From f23f726b2d7bb96b08f89ca837b3e100e2bcdeb0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Hru=C5=A1ka?= <ondra@ondrovo.com>
Date: Mon, 10 Apr 2023 12:00:02 +0200
Subject: [PATCH] fix float formatting

---
 Lib/snprintf/snprintf.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/Lib/snprintf/snprintf.c b/Lib/snprintf/snprintf.c
index fdf59c9..bb75b1a 100644
--- a/Lib/snprintf/snprintf.c
+++ b/Lib/snprintf/snprintf.c
@@ -655,6 +655,8 @@ static void fmtfp(char *buffer, size_t *currlen, size_t maxlen,
     int zpadlen = 0;
     int caps = 0;
     int index;
+    int fzeropad = 0;
+    int fzerocnt = 0;
     double intpart;
     double fracpart;
     double temp;
@@ -728,6 +730,13 @@ static void fmtfp(char *buffer, size_t *currlen, size_t maxlen,
 
     /* Convert fractional part */
     if (fracpart) {
+        // leading zeros in the fractional part
+        fzeropad = 0;
+        fzerocnt = max - 1;
+        while (fracpart < POW10(fzerocnt)) {
+            fzeropad++;
+            fzerocnt--;
+        }
         do {
             temp = fracpart;
             my_modf(fracpart * 0.1, &fracpart);
@@ -785,8 +794,19 @@ static void fmtfp(char *buffer, size_t *currlen, size_t maxlen,
     if (max > 0) {
         dopr_outch(buffer, currlen, maxlen, '.');
 
-        while (fplace > 0)
+        if (zpadlen > fzeropad) {
+            zpadlen -= fzeropad;
+        } else {
+            zpadlen = 0;
+        }
+
+        while (fzeropad-- > 0) {
+            dopr_outch(buffer, currlen, maxlen, '0');
+        }
+
+        while (fplace > 0) {
             dopr_outch(buffer, currlen, maxlen, fconvert[--fplace]);
+        }
     }
 
     while (zpadlen > 0) {