gl_get_sizeof_type.c

/// Takes a symbolic type constant and returns its size
/// Probably missing a few types but those were the most important
size_t get_sizeof_type(GLenum type)
{
	switch(type)
	{
		case GL_BYTE:
		case GL_UNSIGNED_BYTE:
			return sizeof(GLbyte);
		case GL_SHORT:
		case GL_UNSIGNED_SHORT:
			return sizeof(GLshort);
		case GL_INT_2_10_10_10_REV:
		case GL_INT:
		case GL_UNSIGNED_INT_2_10_10_10_REV:
		case GL_UNSIGNED_INT:
			return sizeof(GLint);
		case GL_FLOAT:
			return sizeof(GLfloat);
		case GL_DOUBLE:
			return sizeof(GLdouble);
		case GL_FIXED:
			return sizeof(GLfixed);
		case GL_HALF_FLOAT:
			return sizeof(GLhalf);
	}

	return 0;
}

Very helpful, thanks!