fix(printf): fixed support of NaN

(hot) fixes #37

3 files changed, 17 insertions, 3 deletions

diff --git a/README.md b/README.md
index 33736fc..0b39488 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 (> 350 test cases) passing

+ - Extensive test suite (> 370 test cases) passing

  - Simply the best *printf* around the net

  - MIT license

 

diff --git a/printf.c b/printf.c
index ce67626..d73da2f 100644
--- a/printf.c
+++ b/printf.c
@@ -311,6 +311,14 @@ static size_t _ftoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, d
   // powers of 10

   static const double pow10[] = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000 };

 

+  // test for NaN

+  if (value != value) {

+    out('n', buffer, idx++, maxlen);

+    out('a', buffer, idx++, maxlen);

+    out('n', buffer, idx++, maxlen);

+    return idx;

+  }

+

   // test for negative

   bool negative = false;

   if (value < 0) {

@@ -341,8 +349,10 @@ static size_t _ftoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, d
       ++whole;

     }

   }

-  else if ((diff == 0.5) && ((frac == 0U) || (frac & 1U))) {

-    // if halfway, round up if odd, OR if last digit is 0

+  else if (diff < 0.5) {

+  }

+  else if ((frac == 0U) || (frac & 1U)) {

+    // if halfway, round up if odd OR if last digit is 0

     ++frac;

   }

 

diff --git a/test/test_suite.cpp b/test/test_suite.cpp
index 66ba5f3..2103a5b 100644
--- a/test/test_suite.cpp
+++ b/test/test_suite.cpp
@@ -31,6 +31,7 @@
 #include "catch.hpp"

 

 #include <string.h>

+#include <math.h>

 

 namespace test {

   // use functions in own test namespace to avoid stdio conflicts

@@ -1019,6 +1020,9 @@ TEST_CASE("length", "[]" ) {
 TEST_CASE("float", "[]" ) {

   char buffer[100];

 

+  test::sprintf(buffer, "%.4f", NAN);   // using the NAN macro of math.h

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

+

   test::sprintf(buffer, "%.4f", 3.1415354);

   REQUIRE(!strcmp(buffer, "3.1415"));