charConv: optimize away a boatload of strdups during update (try #2)

This was originally introduced in r3718, but reverted r3859 since the
original r3718 commit was incorrect (and I was too excited about
the speedup and also lacking in UTF-8 files to notice :x)

git-svn-id: https://svn.musicpd.org/mpd/trunk@4517 09075e82-0dd4-0310-85a5-a0d7c8717e4f

1 files changed, 13 insertions, 4 deletions

diff --git a/src/charConv.c b/src/charConv.c
index 05c03167e..4e4aa864a 100644
--- a/src/charConv.c
+++ b/src/charConv.c
@@ -45,10 +45,19 @@ static void closeCharSetConversion();
 
 int setCharSetConversion(char *to, char *from)
 {
-	if (char_conv_to && char_conv_from &&
-	    strcmp(to, char_conv_to) == 0 && strcmp(from, char_conv_from) == 0)
-	{
-		return 0;
+	if (char_conv_to && char_conv_from) {
+		if (char_conv_latin1ToUtf8 &&
+		    !strcmp(from, char_conv_to) &&
+		    !strcmp(to, char_conv_from)) {
+			char *swap = char_conv_from;
+			char_conv_from = char_conv_to;
+			char_conv_to = swap;
+			char_conv_latin1ToUtf8 *= -1;
+			return 0;
+		} else if (!strcmp(to, char_conv_to) &&
+		           !strcmp(from,char_conv_from)) {
+			return 0;
+		}
 	}
 
 	closeCharSetConversion();