go: update modules

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

vendor/github.com/xrash/smetrics/jaro.go

@@ -0,0 +1,86 @@
+package smetrics
+
+import (
+	"math"
+)
+
+// The Jaro distance. The result is 1 for equal strings, and 0 for completely different strings.
+func Jaro(a, b string) float64 {
+	// If both strings are zero-length, they are completely equal,
+	// therefore return 1.
+	if len(a) == 0 && len(b) == 0 {
+		return 1
+	}
+
+	// If one string is zero-length, strings are completely different,
+	// therefore return 0.
+	if len(a) == 0 || len(b) == 0 {
+		return 0
+	}
+
+	// Define the necessary variables for the algorithm.
+	la := float64(len(a))
+	lb := float64(len(b))
+	matchRange := int(math.Max(0, math.Floor(math.Max(la, lb)/2.0)-1))
+	matchesA := make([]bool, len(a))
+	matchesB := make([]bool, len(b))
+	var matches float64 = 0
+
+	// Step 1: Matches
+	// Loop through each character of the first string,
+	// looking for a matching character in the second string.
+	for i := 0; i < len(a); i++ {
+		start := int(math.Max(0, float64(i-matchRange)))
+		end := int(math.Min(lb-1, float64(i+matchRange)))
+
+		for j := start; j <= end; j++ {
+			if matchesB[j] {
+				continue
+			}
+
+			if a[i] == b[j] {
+				matchesA[i] = true
+				matchesB[j] = true
+				matches++
+				break
+			}
+		}
+	}
+
+	// If there are no matches, strings are completely different,
+	// therefore return 0.
+	if matches == 0 {
+		return 0
+	}
+
+	// Step 2: Transpositions
+	// Loop through the matches' arrays, looking for
+	// unaligned matches. Count the number of unaligned matches.
+	unaligned := 0
+	j := 0
+	for i := 0; i < len(a); i++ {
+		if !matchesA[i] {
+			continue
+		}
+
+		for !matchesB[j] {
+			j++
+		}
+
+		if a[i] != b[j] {
+			unaligned++
+		}
+
+		j++
+	}
+
+	// The number of unaligned matches divided by two, is the number of _transpositions_.
+	transpositions := math.Floor(float64(unaligned / 2))
+
+	// Jaro distance is the average between these three numbers:
+	// 1. matches / length of string A
+	// 2. matches / length of string B
+	// 3. (matches - transpositions/matches)
+	// So, all that divided by three is the final result.
+	return ((matches / la) + (matches / lb) + ((matches - transpositions) / matches)) / 3.0
+}