1 files changed, 45 insertions, 21 deletions

diff --git a/metrics.go b/metrics.go
index 74aae15..b6ab6d4 100644
--- a/metrics.go
+++ b/metrics.go
@@ -35,25 +35,28 @@ type Sample struct{
 func (self Sample) cmpString() string{
     return SortLabels(self.labels).String()
 }
-func (self Sample) String() string{
-    ret := ""
+func (self Sample) WriteString(b *strings.Builder){
     firstLabel := 0
     if self.labels.Len() != 0 && self.labels[0].Name == labels.MetricName{
         firstLabel = 1
-        ret += self.labels[0].Value
+        b.WriteString(self.labels[0].Value)
     }
     if len(self.labels[firstLabel:]) > 0{
-        ret += "{"
+        b.WriteString("{")
         for i, l := range self.labels[firstLabel:]{
             if i != 0{
-                ret += ","
+                b.WriteString(",")
             }
-            ret += l.Name + "=" + `"` + Escape(l.Value) + `"`
+            b.WriteString(l.Name + "=" + `"` + Escape(l.Value) + `"`)
         }
-        ret += "}"
+        b.WriteString("}")
     }
-    ret += fmt.Sprintf(" %g%s", self.value, self.suffix)
-    return ret
+    b.WriteString(fmt.Sprintf(" %g%s", self.value, self.suffix))
+}
+func (self Sample) String() string{
+    b := strings.Builder{}
+    self.WriteString(&b)
+    return b.String()
 }
 
 type MetricFamily struct{
@@ -76,16 +79,31 @@ type MetricSampleSet struct{
     Name string
     Labels []MetricSampleLabel
 }
-func (self MetricFamily) Header() string{
-    ret := ""
-    ret += fmt.Sprintf("# TYPE %s %s\n", self.name, self.ty)
+func (self MetricFamily) WriteHeader(b *strings.Builder){
+    b.WriteString("# TYPE ")
+    b.WriteString(self.name)
+    b.WriteString(" ")
+    b.WriteString(string(self.ty))
+    b.WriteString("\n")
     if self.unit != ""{
-        ret += fmt.Sprintf("# UNIT %s %s\n", self.name, self.unit)
+        b.WriteString("# UNIT ")
+        b.WriteString(self.name)
+        b.WriteString(" ")
+        b.WriteString(self.unit)
+        b.WriteString("\n")
     }
     if self.help != ""{
-        ret += fmt.Sprintf("# HELP %s %s\n", self.name, Escape(self.help))
+        b.WriteString("# HELP ")
+        b.WriteString(self.name)
+        b.WriteString(" ")
+        b.WriteString(Escape(self.help))
+        b.WriteString("\n")
     }
-    return ret
+}
+func (self MetricFamily) Header() string{
+    b := strings.Builder{}
+    self.WriteHeader(&b)
+    return b.String()
 }
 func (self MetricFamily) MetricNamesLabels() []MetricSampleSet{
     switch self.ty{
@@ -203,9 +221,8 @@ func (self MetricFamilies) Clone() MetricFamilies{
     }
     return ret
 }
-func (self MetricFamilies) String() string{
+func (self MetricFamilies) WriteString(b *strings.Builder){
     samples := maps.Clone(self.samples)
-    ret := ""
     for _, mf := range self.metas{
         // labels, __name__
         ms := map[string]map[string]*[]Sample{}
@@ -238,7 +255,7 @@ func (self MetricFamilies) String() string{
         if len(ms) == 0{
             continue
         }
-        ret += mf.Header()
+        mf.WriteHeader(b)
         for _, s := range ms{
             for _, mss := range mf.MetricNamesLabels(){
                 if s[mss.Name] == nil{
@@ -276,17 +293,24 @@ func (self MetricFamilies) String() string{
                     return 0
                 })
                 for _, m := range *s[mss.Name]{
-                    ret += m.String() + "\n"
+                    m.WriteString(b)
+                    b.WriteString("\n")
                 }
             }
         }
     }
     for _, mn := range samples{
         for _, m := range mn{
-            ret += m.String() + "\n"
+            m.WriteString(b)
+            b.WriteString("\n")
         }
     }
-    return ret + "# EOF\n"
+    b.WriteString("# EOF\n")
+}
+func (self MetricFamilies) String() string{
+    b := strings.Builder{}
+    self.WriteString(&b)
+    return b.String()
 }
 func (self *MetricFamilies) addSampleWithKeys(s Sample, mn string, sk string){
     if self.samples[mn] == nil{