From 356c829b767863512da1792c048f6ddbeb8457a3 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@duempel.org>
Date: Wed, 30 Sep 2015 22:03:01 +0200
Subject: util/StringView: new utility class

---
 src/tag/TagPool.cxx | 42 +++++++++++++++++++-----------------------
 1 file changed, 19 insertions(+), 23 deletions(-)

(limited to 'src/tag/TagPool.cxx')

diff --git a/src/tag/TagPool.cxx b/src/tag/TagPool.cxx
index 0280948fd..88b2ba333 100644
--- a/src/tag/TagPool.cxx
+++ b/src/tag/TagPool.cxx
@@ -22,6 +22,7 @@
 #include "TagItem.hxx"
 #include "util/Cast.hxx"
 #include "util/VarSize.hxx"
+#include "util/StringView.hxx"
 
 #include <assert.h>
 #include <string.h>
@@ -37,39 +38,37 @@ struct TagPoolSlot {
 	TagItem item;
 
 	TagPoolSlot(TagPoolSlot *_next, TagType type,
-		    const char *value, size_t length)
+		    StringView value)
 		:next(_next), ref(1) {
 		item.type = type;
-		memcpy(item.value, value, length);
-		item.value[length] = 0;
+		memcpy(item.value, value.data, value.size);
+		item.value[value.size] = 0;
 	}
 
 	static TagPoolSlot *Create(TagPoolSlot *_next, TagType type,
-				   const char *value, size_t length);
+				   StringView value);
 } gcc_packed;
 
 TagPoolSlot *
 TagPoolSlot::Create(TagPoolSlot *_next, TagType type,
-		    const char *value, size_t length)
+		    StringView value)
 {
 	TagPoolSlot *dummy;
 	return NewVarSize<TagPoolSlot>(sizeof(dummy->item.value),
-				       length + 1,
+				       value.size + 1,
 				       _next, type,
-				       value, length);
+				       value);
 }
 
 static TagPoolSlot *slots[NUM_SLOTS];
 
 static inline unsigned
-calc_hash_n(TagType type, const char *p, size_t length)
+calc_hash(TagType type, StringView p)
 {
 	unsigned hash = 5381;
 
-	assert(p != nullptr);
-
-	while (length-- > 0)
-		hash = (hash << 5) + hash + *p++;
+	for (auto ch : p)
+		hash = (hash << 5) + hash + ch;
 
 	return hash ^ type;
 }
@@ -97,9 +96,9 @@ tag_item_to_slot(TagItem *item)
 }
 
 static inline TagPoolSlot **
-tag_value_slot_p(TagType type, const char *value, size_t length)
+tag_value_slot_p(TagType type, StringView value)
 {
-	return &slots[calc_hash_n(type, value, length) % NUM_SLOTS];
+	return &slots[calc_hash(type, value) % NUM_SLOTS];
 }
 
 static inline TagPoolSlot **
@@ -109,13 +108,12 @@ tag_value_slot_p(TagType type, const char *value)
 }
 
 TagItem *
-tag_pool_get_item(TagType type, const char *value, size_t length)
+tag_pool_get_item(TagType type, StringView value)
 {
-	auto slot_p = tag_value_slot_p(type, value, length);
+	auto slot_p = tag_value_slot_p(type, value);
 	for (auto slot = *slot_p; slot != nullptr; slot = slot->next) {
 		if (slot->item.type == type &&
-		    length == strlen(slot->item.value) &&
-		    memcmp(value, slot->item.value, length) == 0 &&
+		    value.Equals(slot->item.value) &&
 		    slot->ref < 0xff) {
 			assert(slot->ref > 0);
 			++slot->ref;
@@ -123,7 +121,7 @@ tag_pool_get_item(TagType type, const char *value, size_t length)
 		}
 	}
 
-	auto slot = TagPoolSlot::Create(*slot_p, type, value, length);
+	auto slot = TagPoolSlot::Create(*slot_p, type, value);
 	*slot_p = slot;
 	return &slot->item;
 }
@@ -141,11 +139,9 @@ tag_pool_dup_item(TagItem *item)
 	} else {
 		/* the reference counter overflows above 0xff;
 		   duplicate the item, and start with 1 */
-		size_t length = strlen(item->value);
-		auto slot_p = tag_value_slot_p(item->type,
-					       item->value, length);
+		auto slot_p = tag_value_slot_p(item->type, item->value);
 		slot = TagPoolSlot::Create(*slot_p, item->type,
-					   item->value, strlen(item->value));
+					   item->value);
 		*slot_p = slot;
 		return &slot->item;
 	}
-- 
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