hugo/resources/page/pages_prev_next.go
Bjørn Erik Pedersen 653e6856ea resources/page: Use binary search in Pages.Prev/Next if possible
This is obviously much faster for lager data sets:

```bash
name                         old time/op    new time/op    delta
SearchPage/ByWeight-100-4       267ns ± 4%     272ns ± 5%     ~     (p=0.457 n=4+4)
SearchPage/ByWeight-5000-4     10.8µs ± 3%     1.2µs ± 2%  -88.99%  (p=0.029 n=4+4)
SearchPage/ByWeight-10000-4    21.1µs ± 1%     1.4µs ±11%  -93.28%  (p=0.029 n=4+4)
```

See #4500
2019-10-13 12:36:17 +02:00

35 lines
968 B
Go

// Copyright 2019 The Hugo Authors. All rights reserved.
//
// 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 page
// Next returns the next page reletive to the given
func (p Pages) Next(cur Page) Page {
x := searchPage(cur, p)
if x <= 0 {
return nil
}
return p[x-1]
}
// Prev returns the previous page reletive to the given
func (p Pages) Prev(cur Page) Page {
x := searchPage(cur, p)
if x == -1 || len(p)-x < 2 {
return nil
}
return p[x+1]
}