init

[irc.git] / software / ircd / www.irc.org / ftp / irc / server / irc2.11.2p3 / common / support.c

/************************************************************************
 *   IRC - Internet Relay Chat, common/support.c
 *   Copyright (C) 1990, 1991 Armin Gruner
 *
 *   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 1, 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.
 */

#ifndef lint
static const volatile char rcsid[] = "@(#)$Id: support.c,v 1.46 2009/03/15 01:25:32 chopin Exp $";
#endif

#include "os.h"
#include "s_defines.h"
#define SUPPORT_C
#include "s_externs.h"
#undef SUPPORT_C

#ifdef INET6
char ipv6string[INET6_ADDRSTRLEN];
#endif

unsigned char minus_one[]={ 255, 255, 255, 255, 255, 255, 255, 255, 255,
                                        255, 255, 255, 255, 255, 255, 255, 0};


char	*mystrdup(char *s)
{
	/* Portable strdup(), contributed by mrg, thanks!  -roy */

	char	*t;

	t = (char *) MyMalloc(strlen(s) + 1);
	if (t)
		return ((char *)strcpy(t, s));
	return NULL;
}

#if defined(JAPANESE) && defined(HAVE_STRTOKEN)
/* I doubt library strtoken knows about JIS encoding and commas. --Beeth */
#undef HAVE_STRTOKEN
#undef strtoken
#endif

#if !defined(HAVE_STRTOKEN)
/*
** 	strtoken.c --  	walk through a string of tokens, using a set
**			of separators
**			argv 9/90
*/

char	*strtoken(char **save, char *str, char *fs)
{
    char *pos = *save;	/* keep last position across calls */
    Reg char *tmp;

    if (str)
	pos = str;		/* new string scan */

    while (pos && *pos && index(fs, *pos) != NULL)
	pos++; 		 	/* skip leading separators */

    if (!pos || !*pos)
	return (pos = *save = NULL); 	/* string contains only sep's */

    tmp = pos; 			/* now, keep position of the token */

#ifdef JAPANESE
    /* We have to make special case for Japanese names when comma is
    ** a separator, as they may contain it between JIS marks. --Beeth. */
    if (fs[0] == ',' && fs[1] == '\0')
    {
       int flag = 0;
       while (*pos)
       {
           if (!flag && *pos == ',')
           {
               break;
           }
           else if (pos[0] == '\033'
                   && (pos[1] == '$' || pos[1] == '(')
                   && pos[2] == 'B')
           {
               flag = (pos[1] == '$') ? 1 : 0;
               pos += 2;
           }
           pos++;
       }
    }
    else
    /* This came from original jp patch, but I believe it is wrong for
    ** cases when fs is two or more letters (index() allows it) and contains 
    ** comma. Fortunately ircd does not use such, yet it is something 
    ** to remember. --Beeth. */
#endif
    {
    while (*pos && index(fs, *pos) == NULL)
	pos++; 			/* skip content of the token */
    }

    if (*pos)
	*pos++ = '\0';		/* remove first sep after the token */
    else
	pos = NULL;		/* end of string */

    *save = pos;
    return(tmp);
}
#endif /* HAVE_STRTOKEN */

#if !defined(HAVE_STRTOK)
/*
** NOT encouraged to use!
*/

char	*strtok(char *str, char *fs)
{
	static char *pos;

	return strtoken(&pos, str, fs);
}

#endif /* HAVE_STRTOK */

#if !defined(HAVE_STRERROR)
/*
**	strerror - return an appropriate system error string to a given errno
**
**		   argv 11/90
*/

char	*strerror(int err_no)
{
	static	char	buff[40];
	char	*errp;

	errp = (err_no > sys_nerr ? (char *)NULL : sys_errlist[err_no]);

	if (errp == (char *)NULL)
	    {
		errp = buff;
		sprintf(errp, "Unknown Error %d", err_no);
	    }
	return errp;
}

