Initial QSfera import

Server/vendor/github.com/trustelem/zxcvbn/matching/sequence.go

@@ -0,0 +1,78 @@
+package matching
+
+import (
+	"regexp"
+
+	"github.com/trustelem/zxcvbn/match"
+)
+
+type sequenceMatch struct{}
+
+const maxDelta = 5
+
+func abs(a int) int {
+	if a < 0 {
+		return -a
+	}
+	return a
+}
+
+var reLower = regexp.MustCompile(`^[a-z]+$`)
+var reUpper = regexp.MustCompile(`^[A-Z]+$`)
+var reDigits = regexp.MustCompile(`^\d+$`)
+
+func (sequenceMatch) Matches(password string) []*match.Match {
+	matches := []*match.Match{}
+	if len(password) == 1 {
+		return matches
+	}
+
+	update := func(i, j, delta int) {
+		absDelta := abs(delta)
+		if j-i > 1 || absDelta == 1 {
+			if absDelta > 0 && absDelta <= maxDelta {
+				token := password[i : j+1]
+				// conservatively stick with roman alphabet size.
+				// (this could be improved)
+				seqName := "unicode"
+				seqSpace := 26
+				if reLower.MatchString(token) {
+					seqName = "lower"
+				} else if reUpper.MatchString(token) {
+					seqName = "upper"
+				} else if reDigits.MatchString(token) {
+					seqName = "digits"
+					seqSpace = 10
+				}
+				matches = append(matches, &match.Match{
+					Pattern:       "sequence",
+					I:             i,
+					J:             j,
+					Token:         password[i : j+1],
+					SequenceName:  seqName,
+					SequenceSpace: seqSpace,
+					Ascending:     delta > 0,
+				})
+			}
+		}
+	}
+
+	i := 0
+	lastDelta := 0 // null
+	for k := 1; k <= len(password)-1; k++ {
+		delta := int(password[k]) - int(password[k-1])
+		if k == 1 {
+			lastDelta = delta
+		}
+		if delta == lastDelta {
+			continue
+		}
+		j := k - 1
+		update(i, j, lastDelta)
+		i = j
+		lastDelta = delta
+	}
+
+	update(i, len(password)-1, lastDelta)
+	return matches
+}