mirror of
https://codeberg.org/forgejo/forgejo.git
synced 2024-12-14 11:48:09 -05:00
106 lines
2.2 KiB
Go
106 lines
2.2 KiB
Go
|
// Copyright (c) 2014 Couchbase, Inc.
|
||
|
//
|
||
|
// 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 search
|
||
|
|
||
|
import (
|
||
|
"math"
|
||
|
)
|
||
|
|
||
|
func LevenshteinDistance(a, b string) int {
|
||
|
la := len(a)
|
||
|
lb := len(b)
|
||
|
d := make([]int, la+1)
|
||
|
var lastdiag, olddiag, temp int
|
||
|
|
||
|
for i := 1; i <= la; i++ {
|
||
|
d[i] = i
|
||
|
}
|
||
|
for i := 1; i <= lb; i++ {
|
||
|
d[0] = i
|
||
|
lastdiag = i - 1
|
||
|
for j := 1; j <= la; j++ {
|
||
|
olddiag = d[j]
|
||
|
min := d[j] + 1
|
||
|
if (d[j-1] + 1) < min {
|
||
|
min = d[j-1] + 1
|
||
|
}
|
||
|
if a[j-1] == b[i-1] {
|
||
|
temp = 0
|
||
|
} else {
|
||
|
temp = 1
|
||
|
}
|
||
|
if (lastdiag + temp) < min {
|
||
|
min = lastdiag + temp
|
||
|
}
|
||
|
d[j] = min
|
||
|
lastdiag = olddiag
|
||
|
}
|
||
|
}
|
||
|
return d[la]
|
||
|
}
|
||
|
|
||
|
// LevenshteinDistanceMax same as LevenshteinDistance but
|
||
|
// attempts to bail early once we know the distance
|
||
|
// will be greater than max
|
||
|
// in which case the first return val will be the max
|
||
|
// and the second will be true, indicating max was exceeded
|
||
|
func LevenshteinDistanceMax(a, b string, max int) (int, bool) {
|
||
|
la := len(a)
|
||
|
lb := len(b)
|
||
|
|
||
|
ld := int(math.Abs(float64(la - lb)))
|
||
|
if ld > max {
|
||
|
return max, true
|
||
|
}
|
||
|
|
||
|
d := make([]int, la+1)
|
||
|
var lastdiag, olddiag, temp int
|
||
|
|
||
|
for i := 1; i <= la; i++ {
|
||
|
d[i] = i
|
||
|
}
|
||
|
for i := 1; i <= lb; i++ {
|
||
|
d[0] = i
|
||
|
lastdiag = i - 1
|
||
|
rowmin := max + 1
|
||
|
for j := 1; j <= la; j++ {
|
||
|
olddiag = d[j]
|
||
|
min := d[j] + 1
|
||
|
if (d[j-1] + 1) < min {
|
||
|
min = d[j-1] + 1
|
||
|
}
|
||
|
if a[j-1] == b[i-1] {
|
||
|
temp = 0
|
||
|
} else {
|
||
|
temp = 1
|
||
|
}
|
||
|
if (lastdiag + temp) < min {
|
||
|
min = lastdiag + temp
|
||
|
}
|
||
|
if min < rowmin {
|
||
|
rowmin = min
|
||
|
}
|
||
|
d[j] = min
|
||
|
|
||
|
lastdiag = olddiag
|
||
|
}
|
||
|
// after each row if rowmin isn't less than max stop
|
||
|
if rowmin > max {
|
||
|
return max, true
|
||
|
}
|
||
|
}
|
||
|
return d[la], false
|
||
|
}
|