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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 v3 next 08/17] tools/nolibc/printf: Output pad characters in 16 byte chunks
Date: Mon, 23 Feb 2026 10:17:26 +0000	[thread overview]
Message-ID: <20260223101735.2922-9-david.laight.linux@gmail.com> (raw)
In-Reply-To: <20260223101735.2922-1-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>
---

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 5c8f233336b9..ea6c514c4b7a 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;
 
@@ -411,10 +411,14 @@ 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:[~2026-02-23 10:35 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-23 10:17 [PATCH v3 next 00/17] Enhance printf() david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 01/17] tools/nolibc: Add _NOLIBC_OPTIMIZER_HIDE_VAR() to compiler.h david.laight.linux
2026-02-25 21:25   ` Thomas Weißschuh
2026-02-25 22:17     ` David Laight
2026-02-25 22:24       ` Thomas Weißschuh
2026-02-23 10:17 ` [PATCH v3 next 02/17] tools/nolibc: Optimise and common up the number to ascii functions david.laight.linux
2026-02-25 21:40   ` Thomas Weißschuh
2026-02-25 22:09     ` David Laight
2026-02-23 10:17 ` [PATCH v3 next 03/17] selftests/nolibc: Fix build with host headers and libc david.laight.linux
2026-02-25 21:24   ` Thomas Weißschuh
2026-02-23 10:17 ` [PATCH v3 next 04/17] selftests/nolibc: Improve reporting of vfprintf() errors david.laight.linux
2026-02-25 21:56   ` Thomas Weißschuh
2026-02-26 10:12     ` David Laight
2026-02-26 21:39       ` Thomas Weißschuh
2026-02-23 10:17 ` [PATCH v3 next 05/17] tools/nolibc: Implement strerror() in terms of strerror_r() david.laight.linux
2026-02-25 22:09   ` Thomas Weißschuh
2026-02-25 22:58     ` David Laight
2026-02-23 10:17 ` [PATCH v3 next 06/17] tools/nolibc/printf: Change variables 'c' to 'ch' and 'tmpbuf[]' to 'outbuf[]' david.laight.linux
2026-02-25 22:23   ` Thomas Weißschuh
2026-02-23 10:17 ` [PATCH v3 next 07/17] tools/nolibc/printf: Move snprintf length check to callback david.laight.linux
2026-02-25 22:37   ` Thomas Weißschuh
2026-02-25 23:12     ` David Laight
2026-02-26 21:29       ` Thomas Weißschuh
2026-02-26 22:11         ` David Laight
2026-02-23 10:17 ` david.laight.linux [this message]
2026-02-23 10:17 ` [PATCH v3 next 09/17] tools/nolibc/printf: Simplify __nolibc_printf() david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 10/17] tools/nolibc/printf: Use goto and reduce indentation david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 11/17] tools/nolibc/printf: Use bit-masks to hold requested flag, length and conversion chars david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 12/17] tools/nolibc/printf: Handle "%s" with the numeric formats david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 13/17] tools/nolibc/printf: Add support for conversion flags david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 14/17] tools/nolibc/printf: Add support for left aligning fields david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 15/17] tools/nolibc/printf: Add support for zero padding and field precision david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 16/17] tools/nolibc/printf: Add support for octal output david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 17/17] selftests/nolibc: Use printf variable field widths and precisions david.laight.linux

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