[PATCH 2/2] lib/charset: fix u16_strlcat() return value

[Matthias Schiffer]

strlcat returns min(strlen(dest), count)+strlen(src). Make u16_strlcat's
behaviour the same for consistency.

Fixes: eca08ce94ceb ("lib/charset: add u16_strlcat() function")
Signed-off-by: Matthias Schiffer <matthias.schiffer at ew.tq-group.com>
---
 lib/charset.c     | 8 ++++----
 test/unicode_ut.c | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/lib/charset.c b/lib/charset.c
index b1842755eb1..5e4c4f948a4 100644
--- a/lib/charset.c
+++ b/lib/charset.c
@@ -444,14 +444,14 @@ u16 *u16_strdup(const void *src)
 
 size_t u16_strlcat(u16 *dest, const u16 *src, size_t count)
 {
-	size_t destlen = u16_strlen(dest);
+	size_t destlen = u16_strnlen(dest, count);
 	size_t srclen = u16_strlen(src);
-	size_t ret = destlen + srclen + 1;
+	size_t ret = destlen + srclen;
 
 	if (destlen >= count)
 		return ret;
-	if (ret > count)
-		srclen -= ret - count;
+	if (ret >= count)
+		srclen -= (ret - count + 1);
 	memcpy(&dest[destlen], src, 2 * srclen);
 	dest[destlen + srclen] = 0x0000;
 
diff --git a/test/unicode_ut.c b/test/unicode_ut.c
index b27d7116b9e..a9356e2b60d 100644
--- a/test/unicode_ut.c
+++ b/test/unicode_ut.c
@@ -808,12 +808,12 @@ static int unicode_test_u16_strlcat(struct unit_test_state *uts)
 	/* dest and src are empty string */
 	memset(buf, 0, sizeof(buf));
 	ret = u16_strlcat(buf, &null_src, sizeof(buf));
-	ut_asserteq(1, ret);
+	ut_asserteq(0, ret);
 
 	/* dest is empty string */
 	memset(buf, 0, sizeof(buf));
 	ret = u16_strlcat(buf, src, sizeof(buf));
-	ut_asserteq(5, ret);
+	ut_asserteq(4, ret);
 	ut_assert(!unicode_test_u16_strcmp(buf, src, 40));
 
 	/* src is empty string */
@@ -821,14 +821,14 @@ static int unicode_test_u16_strlcat(struct unit_test_state *uts)
 	buf[39] = 0;
 	memcpy(buf, dest, sizeof(dest));
 	ret = u16_strlcat(buf, &null_src, sizeof(buf));
-	ut_asserteq(6, ret);
+	ut_asserteq(5, ret);
 	ut_assert(!unicode_test_u16_strcmp(buf, dest, 40));
 
 	for (i = 0; i <= 40; i++) {
 		memset(buf, 0xCD, (sizeof(buf) - sizeof(u16)));
 		buf[39] = 0;
 		memcpy(buf, dest, sizeof(dest));
-		expected = 10;
+		expected = min(5, i) + 4;
 		ret = u16_strlcat(buf, src, i);
 		ut_asserteq(expected, ret);
 		if (i <= 6) {
-- 
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