From 7a4cb05709d3901ca76d876f4fd93e787890c4da Mon Sep 17 00:00:00 2001
From: Vladimir Panteleev <108007295+VPanteleev-S7@users.noreply.github.com>
Date: Sun, 23 Mar 2025 20:30:59 +0000
Subject: [PATCH] arsd.postgres: Add fast path for field name conversion

Skip the slow std.uni.toLower call unless it's necessary.
---
 postgres.d | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/postgres.d b/postgres.d
index 107987e..d722c7d 100644
--- a/postgres.d
+++ b/postgres.d
@@ -179,13 +179,21 @@ class PostgreSql : Database {
 		PGconn* conn;
 }
 
+private string toLowerFast(string s) {
+	import std.ascii : isUpper;
+	foreach (c; s)
+		if (c >= 0x80 || isUpper(c))
+			return toLower(s);
+	return s;
+}
+
 ///
 class PostgresResult : ResultSet {
 	// name for associative array to result index
 	int getFieldIndex(string field) {
 		if(mapping is null)
 			makeFieldMapping();
-		field = field.toLower;
+		field = field.toLowerFast;
 		if(field in mapping)
 			return mapping[field];
 		else throw new Exception("no mapping " ~ field);