vbo: introduce vbo_sizeof_ib_type() function

introduce vbo_sizeof_ib_type() function to return the index data type
size. I see some place use switch(ib->type) to get the index data type,
which is sort of duplicate.

Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

src/mesa/state_tracker/st_draw.c

@@ -584,20 +584,7 @@ setup_index_buffer(struct gl_context *ctx,
    if (ib) {
       struct gl_buffer_object *bufobj = ib->obj;
 
-      switch (ib->type) {
-      case GL_UNSIGNED_INT:
-         ibuffer->index_size = 4;
-         break;
-      case GL_UNSIGNED_SHORT:
-         ibuffer->index_size = 2;
-         break;
-      case GL_UNSIGNED_BYTE:
-         ibuffer->index_size = 1;
-         break;
-      default:
-         assert(0);
-	 return;
-      }
+      ibuffer->index_size = vbo_sizeof_ib_type(ib->type);
 
       /* get/create the index buffer object */
       if (_mesa_is_bufferobj(bufobj)) {

src/mesa/state_tracker/st_draw_feedback.c

@@ -218,20 +218,9 @@ st_feedback_draw_vbo(struct gl_context *ctx,
    if (ib) {
       struct gl_buffer_object *bufobj = ib->obj;
 
-      switch (ib->type) {
-      case GL_UNSIGNED_INT:
-         ibuffer.index_size = 4;
-         break;
-      case GL_UNSIGNED_SHORT:
-         ibuffer.index_size = 2;
-         break;
-      case GL_UNSIGNED_BYTE:
-         ibuffer.index_size = 1;
-         break;
-      default:
-         assert(0);
-	 goto out_unref_vertex;
-      }
+      ibuffer.index_size = vbo_sizeof_ib_type(ib->type);
+      if (ibuffer.index_size == 0)
+         goto out_unref_vertex;
 
       if (bufobj && bufobj->Name) {
          struct st_buffer_object *stobj = st_buffer_object(bufobj);

src/mesa/tnl/t_draw.c

@@ -349,26 +349,10 @@ static void bind_indices( struct gl_context *ctx,
 
    if (_mesa_is_bufferobj(ib->obj) && !_mesa_bufferobj_mapped(ib->obj)) {
       /* if the buffer object isn't mapped yet, map it now */
-      unsigned map_size;
-
-      switch (ib->type) {
-      case GL_UNSIGNED_BYTE:
-	 map_size = ib->count * sizeof(GLubyte);
-	 break;
-      case GL_UNSIGNED_SHORT:
-	 map_size = ib->count * sizeof(GLushort);
-	 break;
-      case GL_UNSIGNED_INT:
-	 map_size = ib->count * sizeof(GLuint);
-	 break;
-      default:
-	 assert(0);
-	 map_size = 0;
-      }
-
       bo[*nr_bo] = ib->obj;
       (*nr_bo)++;
-      ptr = ctx->Driver.MapBufferRange(ctx, (GLsizeiptr) ib->ptr, map_size,
+      ptr = ctx->Driver.MapBufferRange(ctx, (GLsizeiptr) ib->ptr,
+                                       ib->count * vbo_sizeof_ib_type(ib->type),
 				       GL_MAP_READ_BIT, ib->obj);
       assert(ib->obj->Pointer);
    } else {

src/mesa/vbo/vbo.h

@@ -122,6 +122,10 @@ void vbo_rebase_prims( struct gl_context *ctx,
 		       GLuint min_index,
 		       GLuint max_index,
 		       vbo_draw_func draw );
+
+int
+vbo_sizeof_ib_type(GLenum type);
+
 void
 vbo_get_minmax_index(struct gl_context *ctx, const struct _mesa_prim *prim,
 		     const struct _mesa_index_buffer *ib,

src/mesa/vbo/vbo_exec_array.c

@@ -75,6 +75,22 @@ vbo_check_buffers_are_unmapped(struct gl_context *ctx)
    assert(!_mesa_bufferobj_mapped(exec->vtx.bufferobj));
 }
 
+int
+vbo_sizeof_ib_type(GLenum type)
+{
+   switch (type) {
+   case GL_UNSIGNED_INT:
+      return sizeof(GLuint);
+   case GL_UNSIGNED_SHORT:
+      return sizeof(GLushort);
+   case GL_UNSIGNED_BYTE:
+      return sizeof(GLubyte);
+   default:
+      assert(!"unsupported index data type");
+      /* In case assert is turned off */
+      return 0;
+   }
+}
 
 
 /**
@@ -96,24 +112,8 @@ vbo_get_minmax_index(struct gl_context *ctx,
    GLuint i;
 
    if (_mesa_is_bufferobj(ib->obj)) {
-      unsigned map_size;
-
-      switch (ib->type) {
-      case GL_UNSIGNED_INT:
-	 map_size = count * sizeof(GLuint);
-	 break;
-      case GL_UNSIGNED_SHORT:
-	 map_size = count * sizeof(GLushort);
-	 break;
-      case GL_UNSIGNED_BYTE:
-	 map_size = count * sizeof(GLubyte);
-	 break;
-      default:
-	 assert(0);
-	 map_size = 0;
-      }
-
-      indices = ctx->Driver.MapBufferRange(ctx, (GLsizeiptr) ib->ptr, map_size,
+      indices = ctx->Driver.MapBufferRange(ctx, (GLsizeiptr) ib->ptr,
+                                           count * vbo_sizeof_ib_type(ib->type),
 					   GL_MAP_READ_BIT, ib->obj);
    } else {
       indices = ib->ptr;
@@ -1053,7 +1053,7 @@ vbo_validated_multidrawelements(struct gl_context *ctx, GLenum mode,
    struct vbo_exec_context *exec = &vbo->exec;
    struct _mesa_index_buffer ib;
    struct _mesa_prim *prim;
-   unsigned int index_type_size = 0;
+   unsigned int index_type_size = vbo_sizeof_ib_type(type);
    uintptr_t min_index_ptr, max_index_ptr;
    GLboolean fallback = GL_FALSE;
    int i;
@@ -1083,20 +1083,6 @@ vbo_validated_multidrawelements(struct gl_context *ctx, GLenum mode,
    if (ctx->NewState)
       _mesa_update_state( ctx );
 
-   switch (type) {
-   case GL_UNSIGNED_INT:
-      index_type_size = 4;
-      break;
-   case GL_UNSIGNED_SHORT:
-      index_type_size = 2;
-      break;
-   case GL_UNSIGNED_BYTE:
-      index_type_size = 1;
-      break;
-   default:
-      assert(0);
-   }
-
    min_index_ptr = (uintptr_t)indices[0];
    max_index_ptr = 0;
    for (i = 0; i < primcount; i++) {