X-Git-Url: https://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Fhtable%2Fhtable.c;h=59048dc0ada0df95b23583e0dfbba65d3c96768c;hb=c23a40c7f1ac9fad0146b46988a41f196aae933f;hp=0a01ead8978ad4c4e914a37dbe029c2ef1219004;hpb=60cc720d0797fc49325437ea36a9ffd909c75ed0;p=ccan

diff --git a/ccan/htable/htable.c b/ccan/htable/htable.c
index 0a01ead8..59048dc0 100644
--- a/ccan/htable/htable.c
+++ b/ccan/htable/htable.c
@@ -52,6 +52,29 @@ void htable_init(struct htable *ht,
 	ht->table = &ht->perfect_bit;
 }
 
+bool htable_init_sized(struct htable *ht,
+		       size_t (*rehash)(const void *, void *),
+		       void *priv, size_t expect)
+{
+	htable_init(ht, rehash, priv);
+
+	/* Don't go insane with sizing. */
+	for (ht->bits = 1; ((size_t)3 << ht->bits) / 4 < expect; ht->bits++) {
+		if (ht->bits == 30)
+			break;
+	}
+
+	ht->table = calloc(1 << ht->bits, sizeof(size_t));
+	if (!ht->table) {
+		ht->table = &ht->perfect_bit;
+		return false;
+	}
+	ht->max = ((size_t)3 << ht->bits) / 4;
+	ht->max_with_deleted = ((size_t)9 << ht->bits) / 10;
+
+	return true;
+}
+	
 void htable_clear(struct htable *ht)
 {
 	if (ht->table != &ht->perfect_bit)
@@ -197,8 +220,17 @@ static COLD void update_common(struct htable *ht, const void *p)
 	uintptr_t maskdiff, bitsdiff;
 
 	if (ht->elems == 0) {
-		ht->common_mask = -1;
-		ht->common_bits = (uintptr_t)p;
+		/* Always reveal one bit of the pointer in the bucket,
+		 * so it's not zero or HTABLE_DELETED (1), even if
+		 * hash happens to be 0.  Assumes (void *)1 is not a
+		 * valid pointer. */
+		for (i = sizeof(uintptr_t)*CHAR_BIT - 1; i > 0; i--) {
+			if ((uintptr_t)p & ((uintptr_t)1 << i))
+				break;
+		}
+
+		ht->common_mask = ~((uintptr_t)1 << i);
+		ht->common_bits = ((uintptr_t)p & ht->common_mask);
 		ht->perfect_bit = 1;
 		return;
 	}