[musl] [PATCH] printf core: fix gratuitous integer formatting buffer size

[musl] [PATCH] printf core: fix gratuitous integer formatting buffer size

[Rich Felker]

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Heads up: if there are no objections, I'm planning to commit this so
that the C23 patches don't have to deal with it.

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From 40834f6c1e30cc25c608678c372db498a3d9dbc3 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Mon, 12 Jun 2023 20:04:22 -0400
Subject: [PATCH] printf core: fix gratuitous integer formatting buffer size

the extra terms 3 and LDBL_MANT_DIG/4 are remnants of a proto-musl
implementation of printf where the sign/prefix and floating point
conversions were performed naively into this buffer. having them there
obscures the actual intended buffer size (sufficient to hold between 2
and 3 octal digits per byte, rounded up to 3 for simplicity) and
interferes with upcoming work to add C2x binary formats which would
otherwise be stuck having to explain a similar fix to buffer size as
part of an unrelated change.
---
 src/stdio/vfprintf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/stdio/vfprintf.c b/src/stdio/vfprintf.c
index c551ccf0..33019ff1 100644
--- a/src/stdio/vfprintf.c
+++ b/src/stdio/vfprintf.c
@@ -437,7 +437,7 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
 	unsigned st, ps;
 	int cnt=0, l=0;
 	size_t i;
-	char buf[sizeof(uintmax_t)*3+3+LDBL_MANT_DIG/4];
+	char buf[sizeof(uintmax_t)*3];
 	const char *prefix;
 	int t, pl;
 	wchar_t wc[2], *ws;
-- 
2.21.0