words: new package Damerau Levenshtein distance function. (#3929)

cmd/damerau-levenshtein.go

@@ -1,66 +0,0 @@
-/*
- * Minio Client (C) 2014-2016 Minio, 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 cmd
-
-import (
-	"math"
-)
-
-// Returns the minimum value of a slice of integers
-func minimum(integers []int) (minVal int) {
-	minVal = math.MaxInt32
-	for _, v := range integers {
-		if v < minVal {
-			minVal = v
-		}
-	}
-	return
-}
-
-// DamerauLevenshteinDistance calculates distance between two strings using an algorithm
-// described in https://en.wikipedia.org/wiki/Damerau-Levenshtein_distance
-func DamerauLevenshteinDistance(a string, b string) int {
-	d := make([][]int, len(a)+1)
-	for i := 1; i <= len(a)+1; i++ {
-		d[i-1] = make([]int, len(b)+1)
-	}
-	for i := 0; i <= len(a); i++ {
-		d[i][0] = i
-	}
-	for j := 0; j <= len(b); j++ {
-		d[0][j] = j
-	}
-	var cost int
-	for i := 1; i <= len(a); i++ {
-		for j := 1; j <= len(b); j++ {
-			if a[i-1] == b[j-1] {
-				cost = 0
-			} else {
-				cost = 1
-			}
-			d[i][j] = minimum([]int{
-				d[i-1][j] + 1,
-				d[i][j-1] + 1,
-				d[i-1][j-1] + cost,
-			})
-			if i > 1 && j > 1 && a[i-1] == b[j-2] && a[i-2] == b[j-1] {
-				d[i][j] = minimum([]int{d[i][j], d[i-2][j-2] + cost}) // transposition
-			}
-		}
-	}
-	return d[len(a)][len(b)]
-}

cmd/damerau-levenshtein_test.go

@@ -1,66 +0,0 @@
-/*
- * Minio Cloud Storage, (C) 2016 Minio, 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 cmd
-
-import (
-	"math"
-	"testing"
-)
-
-// Test minimum function which calculates the minimal value in a list of integers
-func TestMinimum(t *testing.T) {
-	type testCase struct {
-		listval  []int
-		expected int
-		pass     bool
-	}
-	testCases := []testCase{
-		{listval: []int{3, 4, 15}, expected: 3},
-		{listval: []int{}, expected: math.MaxInt32},
-	}
-	// Validate all the test cases.
-	for i, tt := range testCases {
-		val := minimum(tt.listval)
-		if val != tt.expected {
-			t.Errorf("Test %d:, Expected %d, got %d", i+1, tt.expected, val)
-		}
-	}
-}
-
-// Test DamerauLevenshtein which calculates the difference distance between two words
-func TestDamerauLevenshtein(t *testing.T) {
-	type testCase struct {
-		word1    string
-		word2    string
-		distance int
-	}
-	testCases := []testCase{
-		{word1: "", word2: "", distance: 0},
-		{word1: "a", word2: "a", distance: 0},
-		{word1: "a", word2: "b", distance: 1},
-		{word1: "rm", word2: "tm", distance: 1},
-		{word1: "version", word2: "evrsion", distance: 1},
-		{word1: "version", word2: "bersio", distance: 2},
-	}
-	// Validate all the test cases.
-	for i, tt := range testCases {
-		d := DamerauLevenshteinDistance(tt.word1, tt.word2)
-		if d != tt.distance {
-			t.Errorf("Test %d:, Expected %d, got %d", i+1, tt.distance, d)
-		}
-	}
-}

cmd/main.go

@@ -23,6 +23,7 @@ import (
 	"github.com/minio/cli"
 	"github.com/minio/mc/pkg/console"
 	"github.com/minio/minio/pkg/trie"
+	"github.com/minio/minio/pkg/words"
 )
 
 // global flags for minio.
@@ -86,7 +87,7 @@ func newApp() *cli.App {
 			}
 			// 2 is arbitrary and represents the max
 			// allowed number of typed errors
-			if DamerauLevenshteinDistance(command, value.(string)) < 2 {
+			if words.DamerauLevenshteinDistance(command, value.(string)) < 2 {
 				closestCommands = append(closestCommands, value.(string))
 			}
 		}