Parsing: make it faster.

zgenerate.go

@@ -1,6 +1,7 @@
 package dns
 
 import (
+	"bytes"
 	"fmt"
 	"strconv"
 	"strings"
@@ -62,7 +63,7 @@ BuildRR:
 	for i := start; i <= end; i += step {
 		var (
 			escape bool
-			dom    string
+			dom    bytes.Buffer
 			mod    string
 			err    string
 			offset int
@@ -72,7 +73,7 @@ BuildRR:
 			switch s[j] {
 			case '\\':
 				if escape {
-					dom += "\\"
+					dom.WriteByte('\\')
 					escape = false
 					continue
 				}
@@ -81,17 +82,17 @@ BuildRR:
 				mod = "%d"
 				offset = 0
 				if escape {
-					dom += "$"
+					dom.WriteByte('$')
 					escape = false
 					continue
 				}
 				escape = false
 				if j+1 >= len(s) { // End of the string
-					dom += fmt.Sprintf(mod, i+offset)
+					dom.WriteString(fmt.Sprintf(mod, i+offset))
 					continue
 				} else {
 					if s[j+1] == '$' {
-						dom += "$"
+						dom.WriteByte('$')
 						j++
 						continue
 					}
@@ -108,17 +109,17 @@ BuildRR:
 					}
 					j += 2 + sep // Jump to it
 				}
-				dom += fmt.Sprintf(mod, i+offset)
+				dom.WriteString(fmt.Sprintf(mod, i+offset))
 			default:
 				if escape { // Pretty useless here
 					escape = false
 					continue
 				}
-				dom += string(s[j])
+				dom.WriteByte(s[j])
 			}
 		}
 		// Re-parse the RR and send it on the current channel t
-		rx, e := NewRR("$ORIGIN " + o + "\n" + dom)
+		rx, e := NewRR("$ORIGIN " + o + "\n" + dom.String())
 		if e != nil {
 			return e.(*ParseError).err
 		}