diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index 3ab273575..9b3451ea1 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -8025,47 +8025,44 @@ std::string Tokenizer::simplifyString(const std::string &source)
 {
     std::string str = source;
 
-    // true when previous char is a \ .
-    bool escaped = false;
-    for (std::string::size_type i = 0; i + 2 < str.size(); ++i) {
-        if (!escaped) {
-            if (str[i] == '\\')
-                escaped = true;
-
+    for (std::string::size_type i = 0; i + 1U < str.size(); ++i) {
+        if (str[i] != '\\')
             continue;
-        }
 
-        if (str[i] == 'x') {
-            // Hex value
-            if (str[i+1] == '0' && str[i+2] == '0')
-                str.replace(i, 3, "0");
-            else if (i > 0) {
-                // We will replace all other character as 'a'
-                // If that causes problems in the future, this can
-                // be improved. But for now, this should be OK.
-                unsigned int n = 1;
-                while (n < 2 && std::isxdigit(str[i+1+n]))
-                    ++n;
-                --i;
-                n += 2;
-                str.replace(i, n, "a");
+        int c = 'a';   // char
+        unsigned int sz = 0;    // size of stringdata
+        if (str[i+1] == 'x') {
+            sz = 2;
+            while (std::isxdigit(str[i+sz]) && sz < 4)
+                sz++;
+            if (sz > 2) {
+                std::istringstream istr(str.substr(i+2, sz-2));
+                istr >> std::hex >> c;
             }
-        } else if (MathLib::isOctalDigit(str[i])) {
-            if (MathLib::isOctalDigit(str[i+1]) &&
-                MathLib::isOctalDigit(str[i+2])) {
-                if (str[i+1] == '0' && str[i+2] == '0')
-                    str.replace(i, 3, "0");
-                else {
-                    // We will replace all other character as 'a'
-                    // If that causes problems in the future, this can
-                    // be improved. But for now, this should be OK.
-                    --i;
-                    str.replace(i, 4, "a");
-                }
+        } else if (MathLib::isOctalDigit(str[i+1])) {
+            sz = 2;
+            while (MathLib::isOctalDigit(str[i+sz]) && sz < 4)
+                sz++;
+            std::istringstream istr(str.substr(i+1, sz-1));
+            istr >> std::oct >> c;
+            if (sz == 2) {
+                if (c == 0) {
+                    str = str.substr(0,i) + "\"";
+                    continue;
+                } else
+                    str[i+1] = (char)c;
             }
         }
 
-        escaped = false;
+        if (sz <= 2)
+            i++;
+        else if (i+sz < str.size()) {
+            if (c == 0)
+                str = str.substr(0,i) + "\"";
+            else
+                str.replace(i, sz, std::string(1U, (char)c));
+        } else
+            str.replace(i, str.size() - i - 1U, "a");
     }
 
     return str;
diff --git a/test/testsimplifytokens.cpp b/test/testsimplifytokens.cpp
index 63bc18d22..a87fb7e8b 100644
--- a/test/testsimplifytokens.cpp
+++ b/test/testsimplifytokens.cpp
@@ -183,8 +183,6 @@ private:
 
         TEST_CASE(simplifyAtol)
 
-        TEST_CASE(simplifyHexInString)
-
         TEST_CASE(simplifyTypedef1)
         TEST_CASE(simplifyTypedef2)
         TEST_CASE(simplifyTypedef3)
@@ -3603,28 +3601,6 @@ private:
         ASSERT_EQUALS("a = 10 ;", tok("a = atol(\"0xa\");"));
     }
 
-    void simplifyHexInString() {
-        ASSERT_EQUALS("\"a\"", tok("\"\\x61\""));
-        ASSERT_EQUALS("\"a\"", tok("\"\\141\""));
-
-        ASSERT_EQUALS("\"\\0\"", tok("\"\\x00\""));
-        ASSERT_EQUALS("\"\\0\"", tok("\"\\000\""));
-
-        ASSERT_EQUALS("\"\\nhello\"", tok("\"\\nhello\""));
-
-        ASSERT_EQUALS("\"aaa\"", tok("\"\\x61\\x61\\x61\""));
-        ASSERT_EQUALS("\"aaa\"", tok("\"\\141\\141\\141\""));
-
-        ASSERT_EQUALS("\"\\\\x61\"", tok("\"\\\\x61\""));
-
-        // These tests can fail, if other characters are handled
-        // more correctly. But for now all non null characters should
-        // become 'a'
-        ASSERT_EQUALS("\"a\"", tok("\"\\x62\""));
-        ASSERT_EQUALS("\"a\"", tok("\"\\177\""));
-    }
-
-
     std::string simplifyTypedef(const char code[]) {
         errout.str("");
 
diff --git a/test/testtokenize.cpp b/test/testtokenize.cpp
index 4f93a0cba..cbce44428 100644
--- a/test/testtokenize.cpp
+++ b/test/testtokenize.cpp
@@ -5630,9 +5630,27 @@ private:
         Settings settings;
         Tokenizer tokenizer(&settings, this);
         ASSERT_EQUALS("\"abc\"", tokenizer.simplifyString("\"abc\""));
-        ASSERT_EQUALS("\"a\"", tokenizer.simplifyString("\"\\x3\""));
-        ASSERT_EQUALS("\"a\"", tokenizer.simplifyString("\"\\x33\""));
-        ASSERT_EQUALS("\"a3\"", tokenizer.simplifyString("\"\\x333\""));
+        ASSERT_EQUALS("\"\n\"", tokenizer.simplifyString("\"\\xa\""));
+        ASSERT_EQUALS("\"3\"", tokenizer.simplifyString("\"\\x33\""));
+        ASSERT_EQUALS("\"33\"", tokenizer.simplifyString("\"\\x333\""));
+
+        ASSERT_EQUALS("\"a\"", tokenizer.simplifyString("\"\\x61\""));
+        ASSERT_EQUALS("\"\n1\"", tokenizer.simplifyString("\"\\0121\""));
+
+        ASSERT_EQUALS("\"3\"", tokenizer.simplifyString("\"\\x33\""));
+        ASSERT_EQUALS("\" 0\"", tokenizer.simplifyString("\"\\0400\""));
+
+        ASSERT_EQUALS("\"\\nhello\"", tokenizer.simplifyString("\"\\nhello\""));
+
+        ASSERT_EQUALS("\"aaa\"", tokenizer.simplifyString("\"\\x61\\x61\\x61\""));
+        ASSERT_EQUALS("\"\n1\n1\n1\"", tokenizer.simplifyString("\"\\0121\\0121\\0121\""));
+
+        ASSERT_EQUALS("\"\\\\x61\"", tokenizer.simplifyString("\"\\\\x61\""));
+        ASSERT_EQUALS("\"b\"", tokenizer.simplifyString("\"\\x62\""));
+        ASSERT_EQUALS("\" 7\"", tokenizer.simplifyString("\"\\0407\""));
+
+        // terminate a string at null character.
+        ASSERT_EQUALS("\"a\"", tokenizer.simplifyString("\"a\\0\""));
     }
 
     void simplifyConst() {