1 files changed, 111 insertions, 0 deletions
diff --git a/lib/argv-iter.c b/lib/argv-iter.c
new file mode 100644
index 0000000..dc63d73
--- /dev/null
+++ b/lib/argv-iter.c
@@ -0,0 +1,111 @@
+/* Iterate over arguments from argv or --files0-from=FILE
+   Copyright (C) 2008-2023 Free Software Foundation, Inc.
+
+   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 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, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Jim Meyering.  */
+
+#include <config.h>
+#include "argv-iter.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+struct argv_iterator
+{
+  /* Test FP to determine whether in read-mode or argv-mode. */
+  /* file-mode: fp records position */
+  FILE *fp;
+  size_t item_idx;
+  char *tok;
+  size_t buf_len;
+
+  /* argv-mode: record just argv and current pointer */
+  char **arg_list;
+  char **p;
+};
+
+struct argv_iterator *
+argv_iter_init_argv (char **argv)
+{
+  struct argv_iterator *ai = malloc (sizeof *ai);
+  if (!ai)
+    return NULL;
+  ai->fp = NULL;
+  ai->arg_list = argv;
+  ai->p = argv;
+  return ai;
+}
+
+/* Initialize to read from the stream, FP.
+   The input is expected to contain a list of NUL-delimited tokens.  */
+struct argv_iterator *
+argv_iter_init_stream (FILE *fp)
+{
+  struct argv_iterator *ai = malloc (sizeof *ai);
+  if (!ai)
+    return NULL;
+  ai->fp = fp;
+  ai->tok = NULL;
+  ai->buf_len = 0;
+
+  ai->item_idx = 0;
+  ai->arg_list = NULL;
+  return ai;
+}
+
+char *
+argv_iter (struct argv_iterator *ai, enum argv_iter_err *err)
+{
+  if (ai->fp)
+    {
+      ssize_t len = getdelim (&ai->tok, &ai->buf_len, '\0', ai->fp);
+      if (len < 0)
+        {
+          *err = feof (ai->fp) ? AI_ERR_EOF : AI_ERR_READ;
+          return NULL;
+        }
+
+      *err = AI_ERR_OK;
+      ai->item_idx++;
+      return ai->tok;
+    }
+  else
+    {
+      if (*(ai->p) == NULL)
+        {
+          *err = AI_ERR_EOF;
+          return NULL;
+        }
+      else
+        {
+          *err = AI_ERR_OK;
+          return *(ai->p++);
+        }
+    }
+}
+
+size_t
+argv_iter_n_args (struct argv_iterator const *ai)
+{
+  return ai->fp ? ai->item_idx : ai->p - ai->arg_list;
+}
+
+void
+argv_iter_free (struct argv_iterator *ai)
+{
+  if (ai->fp)
+    free (ai->tok);
+  free (ai);
+}