2WC(wchar_t *out, const char *in, size_t outLen) const;
-    virtual size_t WC2MB(char *out, const wchar_t *in, size_t outLen) const = 0;
+    virtual size_t WC2MB(char *out, const wchar_t *in, size_t outLen) const;
 
 
     // virtual dtor for any base class

src/common/strconv.cpp

@@ -316,6 +316,30 @@ wxMBConv::FromWChar(char *dst, size_t dstLen,
     return dstWritten;
 }
 
+size_t wxMBConv::MB2WC(wchar_t *out, const char *in, size_t outLen) const
+{
+    size_t rc = ToWChar(out, outLen, in);
+    if ( rc != wxCONV_FAILED )
+    {
+        // ToWChar() returns the buffer length, i.e. including the trailing
+        // NUL, while this method doesn't take it into account
+        rc--;
+    }
+
+    return rc;
+}
+
+size_t wxMBConv::WC2MB(char *out, const wchar_t *in, size_t outLen) const
+{
+    size_t rc = FromWChar(out, outLen, in);
+    if ( rc != wxCONV_FAILED )
+    {
+        rc -= GetMBNulLen();
+    }
+
+    return rc;
+}
+
 wxMBConv::~wxMBConv()
 {
     // nothing to do here (necessary for Darwin linking probably)