Improve item meta handling

3 files changed, 79 insertions, 35 deletions

diff --git a/itemmeta.go b/itemmeta.go
new file mode 100644
index 0000000..2282dff
--- /dev/null
+++ b/itemmeta.go
@@ -0,0 +1,74 @@
+package mt
+
+import "strings"
+
+type ItemMeta string
+
+var sanitizer = strings.NewReplacer(
+	string(1), "",
+	string(2), "",
+	string(3), "",
+)
+
+func NewItemMeta(fields []Field) ItemMeta {
+	if len(fields) == 0 {
+		return ""
+	}
+
+	b := new(strings.Builder)
+	b.WriteByte(1)
+	for _, f := range fields {
+		sanitizer.WriteString(b, f.Name)
+		b.WriteByte(2)
+		sanitizer.WriteString(b, f.Value)
+		b.WriteByte(3)
+	}
+	return ItemMeta(b.String())
+}
+
+func (m ItemMeta) Fields() []Field {
+	var f []Field
+	if len(m) > 0 && m[0] == 1 {
+		m = m[1:]
+		eat := func(stop byte) string {
+			for i := 0; i < len(m); i++ {
+				if m[i] == stop {
+					defer func() {
+						m = m[i+1:]
+					}()
+					return string(m[:i])
+				}
+			}
+			defer func() {
+				m = ""
+			}()
+			return string(m)
+		}
+		for len(m) > 0 {
+			f = append(f, Field{eat(2), eat(3)})
+		}
+		return f
+	}
+
+	return []Field{{"", string(m)}}
+}
+
+func (m ItemMeta) Field(name string) (s string, ok bool) {
+	for _, f := range m.Fields() {
+		if f.Name == name {
+			s, ok = f.Value, true
+		}
+	}
+	return
+}
+
+func (m *ItemMeta) SetField(name, value string) {
+	var fields []Field
+	for _, f := range m.Fields() {
+		if f.Name != name {
+			fields = append(fields, f)
+		}
+	}
+	fields = append(fields, Field{name, value})
+	*m = NewItemMeta(fields)
+}
diff --git a/mt.go b/mt.go
new file mode 100644
index 0000000..c5d665d
--- /dev/null
+++ b/mt.go
@@ -0,0 +1,5 @@
+package mt
+
+type Field struct {
+	Name, Value string
+}
diff --git a/stack.go b/stack.go
index 12c6338..4e7cc18 100644
--- a/stack.go
+++ b/stack.go
@@ -22,41 +22,6 @@ type Item struct {
 	ItemMeta
 }
 
-type ItemMeta string
-
-func (m ItemMeta) Field(name string) (s string, ok bool) {
-	if len(m) > 0 && m[0] == 1 {
-		m = m[1:]
-		eat := func(stop byte) string {
-			for i := 0; i < len(m); i++ {
-				if m[i] == stop {
-					defer func() {
-						m = m[i+1:]
-					}()
-					return string(m[:i])
-				}
-			}
-			defer func() {
-				m = ""
-			}()
-			return string(m)
-		}
-		for len(m) > 0 {
-			if eat(2) == name {
-				s = eat(3)
-				ok = true
-			}
-		}
-		return
-	}
-
-	if name == "" {
-		return string(m), true
-	}
-
-	return "", false
-}
-
 func (s Stack) String() string {
 	if s.Count == 0 {
 		return ""