From b40343bc8c219910e49774ff8da56fb60557b0b9 Mon Sep 17 00:00:00 2001
From: Laurent Mazet <laurent.mazet@thalesgroup.com>
Date: Tue, 6 Dec 2022 13:51:26 +0100
Subject: [PATCH] add some format info print function

---
 fprintf.c | 45 ++++++++++++++++++++++++++++++++++++---------
 1 file changed, 36 insertions(+), 9 deletions(-)

diff --git a/fprintf.c b/fprintf.c
index 405957e..6d60b82 100644
--- a/fprintf.c
+++ b/fprintf.c
@@ -15,11 +15,11 @@
 #include <stddef.h>
 #include <stdio.h>
 
-inline unsigned int nextpow10 (unsigned int x) {
+inline unsigned int nextpow (unsigned int x, int base) {
     unsigned int n = 0;
     while (x) {
         n++;
-        x = x / 10;
+        x = x / base;
     }
     return (n == 0) ? 1 : n;
 }
@@ -37,7 +37,6 @@ size_t myfprintf (FILE *fid, const char *fmt, ...)
         char *s;
         int d = 0;
         unsigned int u;
-        void *p;
         char c = *fmt++;
 
         /* copy standard char */
@@ -45,7 +44,19 @@ size_t myfprintf (FILE *fid, const char *fmt, ...)
             *str++ = c;
         } else {
             int t = 0;
-            size_t i;
+	        char w = '0';
+            size_t i, sz = 0;
+            void *p = NULL;
+
+            /* stamp */
+            if ((*fmt == ' ') || (*fmt == '0')) {
+                w = *fmt++;
+            }
+
+            /* size */
+            if ((*fmt >= '1') && (*fmt <= '9')) {
+                sz = *fmt++ - '0';
+            }
 
             /* process format char */
             switch (*fmt++) {
@@ -63,19 +74,35 @@ size_t myfprintf (FILE *fid, const char *fmt, ...)
                 /* fall through */
             case 'u': /* unsigned int */
                 u = (t) ? (unsigned int)d : va_arg (ap, unsigned int);
-                for (i = nextpow10 (u), s = str; i > 0; i--, s++) {
+                for (i = nextpow (u, 10), s = str; i > 0; i--, s++) {
                     str[i - 1] = '0' + (u % 10);
                     u /= 10;
                 }
                 str = s;
                 break;
             case 'p': /* pointer */
-                p = va_arg (ap, void *);
                 *str++ = '0';
                 *str++ = 'x';
-                for (i = sizeof (void *) * 2; i > 0; i--) {
+                w = '0';
+                sz = sizeof (void *) * 2;
+                p = va_arg (ap, void *);
+                /* fall through */
+            case 'x': /* integer hexa */
+                if (!p) {
+                    u = va_arg (ap, unsigned int);
+                    p = (void *)u;
+                    if (sz == 0) {
+                        sz = nextpow (u, 16);
+                    }
+                }
+                for (i = sz, t = 1; i > 0; i--) {
                     char x = (char)(((uintptr_t)p >> (i * 4 - 4)) & 0xf);
-                    *str++ = (x > 9) ? 'a' + x - 10 : '0' + x;
+                    if ((t == 1) && (x == 0)) {
+                        *str++ = w;
+                    } else {
+                        *str++ = (x > 9) ? 'a' + x - 10 : '0' + x;
+                        t = 0;
+                    }
                 }
                 break;
             case 's': /* string */
@@ -99,4 +126,4 @@ size_t myfprintf (FILE *fid, const char *fmt, ...)
     return 0;
 }
 
-/* vim: set ts=4 sw=4 et */
+/* vim: set ts=4 sw=4 et: */
-- 
2.30.2