[Mesa-dev] [PATCH 2/7] gallium/auxiliary: Add u_bitcast.h header.

[Roland Scheidegger]

Am 29.07.2016 um 00:35 schrieb Matt Turner:
> ---
>  src/gallium/auxiliary/Makefile.sources |  1 +
>  src/gallium/auxiliary/util/u_bitcast.h | 57 ++++++++++++++++++++++++++++++++++
>  2 files changed, 58 insertions(+)
>  create mode 100644 src/gallium/auxiliary/util/u_bitcast.h
> 
> diff --git a/src/gallium/auxiliary/Makefile.sources b/src/gallium/auxiliary/Makefile.sources
> index e0311bf..26f7eee 100644
> --- a/src/gallium/auxiliary/Makefile.sources
> +++ b/src/gallium/auxiliary/Makefile.sources
> @@ -175,6 +175,7 @@ C_SOURCES := \
>  	translate/translate_generic.c \
>  	translate/translate_sse.c \
>  	util/dbghelp.h \
> +	util/u_bitcast.h \
>  	util/u_bitmask.c \
>  	util/u_bitmask.h \
>  	util/u_blend.h \
> diff --git a/src/gallium/auxiliary/util/u_bitcast.h b/src/gallium/auxiliary/util/u_bitcast.h
> new file mode 100644
> index 0000000..b1f9938
> --- /dev/null
> +++ b/src/gallium/auxiliary/util/u_bitcast.h
> @@ -0,0 +1,57 @@
> +/**************************************************************************
> + *
> + * Copyright © 2016 Intel Corporation
> + * All Rights Reserved.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the
> + * "Software"), to deal in the Software without restriction, including
> + * without limitation the rights to use, copy, modify, merge, publish,
> + * distribute, sub license, and/or sell copies of the Software, and to
> + * permit persons to whom the Software is furnished to do so, subject to
> + * the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the
> + * next paragraph) shall be included in all copies or substantial portions
> + * of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
> + * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
> + * IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR
> + * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
> + * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
> + * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
> + *
> + **************************************************************************/
> +
> +#ifndef U_BITCAST_H_
> +#define U_BITCAST_H_
> +
> +#include <string.h>
> +
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +
> +static inline unsigned
> +u_bitcast_f2u(float f)
> +{
> +   unsigned u;
> +   memcpy(&u, &f, sizeof(u));
> +   return u;
> +}
> +
> +static inline float
> +u_bitcast_u2f(unsigned u)
> +{
> +   float f;
> +   memcpy(&f, &u, sizeof(f));
> +   return f;
> +}
> +
> +#ifdef __cplusplus
> +}
> +#endif
> +
> +#endif /* U_BITCAST_H_ */
> 

I think traditionally we've used the union fi from u_math.h to do this.
That said, I don't have anything against using an inline memcpy helper
function instead - both should hopefully get optimized away...

Roland