#endif /* HAVE_STRERROR */

/**
 ** myctime()
 **   This is like standard ctime()-function, but it zaps away
 **   the newline from the end of that string. Also, it takes
 **   the time value as parameter, instead of pointer to it.
 **   Note that it is necessary to copy the string to alternate
 **   buffer (who knows how ctime() implements it, maybe it statically
 **   has newline there and never 'refreshes' it -- zapping that
 **   might break things in other places...)
 **
 **/

char	*myctime(time_t value)
{
	static	char	buf[28];
	Reg	char	*p;

	(void)strcpy(buf, ctime(&value));
	if ((p = (char *)index(buf, '\n')) != NULL)
		*p = '\0';

	return buf;
}

/*
** mybasename()
**	removes path from a filename
*/
char	*mybasename(char *path)
{
	char *lastslash;

	if ((lastslash = rindex(path, '/')))
	{
		return lastslash + 1;
	}
	return path;
}

#ifdef INET6
/*
 * inetntop: return the : notation of a given IPv6 internet number.
 *	     or the dotted-decimal notation for IPv4
 *           make sure the compressed representation (rfc 1884) isn't used.
 */
char	*inetntop(int af, const void *in, char *out, size_t the_size)
{
	static char local_ipv6string[INET6_ADDRSTRLEN];

	if (the_size > sizeof(local_ipv6string))
	{
		the_size = sizeof(local_ipv6string);
	}
	
	if (!inet_ntop(af, in, local_ipv6string, the_size))
	{
		/* good that every function calling this one
		 * checks the return value ... NOT */
		return NULL;
	}	
	/* quick and dirty hack to give ipv4 just ipv4 instead of
	 * ::ffff:ipv4 - Q */
	if (af == AF_INET6 && IN6_IS_ADDR_V4MAPPED((const struct in6_addr *)in))
	{
		char	*p;

		if (!(p = strstr(local_ipv6string, ":ffff:")) &&
			!(p = strstr(local_ipv6string, ":FFFF:")))
		{
			return NULL;	/* crash and burn */
		}
		strcpy(out, p + 6);
		return out;
	}
	if (strstr(local_ipv6string, "::"))
	    {
		char cnt = 0, *cp = local_ipv6string, *op = out;

		while (*cp)
		    {
			if (*cp == ':')
				cnt += 1;
			if (*cp++ == '.')
			    {
				cnt += 1;
				break;
			    }
		    }
		cp = local_ipv6string;
		while (*cp)
		    {
			*op++ = *cp++;
			if (*(cp-1) == ':' && *cp == ':')
			    {
				if ((cp-1) == local_ipv6string)
				    {
					op--;
					*op++ = '0';
					*op++ = ':';
				    }

				*op++ = '0';
				while (cnt++ < 7)
				    {
					*op++ = ':';
					*op++ = '0';
				    }
			    }
		    }
		if (*(op-1)==':') *op++ = '0';
		*op = '\0';
#ifndef	CLIENT_COMPILE
		Debug((DEBUG_DNS,"Expanding `%s' -> `%s'", local_ipv6string,
		       out));
#endif
	    }
	else
		bcopy(local_ipv6string, out,	the_size);

	return out;
}

/* inetpton(af, src, dst)
**
** This is a wrapper for inet_pton(), so we can use ipv4 addresses with an
** af of AF_INET6, and that it gets converted to ipv4 mapped ipv6.
*/
int	inetpton(int af, const char *src, void *dst)
{
	int	i;

	/* an empty string should listen to all */
	if (af == AF_INET6 && *src && !strchr(src, ':'))
	    {
		i = inet_pton(AF_INET, src, dst);

		/* ugly hack */
		memcpy((char *)dst + 12, dst, 4);
		memset(dst, 0, 10);
		memset((char *)dst + 10, 0xff, 2);
		return i;
	    }
	return inet_pton(af, src, dst);
}
#endif

