Add text package for specific functions on text strings

util/text/text.go

@@ -0,0 +1,66 @@
+// Copyright © 2016 Abcum Ltd
+//
+// 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 text
+
+func Levenshtein(one, two string) int {
+
+	var cost, olddiag, lastdiag int
+
+	s1 := []rune(one)
+	s2 := []rune(two)
+
+	l1 := len(s1)
+	l2 := len(s2)
+
+	column := make([]int, l1+1)
+
+	for y := 1; y <= l1; y++ {
+		column[y] = y
+	}
+
+	for x := 1; x <= l2; x++ {
+		column[0] = x
+		lastdiag = x - 1
+		for y := 1; y <= l1; y++ {
+			olddiag = column[y]
+			cost = 0
+			if s1[y-1] != s2[x-1] {
+				cost = 1
+			}
+			column[y] = min(
+				column[y]+1,
+				column[y-1]+1,
+				lastdiag+cost,
+			)
+			lastdiag = olddiag
+		}
+	}
+
+	return column[l1]
+
+}
+
+func min(a, b, c int) int {
+	if a < b {
+		if a < c {
+			return a
+		}
+	} else {
+		if b < c {
+			return b
+		}
+	}
+	return c
+}