printf: add %d, %u and %x

1 files changed, 23 insertions, 6 deletions

diff --git a/lib/string/itoa.c b/lib/string/itoa.c
index 5eefb37..3708be2 100644
--- a/lib/string/itoa.c
+++ b/lib/string/itoa.c
@@ -1,13 +1,30 @@
-#include "string.h"
+#include <stdbool.h>
+#include <string.h>
+
+static const char *numbers = "0123456789abcdef";
+
+char *
+itoa(char *p, int x, int base)
+{
+  const bool is_negative = (x < 0);
+  if (is_negative) x = -x;
+
+  p = utoa(p, x, base);
+
+  if (is_negative) *--p = '-';
+  return p;
+}
 
 char *
-itoa(char *p, unsigned x)
+utoa(char *p, unsigned x, int base)
 {
-  p += 3 * sizeof(int);
-  *--p = 0;
+  p += 3 * sizeof(unsigned);
+  *--p = '\0';
+
   do {
-    *--p = '0' + x % 10;
-    x /= 10;
+    *--p = numbers[x % base];
+    x /= base;
   } while (x);
+
   return p;
 }