From: Jay Krell <jaykrell@microsoft.com>
Date: Wed, 10 Jul 2019 16:06:51 +0000 (-0700)
Subject: Remove quadratic behavior from g_strconcat. (mono/mono#15630)
X-Git-Tag: submit/tizen/20210909.063632~10331^2~5^2~994
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1c504343fd5de8370bec1f255c6a4370443123e4;p=platform%2Fupstream%2Fdotnet%2Fruntime.git

Remove quadratic behavior from g_strconcat. (mono/mono#15630)

Prefer strlen + memcpy over strcat.

Commit migrated from https://github.com/mono/mono/commit/7a486d8f438434159e1a7f0f8762a76b2faffeac
---

diff --git a/src/mono/mono/eglib/gstr.c b/src/mono/mono/eglib/gstr.c
index b43f3d9..d6b26b4 100644
--- a/src/mono/mono/eglib/gstr.c
+++ b/src/mono/mono/eglib/gstr.c
@@ -276,26 +276,28 @@ gchar *
 g_strconcat (const gchar *first, ...)
 {
 	va_list args;
-	size_t total = 0;
 	char *s, *ret;
 	g_return_val_if_fail (first != NULL, NULL);
 
-	total += strlen (first);
+	size_t len = strlen (first);
 	va_start (args, first);
 	for (s = va_arg (args, char *); s != NULL; s = va_arg(args, char *)){
-		total += strlen (s);
+		len += strlen (s);
 	}
 	va_end (args);
 	
-	ret = g_malloc (total + 1);
+	ret = (char*)g_malloc (len + 1);
 	if (ret == NULL)
 		return NULL;
 
-	ret [total] = 0;
-	strcpy (ret, first);
+	ret [len] = 0;
+	len = strlen (first);
+	memcpy (ret, first, len);
 	va_start (args, first);
+	first = ret; // repurpose first as cursor
 	for (s = va_arg (args, char *); s != NULL; s = va_arg(args, char *)){
-		strcat (ret, s);
+		first += len;
+		memcpy ((char*)first, s, len = strlen (s));
 	}
 	va_end (args);
 
@@ -512,7 +514,7 @@ g_strjoin (const gchar *separator, ...)
 	if (slen > 0 && len > 0)
 		len -= slen;
 
-	res = g_malloc (len + 1);
+	res = (char*)g_malloc (len + 1);
 	va_start (args, separator);
 	s = va_arg (args, char *);
 	r = g_stpcpy (res, s);