[Mesa-dev] [PATCH 1/2] mesa: Refactor handling of extension strings

[Chad Versace]

On 01/10/2011 07:18 AM, Brian Paul wrote:
> Why not just defined the GL, ES1 and ES2 bits to be 1 << gl_api like this:
> 
> GL = 1 << API_OPENGL
> ES1 = 1 << API_OPENGLES
> ES2 = 1 << API_OPENGLES2
> 
> That'd make api_bit() trivial.

Ah, I've never seen that trick before: bit-shifing on enum values. I've
accordingly modified patch 1/2 by amending the following:

[Beware of Thunderbird line wraps...]
@@ -37,22 +37,9 @@
 #include "mfeatures.h"
 #include "mtypes.h"

-static const uint8_t GL  = 1 << 0;
-static const uint8_t ES1 = 1 << 1;
-static const uint8_t ES2 = 1 << 2;
-
-static unsigned
-api_bit(struct gl_context* ctx)
-{
-   switch(ctx->API) {
-   case API_OPENGL:    return GL;
-   case API_OPENGLES:  return ES1;
-   case API_OPENGLES2: return ES2;
-   default:
-      assert(0);
-      return 0;
-   }
-}
+static const uint8_t GL  = 1 << API_OPENGL;
+static const uint8_t ES1 = 1 << API_OPENGLES;
+static const uint8_t ES2 = 1 << API_OPENGLES2;

 /**
  * \brief An element of the \c extension_table.
@@ -841,7 +828,7 @@ _mesa_make_extension_string(struct gl_context *ctx)

    /* Compute length of the extension string. */
    for (const struct extension *i = extension_table; i->name != 0; ++i) {
-      if (base[i->offset] && (i->api_set & api_bit(ctx))) {
+      if (base[i->offset] && (i->api_set & (1 << ctx->API))) {
 	 length += strlen(i->name) + 1; /* +1 for space */
       }
    }
@@ -857,7 +844,7 @@ _mesa_make_extension_string(struct gl_context *ctx)

    /* Build the extension string.*/
    for (const struct extension *i = extension_table; i->name != 0; ++i) {
-      if (base[i->offset] && (i->api_set & api_bit(ctx))) {
+      if (base[i->offset] && (i->api_set & (1 << ctx->API))) {
          strcat(exts, i->name);
          strcat(exts, " ");
       }

--------------------------------------------------------------------------

>> +   { 0, 0, 0, },
> 
> Some compilers will complain about the trailing comma after the 0 there.

Trailing comma has been removed.

-- 
Chad Versace
chad.versace at intel.com
chad at chad-versace.us