1  /*
       2   * ordchr.c - Builtin functions that provide ord() and chr() functions.
       3   *
       4   * Arnold Robbins
       5   * arnold@skeeve.com
       6   * 8/2001
       7   * Revised 6/2004
       8   * Revised 5/2012
       9   */
      10  
      11  /*
      12   * Copyright (C) 2001, 2004, 2011, 2012, 2013, 2018, 2020, 2021,
      13   * the Free Software Foundation, Inc.
      14   *
      15   * This file is part of GAWK, the GNU implementation of the
      16   * AWK Programming Language.
      17   *
      18   * GAWK is free software; you can redistribute it and/or modify
      19   * it under the terms of the GNU General Public License as published by
      20   * the Free Software Foundation; either version 3 of the License, or
      21   * (at your option) any later version.
      22   *
      23   * GAWK is distributed in the hope that it will be useful,
      24   * but WITHOUT ANY WARRANTY; without even the implied warranty of
      25   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      26   * GNU General Public License for more details.
      27   *
      28   * You should have received a copy of the GNU General Public License
      29   * along with this program; if not, write to the Free Software
      30   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
      31   */
      32  
      33  #ifdef HAVE_CONFIG_H
      34  #include <config.h>
      35  #endif
      36  
      37  #include <stdio.h>
      38  #include <assert.h>
      39  #include <stdlib.h>
      40  #include <string.h>
      41  #include <unistd.h>
      42  
      43  #include <sys/types.h>
      44  #include <sys/stat.h>
      45  
      46  #include "gawkapi.h"
      47  
      48  #include "gettext.h"
      49  #define _(msgid)  gettext(msgid)
      50  #define N_(msgid) msgid
      51  
      52  static const gawk_api_t *api;	/* for convenience macros to work */
      53  static awk_ext_id_t ext_id;
      54  static const char *ext_version = "ordchr extension: version 1.0";
      55  static awk_bool_t (*init_func)(void) = NULL;
      56  
      57  int plugin_is_GPL_compatible;
      58  
      59  /*  do_ord --- return numeric value of first char of string */
      60  
      61  static awk_value_t *
      62  do_ord(int nargs, awk_value_t *result, struct awk_ext_func *unused)
      63  {
      64  	awk_value_t str;
      65  	double ret = -1;
      66  
      67  	assert(result != NULL);
      68  
      69  	if (get_argument(0, AWK_STRING, & str)) {
      70  		ret = (unsigned char) str.str_value.str[0];
      71  	} else if (do_lint)
      72  		lintwarn(ext_id, _("ord: first argument is not a string"));
      73  
      74  	/* Set the return value */
      75  	return make_number(ret, result);
      76  }
      77  
      78  /*  do_chr --- turn numeric value into a string */
      79  
      80  static awk_value_t *
      81  do_chr(int nargs, awk_value_t *result, struct awk_ext_func *unused)
      82  {
      83  	awk_value_t num;
      84  	unsigned int ret = 0;
      85  	double val = 0.0;
      86  	char str[2];
      87  
      88  	str[0] = str[1] = '\0';
      89  
      90  	assert(result != NULL);
      91  
      92  	if (get_argument(0, AWK_NUMBER, & num)) {
      93  		val = num.num_value;
      94  		ret = val;	/* convert to int */
      95  		ret &= 0xff;
      96  		str[0] = ret;
      97  		str[1] = '\0';
      98  	} else if (do_lint)
      99  		lintwarn(ext_id, _("chr: first argument is not a number"));
     100  
     101  	/* Set the return value */
     102  	return make_const_string(str, 1, result);
     103  }
     104  
     105  static awk_ext_func_t func_table[] = {
     106  	{ "ord", do_ord, 1, 1, awk_false, NULL },
     107  	{ "chr", do_chr, 1, 1, awk_false, NULL },
     108  };
     109  
     110  /* define the dl_load function using the boilerplate macro */
     111  
     112  dl_load_func(func_table, ord_chr, "")