if.c
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/* GNU mailutils - a suite of utilities for electronic mail
Copyright (C) 1999, 2001 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 2, 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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "mail.h"
#define COND_STK_SIZE 64
#define COND_STK_INCR 16
static int *_cond_stack; /* Stack of conditions */
static int _cond_stack_size; /* Number of elements allocated this far */
static int _cond_level; /* Number of nested `if' blocks */
static void _cond_push(int val);
static int _cond_pop(void);
int
if_cond()
{
if (_cond_level == 0)
return 1;
return _cond_stack[_cond_level-1];
}
void
_cond_push(int val)
{
if (!_cond_stack)
{
_cond_stack = calloc(COND_STK_SIZE, sizeof(_cond_stack[0]));
_cond_stack_size = COND_STK_SIZE;
_cond_level = 0;
}
else if (_cond_level >= _cond_stack_size)
{
_cond_stack_size += COND_STK_INCR;
_cond_stack = realloc(_cond_stack,
sizeof(_cond_stack[0])*_cond_stack_size);
}
if (!_cond_stack)
{
util_error("not enough memory");
exit (EXIT_FAILURE);
}
_cond_stack[_cond_level++] = val;
}
int
_cond_pop()
{
if (_cond_level == 0)
{
util_error("internal error: condition stack underflow");
abort();
}
return _cond_stack[--_cond_level];
}
/*
* i[f] s|r|t
* mail-commands
* el[se]
* mail-commands
* en[dif]
*/
int
mail_if (int argc, char **argv)
{
char *mode;
int cond;
if (argc != 2)
{
util_error("if requires an argument: s | r | t");
return 1;
}
if (argv[1][1] != 0)
{
util_error("valid if arguments are: s | r | t");
return 1;
}
if (util_getenv (&mode, "mode", Mail_env_string, 1))
exit (EXIT_FAILURE);
if (if_cond() == 0)
/* Propagate negative condition */
cond = 0;
else
{
switch (argv[1][0])
{
case 's': /* Send mode */
cond = strcmp(mode, "send") == 0;
break;
case 'r': /* Read mode */
cond = strcmp(mode, "send") != 0;
break;
case 't': /* Reading from a terminal */
cond = interactive;
break;
default:
util_error("valid if arguments are: s | r | t");
return 1;
}
}
_cond_push(cond);
return 0;
}
int
mail_else (int argc, char **argv)
{
int cond;
(void)argc; (void)argv;
if (_cond_level == 0)
{
util_error("else without matching if");
return 1;
}
cond = _cond_pop();
if (_cond_level == 0)
cond = !cond;
_cond_push(cond);
return 0;
}
int
mail_endif (int argc, char **argv)
{
(void)argc; (void)argv;
if (_cond_level == 0)
{
util_error("endif without matching if");
return 1;
}
_cond_pop();
return 1;
}