| // Copyright 2014-2017 Ulrich Kunitz. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package hash |
| |
| // Roller provides an interface for rolling hashes. The hash value will become |
| // valid after hash has been called Len times. |
| type Roller interface { |
| Len() int |
| RollByte(x byte) uint64 |
| } |
| |
| // Hashes computes all hash values for the array p. Note that the state of the |
| // roller is changed. |
| func Hashes(r Roller, p []byte) []uint64 { |
| n := r.Len() |
| if len(p) < n { |
| return nil |
| } |
| h := make([]uint64, len(p)-n+1) |
| for i := 0; i < n-1; i++ { |
| r.RollByte(p[i]) |
| } |
| for i := range h { |
| h[i] = r.RollByte(p[i+n-1]) |
| } |
| return h |
| } |