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Date: Mon, 15 May 2023 18:04:48 +0800
From: "847567161" <847567161@...com>
To: "musl" <musl@...ts.openwall.com>
Subject: Re: Re: Re: [Patch 1/1] vfprintf: optimize vfprintf performance 

Hi，

  I'm sorry for the incorrect format diff. I updated it.
  As we discussed earlier, I made a patch to get nl_arg when we see '$' ranther than visit the format anyway.
Could you please help me review it？

https://www.openwall.com/lists/musl/2023/05/06/1
https://www.openwall.com/lists/musl/2023/05/06/2
https://www.openwall.com/lists/musl/2023/05/06/3
https://www.openwall.com/lists/musl/2023/05/06/4
https://www.openwall.com/lists/musl/2023/05/06/5
https://www.openwall.com/lists/musl/2023/05/07/1
https://www.openwall.com/lists/musl/2023/05/07/2


---------------------------------
diff --git a/src/stdio/vfprintf.c b/src/stdio/vfprintf.c
old mode 100644
new mode 100755
index 9b961e7f..3294e23b
--- a/src/stdio/vfprintf.c
+++ b/src/stdio/vfprintf.c
@@ -427,7 +427,7 @@ static int getint(char **s) {
 	return i;
 }
 
-static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg, int *nl_type)
+static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg, int *nl_type, union arg* nl_arg_ptr)
 {
 	char *a, *z, *s=(char *)fmt;
 	unsigned l10n=0, fl;
@@ -462,6 +462,12 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
 		if (l) continue;
 
 		if (isdigit(s[1]) &amp;&amp; s[2]=='$') {
+			if (nl_arg_ptr == NULL) {
+				nl_arg_ptr = nl_arg;
+				if (printf_core(0, fmt, ap, nl_arg, nl_type, nl_arg_ptr) &lt; 0) {
+					return -1;
+				}
+			}
 			l10n=1;
 			argpos = s[1]-'0';
 			s+=3;
@@ -477,6 +483,12 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
 		/* Read field width */
 		if (*s=='*') {
 			if (isdigit(s[1]) &amp;&amp; s[2]=='$') {
+				if (nl_arg_ptr == NULL) {
+					nl_arg_ptr = nl_arg;
+					if (printf_core(0, fmt, ap, nl_arg, nl_type, nl_arg_ptr) &lt; 0) {
+						return -1;
+					}
+				}
 				l10n=1;
 				nl_type[s[1]-'0'] = INT;
 				w = nl_arg[s[1]-'0'].i;
@@ -491,6 +503,12 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
 		/* Read precision */
 		if (*s=='.' &amp;&amp; s[1]=='*') {
 			if (isdigit(s[2]) &amp;&amp; s[3]=='$') {
+				if (nl_arg_ptr == NULL) {
+					nl_arg_ptr = nl_arg;
+					if (printf_core(0, fmt, ap, nl_arg, nl_type, nl_arg_ptr) &lt; 0) {
+						return -1;
+					}
+				}
 				nl_type[s[2]-'0'] = INT;
 				p = nl_arg[s[2]-'0'].i;
 				s+=4;
@@ -659,16 +677,13 @@ int vfprintf(FILE *restrict f, const char *restrict fmt, va_list ap)
 	va_list ap2;
 	int nl_type[NL_ARGMAX+1] = {0};
 	union arg nl_arg[NL_ARGMAX+1];
+	union arg* nl_arg_ptr = NULL;
 	unsigned char internal_buf[80], *saved_buf = 0;
 	int olderr;
 	int ret;
 
 	/* the copy allows passing va_list* even if va_list is an array */
 	va_copy(ap2, ap);
-	if (printf_core(0, fmt, &amp;ap2, nl_arg, nl_type) &lt; 0) {
-		va_end(ap2);
-		return -1;
-	}
 
 	FLOCK(f);
 	olderr = f-&gt;flags &amp; F_ERR;
@@ -680,7 +695,7 @@ int vfprintf(FILE *restrict f, const char *restrict fmt, va_list ap)
 		f-&gt;wpos = f-&gt;wbase = f-&gt;wend = 0;
 	}
 	if (!f-&gt;wend &amp;&amp; __towrite(f)) ret = -1;
-	else ret = printf_core(f, fmt, &amp;ap2, nl_arg, nl_type);
+	else ret = printf_core(f, fmt, &amp;ap2, nl_arg, nl_type, nl_arg_ptr);
 	if (saved_buf) {
 		f-&gt;write(f, 0, 0);
 		if (!f-&gt;wpos) ret = -1;

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