Re: [Devel] RE: compiling FreeType library for 64 bit code

[David Turner]

Hello Keith,

Keith Trummel wrote:
> FYI,
>
>     Changing line 186 in the file ftcache.h from
>
> #define FTC_FACE_ID_HASH( i )  ((FT_UInt32)(FT_Pointer)( i ))
>
> to be:
>
> #define FTC_FACE_ID_HASH( i )  ((FT_UInt32)((unsigned long) i &
> 0xffffffffL))
>
> fixes the problem when producing 64 bit code both using Sun's C++ compiler
> and IBM's C++ compiler.  Presumably, it also still keeps the hashing
> performance reasonable.
>
> Keith
Thanks for spotting this. However I suspect that:

 - FT_UInt32 is really a typedef for "unsigned int" on your
   system.

 - your compilers refuse to directly cast a pointer into
   an "unsigned int", but will accept casts to "unsigned long"
   instead (which are, I assume 64-bit)

 - your fix will not work very well for everyone. Certain
   compilers will warn or refuse to cast any typed pointer to
   a ulong (they only want a void*); and the AND mask is
   superfluous (since the exact same operation is performed
   by the cast to FT_UInt32)

I'd thus rather suggest changing it to:

#define  FTC_FACE_ID_HASH( i )  ((FT_UInt32)(FT_ULong)(FT_Pointer)(i))

or even better:

#define  FT_POINTER_TO_ULONG(p)  ((FT_ULong)(FT_Pointer)(p))
#define  FTC_FACE_ID_HASH( i )   ((FT_UInt32)(( FT_POINTER_TO_ULONG(p) >> 3 ) ^ 
 \
                                              ( FT_POINTER_TO_ULONG(p) << 7 ) ))

which gets rid of 8-byte alignment effects which are so common with
"malloc-ed" memory addresses.

Werner, I don't have access to the CVS repository. Could you check this in ??

Thanks for spotting it through..

Regards,

- David Turner
- The FreeType Project  (www.freetype.org)


> > -----Original Message-----
> > From: 	Keith Trummel  
> > Sent:	Thursday, October 17, 2002 3:29 PM
> > To:     'address@hidden'
> > Subject:        compiling FreeType library for 64 bit code
> >
> > Hello,
> >
> >    I was wondering if anyone had compiled the FreeType library (2.1.2)
> > for use with a 64 bit executable.  When I attempted to compile the code on
> > Solaris I get problems because there are several places where it attempts
> > to convert pointers to 32 bit ints.
> > Specifically when compiling the code in the cache subdirectory I get:
> >
> > "src/cache/ftcimage.c", line 243: Error: Cannot cast from void* to
> > unsigned.
> > "src/cache/ftcsbits.c", line 392: Error: Cannot cast from void* to
> > unsigned.
> > "src/cache/ftccmap.c", line 220: Error: Cannot cast from void* to
> > unsigned.
> >
> > Keith Trummel
> > Scene7 Inc.
>
>
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