Re: [ft-devel] ftvalid

[mpsuzuki]

I think the original design (check face, then check tables, and
finally check service-availability) was by Werner, on 2004.
At that time, the modularization of validators was not expected.
Please check:

http://cvs.savannah.gnu.org/viewcvs/freetype/freetype2/src/base/ftotval.c?rev=1.1&view=markup

Regards,
mpsuzuki

On Fri, 16 Jun 2006 06:17:44 +0900 (JST)
Masatake YAMATO <address@hidden> wrote:

>At George's suggestons, I've rewritten some part of ftvalid.
>In my new code ftvalid tries to detect gxvalid is available 
>or not with following code:
>
>   /* Checking availability of FT_TrueTypeGX_Validate 
>      before running validator */
>   error = FT_TrueTypeGX_Validate(  NULL, 0, NULL, 0  );
>   if ( error == FT_Err_Unimplemented_Feature )
>      panic (error, "FT_TrueTypeGX_Validate is not available );
>
>However, this code doesn't work. NULL and zero args are checked
>before checking the module availability in FT_TrueTypeGX_Validate.
>
>  FT_EXPORT_DEF( FT_Error )
>  FT_TrueTypeGX_Validate( FT_Face   face,
>                          FT_UInt   validation_flags,
>                          FT_Bytes  tables[FT_VALIDATE_GX_LENGTH],
>                          FT_UInt   table_length )
>  {
>    FT_Service_GXvalidate  service;
>    FT_Error               error;
>
>
>    if ( !face )
>    {
>      error = FT_Err_Invalid_Face_Handle; <<<<<<<<<<<<<<<<<<<<<<<<<
>      goto Exit;
>    }
>
>    if ( tables == NULL )
>    {
>      error = FT_Err_Invalid_Argument;   <<<<<<<<<<<<<<<<<<<<<<<<<<
>      goto Exit;
>    }
>
>    FT_FACE_FIND_GLOBAL_SERVICE( face, service, GX_VALIDATE );
>
>    if ( service )
>      error = service->validate( face,
>                                 validation_flags,
>                                 tables,
>                                 table_length );
>    else
>      error = FT_Err_Unimplemented_Feature; <<<<<<<<<<<<< FINALY...
>
>  Exit:
>    return error;
>  }
>
>
>I think FT_Err_Unimplemented_Feature should be returned immediately
>if gxvalid module is not available. However, current implementation
>requires non-NULL face and non-NULL tables in any case.
>libfreetype2.so itself knows gxvalid module is available or not.
>
>Toshiya-san, do you remember who wrote this code? Did I?
>
>Masatake YAMATO