#if !defined(HAVE_INET_NTOA)
/*
**	inetntoa  --	changed name to remove collision possibility and
**			so behaviour is gaurunteed to take a pointer arg.
**			-avalon 23/11/92
**	inet_ntoa --	returned the dotted notation of a given
**			internet number (some ULTRIX don't have this)
**			argv 11/90).
**	inet_ntoa --	its broken on some Ultrix/Dynix too. -avalon
*/

char	*inetntoa(char *in)
{
	static	char	buf[16];
	Reg	u_char	*s = (u_char *)in;
	Reg	int	a,b,c,d;

	a = (int)*s++;
	b = (int)*s++;
	c = (int)*s++;
	d = (int)*s;
	(void)sprintf(buf, "%d.%d.%d.%d", a,b,c,d );

	return buf;
}
#endif

#if !defined(HAVE_INET_NETOF)
/*
**	inet_netof --	return the net portion of an internet number
**			argv 11/90
*/
int inetnetof(struct in_addr in)
{
    register u_long i = ntohl(in.s_addr);
    
    if (IN_CLASSA(i))
	    return (((i)&IN_CLASSA_NET) >> IN_CLASSA_NSHIFT);
    else if (IN_CLASSB(i))
	    return (((i)&IN_CLASSB_NET) >> IN_CLASSB_NSHIFT);
    else
	    return (((i)&IN_CLASSC_NET) >> IN_CLASSC_NSHIFT);
}
#endif

#if !defined(HAVE_INET_ADDR)
# ifndef INADDR_NONE
#  define INADDR_NONE   0xffffffff
# endif
/*
 * Ascii internet address interpretation routine.
 * The value returned is in network order.
 */
u_long	inetaddr(const char *cp)
{
	struct in_addr val;

	if (inetaton(cp, &val))
		return (val.s_addr);
	return (INADDR_NONE);
}
#endif

#if !defined(HAVE_INET_ATON)
/* 
 * Check whether "cp" is a valid ascii representation
 * of an Internet address and convert to a binary address.
 * Returns 1 if the address is valid, 0 if not.
 * This replaces inet_addr, the return value from which
 * cannot distinguish between failure and a local broadcast address.
 */
int	inetaton(const char *cp, struct in_addr *addr)
{
	register u_long val;
	register int base, n;
	register char c;
	u_int parts[4];
	register u_int *pp = parts;

	c = *cp;
	for (;;) {
		/*
		 * Collect number up to ``.''.
		 * Values are specified as for C:
		 * 0x=hex, 0=octal, isdigit=decimal.
		 */
		if (!isdigit(c))
			return (0);
		val = 0; base = 10;
		if (c == '0') {
			c = *++cp;
			if (c == 'x' || c == 'X')
				base = 16, c = *++cp;
			else
				base = 8;
		}
		for (;;) {
			if (isascii(c) && isdigit(c)) {
				val = (val * base) + (c - '0');
				c = *++cp;
			} else if (base == 16 && isascii(c) && isxdigit(c)) {
				val = (val << 4) |
					(c + 10 - (islower(c) ? 'a' : 'A'));
				c = *++cp;
			} else
				break;
		}
		if (c == '.') {
			/*
			 * Internet format:
			 *	a.b.c.d
			 *	a.b.c	(with c treated as 16 bits)
			 *	a.b	(with b treated as 24 bits)
			 */
			if (pp >= parts + 3)
				return (0);
			*pp++ = val;
			c = *++cp;
		} else
			break;
	}
	/*
	 * Check for trailing characters.
	 */
	if (c != '\0' && (!isascii(c) || !isspace(c)))
		return (0);
	/*
	 * Concoct the address according to
	 * the number of parts specified.
	 */
	n = pp - parts + 1;
	switch (n) {

	case 0:
		return (0);		/* initial nondigit */

	case 1:				/* a -- 32 bits */
		break;

	case 2:				/* a.b -- 8.24 bits */
		if (val > 0xffffff)
			return (0);
		val |= parts[0] << 24;
		break;

	case 3:				/* a.b.c -- 8.8.16 bits */
		if (val > 0xffff)
			return (0);
		val |= (parts[0] << 24) | (parts[1] << 16);
		break;

	case 4:				/* a.b.c.d -- 8.8.8.8 bits */
		if (val > 0xff)
			return (0);
		val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
		break;
	}
	if (addr)
		addr->s_addr = htonl(val);
	return (1);
}
#endif

