Pointers to different things need not be represented in the same way.

Use the fact that we only can store structs in the table to make the
complex pointer use safe. Unfortunately the equal and hash functions
need to take void * arguments.

misc/hashtable.c

@@ -3,19 +3,19 @@
 
 #include "hashtable.h"
 
-#define KEYP(tbl, o) ((o) + (tbl)->keyoff)
-#define CHAINP(tbl, o) *((void **)((o) + (tbl)->chainoff))
-
 struct _htbl {
     int (*eq)(const void *, const void *);
     uint32_t (*hash)(const void *);
-    void **buckets;
+    struct _any **buckets;
     size_t buckcnt;
     size_t size;
     size_t keyoff;
     size_t chainoff;
 };
 
+#define KEYP(tbl, o) ((void *)(o) + (tbl)->keyoff)
+#define CHAINP(tbl, o) *(struct _any **)((void *)(o) + (tbl)->chainoff)
+
 struct _htbl *
 _htbl_create(int (*eq)(const void *, const void *),
     uint32_t (*hash)(const void *), size_t keyoff, size_t chainoff)
@@ -44,11 +44,11 @@ _htbl_free(struct _htbl *tbl)
     free(tbl);
 }
 
-static void *
-bucket_rev(struct _htbl *tbl, void *p, void *n)
+static struct _any *
+bucket_rev(struct _htbl *tbl, struct _any *p, struct _any *n)
 {
     while (n != NULL) {
-        void *s = CHAINP(tbl, n);
+        struct _any *s = CHAINP(tbl, n);
         CHAINP(tbl, n) = p;
         p = n;
         n = s;
@@ -57,7 +57,7 @@ bucket_rev(struct _htbl *tbl, void *p, void *n)
 }
 
 static void
-bucket_insert(struct _htbl *tbl, void *o)
+bucket_insert(struct _htbl *tbl, struct _any *o)
 {
     size_t bi = tbl->hash(KEYP(tbl, o)) % tbl->buckcnt;
     CHAINP(tbl, o) = tbl->buckets[bi];
@@ -69,8 +69,8 @@ _htbl_grow(struct _htbl *tbl)
 {
     size_t ncnt = 2 * tbl->buckcnt + 1;
     size_t ocnt = tbl->buckcnt;
-    void **obuckets = tbl->buckets;
-    void **nbuckets = calloc(ncnt, sizeof(*nbuckets));
+    struct _any **obuckets = tbl->buckets;
+    struct _any **nbuckets = calloc(ncnt, sizeof(*nbuckets));
     if (nbuckets == NULL)
         return;
 
@@ -78,9 +78,9 @@ _htbl_grow(struct _htbl *tbl)
     tbl->buckets = nbuckets;
 
     for (size_t i = 0; i < ocnt; i++) {
-        void *o = bucket_rev(tbl, NULL, obuckets[i]);
+        struct _any *o = bucket_rev(tbl, NULL, obuckets[i]);
         while (o != NULL) {
-            void *s = CHAINP(tbl, o);
+            struct _any *s = CHAINP(tbl, o);
             bucket_insert(tbl, o);
             o = s;
         }
@@ -90,7 +90,7 @@ _htbl_grow(struct _htbl *tbl)
 }
 
 void
-_htbl_insert(struct _htbl *tbl, void *o)
+_htbl_insert(struct _htbl *tbl, struct _any *o)
 {
     bucket_insert(tbl, o);
     tbl->size++;
@@ -98,21 +98,22 @@ _htbl_insert(struct _htbl *tbl, void *o)
         _htbl_grow(tbl);
 }
 
-void *
+struct _any *
 _htbl_find(struct _htbl *tbl, const void *key)
 {
+    struct _any *ret;
     size_t bi = tbl->hash(key) % tbl->buckcnt;
-    for (void *ret = tbl->buckets[bi]; ret != NULL; ret = CHAINP(tbl, ret))
+    for (ret = tbl->buckets[bi]; ret != NULL; ret = CHAINP(tbl, ret))
         if (tbl->eq(KEYP(tbl, ret), key))
             return ret;
     return NULL;
 }
 
