chore(printf): cleanup secure strlen() function, added test cases

3 files changed, 31 insertions, 6 deletions

diff --git a/README.md b/README.md
index 945d66b..33031e9 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ Therefore I decided to write an own, final implementation which meets the follow
  - Support of decimal/floating number representation (with an own fast itoa/ftoa)

  - Reentrant and thread-safe, malloc free, no static vars/buffers

  - LINT and compiler L4 warning free, mature, coverity clean, automotive ready

- - Extensive test suite (> 340 test cases) passing

+ - Extensive test suite (> 350 test cases) passing

  - Simply the best *printf* around the net

  - MIT license

 

diff --git a/printf.c b/printf.c
index 9905032..df88d3d 100644
--- a/printf.c
+++ b/printf.c
@@ -139,14 +139,13 @@ static inline void _out_fct(char character, void* buffer, size_t idx, size_t max
 }

 

 

-// internal strlen

+// internal secure strlen

 // \return The length of the string (excluding the terminating 0)

 //         limited by 'max' size if non-zero

-static inline unsigned int _strlen(const char* str, size_t max)

+static inline unsigned int _strnlen_s(const char* str, size_t maxsize)

 {

   const char* s;

-  size_t n = max;

-  for (s = str; *s && (max?n--:1); ++s);

+  for (s = str; *s && maxsize--; ++s);

   return (unsigned int)(s - str);

 }

 

@@ -649,7 +648,7 @@ static int _vsnprintf(out_fct_type out, char* buffer, const size_t maxlen, const
 

       case 's' : {

         char* p = va_arg(va, char*);

-        unsigned int l = _strlen(p, precision);

+        unsigned int l = _strnlen_s(p, precision ? precision : (size_t)-1);

         // pre padding

         if (flags & FLAGS_PRECISION) {

           l = (l < precision ? l : precision);

diff --git a/test/test_suite.cpp b/test/test_suite.cpp
index 272f4c4..bcddd4f 100644
--- a/test/test_suite.cpp
+++ b/test/test_suite.cpp
@@ -1187,6 +1187,32 @@ TEST_CASE("unknown flag", "[]" ) {
 }

 

 

+TEST_CASE("string length", "[]" ) {

+  char buffer[100];

+

+  test::sprintf(buffer, "%.4s", "This is a test");

+  REQUIRE(!strcmp(buffer, "This"));

+

+  test::sprintf(buffer, "%.4s", "test");

+  REQUIRE(!strcmp(buffer, "test"));

+

+  test::sprintf(buffer, "%.7s", "123");

+  REQUIRE(!strcmp(buffer, "123"));

+

+  test::sprintf(buffer, "%.7s", "");

+  REQUIRE(!strcmp(buffer, ""));

+

+  test::sprintf(buffer, "%.4s%.2s", "123456", "abcdef");

+  REQUIRE(!strcmp(buffer, "1234ab"));

+

+  test::sprintf(buffer, "%.4.2s", "123456");

+  REQUIRE(!strcmp(buffer, ".2s"));

+

+  test::sprintf(buffer, "%.*s", 3, "123456");

+  REQUIRE(!strcmp(buffer, "123"));

+}

+

+

 TEST_CASE("buffer length", "[]" ) {

   char buffer[100];

   int ret;