Is there any convenient CopyMemory function in Phobos?

[annonimous]

See you need copy only if     if (pEmfRecord->iType ==
EMR_RECTANGLE).
You can cast it and check it, else you perform with old
parameters.

Something like this

        if (pEmfRecord->iType == EMR_RECTANGLE)
        {
           pEmfr->iType = EMR_ELLIPSE ;

           PlayEnhMetaFileRecord (hdc, pHandleTable, pEmfr,
iHandles) ;

           free (pEmfr) ;
       }
       else
            PlayEnhMetaFileRecord (hdc, pHandleTable, pEmfRecord,
iHandles) ;

On Monday, 13 June 2011 at 23:31:56 UTC, Andrej Mitrovic wrote:
> Apparently in the Windows API there's a whole lot of 
> byte-copying going around.
>
> Here's an example:
>
> int CALLBACK EnhMetaFileProc (HDC hdc, HANDLETABLE * 
> pHandleTable,
>                               CONST ENHMETARECORD * pEmfRecord,
>                               int iHandles, LPARAM pData)
> {
>      ENHMETARECORD * pEmfr ;
>
>      pEmfr = (ENHMETARECORD *) malloc (pEmfRecord->nSize) ;
>
>      CopyMemory (pEmfr, pEmfRecord, pEmfRecord->nSize) ;
>
>      if (pEmfr->iType == EMR_RECTANGLE)
>           pEmfr->iType = EMR_ELLIPSE ;
>
>      PlayEnhMetaFileRecord (hdc, pHandleTable, pEmfr, iHandles) 
> ;
>
>      free (pEmfr) ;
>
>      return TRUE ;
> }
>
> The nSize field specifies the byte size of the structure 
> pointed to by
> pEmfRecord. The reason copying is required is because of this 
> code:
>      if (pEmfr->iType == EMR_RECTANGLE)
>           pEmfr->iType = EMR_ELLIPSE ;
>
> pEmfRecord itself is const, so new memory has to be allocated 
> first
> and then the memory from pEmfRecord is copied there, and then 
> the
> iType field is changed. A simple pointer dereference won't copy 
> all
> the bytes, since this is one of those variable-length structure 
> types
> you often see in C code.
>
> In D I've used the slice trick to assign a byte range of data 
> from one
> memory location to another:
> extern (Windows)
> int EnhMetaFileProc(HDC hdc, HANDLETABLE* pHandleTable,
>                     const ENHMETARECORD* pEmfRecord,
>                     int iHandles, LPARAM pData)
> {
>     ENHMETARECORD* pEmfr;
>     immutable newlength = pEmfRecord.nSize;
>
>     pEmfr = cast(ENHMETARECORD*)GC.malloc(newlength);
>
>     (cast(ubyte*)pEmfr)[0..newlength] = 
> (cast(ubyte*)pEmfRecord)[0..newlength];
>
>     if (pEmfr.iType == EMR_RECTANGLE)
>         pEmfr.iType = EMR_ELLIPSE;
>
>     PlayEnhMetaFileRecord(hdc, pHandleTable, pEmfr, iHandles);
>
>     GC.free(pEmfr);
>     return TRUE;
> }
>
> That's quite ugly.. Is there a Phobos/Druntime and maybe
> platform-independent function that can do byte-memory copies in 
> a
> simple way? Something like this is what I need:
> CopyBytes(dest, src, bytecount);
>
> Btw, CopyMemory is a WinAPI specific function, but I can't even 
> link
> to it (it's actually an alias to RtlCopyMemory, but it's not in
> kernel32.lib for some reason even though MSDN says it is).