[Mesa-dev] [PATCH 2/3] mesa: Add _mesa_enum_to_string2()

[Ian Romanick]

On 08/11/2016 10:11 AM, Chad Versace wrote:
> The new function is identical to _mesa_enum_to_string(), except that it
> returns false if the given number is an invalid enum. Bundling
> validation and lookup into a single function allows us to do both with
> a single lookup into the enum table.
> 
> Cc: Haixia Shi <hshi at chromium.org>
> Change-Id: I83d9a6e53223d1a971cf8dc22cb34b05b48d7889
> ---
>  src/mapi/glapi/gen/gl_enums.py | 20 ++++++++++++++++----
>  src/mesa/main/enums.h          |  2 ++
>  2 files changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/src/mapi/glapi/gen/gl_enums.py b/src/mapi/glapi/gen/gl_enums.py
> index 4fc43ab..af21aaf 100644
> --- a/src/mapi/glapi/gen/gl_enums.py
> +++ b/src/mapi/glapi/gen/gl_enums.py
> @@ -89,6 +89,17 @@ static char token_tmp[20];
>   */
>  const char *_mesa_enum_to_string( int nr )
>  {
> +   const char *str;
> +   _mesa_enum_to_string2(nr, &str);
> +   return str;
> +}
> +
> +/**
> + * Identical to _mesa_enum_to_string(), except that this function returns false
> + * when the number is an invalid enum.
> + */
> +bool _mesa_enum_to_string2(int nr, const char **str)
> +{
>     enum_elt *elt;
>  

Add an

   assert(str != NULL);

and maybe document that in the function header.

>     elt = bsearch(& nr, enum_string_table_offsets,
> @@ -97,13 +108,14 @@ const char *_mesa_enum_to_string( int nr )
>                   (cfunc) compar_nr);
>  
>     if (elt != NULL) {
> -      return &enum_string_table[elt->offset];
> -   }
> -   else {
> +      *str = &enum_string_table[elt->offset];
> +      return true;
> +   } else {
>        /* this is not re-entrant safe, no big deal here */
>        _mesa_snprintf(token_tmp, sizeof(token_tmp) - 1, "0x%x", nr);
>        token_tmp[sizeof(token_tmp) - 1] = '\\0';
> -      return token_tmp;
> +      *str = token_tmp;
> +      return false;
>     }
>  }
>  
> diff --git a/src/mesa/main/enums.h b/src/mesa/main/enums.h
> index 0e18cd4..ae804d6 100644
> --- a/src/mesa/main/enums.h
> +++ b/src/mesa/main/enums.h
> @@ -36,6 +36,7 @@
>  #ifndef _ENUMS_H_
>  #define _ENUMS_H_
>  
> +#include <stdbool.h>
>  
>  #ifdef __cplusplus
>  extern "C" {
> @@ -43,6 +44,7 @@ extern "C" {
>  
>  
>  extern const char *_mesa_enum_to_string( int nr );
> +bool _mesa_enum_to_string2(int nr, const char **str);
>  
>  /* Get the name of an enum given that it is a primitive type.  Avoids
>   * GL_FALSE/GL_POINTS ambiguity and others.
>