#if defined(DEBUGMODE) && !defined(CLIENT_COMPILE)
void	dumpcore(char *msg, ...)
{
	static	time_t	lastd = 0;
	static	int	dumps = 0;
	char	corename[12];
	time_t	now;
	int	p;
	va_list	va;
	char	s[BUFSIZE];

	now = time(NULL);

	if (!lastd)
		lastd = now;
	else if (now - lastd < 60 && dumps > 2)
		(void)s_die(0);
	if (now - lastd > 60)
	    {
		lastd = now;
		dumps = 1;
	    }
	else
		dumps++;
	p = getpid();
	if (fork()>0) {
		kill(p, 3);
		kill(p, 9);
	}
	write_pidfile();
	sprintf(corename, "core.%d", p);
	(void)rename("core", corename);
	va_start(va, msg);
	vsprintf(s, msg, va);
	va_end(va);
	Debug((DEBUG_FATAL, s));
	sendto_flag(SCH_ERROR, "Dumped core : core.%d", p);
	Debug((DEBUG_FATAL, s));
	sendto_flag(SCH_ERROR, s);
	(void)s_die(0);
}
#endif

#if defined(DEBUGMODE) && !defined(CLIENT_COMPILE) && defined(DO_DEBUG_MALLOC)

static	char	*marray[100000];
static	int	mindex = 0;

#define	SZ_EX	(sizeof(char *) + sizeof(size_t) + 4)
#define	SZ_CHST	(sizeof(char *) + sizeof(size_t))
#define	SZ_CH	(sizeof(char *))
#define	SZ_ST	(sizeof(size_t))

char	*MyMalloc(size_t x)
{
	register int	i;
	register char	**s;
	char	*ret;

	ret = (char *)malloc(x + (size_t)SZ_EX);

	if (!ret)
	    {
# ifndef	CLIENT_COMPILE
		outofmemory();
# else
		perror("malloc");
		exit(-1);
# endif
	    }
	bzero(ret, (int)x + SZ_EX);
	bcopy((char *)&ret, ret, SZ_CH);
	bcopy((char *)&x, ret + SZ_CH, SZ_ST);
	bcopy("VAVA", ret + SZ_CHST + (int)x, 4);
	Debug((DEBUG_MALLOC, "MyMalloc(%ld) = %#x", x, ret + SZ_CHST));
	for(i = 0, s = marray; *s && i < mindex; i++, s++)
		;
 	if (i < 100000)
	    {
		*s = ret;
		if (i == mindex)
			mindex++;
	    }
	return ret + SZ_CHST;
}

char    *MyRealloc(char *x, size_t y)
{
	register int	l;
	register char	**s;
	char	*ret, *cp;
	size_t	i;
	int	k;

	if (x != NULL)
	  {
	      x -= SZ_CHST;
	      bcopy(x, (char *)&cp, SZ_CH);
	      bcopy(x + SZ_CH, (char *)&i, SZ_ST);
	      bcopy(x + (int)i + SZ_CHST, (char *)&k, 4);
	      if (bcmp((char *)&k, "VAVA", 4) || (x != cp))
		      dumpcore("MyRealloc %#x %d %d %#x %#x", x, y, i, cp, k);
	  }
	ret = (char *)realloc(x, y + (size_t)SZ_EX);

