+typedef struct ptable_ent {
+ struct ptable_ent *next;
+ const void * key;
+ void * val;
+} ptable_ent;
+
+typedef struct ptable {
+ ptable_ent **ary;
+ UV max;
+ UV items;
+} ptable;
+
+#ifndef PTABLE_VAL_FREE
+# define PTABLE_VAL_FREE(V)
+#endif
+
+STATIC ptable *ptable_new(void) {
+ ptable *t = PerlMemShared_malloc(sizeof *t);
+ t->max = 127;
+ t->items = 0;
+ t->ary = PerlMemShared_calloc(t->max + 1, sizeof *t->ary);
+ return t;
+}
+
+#define PTABLE_HASH(ptr) \
+ ((PTR2UV(ptr) >> 3) ^ (PTR2UV(ptr) >> (3 + 7)) ^ (PTR2UV(ptr) >> (3 + 17)))
+
+STATIC ptable_ent *ptable_find(const ptable * const t, const void * const key) {
+ ptable_ent *ent;
+ const UV hash = PTABLE_HASH(key);
+
+ ent = t->ary[hash & t->max];
+ for (; ent; ent = ent->next) {
+ if (ent->key == key)
+ return ent;
+ }
+
+ return NULL;
+}
+
+STATIC void *ptable_fetch(const ptable * const t, const void * const key) {
+ const ptable_ent *const ent = ptable_find(t, key);
+
+ return ent ? ent->val : NULL;
+}
+
+STATIC void ptable_split(ptable * const t) {
+ ptable_ent **ary = t->ary;
+ const UV oldsize = t->max + 1;
+ UV newsize = oldsize * 2;
+ UV i;
+
+ ary = PerlMemShared_realloc(ary, newsize * sizeof(*ary));
+ Zero(&ary[oldsize], newsize - oldsize, sizeof(*ary));
+ t->max = --newsize;
+ t->ary = ary;
+
+ for (i = 0; i < oldsize; i++, ary++) {
+ ptable_ent **curentp, **entp, *ent;
+ if (!*ary)
+ continue;
+ curentp = ary + oldsize;
+ for (entp = ary, ent = *ary; ent; ent = *entp) {
+ if ((newsize & PTABLE_HASH(ent->key)) != i) {
+ *entp = ent->next;
+ ent->next = *curentp;
+ *curentp = ent;
+ continue;
+ } else
+ entp = &ent->next;
+ }
+ }
+}
+
+STATIC void ptable_store(ptable * const t, const void * const key, void * const val) {
+ ptable_ent *ent = ptable_find(t, key);
+
+ if (ent) {
+ void *oldval = ent->val;
+ PTABLE_VAL_FREE(oldval);
+ ent->val = val;
+ } else {
+ const UV i = PTABLE_HASH(key) & t->max;
+ ent = PerlMemShared_malloc(sizeof *ent);
+ ent->key = key;
+ ent->val = val;
+ ent->next = t->ary[i];
+ t->ary[i] = ent;
+ t->items++;
+ if (ent->next && t->items > t->max)
+ ptable_split(t);
+ }
+}
+
+#if 0
+
+STATIC void ptable_clear(ptable * const t) {
+ if (t && t->items) {
+ register ptable_ent ** const array = t->ary;
+ UV i = t->max;
+
+ do {
+ ptable_ent *entry = array[i];
+ while (entry) {
+ ptable_ent * const oentry = entry;
+ void *val = oentry->val;
+ entry = entry->next;
+ PTABLE_VAL_FREE(val);
+ PerlMemShared_free(entry);
+ }
+ array[i] = NULL;
+ } while (i--);
+
+ t->items = 0;
+ }
+}
+
+STATIC void ptable_free(ptable * const t) {
+ if (!t)
+ return;
+ ptable_clear(t);
+ PerlMemShared_free(t->ary);
+ PerlMemShared_free(t);
+}
+
+#endif