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From: david.laight.linux@gmail.com
To: "Willy Tarreau" <w@1wt.eu>,
	"Thomas Weißschuh" <linux@weissschuh.net>,
	linux-kernel@vger.kernel.org, "Cheng Li" <lechain@gmail.com>
Cc: David Laight <david.laight.linux@gmail.com>
Subject: [PATCH v5 next 05/17] tools/nolibc/printf: Output pad characters in 16 byte chunks
Date: Sun,  8 Mar 2026 11:37:30 +0000	[thread overview]
Message-ID: <20260308113742.12649-6-david.laight.linux@gmail.com> (raw)
In-Reply-To: <20260308113742.12649-1-david.laight.linux@gmail.com>

From: David Laight <david.laight.linux@gmail.com>

Simple to do and saves calls to the callback function.

Change variables written, width and len to 'signed int' to get
better code.

Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: David Laight <david.laight.linux@gmail.com>
---

Unchanged for v4 and v5.

For v3:
- Change to signed variables here rather than a later patch.

 tools/include/nolibc/stdio.h | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
index 17ca206f77fe..c6d5d075f012 100644
--- a/tools/include/nolibc/stdio.h
+++ b/tools/include/nolibc/stdio.h
@@ -312,8 +312,8 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
 {
 	char escape, lpref, ch;
 	unsigned long long v;
-	unsigned int written, width;
-	size_t len, ofs;
+	int written, width, len;
+	size_t ofs;
 	char outbuf[21];
 	const char *outstr;
 
@@ -415,10 +415,14 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
 			outstr = fmt;
 			len = ofs - 1;
 		flush_str:
-			while (width-- > len) {
-				if (cb(state, " ", 1) != 0)
+			width -= len;
+			while (width > 0) {
+				/* Output pad in 16 byte blocks with the small block first. */
+				int pad_len = ((width - 1) & 15) + 1;
+				width -= pad_len;
+				written += pad_len;
+				if (cb(state, "                ", pad_len) != 0)
 					return -1;
-				written += 1;
 			}
 			if (cb(state, outstr, len) != 0)
 				return -1;
-- 
2.39.5


  parent reply	other threads:[~2026-03-08 11:37 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-08 11:37 [PATCH v5 next 00/17] Enhance printf() david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 01/17] tools/nolibc: Add _NOLIBC_OPTIMIZER_HIDE_VAR() to compiler.h david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 02/17] selftests/nolibc: Rename w to written in expect_vfprintf() david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 03/17] tools/nolibc: Implement strerror() in terms of strerror_r() david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 04/17] tools/nolibc: Rename the 'errnum' parameter to strerror() david.laight.linux
2026-03-08 11:37 ` david.laight.linux [this message]
2026-03-08 11:37 ` [PATCH v5 next 06/17] tools/nolibc/printf: Simplify __nolibc_printf() david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 07/17] tools/nolibc/printf: Use goto and reduce indentation david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 08/17] tools/nolibc/printf: Use bit-masks to hold requested flag, length and conversion chars david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 09/17] tools/nolibc/printf: Add support for length modifiers tzqL and formats iX david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 10/17] tools/nolibc/printf: Handle "%s" with the numeric formats david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 11/17] tools/nolibc/printf: Prepend sign to converted number david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 12/17] tools/nolibc/printf: Add support for conversion flags space and plus david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 13/17] tools/nolibc/printf: Special case 0 and add support for %#x david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 14/17] tools/nolibc/printf: Add support for left aligning fields david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 15/17] tools/nolibc/printf: Add support for zero padding and field precision david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 16/17] tools/nolibc/printf: Add support for octal output david.laight.linux
2026-03-08 11:37 ` [PATCH v5 next 17/17] selftests/nolibc: Use printf variable field widths and precisions david.laight.linux
2026-03-08 11:58 ` [PATCH v5 next 00/17] Enhance printf() Willy Tarreau
2026-03-08 21:01 ` Thomas Weißschuh
2026-03-08 22:41   ` David Laight
2026-03-09  6:55     ` Willy Tarreau
2026-03-09  9:20       ` David Laight
2026-03-13 20:07     ` Thomas Weißschuh
2026-03-13 22:40       ` David Laight
2026-03-14  4:48         ` Willy Tarreau

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