NEWS.stable: log cherry-pick [e446f25]->[c092018] relocatable-shell: Update suggested...

[gnulib.git] / lib / xvasprintf.c

diff --git a/lib/xvasprintf.c b/lib/xvasprintf.c
index beea45a..7a4029e 100644 (file)
--- a/lib/xvasprintf.c
+++ b/lib/xvasprintf.c
@@ -1,41 +1,108 @@
 /* vasprintf and asprintf with out-of-memory checking.
-   Copyright (C) 1999, 2002-2004 Free Software Foundation, Inc.
+   Copyright (C) 1999, 2002-2004, 2006-2014 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify
+   This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
-   You should have received a copy of the GNU General Public License along
-   with this program; if not, write to the Free Software Foundation,
-   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-#ifdef HAVE_CONFIG_H
-# include <config.h>
-#endif
+#include <config.h>
 
 /* Specification.  */
 #include "xvasprintf.h"
 
 #include <errno.h>
+#include <limits.h>
+#include <string.h>
+#include <stdio.h>
 
-#include "vasprintf.h"
 #include "xalloc.h"
 
+/* Checked size_t computations.  */
+#include "xsize.h"
+
+static char *
+xstrcat (size_t argcount, va_list args)
+{
+  char *result;
+  va_list ap;
+  size_t totalsize;
+  size_t i;
+  char *p;
+
+  /* Determine the total size.  */
+  totalsize = 0;
+  va_copy (ap, args);
+  for (i = argcount; i > 0; i--)
+    {
+      const char *next = va_arg (ap, const char *);
+      totalsize = xsum (totalsize, strlen (next));
+    }
+  va_end (ap);
+
+  /* Test for overflow in the summing pass above or in (totalsize + 1) below.
+     Also, don't return a string longer than INT_MAX, for consistency with
+     vasprintf().  */
+  if (totalsize == SIZE_MAX || totalsize > INT_MAX)
+    {
+      errno = EOVERFLOW;
+      return NULL;
+    }
+
+  /* Allocate and fill the result string.  */
+  result = XNMALLOC (totalsize + 1, char);
+  p = result;
+  for (i = argcount; i > 0; i--)
+    {
+      const char *next = va_arg (args, const char *);
+      size_t len = strlen (next);
+      memcpy (p, next, len);
+      p += len;
+    }
+  *p = '\0';
+
+  return result;
+}
+
 char *
 xvasprintf (const char *format, va_list args)
 {
   char *result;
 
+  /* Recognize the special case format = "%s...%s".  It is a frequently used
+     idiom for string concatenation and needs to be fast.  We don't want to
+     have a separate function xstrcat() for this purpose.  */
+  {
+    size_t argcount = 0;
+    const char *f;
+
+    for (f = format;;)
+      {
+        if (*f == '\0')
+          /* Recognized the special case of string concatenation.  */
+          return xstrcat (argcount, args);
+        if (*f != '%')
+          break;
+        f++;
+        if (*f != 's')
+          break;
+        f++;
+        argcount++;
+      }
+  }
+
   if (vasprintf (&result, format, args) < 0)
     {
       if (errno == ENOMEM)
-       xalloc_die ();
+        xalloc_die ();
       return NULL;
     }