newline battles continue

vendor/github.com/xdg/stringprep/profile.go

@@ -0,0 +1,75 @@
+package stringprep
+
+import (
+	"golang.org/x/text/unicode/norm"
+)
+
+// Profile represents a stringprep profile.
+type Profile struct {
+	Mappings  []Mapping
+	Normalize bool
+	Prohibits []Set
+	CheckBiDi bool
+}
+
+var errProhibited = "prohibited character"
+
+// Prepare transforms an input string to an output string following
+// the rules defined in the profile as defined by RFC-3454.
+func (p Profile) Prepare(s string) (string, error) {
+	// Optimistically, assume output will be same length as input
+	temp := make([]rune, 0, len(s))
+
+	// Apply maps
+	for _, r := range s {
+		rs, ok := p.applyMaps(r)
+		if ok {
+			temp = append(temp, rs...)
+		} else {
+			temp = append(temp, r)
+		}
+	}
+
+	// Normalize
+	var out string
+	if p.Normalize {
+		out = norm.NFKC.String(string(temp))
+	} else {
+		out = string(temp)
+	}
+
+	// Check prohibited
+	for _, r := range out {
+		if p.runeIsProhibited(r) {
+			return "", Error{Msg: errProhibited, Rune: r}
+		}
+	}
+
+	// Check BiDi allowed
+	if p.CheckBiDi {
+		if err := passesBiDiRules(out); err != nil {
+			return "", err
+		}
+	}
+
+	return out, nil
+}
+
+func (p Profile) applyMaps(r rune) ([]rune, bool) {
+	for _, m := range p.Mappings {
+		rs, ok := m.Map(r)
+		if ok {
+			return rs, true
+		}
+	}
+	return nil, false
+}
+
+func (p Profile) runeIsProhibited(r rune) bool {
+	for _, s := range p.Prohibits {
+		if s.Contains(r) {
+			return true
+		}
+	}
+	return false
+}