github.com/dubbogo/gost@v1.14.0/hash/base_hash.go (about)

     1  /*
     2   * Licensed to the Apache Software Foundation (ASF) under one or more
     3   * contributor license agreements.  See the NOTICE file distributed with
     4   * this work for additional information regarding copyright ownership.
     5   * The ASF licenses this file to You under the Apache License, Version 2.0
     6   * (the "License"); you may not use this file except in compliance with
     7   * the License.  You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   */
    17  
    18  package gxhash
    19  
    20  // BKDRHash BKDR Hash (java str.hashCode())
    21  // s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]
    22  func BKDRHash(str string) int32 {
    23  	h := int32(0)
    24  	base := int32(1)
    25  	s := []rune(str)
    26  	for i := len(s) - 1; i >= 0; i-- {
    27  		h += s[i] * base
    28  		base = base<<5 - base
    29  	}
    30  	return h
    31  }