API cleanup, be less strict with file name arguments.

lib/zip_add_dir.c

diff --git a/lib/zip_add_dir.c b/lib/zip_add_dir.c
index 28a8ad1..84834b5 100644
--- a/lib/zip_add_dir.c
+++ b/lib/zip_add_dir.c
@@ -1,6 +1,6 @@
 /*
   zip_add_dir.c -- add directory
-  Copyright (C) 1999-2009 Dieter Baron and Thomas Klausner
+  Copyright (C) 1999-2012 Dieter Baron and Thomas Klausner
 
   This file is part of libzip, a library to manipulate ZIP archives.
   The authors can be contacted at <libzip@nih.at>
@@ -45,44 +45,5 @@
 ZIP_EXTERN zip_int64_t
 zip_add_dir(struct zip *za, const char *name)
 {
-    int len;
-    zip_int64_t ret;
-    char *s;
-    struct zip_source *source;
-
-    if (ZIP_IS_RDONLY(za)) {
-	_zip_error_set(&za->error, ZIP_ER_RDONLY, 0);
-	return -1;
-    }
-
-    if (name == NULL) {
-	_zip_error_set(&za->error, ZIP_ER_INVAL, 0);
-	return -1;
-    }
-
-    s = NULL;
-    len = strlen(name);
-
-    if (name[len-1] != '/') {
-	if ((s=(char *)malloc(len+2)) == NULL) {
-	    _zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
-	    return -1;
-	}
-	strcpy(s, name);
-	s[len] = '/';
-	s[len+1] = '\0';
-    }
-
-    if ((source=zip_source_buffer(za, NULL, 0, 0)) == NULL) {
-	free(s);
-	return -1;
-    }
-	
-    ret = _zip_replace(za, -1, s ? s : name, source);
-
-    free(s);
-    if (ret < 0)
-	zip_source_free(source);
-
-    return ret;
+    return zip_dir_add(za, name, 0);
 }