	if (!ret)
	    {
# ifndef	CLIENT_COMPILE
		outofmemory();
# else
		perror("realloc");
		exit(-1);
# endif
	    }
	bcopy((char *)&ret, ret, SZ_CH);
	bcopy((char *)&y, ret + SZ_CH, SZ_ST);
	bcopy("VAVA", ret + SZ_CHST + (int)y, 4);
	Debug((DEBUG_NOTICE, "MyRealloc(%#x,%ld) = %#x", x, y, ret + SZ_CHST));
	for(l = 0, s = marray; *s != x && l < mindex; l++, s++)
		;
 	if (l < mindex)
		*s = NULL;
	else if (l == mindex)
		Debug((DEBUG_MALLOC, "%#x !found", x));
	for(l = 0, s = marray; *s && l < mindex; l++,s++)
		;
 	if (l < 100000)
	    {
		*s = ret;
		if (l == mindex)
			mindex++;
	    }
	return ret + SZ_CHST;
}

void	MyFree(void *p)
{
	size_t	i;
	char	*j, *x = p;
	u_char	k[4];
	register int	l;
	register char	**s;

	if (!x)
		return;
	x -= SZ_CHST;

	bcopy(x, (char *)&j, SZ_CH);
	bcopy(x + SZ_CH, (char *)&i, SZ_ST);
	bcopy(x + SZ_CHST + (int)i, (char *)k, 4);

	if (bcmp((char *)k, "VAVA", 4) || (j != x))
		dumpcore("MyFree %#x %ld %#x %#x", x, i, j,
			 (k[3]<<24) | (k[2]<<16) | (k[1]<<8) | k[0]);

	Debug((DEBUG_MALLOC, "MyFree(%#x)",x + SZ_CHST));
#undef	free
	(void)free(x);
#define	free(x)	MyFree(x)

	for (l = 0, s = marray; *s != x && l < mindex; l++, s++)
		;
	if (l < mindex)
		*s = NULL;
	else if (l == mindex)
		Debug((DEBUG_MALLOC, "%#x !found", x));
}
#else
char	*MyMalloc(size_t x)
{
	char *ret = (char *)malloc(x);

	if (!ret)
	    {
# ifndef	CLIENT_COMPILE
		outofmemory();
# else
		perror("malloc");
		exit(-1);
# endif
	    }
	return	ret;
}

char	*MyRealloc(char *x, size_t y)
{
	char *ret = (char *)realloc(x, y);

	if (!ret)
	    {
# ifndef CLIENT_COMPILE
		outofmemory();
# else
		perror("realloc");
		exit(-1);
# endif
	    }
	return ret;
}
#endif


/*
** read a string terminated by \r or \n in from a fd
**
** Created: Sat Dec 12 06:29:58 EST 1992 by avalon
** Returns:
**	0 - EOF
**	-1 - error on read
**     >0 - number of bytes returned (<=num)
** After opening a fd, it is necessary to init dgets() by calling it as
**	dgets(x,y,0);
** to mark the buffer as being empty.
*/
int	dgets(int fd, char *buf, int num)
{
	static	char	dgbuf[8192];
	static	char	*head = dgbuf, *tail = dgbuf;
	register char	*s, *t;
	register int	n, nr;

	/*
	** Sanity checks.
	*/
	if (head == tail)
		*head = '\0';
	if (!num)
	    {
		head = tail = dgbuf;
		*head = '\0';
		return 0;
	    }
	if (num > sizeof(dgbuf) - 1)
		num = sizeof(dgbuf) - 1;
dgetsagain:
	if (head > dgbuf)
	    {
		for (nr = tail - head, s = head, t = dgbuf; nr > 0; nr--)
			*t++ = *s++;
		tail = t;
		head = dgbuf;
	    }
	/*
	** check input buffer for EOL and if present return string.
	*/
	if (head < tail &&
	    ((s = index(head, '\n')) || (s = index(head, '\r'))) && s < tail)
	    {
		n = MIN(s - head + 1, num);	/* at least 1 byte */
dgetsreturnbuf:
		bcopy(head, buf, n);
		head += n;
		if (head == tail)
			head = tail = dgbuf;
		return n;
	    }