-void *
+struct _any *
 _htbl_remove(struct _htbl *tbl, const void *key)
 {
     size_t bi = tbl->hash(key) % tbl->buckcnt;
-    void *p = NULL, *o = tbl->buckets[bi];
+    struct _any *p = NULL, *o = tbl->buckets[bi];
     while (o != NULL && !tbl->eq(KEYP(tbl, o), key)) {
         p = o;
         o = CHAINP(tbl, o);
@@ -128,11 +129,11 @@ _htbl_remove(struct _htbl *tbl, const void *key)
 }
 
 void
-_htbl_tov(struct _htbl *tbl, void **v)
+_htbl_tov(struct _htbl *tbl, struct _any **v)
 {
     size_t vi = 0;
     size_t bi = 0;
-    void *o = tbl->buckets[bi];
+    struct _any *o = tbl->buckets[bi];
     while (vi < tbl->size) {
         while (o == NULL) {
             bi++;
@@ -159,7 +160,7 @@ _htbl_iter_init(struct _htbl *tbl, struct htbl_iter *it)
     it->obj = NULL;
 }
 
-void *
+struct _any *
 _htbl_iter_next(struct htbl_iter *it)
 {
     if (it->cnt == it->tbl->size)

misc/hashtable.h

@@ -5,28 +5,29 @@ struct htbl_iter {
     struct _htbl *tbl;
     size_t bi;
     size_t cnt;
-    void *obj;
+    struct _any *obj;
 };
 
 struct _htbl *_htbl_create(int (*equal)(const void *, const void *),
     uint32_t (*hash)(const void *), size_t keyoff, size_t chainoff);
 void _htbl_free(struct _htbl *tbl);
-void _htbl_insert(struct _htbl *tbl, void *o);
-void *_htbl_remove(struct _htbl *tbl, const void *key);
-void *_htbl_find(struct _htbl *tbl, const void *key);
-void _htbl_tov(struct _htbl *tb, void **v);
+void _htbl_insert(struct _htbl *tbl, struct _any *o);
+struct _any *_htbl_remove(struct _htbl *tbl, const void *key);
+struct _any *_htbl_find(struct _htbl *tbl, const void *key);
+void _htbl_tov(struct _htbl *tb, struct _any **v);
 size_t _htbl_size(struct _htbl *tbl);
 void _htbl_iter_init(struct _htbl *tbl, struct htbl_iter *it);
-void *_htbl_iter_next(struct htbl_iter *it);
+struct _any *_htbl_iter_next(struct htbl_iter *it);
 
-#define HTBLTYPE(name, type, ktype, kname, cname) \
+#define HTBL_ENTRY(name) struct _any *name
+
+#define HTBL_TYPE(name, type, ktype, kname, cname) \
 __attribute__((always_inline)) static inline struct name * \
-name##_create(int (*equal)(const ktype *, const ktype *), \
-    uint32_t (*hash)(const ktype *)) \
+name##_create(int (*equal)(const void *, const void *), \
+    uint32_t (*hash)(const void *)) \
 { \
     return (struct name *) \
-      _htbl_create((int (*)(const void *, const void *))equal, \
-        (uint32_t (*)(const void *))hash, offsetof(struct type, kname), \
+      _htbl_create(equal, hash, offsetof(struct type, kname), \
         offsetof(struct type, cname)); \
 } \
 \
@@ -51,12 +52,12 @@ name##_free(struct name *tbl) \
 __attribute__((always_inline)) static inline void \
 name##_insert(struct name *tbl, struct type *o) \
 { \
-    _htbl_insert((struct _htbl *)tbl, o); \
+    _htbl_insert((struct _htbl *)tbl, (struct _any *)o); \
 } \
 __attribute__((always_inline)) static inline void \
 name##_tov(struct name *tbl, struct type **v) \
 { \
-    _htbl_tov((struct _htbl *)tbl, (void **)v); \
+    _htbl_tov((struct _htbl *)tbl, (struct _any **)v); \
 } \
 \
 __attribute__((always_inline)) static inline size_t \