snprintf() allows limiting the output buffer, while still returning the number of all bytes that would have been written. Implement the limitation logic in preparation for snprintf().
Signed-off-by: Thomas Weißschuh thomas.weissschuh@linutronix.de --- tools/include/nolibc/stdio.h | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h index 434fbaddae7a216159fecf618da85889d631dff7..b484a19466394d55d7d21248031837238b58f3ff 100644 --- a/tools/include/nolibc/stdio.h +++ b/tools/include/nolibc/stdio.h @@ -215,13 +215,13 @@ char *fgets(char *s, int size, FILE *stream) */ typedef int (*_printf_cb)(intptr_t state, const char *buf, size_t size);
-static __attribute__((unused, format(printf, 3, 0))) -int _printf(_printf_cb cb, intptr_t state, const char *fmt, va_list args) +static __attribute__((unused, format(printf, 4, 0))) +int _printf(_printf_cb cb, intptr_t state, size_t n, const char *fmt, va_list args) { char escape, lpref, c; unsigned long long v; unsigned int written; - size_t len, ofs; + size_t len, ofs, w; char tmpbuf[21]; const char *outstr;
@@ -306,8 +306,12 @@ int _printf(_printf_cb cb, intptr_t state, const char *fmt, va_list args) outstr = fmt; len = ofs - 1; flush_str: - if (cb(state, outstr, len) != 0) - break; + if (n) { + w = len < n ? len : n; + n -= w; + if (cb(state, outstr, w) != 0) + break; + }
written += len; do_escape: @@ -331,7 +335,7 @@ static int _fprintf_cb(intptr_t state, const char *buf, size_t size) static __attribute__((unused, format(printf, 2, 0))) int vfprintf(FILE *stream, const char *fmt, va_list args) { - return _printf(_fprintf_cb, (intptr_t)stream, fmt, args); + return _printf(_fprintf_cb, (intptr_t)stream, SIZE_MAX, fmt, args); }
static __attribute__((unused, format(printf, 1, 0)))