From d38d2bc3533dcfb661a3cbb8bd6cd9574c31ab69 Mon Sep 17 00:00:00 2001 From: Max Kellermann Date: Fri, 29 Aug 2008 15:04:49 +0200 Subject: tag: optimize tag_dup(), copy item references Don't call tag_pool_get_item() for duplicating tags, just increase the item's reference counter instead. --- src/tag_pool.c | 43 +++++++++++++++++++++++++++++++++++++------ 1 file changed, 37 insertions(+), 6 deletions(-) (limited to 'src/tag_pool.c') diff --git a/src/tag_pool.c b/src/tag_pool.c index 744a82fdb..89efef1fc 100644 --- a/src/tag_pool.c +++ b/src/tag_pool.c @@ -61,6 +61,19 @@ tag_item_to_slot(struct tag_item *item) return (struct slot*)(((char*)item) - offsetof(struct slot, item)); } +static struct slot *slot_alloc(struct slot *next, + enum tag_type type, + const char *value, int length) +{ + struct slot *slot = xmalloc(sizeof(*slot) + length); + slot->next = next; + slot->ref = 1; + slot->item.type = type; + memcpy(slot->item.value, value, length); + slot->item.value[length] = 0; + return slot; +} + struct tag_item *tag_pool_get_item(enum tag_type type, const char *value, int length) { @@ -76,16 +89,34 @@ struct tag_item *tag_pool_get_item(enum tag_type type, } } - slot = xmalloc(sizeof(*slot) + length); - slot->next = *slot_p; - slot->ref = 1; - slot->item.type = type; - memcpy(slot->item.value, value, length); - slot->item.value[length] = 0; + slot = slot_alloc(*slot_p, type, value, length); *slot_p = slot; return &slot->item; } +struct tag_item *tag_pool_dup_item(struct tag_item *item) +{ + struct slot *slot = tag_item_to_slot(item); + + assert(slot->ref > 0); + + if (slot->ref < 0xff) { + ++slot->ref; + return item; + } else { + /* the reference counter overflows above 0xff; + duplicate the item, and start with 1 */ + size_t length = strlen(item->value); + struct slot **slot_p = + &slots[calc_hash_n(item->type, item->value, + length) % NUM_SLOTS]; + slot = slot_alloc(*slot_p, item->type, + item->value, strlen(item->value)); + *slot_p = slot; + return &slot->item; + } +} + void tag_pool_put_item(struct tag_item *item) { struct slot **slot_p, *slot; -- cgit v1.2.3