#!/bin/sh
# This is a shar archive.
# The rest of this file is a shell script which will extract:
#
# 7_8a.h 7_8a1.h 7_8a2.h 7_8a3.h 7_8a4.h 7_8a5.h 7_8decl.h 7_8x1.c 7_8x2.c 7_8x3.c 7_8x4.c makefile tst.c tst.cmp
#
# To extract the files from this shell archive file simply
# create a directory for this file, move the archive file
# to it and enter the command
#
#	sh filename
# 
# The files will be extracted automatically.
# Note: Do not use csh.
#
# Archive created: Mon Jul 30 23:11:06 EDT 1990
#
echo x - 7_8a.h
sed 's/^X//' > 7_8a.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#define gdlink(TYPE)
#define gdlist(TYPE)
#define gdlinkdeclare(TYPE)
#define gdlistdeclare(TYPE)
#define gdlinkimplement(TYPE)
#define gdlistimplement(TYPE)
!EOF!
ls -l 7_8a.h
echo x - 7_8a1.h
sed 's/^X//' > 7_8a1.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#define gdlink(TYPE) name2(gdlink,TYPE)
#define gdlist(TYPE) name2(gdlist,TYPE)
!EOF!
ls -l 7_8a1.h
echo x - 7_8a2.h
sed 's/^X//' > 7_8a2.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#define gdlinkdeclare(TYPE)			\
	class gdlink(TYPE)			\
	{					\
	    friend class gdlist(TYPE);		\
	    gdlink(TYPE) *next;			\
	    gdlink(TYPE) *prev;			\
	    TYPE e;				\
						\
	    gdlink(TYPE)(TYPE a,		\
		gdlink(TYPE) *n = 0,		\
		gdlink(TYPE) *p = 0)		\
	    { e = a; next = n; prev = p; }	\
						\
	    void insert(gdlink(TYPE) *n);	\
	    void append(gdlink(TYPE) *n);	\
	    void remove();			\
	};
!EOF!
ls -l 7_8a2.h
echo x - 7_8a3.h
sed 's/^X//' > 7_8a3.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#define gdlistdeclare(TYPE)			\
    /* manage a doubly-linked list */		\
    class gdlist(TYPE)				\
    {						\
	gdlink(TYPE) *last;			\
	gdlink(TYPE) *curr;			\
						\
    public:					\
	gdlist(TYPE)() { last = curr = 0; };	\
						\
	gdlist(TYPE)(TYPE a)			\
	{ curr = 0; last = new gdlink(TYPE)(a);	\
	  last->next = last->prev = last;	\
	}					\
						\
	int isempty() { return last != 0; }	\
						\
	void clear();				\
						\
	~gdlist(TYPE)() { clear(); };		\
						\
	/* set current pointer to the */	\
	/* ends of the list */			\
	void reset() { curr = 0; }		\
						\
	/* move around the list, */		\
	/* leaving the links there */		\
	int next(TYPE &e);			\
	int prev(TYPE &e);			\
						\
	/* move around the list, */		\
	/* removing the links */		\
	int getnext(TYPE &e);			\
	int getprev(TYPE &e);			\
						\
	/* manipulate around the beginning */	\
	/* and end of the list */		\
	void insert(TYPE e);			\
	void append(TYPE e);			\
						\
	/* work around the current entry */	\
	void inserthere(TYPE e);		\
	void appendhere(TYPE e);		\
    };
!EOF!
ls -l 7_8a3.h
echo x - 7_8a4.h
sed 's/^X//' > 7_8a4.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#define gdlinkimplement(TYPE)			\
    /* insert a gdlink(TYPE) in */		\
    /* front of this one */			\
    void gdlink(TYPE)::				\
	insert(gdlink(TYPE) *newlink)		\
    {						\
	if (prev)				\
	    prev->next = newlink;		\
						\
	newlink->next = this;			\
	newlink->prev = prev;			\
	prev = newlink;				\
    }						\
						\
    /* append a gdlink(TYPE) after this one */	\
    void gdlink(TYPE)::				\
	append(gdlink(TYPE) *newlink)		\
    {						\
	if (next)				\
	    next->prev = newlink;		\
						\
	newlink->next = next;			\
	newlink->prev = this;			\
	next = newlink;				\
    }						\
						\
    /* remove this link from the list */	\
    void gdlink(TYPE)::remove()			\
    {						\
	if (prev)				\
	    prev->next = next;			\
						\
	if (next)				\
	    next->prev = prev;			\
						\
	next = prev = 0;			\
    }
!EOF!
ls -l 7_8a4.h
echo x - 7_8a5.h
sed 's/^X//' > 7_8a5.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#define gdlistimplement(TYPE)			\
    /* clear the list */			\
    void gdlist(TYPE)::clear()			\
    {						\
	gdlink(TYPE) *l = last;			\
	if (!l) return;				\
						\
	do  {					\
	    gdlink(TYPE) *ll = l;		\
	    l = l->next;			\
	    delete ll;				\
	} while (l != last);			\
						\
	last = 0;				\
    }						\
						\
    /* Get the next entry from a list, */	\
