[waffle] [PATCH 2/4] waffle: use enum list in waffle_enum_to_string()

[Chad Versace]

On Wed 22 Apr 2015, Frank Henigman wrote:
> Use the new WAFFLE_ENUM_LIST macro to implement waffle_enum_to_string()
> instead of specifying all the enums again.
> Now it will no longer be necessary to update waffle_enum_to_string()
> when adding an enum.
> Use bsearch() instead of a case statement, not because it's better,
> but to be symmetric with a new waffle_string_to_enum() function.
> 
> Signed-off-by: Frank Henigman <fjhenigman at google.com>
> ---
>  src/waffle/core/wcore_util.c | 94 ++++++++++++++++++++++----------------------
>  1 file changed, 47 insertions(+), 47 deletions(-)

[snip]

>  const char*
>  wcore_enum_to_string(int32_t e)
>  {
> -    switch (e) {
> -        #define CASE(x) case x: return #x
> -
> -        CASE(WAFFLE_DONT_CARE);
> -        CASE(WAFFLE_NONE);
> -        CASE(WAFFLE_PLATFORM);
> -        CASE(WAFFLE_PLATFORM_ANDROID);
> -        CASE(WAFFLE_PLATFORM_CGL);
> -        CASE(WAFFLE_PLATFORM_GLX);
> -        CASE(WAFFLE_PLATFORM_WAYLAND);
> -        CASE(WAFFLE_PLATFORM_X11_EGL);
> -        CASE(WAFFLE_PLATFORM_GBM);
> -        CASE(WAFFLE_PLATFORM_WGL);
> -        CASE(WAFFLE_PLATFORM_NACL);
> -        CASE(WAFFLE_CONTEXT_API);
> -        CASE(WAFFLE_CONTEXT_OPENGL);
> -        CASE(WAFFLE_CONTEXT_OPENGL_ES1);
> -        CASE(WAFFLE_CONTEXT_OPENGL_ES2);
> -        CASE(WAFFLE_CONTEXT_OPENGL_ES3);
> -        CASE(WAFFLE_CONTEXT_MAJOR_VERSION);
> -        CASE(WAFFLE_CONTEXT_MINOR_VERSION);
> -        CASE(WAFFLE_CONTEXT_PROFILE);
> -        CASE(WAFFLE_CONTEXT_CORE_PROFILE);
> -        CASE(WAFFLE_CONTEXT_COMPATIBILITY_PROFILE);
> -        CASE(WAFFLE_CONTEXT_FORWARD_COMPATIBLE);
> -        CASE(WAFFLE_CONTEXT_DEBUG);
> -        CASE(WAFFLE_RED_SIZE);
> -        CASE(WAFFLE_GREEN_SIZE);
> -        CASE(WAFFLE_BLUE_SIZE);
> -        CASE(WAFFLE_ALPHA_SIZE);
> -        CASE(WAFFLE_DEPTH_SIZE);
> -        CASE(WAFFLE_STENCIL_SIZE);
> -        CASE(WAFFLE_SAMPLE_BUFFERS);
> -        CASE(WAFFLE_SAMPLES);
> -        CASE(WAFFLE_DOUBLE_BUFFERED);
> -        CASE(WAFFLE_ACCUM_BUFFER);
> -        CASE(WAFFLE_DL_OPENGL);
> -        CASE(WAFFLE_DL_OPENGL_ES1);
> -        CASE(WAFFLE_DL_OPENGL_ES2);
> -        CASE(WAFFLE_DL_OPENGL_ES3);
> -        CASE(WAFFLE_WINDOW_WIDTH);
> -        CASE(WAFFLE_WINDOW_HEIGHT);
> -
> -        default: return NULL;
> -
> -        #undef CASE
> -    }
> +    enum_sort();
> +    struct enum_map_entry key = { .value = e };
> +    struct enum_map_entry *found = bsearch(&key,
> +                                           enum_map_value,
> +                                           ARRAY_SIZE(enum_map_value),
> +                                           sizeof(enum_map_value[0]),
> +                                           enum_cmp_value);
> +    if (!found)
> +        return NULL;
> +
> +    return found->name;
>  }

Frank, for generating code like this, you may want to refer to very
similar enum_to_string code in Piglit for which I wrote a generator
script:

    http://cgit.freedesktop.org/piglit/tree/tests/util/piglit-util-gl-enum-gen.c.mako?id=6122d1dba102b53602e5b19dd46d0975d28b6cd4

And another more complex script that generates piglit's GL dispatch:

    http://cgit.freedesktop.org/piglit/tree/tests/util/piglit-dispatch-gen.c.mako?id=6122d1dba102b53602e5b19dd46d0975d28b6cd4

There's *lot* of complex generated code in Piglit that heavily uses Mako
templates. Adding Mako as a Waffle buildtime dependency might be
overkill for the little amount of code generation that Waffle needs to
do. On the other hand, for generating code, Mako templates are more
concise than ad-hoc Python scripts.

Mako, ad-hoc Python, or bash+sed --- It doesn't really matter to me
which gets used to generate this function. But I wanted to introduce you
to Piglit's Mako files anyway, just in case you ever needed to do crazy
complex code generation for some other purpose, for Waffle or any other
project.