py: Implement mp_format_float for doubles and use where appropriate

This allows using (almost) the same code for printing floats everywhere,
removes the dependency on sprintf and uses just snprintf and
applies an msvc-specific fix for snprintf in a single place so
nan/inf are now printed correctly.

1 files changed, 4 insertions, 11 deletions

diff --git a/py/objfloat.c b/py/objfloat.c
index f74e12f9d4..ffb3c71964 100644
--- a/py/objfloat.c
+++ b/py/objfloat.c
@@ -37,31 +37,24 @@
 #if MICROPY_PY_BUILTINS_FLOAT
 
 #include <math.h>
-
-#if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT
 #include "py/formatfloat.h"
-#endif
 
 STATIC void float_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_float_t *o = o_in;
 #if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT
     char buf[16];
-    mp_format_float(o->value, buf, sizeof(buf), 'g', 7, '\0');
-    mp_print_str(print, buf);
-    if (strchr(buf, '.') == NULL && strchr(buf, 'e') == NULL && strchr(buf, 'n') == NULL) {
-        // Python floats always have decimal point (unless inf or nan)
-        mp_print_str(print, ".0");
-    }
+    const int precision = 7;
 #else
     char buf[32];
-    sprintf(buf, "%.16g", (double) o->value);
+    const int precision = 16;
+#endif
+    mp_format_float(o->value, buf, sizeof(buf), 'g', precision, '\0');
     mp_print_str(print, buf);
     if (strchr(buf, '.') == NULL && strchr(buf, 'e') == NULL && strchr(buf, 'n') == NULL) {
         // Python floats always have decimal point (unless inf or nan)
         mp_print_str(print, ".0");
     }
-#endif
 }
 
 STATIC mp_obj_t float_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {