Changeset 36795edf in mainline for kernel

Timestamp:

2021-03-12T19:16:51Z (4 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

a85d5c6

Parents:

17fac946

Message:

Improve lists and other data structures

Provide more standard-compliant member_to_inst implementation that uses
offsetof. Avoid potential undefined behavior in list_foreach and
list_foreach_rev by avoiding assinging an unaligned pointer value. Use
size_t instead of unsigned long for list length.

Location:

kernel/generic/include

Files:

• adt/hash_table.h (modified) (1 diff)
• adt/list.h (modified) (5 diffs)
• adt/odict.h (modified) (2 diffs)
• macros.h (modified) (1 diff)
• member.h (added)

kernel/generic/include/adt/hash_table.h

@@ -41 +41 @@
 #include <stdbool.h>
 #include <macros.h>
+#include <member.h>
 
 /** Opaque hash table link type. */

kernel/generic/include/adt/list.h

@@ -38 +38 @@
 
 #include <assert.h>
+#include <macros.h>
+#include <member.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <stdint.h>
 #include <trace.h>
 
@@ -89 +92 @@
 
 #define list_get_instance(link, type, member) \
-        ((type *) (((void *)(link)) - list_link_to_void(&(((type *) NULL)->member))))
+        member_to_inst(link, type, member)
 
 #define list_foreach(list, member, itype, iterator) \
-        for (itype *iterator = NULL; iterator == NULL; iterator = (itype *) 1) \
+        for (itype *iterator = NULL; iterator == NULL; iterator = &((itype *) NULL)[1]) \
                 for (link_t *_link = (list).head.next; \
                     iterator = list_get_instance(_link, itype, member), \
@@ -98 +101 @@
 
 #define list_foreach_rev(list, member, itype, iterator) \
-        for (itype *iterator = NULL; iterator == NULL; iterator = (itype *) 1) \
+        for (itype *iterator = NULL; iterator == NULL; iterator = &((itype *) NULL)[1]) \
                 for (link_t *_link = (list).head.prev; \
                     iterator = list_get_instance(_link, itype, member), \
@@ -375 +378 @@
  *
  */
-static inline link_t *list_nth(const list_t *list, unsigned long n)
-{
-        unsigned long cnt = 0;
+static inline link_t *list_nth(const list_t *list, size_t n)
+{
+        size_t cnt = 0;
 
         link_t *link = list_first(list);
@@ -391 +394 @@
 }
 
-/** Verify that argument type is a pointer to link_t (at compile time).
- *
- * This can be used to check argument type in a macro.
- */
-static inline const void *list_link_to_void(const link_t *link)
-{
-        return link;
-}
-
 /** Determine if link is used.
  *

kernel/generic/include/adt/odict.h

@@ -37 +37 @@
 
 #include <errno.h>
+#include <member.h>
 #include <stdbool.h>
 #include <stddef.h>
@@ -42 +43 @@
 
 #define odict_get_instance(odlink, type, member) \
-        ((type *)( (void *)(odlink) - ((void *) &((type *) NULL)->member)))
+        member_to_inst(odlink, type, member)
 
 extern void odict_initialize(odict_t *, odgetkey_t, odcmp_t);

kernel/generic/include/macros.h

@@ -160 +160 @@
         })
 
-#define member_to_inst(ptr_member, type, member_identif) \
-        ((type *) (((void *) (ptr_member)) - \
-            ((void *) &(((type *) 0)->member_identif))))
-
 /** Get the size of an array in array elements
  *