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

[Emil Velikov]

On 22 April 2015 at 19:03, Frank Henigman <fjhenigman at google.com> 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(-)
>
> diff --git a/src/waffle/core/wcore_util.c b/src/waffle/core/wcore_util.c
> index b7809a3..b912a30 100644
> --- a/src/waffle/core/wcore_util.c
> +++ b/src/waffle/core/wcore_util.c
> @@ -68,54 +68,54 @@ wcore_calloc(size_t size)
>      return p;
>  }
>
> +struct enum_map_entry {
> +    const char *name;
> +    int32_t value;
> +};
> +
> +static int
> +enum_cmp_value(const void *v1, const void *v2)
> +{
> +    const struct enum_map_entry *e1 = (const struct enum_map_entry *) v1;
> +    const struct enum_map_entry *e2 = (const struct enum_map_entry *) v2;
> +    return e1->value - e2->value;
> +}
> +
> +#define NAME_VALUE(name, value) { #name, value },
> +
> +static struct enum_map_entry enum_map_value[] = {
> +    WAFFLE_ENUM_LIST(NAME_VALUE)
> +};
> +
> +#undef NAME_VALUE
> +
> +#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
> +
> +static void
> +enum_sort()
> +{
> +    static bool sorted = false;
> +    if (sorted)
> +        return;
> +    qsort(enum_map_value, ARRAY_SIZE(enum_map_value), sizeof(enum_map_value[0]),
> +          enum_cmp_value);
> +    sorted = true;
> +}
> +
FWIW I think that this is not something anyone should do at runtime.
Regardless if we manually edit the list or generate it via the
preprocessor/python script we can (and we should) sort it there.

>  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);
Bikeshed: if you split the declaration and assignment this piece won't
feel like so alien in waffle.

Cheers
Emil