fix(printf): fix floating point precision limit

Return the correct count of precision digits now. Fixes #22

1 files changed, 11 insertions, 7 deletions

diff --git a/printf.c b/printf.c
index 0fd6569..c28cf13 100644
--- a/printf.c
+++ b/printf.c
@@ -277,13 +277,14 @@ static size_t _ftoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, d
     value = 0 - value;

   }

 

-  // limit precision

+  // set default precision to 6, if not set explicitly

   if (!(flags & FLAGS_PRECISION)) {

-    prec = 6U;  // by default, precesion is 6

+    prec = 6U;

   }

-  if (prec > 9U) {

-    // precision of >= 10 can lead to overflow errors

-    prec = 9U;

+  // limit precision to 9, cause a prec >= 10 can lead to overflow errors

+  while ((len < PRINTF_FTOA_BUFFER_SIZE) && (prec > 9U)) {

+    buf[len++] = '0';

+    prec--;

   }

 

   int whole = (int)value;

@@ -325,10 +326,13 @@ static size_t _ftoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, d
   else {

     unsigned int count = prec;

     // now do fractional part, as an unsigned number

-    do {

+    while (len < PRINTF_FTOA_BUFFER_SIZE) {

       --count;

       buf[len++] = (char)(48U + (frac % 10U));

-    } while ((len < PRINTF_FTOA_BUFFER_SIZE) && (frac /= 10U));

+      if (!(frac /= 10U)) {

+        break;

+      }

+    }

     // add extra 0s

     while ((len < PRINTF_FTOA_BUFFER_SIZE) && (count-- > 0U)) {

       buf[len++] = '0';