From 08e688d151bbe676353a47b1e8ccfc5ea868db01 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Sun, 19 May 2024 20:47:13 -0400
Subject: libc: vsnprintf: Add '%d' support
Signed-off-by: Ian Moffett <ian@osmora.org>
---
lib/libc/src/stdio/vsnprintf.c | 48 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)
(limited to 'lib/libc/src/stdio')
diff --git a/lib/libc/src/stdio/vsnprintf.c b/lib/libc/src/stdio/vsnprintf.c
index 6cc0a04..112ed1f 100644
--- a/lib/libc/src/stdio/vsnprintf.c
+++ b/lib/libc/src/stdio/vsnprintf.c
@@ -28,6 +28,7 @@
*/
#include <sys/types.h>
+#include <stdint.h>
#include <stdio.h>
static inline void
@@ -48,6 +49,48 @@ printstr(char *buf, size_t size, size_t *off, const char *s)
buf[*off] = 0;
}
+static void
+dec_to_str(int value, char *buf, size_t size, size_t *off)
+{
+ size_t i = 0;
+ uint8_t is_negative = 0;
+ uint8_t tmp;
+ char intbuf[4096];
+
+ if (value == 0) {
+ intbuf[i++] = '0';
+ intbuf[i++] = '\0';
+ printstr(buf, size, off, intbuf);
+ return;
+ }
+
+ if (value < 0) {
+ /* Easier to handle positive numbers */
+ value *= -1;
+ is_negative = 1;
+ }
+
+ while (value > 0) {
+ intbuf[i++] = '0' + (value % 10);
+ value /= 10;
+ }
+
+ if (is_negative) {
+ intbuf[i++] = '-';
+ }
+
+ intbuf[i--] = '\0';
+
+ /* Result is in reverse */
+ for (int j = 0; j < i; ++j, --i) {
+ tmp = intbuf[j];
+ intbuf[j] = intbuf[i];
+ intbuf[i] = tmp;
+ }
+
+ printstr(buf, size, off, intbuf);
+}
+
int
vsnprintf(char *s, size_t size, const char *fmt, va_list ap)
{
@@ -55,6 +98,7 @@ vsnprintf(char *s, size_t size, const char *fmt, va_list ap)
ssize_t num = 0;
char c, c1;
const char *tmp_str;
+ int tmp_num;
while (off < (size - 1)) {
while (*fmt && *fmt != '%') {
@@ -75,6 +119,10 @@ vsnprintf(char *s, size_t size, const char *fmt, va_list ap)
tmp_str = va_arg(ap, const char *);
printstr(s, size, &off, tmp_str);
break;
+ case 'd':
+ tmp_num = va_arg(ap, int);
+ dec_to_str(tmp_num, s, size, &off);
+ break;
}
}
--
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