diff --git a/src/base/system.cpp b/src/base/system.cpp
index eab8ae639..d767d1af2 100644
--- a/src/base/system.cpp
+++ b/src/base/system.cpp
@@ -3041,15 +3041,16 @@ int str_countchr(const char *haystack, char needle)
 void str_hex(char *dst, int dst_size, const void *data, int data_size)
 {
 	static const char hex[] = "0123456789ABCDEF";
-	int b;
-
-	for(b = 0; b < data_size && b < dst_size / 4 - 4; b++)
+	int data_index;
+	int dst_index;
+	for(data_index = 0, dst_index = 0; data_index < data_size && dst_index < dst_size - 3; data_index++)
 	{
-		dst[b * 3] = hex[((const unsigned char *)data)[b] >> 4];
-		dst[b * 3 + 1] = hex[((const unsigned char *)data)[b] & 0xf];
-		dst[b * 3 + 2] = ' ';
-		dst[b * 3 + 3] = 0;
+		dst[data_index * 3] = hex[((const unsigned char *)data)[data_index] >> 4];
+		dst[data_index * 3 + 1] = hex[((const unsigned char *)data)[data_index] & 0xf];
+		dst[data_index * 3 + 2] = ' ';
+		dst_index += 3;
 	}
+	dst[dst_index] = '\0';
 }
 
 static int hexval(char x)
diff --git a/src/test/str.cpp b/src/test/str.cpp
index de6ed7633..be18083b8 100644
--- a/src/test/str.cpp
+++ b/src/test/str.cpp
@@ -200,6 +200,38 @@ TEST(Str, EndswithNocase)
 		str_length(ABCDEFG) - str_length(DEFG));
 }
 
+TEST(Str, HexEncode)
+{
+	char aOut[64];
+	const char *pData = "ABCD";
+	str_hex(aOut, sizeof(aOut), pData, 0);
+	EXPECT_STREQ(aOut, "");
+	str_hex(aOut, sizeof(aOut), pData, 1);
+	EXPECT_STREQ(aOut, "41 ");
+	str_hex(aOut, sizeof(aOut), pData, 2);
+	EXPECT_STREQ(aOut, "41 42 ");
+	str_hex(aOut, sizeof(aOut), pData, 3);
+	EXPECT_STREQ(aOut, "41 42 43 ");
+	str_hex(aOut, sizeof(aOut), pData, 4);
+	EXPECT_STREQ(aOut, "41 42 43 44 ");
+	str_hex(aOut, 1, pData, 4);
+	EXPECT_STREQ(aOut, "");
+	str_hex(aOut, 2, pData, 4);
+	EXPECT_STREQ(aOut, "");
+	str_hex(aOut, 3, pData, 4);
+	EXPECT_STREQ(aOut, "");
+	str_hex(aOut, 4, pData, 4);
+	EXPECT_STREQ(aOut, "41 ");
+	str_hex(aOut, 5, pData, 4);
+	EXPECT_STREQ(aOut, "41 ");
+	str_hex(aOut, 6, pData, 4);
+	EXPECT_STREQ(aOut, "41 ");
+	str_hex(aOut, 7, pData, 4);
+	EXPECT_STREQ(aOut, "41 42 ");
+	str_hex(aOut, 8, pData, 4);
+	EXPECT_STREQ(aOut, "41 42 ");
+}
+
 TEST(Str, HexDecode)
 {
 	char aOut[5] = {'a', 'b', 'c', 'd', 0};