mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-05-16 05:31:37 -04:00
Code Issues Packages Projects Releases Wiki Activity

tools/nolibc/printf: Prepend sign to converted number

Browse Source 
Instead of appending the converted number to the sign, convert first
and then prepend the sign (or "0x").
Use the length returned by u64toh_r() instead of calling strlen().

Needed so that zero padding can be inserted between the sign and digits
in an upcoming patch.

Signed-off-by: David Laight <david.laight.linux@gmail.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260308113742.12649-12-david.laight.linux@gmail.com
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
This commit is contained in:
David Laight
2026-03-08 11:37:36 +00:00
committed by Thomas Weißschuh
parent b43be42434
commit 8df70ee45b
1 changed files with 27 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
tools/include/nolibc/stdio.h
View File

@@ -345,9 +345,10 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
long long signed_v;
int written, width, len;
unsigned int flags, ch_flag;
char outbuf[21];
char outbuf[2 + 22 + 1];
char *out;
const char *outstr;
unsigned int sign_prefix;
written = 0;
while (1) {
@@ -445,32 +446,49 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
goto do_strlen_output;
}
out = outbuf;
/* The 'sign_prefix' can be zero, one or two ("0x") characters.
* Prepended least significant byte first stopping on a zero byte.
*/
sign_prefix = 0;
if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'd', 'i')) {
/* "%d" and "%i" - signed decimal numbers. */
if (signed_v < 0) {
*out++ = '-';
sign_prefix = '-';
v = -(signed_v + 1);
v++;
}
}
/* The value is converted offset into the buffer so that
* the sign/prefix can be added in front.
* The longest digit string is 22 + 1 for octal conversions, the
* space is reserved even though octal isn't currently supported.
*/
out = outbuf + 2;
/* Convert the number to ascii in the required base. */
if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'd', 'i', 'u')) {
/* Base 10 */
u64toa_r(v, out);
len = u64toa_r(v, out);
} else {
/* Base 16 */
if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'p')) {
*(out++) = '0';
*(out++) = 'x';
/* "%p" needs "0x" prepending. */
sign_prefix = '0' << 8 | 'x';
}
u64toh_r(v, out);
len = u64toh_r(v, out);
}
outstr = outbuf;
goto do_strlen_output;
/* Add the 0, 1 or 2 ("0x") sign/prefix characters at the front. */
for (; sign_prefix; sign_prefix >>= 8) {
/* Force gcc to increment len inside the loop. */
_NOLIBC_OPTIMIZER_HIDE_VAR(len);
len++;
*--out = sign_prefix;
}
outstr = out;
goto do_output;
}
if (ch == 'm') {