From 6c7c19e4378b9b9640dc0b250d09264f5cd99572 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Thu, 15 Sep 2022 22:43:39 +0200
Subject: shared/printf: string precision
---
src/shared/printf.c | 8 +++++++-
src/user/app/tests/shared/printf.c | 3 +++
2 files changed, 10 insertions(+), 1 deletion(-)
(limited to 'src')
diff --git a/src/shared/printf.c b/src/shared/printf.c
index 9ab4606..a9cd355 100644
--- a/src/shared/printf.c
+++ b/src/shared/printf.c
@@ -131,7 +131,11 @@ int __printf_internal(const char *fmt, va_list argp,
if (c == '.') {
c = *fmt++;
- while ('0' <= c && c <= '9') {
+ if (c == '*') {
+ // TODO handle negative precision
+ m.precision = va_arg(argp, int);
+ c = *fmt++;
+ } else while ('0' <= c && c <= '9') {
m.precision *= 10;
m.precision += c - '0';
c = *fmt++;
@@ -166,6 +170,8 @@ int __printf_internal(const char *fmt, va_list argp,
const char *s = va_arg(argp, char*);
if (s == NULL) s = "(null)";
len = strlen(s);
+ if (len > m.precision && m.precision != 0)
+ len = m.precision;
pad(&os, &m, len);
output(&os, s, len);
break;
diff --git a/src/user/app/tests/shared/printf.c b/src/user/app/tests/shared/printf.c
index 37b9679..71122f5 100644
--- a/src/user/app/tests/shared/printf.c
+++ b/src/user/app/tests/shared/printf.c
@@ -43,6 +43,9 @@ static void test_printf(void) {
test(!strcmp(buf, " -001"));
snprintf(buf, sizeof buf, "%.5d", 123);
test(!strcmp(buf, "00123"));
+
+ snprintf(buf, sizeof buf, "%.1s,%.10s,%.*s", "hello", "hello", 3, "hello");
+ test(!strcmp(buf, "h,hello,hel"));
}
void r_s_printf(void) {
--
cgit v1.2.3