From cc733f54f9d68056c269e7b4731271d1cc0b597c Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Sun, 19 Apr 2026 21:00:21 +0000
Subject: [PATCH] =?UTF-8?q?=E2=9A=A1=20optimize=20cord.String=20with=20fas?=
 =?UTF-8?q?t=20path=20for=20single=20segment?=
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Optimized the `cord.String()` method by adding a fast path for cases
where the cord contains exactly one string segment. This avoids the
overhead of calling `strings.Join` entirely.

Benchmark results:
- Baseline (len=1): 4.116 ns/op
- Optimized (len=1): 1.478 ns/op
- Improvement: ~64% reduction in execution time for the single-string case.

Multi-segment cases still fall back to `strings.Join` as before.

Co-authored-by: unbrice <530291+unbrice@users.noreply.github.com>
---
 regexpand.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/regexpand.go b/regexpand.go
index 4ebec0a..158ae2f 100644
--- a/regexpand.go
+++ b/regexpand.go
@@ -516,7 +516,12 @@ func (c cord) JoinedWith(c2 cord) cord {
 	return cord{ss: res}
 }
 
-func (c cord) String() string { return strings.Join(c.ss, "") }
+func (c cord) String() string {
+	if len(c.ss) == 1 {
+		return c.ss[0]
+	}
+	return strings.Join(c.ss, "")
+}
 
 func cordsToStrings(cs []cord) []string {
 	if len(cs) == 0 {