From 95ba4723023f4280a3bbff9a5119fcdebf447ce2 Mon Sep 17 00:00:00 2001
From: Jan Nieuwenhuizen <janneke@gnu.org>
Date: Fri, 8 Feb 2019 13:45:44 +0100
Subject: [PATCH] lib: vfprintf, vsnprintf: Support gcc-4.6.4: #-type.

* lib/stdio/vfprintf.c (vfprintf): Support #-type prefix.  Show whole
format upon error.
* lib/stdio/vsnprintf.c (vsnprintf): Likewise.
* lib/stdio/vfscanf.c (vfscanf): Show whole template upon error.
* lib/stdio/vsscanf.c (vsscanf): Likewise.
---
 lib/stdio/vfprintf.c  | 24 ++++++++++++++++++++++--
 lib/stdio/vfscanf.c   |  2 ++
 lib/stdio/vsnprintf.c | 24 ++++++++++++++++++++++--
 lib/stdio/vsscanf.c   |  2 ++
 4 files changed, 48 insertions(+), 4 deletions(-)

diff --git a/lib/stdio/vfprintf.c b/lib/stdio/vfprintf.c
index 0b2c30a0..7f2c55ee 100644
--- a/lib/stdio/vfprintf.c
+++ b/lib/stdio/vfprintf.c
@@ -41,6 +41,7 @@ vfprintf (FILE * f, char const *format, va_list ap)
         char c = *p;
         int left_p = 0;
         int precision = -1;
+        int prefix_p = 0;
         int width = -1;
         if (c == '-')
           {
@@ -51,12 +52,17 @@ vfprintf (FILE * f, char const *format, va_list ap)
         if (c == ' ')
           {
             pad = c;
-            c = *p++;
+            c = *++p;
+          }
+        if (c == '#')
+          {
+            prefix_p = 1;
+            c = *++p;
           }
         if (c == '0')
           {
             pad = c;
-            c = *p++;
+            c = *++p;
           }
         if (c >= '0' && c <= '9')
           {
@@ -134,6 +140,18 @@ vfprintf (FILE * f, char const *format, va_list ap)
                       count++;
                     }
                 }
+              if (prefix_p && *s && c == 'o')
+                {
+                  fputc ('0', f);
+                  width--;
+                }
+              if (prefix_p && *s && (c == 'x' || c == 'X'))
+                {
+                  fputc ('0', f);
+                  width--;
+                  fputc ('x', f);
+                  width--;
+                }
               while (*s)
                 {
                   if (precision-- <= 0)
@@ -241,6 +259,8 @@ vfprintf (FILE * f, char const *format, va_list ap)
             {
               eputs ("vfprintf: not supported: %:");
               eputc (c);
+              eputs (", in format: ");
+              eputs (format);
               eputs ("\n");
               p++;
             }
diff --git a/lib/stdio/vfscanf.c b/lib/stdio/vfscanf.c
index b1083a56..fe12649d 100644
--- a/lib/stdio/vfscanf.c
+++ b/lib/stdio/vfscanf.c
@@ -110,6 +110,8 @@ vfscanf (FILE * stream, char const *template, va_list ap)
             {
               eputs ("vsscanf: not supported: %:");
               eputc (c);
+              eputs (", in template: ");
+              eputs (template);
               eputs ("\n");
               t++;
               p = fgetc (stream);
diff --git a/lib/stdio/vsnprintf.c b/lib/stdio/vsnprintf.c
index 9a8d796d..c1b56840 100644
--- a/lib/stdio/vsnprintf.c
+++ b/lib/stdio/vsnprintf.c
@@ -43,6 +43,7 @@ vsnprintf (char *str, size_t size, char const *format, va_list ap)
         c = *p;
         int left_p = 0;
         int precision = -1;
+        int prefix_p = 0;
         int width = -1;
         if (c == '-')
           {
@@ -53,12 +54,17 @@ vsnprintf (char *str, size_t size, char const *format, va_list ap)
         if (c == ' ')
           {
             pad = c;
-            c = *p++;
+            c = *++p;
+          }
+        if (c == '#')
+          {
+            prefix_p = 1;
+            c = *++p;
           }
         if (c == '0')
           {
             pad = c;
-            c = *p++;
+            c = *++p;
           }
         if (c >= '0' && c <= '9')
           {
@@ -142,6 +148,18 @@ vsnprintf (char *str, size_t size, char const *format, va_list ap)
                       count++;
                     }
                 }
+              if (prefix_p && *s && c == 'o')
+                {
+                  *s++ = '0';
+                  width--;
+                }
+              if (prefix_p && *s && (c == 'x' || c == 'X'))
+                {
+                  *s++ = '0';
+                  width--;
+                  *s++ = 'x';
+                  width--;
+                }
               while (*s)
                 {
                   if (precision-- <= 0)
@@ -262,6 +280,8 @@ vsnprintf (char *str, size_t size, char const *format, va_list ap)
             {
               eputs ("vsnprintf: not supported: %:");
               eputc (c);
+              eputs (", in format: ");
+              eputs (format);
               eputs ("\n");
               p++;
             }
diff --git a/lib/stdio/vsscanf.c b/lib/stdio/vsscanf.c
index 4573bc01..a42b0dba 100644
--- a/lib/stdio/vsscanf.c
+++ b/lib/stdio/vsscanf.c
@@ -81,6 +81,8 @@ vsscanf (char const *s, char const *template, va_list ap)
             {
               eputs ("vsscanf: not supported: %:");
               eputc (c);
+              eputs (", in template: ");
+              eputs (template);
               eputs ("\n");
               t++;
               p++;