+ return hash_string_lookup (avoided_name_table, name);
+}
+\f
+/* Return a safer suffix of FILE_NAME, or "." if it has no safer
+ suffix. Check for fully specified file names and other atrocities.
+ Warn the user if we do not return NAME. If LINK_TARGET is 1,
+ FILE_NAME is the target of a hard link, not a member name. */
+
+char *
+safer_name_suffix (char const *file_name, bool link_target)
+{
+ char const *p;
+
+ if (absolute_names_option)
+ p = file_name;
+ else
+ {
+ /* Skip file system prefixes, leading pathnames that contain
+ "..", and leading slashes. */
+
+ size_t prefix_len = FILESYSTEM_PREFIX_LEN (file_name);
+
+ for (p = file_name + prefix_len; *p; )
+ {
+ if (p[0] == '.' && p[1] == '.' && (ISSLASH (p[2]) || !p[2]))
+ prefix_len = p + 2 - file_name;
+
+ do
+ {
+ char c = *p++;
+ if (ISSLASH (c))
+ break;
+ }
+ while (*p);
+ }
+
+ for (p = file_name + prefix_len; ISSLASH (*p); p++)
+ continue;
+ prefix_len = p - file_name;
+
+ if (prefix_len)
+ {
+ static Hash_table *prefix_table[2];
+ char *prefix = alloca (prefix_len + 1);
+ memcpy (prefix, file_name, prefix_len);
+ prefix[prefix_len] = '\0';
+
+ if (hash_string_insert (&prefix_table[link_target], prefix))
+ {
+ static char const *const diagnostic[] =
+ {
+ N_("Removing leading `%s' from member names"),
+ N_("Removing leading `%s' from hard link targets")
+ };
+ WARN ((0, 0, _(diagnostic[link_target]), prefix));
+ }
+ }
+ }
+
+ if (! *p)
+ {
+ if (p == file_name)
+ {
+ static char const *const diagnostic[] =
+ {
+ N_("Substituting `.' for empty member name"),
+ N_("Substituting `.' for empty hard link target")
+ };
+ WARN ((0, 0, _(diagnostic[link_target])));
+ }
+
+ p = ".";
+ }
+
+ return (char *) p;
+}
+\f
+/* Return the size of the prefix of FILE_NAME that is removed after
+ stripping NUM leading path name components. NUM must be
+ positive. */
+
+size_t
+stripped_prefix_len (char const *file_name, size_t num)
+{
+ char const *p = file_name + FILESYSTEM_PREFIX_LEN (file_name);
+ while (ISSLASH (*p))
+ p++;
+ while (*p)
+ {
+ bool slash = ISSLASH (*p);
+ p++;
+ if (slash)
+ {
+ if (--num == 0)
+ return p - file_name;
+ while (ISSLASH (*p))
+ p++;
+ }
+ }
+ return -1;
+}
+\f
+/* Return nonzero if NAME contains ".." as a path name component. */
+bool
+contains_dot_dot (char const *name)
+{
+ char const *p = name + FILESYSTEM_PREFIX_LEN (name);
+
+ for (;; p++)
+ {
+ if (p[0] == '.' && p[1] == '.' && (ISSLASH (p[2]) || !p[2]))
+ return 1;
+
+ do
+ {
+ if (! *p++)
+ return 0;
+ }
+ while (! ISSLASH (*p));
+ }