On Mon, Mar 02, 2026 at 10:18:05AM +0000, david.laight.linux@gmail.com wrote:
> From: David Laight <david.laight.linux@gmail.com>
>
> Upcoming changes will need to use goto to jump to the code that
> outputs characters.
> Use 'goto do_output' to output a known number of characters.
> Use 'goto do_strlen_output' to output a '\0' terminated string.
>
> Removes a level of indentation from the format processing code.
Nice! I, too, prefer this more explicit way of transitionning between
states. For others, the patch is best reviewed with "git show -b" or
"git diff -b" after applying it (67 lines instead of 200).
David, when changing code indent like this, I often like to suggest
doing this in the commit messages. I'm saying this in case there's
a further respin.
> Signed-off-by: David Laight <david.laight.linux@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Willy
> ---
>
> For v4:
> - Output a single '%' from the format string.
>
> New patch for v3.
> Makes the final code look better and there is less to change if done early.
>
> tools/include/nolibc/stdio.h | 170 +++++++++++++++++++----------------
> 1 file changed, 92 insertions(+), 78 deletions(-)
>
> diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
> index e0b7ff537b14..13fe6c4d7f58 100644
> --- a/tools/include/nolibc/stdio.h
> +++ b/tools/include/nolibc/stdio.h
> @@ -329,103 +329,117 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
> fmt++;
> /* Output characters from the format string. */
> len = fmt - outstr;
> - } else {
> - /* we're in a format sequence */
> + goto do_output;
> + }
>
> - ch = *fmt++;
> + /* we're in a format sequence */
>
> - /* width */
> - while (ch >= '0' && ch <= '9') {
> - width *= 10;
> - width += ch - '0';
> + ch = *fmt++;
>
> - ch = *fmt++;
> - }
> + /* width */
> + while (ch >= '0' && ch <= '9') {
> + width *= 10;
> + width += ch - '0';
> +
> + ch = *fmt++;
> + }
>
> - /* Length modifiers */
> + /* Length modifiers */
> + if (ch == 'l') {
> + lpref = 1;
> + ch = *fmt++;
> if (ch == 'l') {
> - lpref = 1;
> - ch = *fmt++;
> - if (ch == 'l') {
> - lpref = 2;
> - ch = *fmt++;
> - }
> - } else if (ch == 'j') {
> - /* intmax_t is long long */
> lpref = 2;
> ch = *fmt++;
> - } else {
> - lpref = 0;
> }
> + } else if (ch == 'j') {
> + /* intmax_t is long long */
> + lpref = 2;
> + ch = *fmt++;
> + } else {
> + lpref = 0;
> + }
>
> - if (ch == 'c' || ch == 'd' || ch == 'u' || ch == 'x' || ch == 'p') {
> - char *out = outbuf;
> + if (ch == 'c' || ch == 'd' || ch == 'u' || ch == 'x' || ch == 'p') {
> + char *out = outbuf;
>
> - if (ch == 'p')
> + if (ch == 'p')
> + v = va_arg(args, unsigned long);
> + else if (lpref) {
> + if (lpref > 1)
> + v = va_arg(args, unsigned long long);
> + else
> v = va_arg(args, unsigned long);
> - else if (lpref) {
> - if (lpref > 1)
> - v = va_arg(args, unsigned long long);
> - else
> - v = va_arg(args, unsigned long);
> - } else
> - v = va_arg(args, unsigned int);
> -
> - if (ch == 'd') {
> - /* sign-extend the value */
> - if (lpref == 0)
> - v = (long long)(int)v;
> - else if (lpref == 1)
> - v = (long long)(long)v;
> - }
> + } else
> + v = va_arg(args, unsigned int);
>
> - switch (ch) {
> - case 'c':
> - out[0] = v;
> - out[1] = 0;
> - break;
> - case 'd':
> - i64toa_r(v, out);
> - break;
> - case 'u':
> - u64toa_r(v, out);
> - break;
> - case 'p':
> - *(out++) = '0';
> - *(out++) = 'x';
> - __nolibc_fallthrough;
> - default: /* 'x' and 'p' above */
> - u64toh_r(v, out);
> - break;
> - }
> - outstr = outbuf;
> + if (ch == 'd') {
> + /* sign-extend the value */
> + if (lpref == 0)
> + v = (long long)(int)v;
> + else if (lpref == 1)
> + v = (long long)(long)v;
> }
> - else if (ch == 's') {
> - outstr = va_arg(args, char *);
> - if (!outstr)
> - outstr="(null)";
> +
> + switch (ch) {
> + case 'c':
> + out[0] = v;
> + out[1] = 0;
> + break;
> + case 'd':
> + i64toa_r(v, out);
> + break;
> + case 'u':
> + u64toa_r(v, out);
> + break;
> + case 'p':
> + *(out++) = '0';
> + *(out++) = 'x';
> + __nolibc_fallthrough;
> + default: /* 'x' and 'p' above */
> + u64toh_r(v, out);
> + break;
> }
> - else if (ch == 'm') {
> + outstr = outbuf;
> + goto do_strlen_output;
> + }
> +
> + if (ch == 's') {
> + outstr = va_arg(args, char *);
> + if (!outstr)
> + outstr="(null)";
> + goto do_strlen_output;
> + }
> +
> + if (ch == 'm') {
> #ifdef NOLIBC_IGNORE_ERRNO
> - outstr = "unknown error";
> + outstr = "unknown error";
> #else
> - outstr = strerror(errno);
> + outstr = strerror(errno);
> #endif /* NOLIBC_IGNORE_ERRNO */
> - } else {
> - if (ch != '%') {
> - /* Invalid format: back up to output the format characters */
> - fmt = outstr + 1;
> - /* and output a '%' now. */
> - }
> - /* %% is documented as a 'conversion specifier'.
> - * Any flags, precision or length modifier are ignored.
> - */
> - width = 0;
> - outstr = "%";
> - }
> - len = strlen(outstr);
> + goto do_strlen_output;
> }
>
> + if (ch != '%') {
> + /* Invalid format: back up to output the format characters */
> + fmt = outstr + 1;
> + /* and output a '%' now. */
> + }
> + /* %% is documented as a 'conversion specifier'.
> + * Any flags, precision or length modifier are ignored.
> + */
> + len = 1;
> + width = 0;
> + outstr = fmt - 1;
> + goto do_output;
> +
> +do_strlen_output:
> + /* Open coded strlen() (slightly smaller). */
> + for (len = 0;; len++)
> + if (!outstr[len])
> + break;
> +
> +do_output:
> written += len;
>
> width -= len;
> --
> 2.39.5