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/*
* Copyright (C) 2004-2005 The Free Software Foundation, Inc.
*
* Portions Copyright (C) 2004-2005 Derek Price, Ximbiot <http://ximbiot.com>,
* and others.
*
* You may distribute under the terms of the GNU General Public License as
* specified in the README file that comes with the CVS source distribution.
*
* This module uses the hash.c module to implement a stack.
*/
#include "cvs.h"
#include <assert.h>
static void
do_push (List *stack, void *elem, int isstring)
{
Node *p = getnode();
if (isstring)
p->key = elem;
else
p->data = elem;
addnode(stack, p);
}
void
push (List *stack, void *elem)
{
do_push (stack, elem, 0);
}
void
push_string (List *stack, char *elem)
{
do_push (stack, elem, 1);
}
static void *
do_pop (List *stack, int isstring)
{
void *elem;
if (isempty (stack)) return NULL;
if (isstring)
{
elem = stack->list->prev->key;
stack->list->prev->key = NULL;
}
else
{
elem = stack->list->prev->data;
stack->list->prev->data = NULL;
}
delnode (stack->list->prev);
return elem;
}
void *
pop (List *stack)
{
return do_pop (stack, 0);
}
char *
pop_string (List *stack)
{
return do_pop (stack, 1);
}
static void
do_unshift (List *stack, void *elem, int isstring)
{
Node *p = getnode();
if (isstring)
p->key = elem;
else
p->data = elem;
addnode_at_front(stack, p);
}
void
unshift (List *stack, void *elem)
{
do_unshift (stack, elem, 0);
}
void
unshift_string (List *stack, char *elem)
{
do_unshift (stack, elem, 1);
}
static void *
do_shift (List *stack, int isstring)
{
void *elem;
if (isempty (stack)) return NULL;
if (isstring)
{
elem = stack->list->next->key;
stack->list->next->key = NULL;
}
else
{
elem = stack->list->next->data;
stack->list->next->data = NULL;
}
delnode (stack->list->next);
return elem;
}
void *
shift (List *stack)
{
return do_shift (stack, 0);
}
char *
shift_string (List *stack)
{
return do_shift (stack, 1);
}
int
isempty (List *stack)
{
if (stack->list == stack->list->next)
return 1;
return 0;
}
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