lib/argv-iter.c

   1 /* Iterate over arguments from argv or --files0-from=FILE
   2    Copyright (C) 2008-2024 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Jim Meyering.  */
  18
  19 #include <config.h>
  20 #include "argv-iter.h"
  21
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25 struct argv_iterator
  26 {
  27   /* Test FP to determine whether in read-mode or argv-mode. */
  28   /* file-mode: fp records position */
  29   FILE *fp;
  30   size_t item_idx;
  31   char *tok;
  32   size_t buf_len;
  33
  34   /* argv-mode: record just argv and current pointer */
  35   char **arg_list;
  36   char **p;
  37 };
  38
  39 struct argv_iterator *
  40 argv_iter_init_argv (char **argv)
  41 {
  42   struct argv_iterator *ai = malloc (sizeof *ai);
  43   if (!ai)
  44     return NULL;
  45   ai->fp = NULL;
  46   ai->arg_list = argv;
  47   ai->p = argv;
  48   return ai;
  49 }
  50
  51 /* Initialize to read from the stream, FP.
  52    The input is expected to contain a list of NUL-delimited tokens.  */
  53 struct argv_iterator *
  54 argv_iter_init_stream (FILE *fp)
  55 {
  56   struct argv_iterator *ai = malloc (sizeof *ai);
  57   if (!ai)
  58     return NULL;
  59   ai->fp = fp;
  60   ai->tok = NULL;
  61   ai->buf_len = 0;
  62
  63   ai->item_idx = 0;
  64   ai->arg_list = NULL;
  65   return ai;
  66 }
  67
  68 char *
  69 argv_iter (struct argv_iterator *ai, enum argv_iter_err *err)
  70 {
  71   if (ai->fp)
  72     {
  73       ssize_t len = getdelim (&ai->tok, &ai->buf_len, '\0', ai->fp);
  74       if (len < 0)
  75         {
  76           *err = feof (ai->fp) ? AI_ERR_EOF : AI_ERR_READ;
  77           return NULL;
  78         }
  79
  80       *err = AI_ERR_OK;
  81       ai->item_idx++;
  82       return ai->tok;
  83     }
  84   else
  85     {
  86       if (*(ai->p) == NULL)
  87         {
  88           *err = AI_ERR_EOF;
  89           return NULL;
  90         }
  91       else
  92         {
  93           *err = AI_ERR_OK;
  94           return *(ai->p++);
  95         }
  96     }
  97 }
  98
  99 size_t
 100 argv_iter_n_args (struct argv_iterator const *ai)
 101 {
 102   return ai->fp ? ai->item_idx : ai->p - ai->arg_list;
 103 }
 104
 105 void
 106 argv_iter_free (struct argv_iterator *ai)
 107 {
 108   if (ai->fp)
 109     free (ai->tok);
 110   free (ai);
 111 }