From 08e47b4a9eb0091d823dca411ad09001dbca4c4a Mon Sep 17 00:00:00 2001
From: kortschak <dan.kortschak@adelaide.edu.au>
Date: Thu, 21 Aug 2014 15:23:30 +0930
Subject: [PATCH] Do tagger copying with less iteration
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This makes minimal difference to the benchmarks in cayley_test.go (a
variable ±5% on the bigger cases).
---
 graph/iterator.go | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/graph/iterator.go b/graph/iterator.go
index ca17cb5..83f1999 100644
--- a/graph/iterator.go
+++ b/graph/iterator.go
@@ -51,14 +51,16 @@ func (t *Tagger) Fixed() map[string]Value {
 }
 
 func (t *Tagger) CopyFrom(src Iterator) {
-	for _, tag := range src.Tagger().Tags() {
-		t.Add(tag)
-	}
+	st := src.Tagger()
 
-	for k, v := range src.Tagger().Fixed() {
-		t.AddFixed(k, v)
-	}
+	t.tags = append(t.tags, st.tags...)
 
+	if t.fixedTags == nil {
+		t.fixedTags = make(map[string]Value, len(st.fixedTags))
+	}
+	for k, v := range st.fixedTags {
+		t.fixedTags[k] = v
+	}
 }
 
 type Iterator interface {