    /* moving curr forward. */			\
    int gdlist(TYPE)::next(TYPE &a)		\
    {						\
	if (!last)				\
	    return 0;				\
						\
	/* move curr forward, possibly to */	\
	/* the beginning or end of the list. */	\
	if (curr)				\
	    if (curr == last)			\
		{				\
		curr = 0;			\
		return 0;			\
		}				\
						\
	    else				\
		curr = curr->next;		\
						\
	else					\
	    curr = last->next;			\
						\
	a = curr->e;				\
	return 1;				\
    }						\
						\
    /* Get the previous entry from a list, */	\
    /* moving curr backwards. */		\
    int gdlist(TYPE)::prev(TYPE &a)		\
    {						\
	if (!last)				\
	    return 0;				\
						\
	/* move curr backwards, possibly to */	\
	/* the beginning or end of the list. */	\
	if (curr)				\
	    if (curr == last->next)		\
		{				\
		curr = 0;			\
		return 0;			\
		}				\
						\
	    else				\
		curr = curr->prev;		\
						\
	else					\
	    curr = last;			\
						\
	a = curr->e;				\
	return 1;				\
    }						\
						\
    /* Get the next entry from a list, */	\
    /* removing it afterwards. */		\
    /* curr is left alone. */			\
    int gdlist(TYPE)::getnext(TYPE &a)		\
    {						\
	if (!last)				\
	    return 0;				\
						\
	/* choose the link to remove */		\
	gdlink(TYPE) *f;			\
	if (curr)				\
	    if (curr == last)			\
		{				\
		curr = 0;			\
		return 0;			\
		}				\
						\
	    else				\
		f = curr->next;			\
						\
	else					\
	    f = last->next;			\
						\
	a = f->e;				\
						\
	/* remove f from the list */		\
	if (f == last)				\
	    last = 0;				\
						\
	else					\
	    f->remove();			\
						\
	delete f;				\
	return 1;				\
    }						\
						\
    /* Get the previous entry from a list, */	\
    /* removing it afterwards */		\
    int gdlist(TYPE)::getprev(TYPE &a)		\
    {						\
	if (!last)				\
	    return 0;				\
						\
	/* choose the link to remove */		\
	gdlink(TYPE) *f;			\
	if (curr)				\
	    if (curr == last->prev)		\
		{				\
		curr = 0;			\
		return 0;			\
		}				\
						\
	    else				\
		f = curr->prev;			\
						\
	else					\
	    curr = last;			\
						\
	a = f->e;				\
						\
	/* remove f from the list */		\
	if (f == last)				\
	    last = 0;				\
						\
	else					\
	    f->remove();			\
						\
	delete f;				\
	return 1;				\
    }						\
						\
    /* insert an entry at the */		\
    /* beginning of the list */			\
    void gdlist(TYPE)::insert(TYPE a)		\
    {						\
	if (last)				\
	    last->next->			\
		insert(new gdlink(TYPE)(a));	\
						\
	else					\
	    {					\
	    last = new gdlink(TYPE)(a);		\
	    last->next = last->prev = last;	\
	    }					\
    }						\
						\
    /* Append an entry at the end of the */	\
    /* list. This is the same as */		\
    /* gdlist(TYPE)::insert() */		\
    /* except that gdlist(TYPE)::last is */	\
    /* adjusted afterwards. */			\
    void gdlist(TYPE)::append(TYPE a)		\
    {						\
	this->insert(a);			\
	last = last->next;			\
    }						\
						\
    /* Insert an entry before the */		\
    /* current location of the list. */		\
    /* If curr is not set, insert at */		\
    /* the beginning of the list. */		\
    void gdlist(TYPE)::inserthere(TYPE a)	\
    {						\
	if (curr)				\
	    curr->insert(new gdlink(TYPE)(a));	\
						\
	else					\
	    this->insert(a);			\
    }						\
						\
    /* Append an entry after the */		\
    /* current location of the list. */		\
    /* If curr is not set, append at */		\
    /* the end of the list. */			\
    void gdlist(TYPE)::appendhere(TYPE a)	\
    {						\
	if (curr)				\
	    curr->append(new gdlink(TYPE)(a));	\
						\
	else					\
	    this->append(a);			\
    }
!EOF!
ls -l 7_8a5.h
echo x - 7_8decl.h
sed 's/^X//' > 7_8decl.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// Exercise 7.8
// Generic doubly linked list.
// The user would use the generic class gdlink(TYPE)
// for a user type TYPE by the following steps:
//
// declare(gdlink, TYPE)
// declare(gdlist, TYPE)
// implement(gdlink, TYPE)
// implement(gdlist, TYPE)
//
// gdlink(TYPE) X;
// gdlist(TYPE) Y(X);

