Add new function strconcat.

* include/util.h (GNUPG_GCC_A_SENTINEL): New.
* util/strgutil.c (do_strconcat, strconcat): New.

Signed-off-by: Werner Koch <wk@gnupg.org>

include/util.h

@@ -28,6 +28,14 @@
 #include "mpi.h"
 #include "compat.h"
 
+/* GCC attributes.  */
+#if __GNUC__ >= 4
+# define GNUPG_GCC_A_SENTINEL(a) __attribute__ ((sentinel(a)))
+#else
+# define GNUPG_GCC_A_SENTINEL(a)
+#endif
+
+
 typedef struct {
      int  *argc;	    /* pointer to argc (value subject to change) */
      char ***argv;	    /* pointer to argv (value subject to change) */
@@ -177,6 +185,8 @@ unsigned int check_trailing_chars( const byte *line, unsigned int len,
                                    const char *trimchars );
 unsigned int check_trailing_ws( const byte *line, unsigned int len );
 int string_count_chr( const char *string, int c );
+int has_invalid_email_chars (const char *s);
+int is_valid_mailbox (const char *name);
 int set_native_charset( const char *newset );
 const char* get_native_charset(void);
 char *native_to_utf8( const char *string );
@@ -238,7 +248,7 @@ int write_w32_registry_string(const char *root, const char *dir,
 char *xasprintf (const char *fmt, ...);
 char *xtryasprintf (const char *fmt, ...);
 char *xtryvasprintf (const char *fmt, va_list arg_ptr);
-
+char *strconcat (const char *s1, ...) GNUPG_GCC_A_SENTINEL(0);
 
 /*-- pka.c --*/
 char *get_pka_info (const char *address, unsigned char *fpr);

util/strgutil.c

@@ -1166,6 +1166,59 @@ xtryvasprintf (const char *fmt, va_list arg_ptr)
 }
 
 
+static char *
+do_strconcat (const char *s1, va_list arg_ptr)
+{
+  const char *argv[48];
+  size_t argc;
+  size_t needed;
+  char *buffer, *p;
+
+  argc = 0;
+  argv[argc++] = s1;
+  needed = strlen (s1);
+  while (((argv[argc] = va_arg (arg_ptr, const char *))))
+    {
+      needed += strlen (argv[argc]);
+      if (argc >= DIM (argv)-1)
+        {
+          errno = EINVAL;
+          return NULL;
+        }
+      argc++;
+    }
+  needed++;
+  buffer = xtrymalloc (needed);
+  if (buffer)
+    {
+      for (p = buffer, argc=0; argv[argc]; argc++)
+        p = stpcpy (p, argv[argc]);
+    }
+  return buffer;
+}
+
+
+/* Concatenate the string S1 with all the following strings up to a
+   NULL.  Returns a malloced buffer with the new string or NULL on a
+   malloc error or if too many arguments are given.  */
+char *
+strconcat (const char *s1, ...)
+{
+  va_list arg_ptr;
+  char *result;
+
+  if (!s1)
+    result = xtrystrdup ("");
+  else
+    {
+      va_start (arg_ptr, s1);
+      result = do_strconcat (s1, arg_ptr);
+      va_end (arg_ptr);
+    }
+  return result;
+}
+
+
 /****************************************************
  ******** locale insensitive ctype functions ********
  ****************************************************/