From 43bfc2b6b5477b24d831f49a6ab2123ce95ba747 Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Mon, 10 May 2010 11:16:24 -0700 Subject: [PATCH] exec_list: Add macros to get ptr to structure containing a node This has some ugly hackery to work-around C++ fail. I have emperically determined that it works in all the cases that matter. --- list.h | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/list.h b/list.h index afa32f1ed97..26941746b45 100644 --- a/list.h +++ b/list.h @@ -64,6 +64,9 @@ #ifndef LIST_CONTAINER_H #define LIST_CONTAINER_H +#ifndef __cplusplus +#include +#endif #include struct exec_node { @@ -140,6 +143,30 @@ struct exec_node { #endif }; + +#ifdef __cplusplus +/* This macro will not work correctly if `t' uses virtual inheritance. If you + * are using virtual inheritance, you deserve a slow and painful death. Enjoy! + */ +#define exec_list_offsetof(t, f, p) \ + (((char *) &((t *) p)->f) - ((char *) p)) +#else +#define exec_list_offsetof(t, f, p) offsetof(t, f) +#endif + +/** + * Get a pointer to the structure containing an exec_node + * + * Given a pointer to an \c exec_node embedded in a structure, get a pointer to + * the containing structure. + * + * \param type Base type of the structure containing the node + * \param node Pointer to the \c exec_node + * \param field Name of the field in \c type that is the embedded \c exec_node + */ +#define exec_node_data(type, node, field) \ + ((type *) (((char *) node) - exec_list_offsetof(type, field, node))) + #ifdef __cplusplus struct exec_node; -- 2.30.2