#ifndef DLINK_H
# define DLINK_H
#include <generic.h>

#include "7_8a1.h"		// EXPAND	gdlink(TYPE), gdlist(TYPE)

#include "7_8a2.h"		// EXPAND	gdlinkdeclare(TYPE)

#include "7_8a3.h"		// EXPAND	gdlistdeclare(TYPE)

#include "7_8a4.h"		// EXPAND	gdlinkimplement(TYPE)

#include "7_8a5.h"		// EXPAND	gdlistimplement(TYPE)
#endif /* DLINK_H */
!EOF!
ls -l 7_8decl.h
echo x - 7_8x1.c
sed 's/^X//' > 7_8x1.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
declare(GENERIC,int)
implement(GENERIC,int)
!EOF!
ls -l 7_8x1.c
echo x - 7_8x2.c
sed 's/^X//' > 7_8x2.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
GENERIC(int) x;
!EOF!
ls -l 7_8x2.c
echo x - 7_8x3.c
sed 's/^X//' > 7_8x3.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#define GENERIC(type)
#define GENERICdeclare(type)
#define GENERICimplement(type)
!EOF!
ls -l 7_8x3.c
echo x - 7_8x4.c
sed 's/^X//' > 7_8x4.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#ifndef CLASS_H
#define CLASS_H
// ...
#endif /* CLASS_H */
!EOF!
ls -l 7_8x4.c
echo x - makefile
sed 's/^X//' > makefile << '!EOF!'
CC= CC -I. -I../../CC
CFLAGS=

all: tst

tst: tst.o
	$(CC) -o tst tst.o

tst.o: tst.c 7_8decl.h 7_8a1.h 7_8a2.h 7_8a3.h 7_8a4.h 7_8a5.h
	$(CC) -c tst.c

CMP= tst.cmp
OUT= tst.out

tst.out: tst ; tst > tst.out

test: all $(CMP) $(OUT)
	cmp tst.out tst.cmp
	@echo test done
!EOF!
ls -l makefile
echo x - tst.c
sed 's/^X//' > tst.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#include "7_8decl.h"

#include <stream.h>

typedef void *Ent;

declare(gdlink,Ent)
declare(gdlist,Ent)
implement(gdlink,Ent)
implement(gdlist,Ent)

main()
{
    gdlist(Ent) xdlist("hello");
    xdlist.append("there");
    xdlist.append("how");
    xdlist.append("are");
    xdlist.append("you");
    xdlist.append("today");
    void *x;
    cout << "forwards\n";
    while (xdlist.next(x))
	cout << "'" << (char*)x << "'\n";
    cout << "\nbackwards\n";
    while (xdlist.prev(x))
	cout << "'" << (char*)x << "'\n";
    xdlist.next(x);
    xdlist.next(x);
    xdlist.inserthere("Beep");
    xdlist.appendhere("Boop");
    xdlist.reset();
    cout << "\nforwards, removing\n";
    while (xdlist.getnext(x))
	cout << "'" << (char*)x << "'\n";
    cout << "\nbackwards\n";
    while (xdlist.getprev(x))
	cout << "'" << (char*)x << "'\n";
    return 0;
}
!EOF!
ls -l tst.c
echo x - tst.cmp
sed 's/^X//' > tst.cmp << '!EOF!'
forwards
'hello'
'there'
'how'
'are'
'you'
'today'

backwards
'today'
'you'
'are'
'how'
'there'
'hello'

forwards, removing
'hello'
'Beep'
'there'
'Boop'
'how'
'are'
'you'
'today'

backwards
!EOF!
ls -l tst.cmp
# The following exit is to ensure that extra garbage 
# after the end of the shar file will be ignored.
exit 0