新增排行榜服务

util/algorithms/skip/interface.go

@@ -0,0 +1,47 @@
+/*
+Copyright 2014 Workiva, LLC
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package skip
+
+// Comparator is a generic interface that represents items that can
+// be compared.
+type Comparator interface {
+	// Compare compares this interface with another.  Returns a positive
+	// number if this interface is greater, 0 if equal, negative number
+	// if less.
+	Compare(Comparator) int
+}
+
+// Comparators is a typed list of type Comparator.
+type Comparators []Comparator
+
+// Iterator defines an interface that allows a consumer to iterate
+// all results of a query.  All values will be visited in-order.
+type Iterator interface {
+	// Next returns a bool indicating if there is future value
+	// in the iterator and moves the iterator to that value.
+	Next() bool
+	// Prev returns a bool indicating if there is Previous value
+	// in the iterator and moves the iterator to that value.
+	Prev() bool
+	// Value returns a Comparator representing the iterator's current
+	// position.  If there is no value, this returns nil.
+	Value() Comparator
+	// exhaust is a helper method that will iterate this iterator
+	// to completion and return a list of resulting Entries
+	// in order.
+	exhaust() Comparators
+}