	if (tail - head >= num)		/* dgets buf is big enough */
	    {
		n = num;
		goto dgetsreturnbuf;
	    }

	n = sizeof(dgbuf) - (tail - dgbuf) - 1;
	nr = read(fd, tail, n);
	if (nr == -1)
	    {
		head = tail = dgbuf;
		return -1;
	    }
	if (!nr)
	    {
		if (tail > head)
		    {
			n = MIN(tail - head, num);
			goto dgetsreturnbuf;
		    }
		head = tail = dgbuf;
		return 0;
	    }
	tail += nr;
	*tail = '\0';
	for (t = head; (s = index(t, '\n')); )
	    {
		if ((s > head) && (s > dgbuf))
		    {
			t = s-1;
			for (nr = 0; *t == '\\'; nr++)
				t--;
			if (nr & 1)
			    {
				t = s+1;
				s--;
				nr = tail - t;
				while (nr--)
					*s++ = *t++;
				tail -= 2;
				*tail = '\0';
			    }
			else
				s++;
		    }
		else
			s++;
		t = s;
	    }
	*tail = '\0';
	goto dgetsagain;
}

/*
 * Make 'readable' version string.
 */
char	*make_version(void)
{
	int ve, re, mi, dv, pl;
	char ver[15];

	sscanf(PATCHLEVEL, "%2d%2d%2d%2d%2d", &ve, &re, &mi, &dv, &pl);
	/* version & revision */
	sprintf(ver, "%d.%d", ve, (mi == 99) ? re + 1 : re);
	if (mi == 99) mi = -1;
	/* minor revision */
	sprintf(ver + strlen(ver), ".%d", dv ? mi+1 : mi);
	if (dv)	/* alpha/beta, note how visual patchlevel is raised above */
		sprintf(ver + strlen(ver), "%c%d", DEVLEVEL, dv);
	if (pl)	/* patchlevel */
		sprintf(ver + strlen(ver), "p%d", pl);
	return mystrdup(ver);
}

#ifndef CLIENT_COMPILE
/* Make RPL_ISUPPORT (005) numeric contents */
char	**make_isupport(void)
{
	char **tis;
	
	tis = (char **) MyMalloc(3 * sizeof(char *));
	
	/* Warning: There must be up to 12 tokens in each string */
	tis[0] = (char *) MyMalloc(BUFSIZE);
	sprintf(tis[0],
		"RFC2812 PREFIX=(ov)@+ CHANTYPES=#&!+ MODES=%d "
		"CHANLIMIT=#&!+:%d "
		"NICKLEN=%d TOPICLEN=%d KICKLEN=%d MAXLIST=beIR:%d "
		"CHANNELLEN=%d IDCHAN=!:%d CHANMODES=beIR,k,l,imnpstaqr",
		MAXMODEPARAMS, MAXCHANNELSPERUSER,
		LOCALNICKLEN, TOPICLEN, TOPICLEN, MAXBANS, CHANNELLEN, CHIDLEN);

	tis[1] = (char *) MyMalloc(BUFSIZE);
	sprintf(tis[1],	"PENALTY FNC EXCEPTS=e INVEX=I CASEMAPPING=ascii");
	if (networkname)
	{
		strcat(tis[1], " NETWORK=");
		strcat(tis[1], networkname);
	}

	tis[2] = NULL;

	return tis;
}
#endif

#ifndef HAVE_TRUNCATE
/* truncate: set a file to a specified length
 * I don't know of any UNIX that doesn't have truncate, but CYGWIN32 beta18
 * doesn't have it.  -krys
 * Replacement version from Dave Miller.
 */
int	truncate(const char *path, off_t length)
{
	int fd, res;
	fd = open(path, O_WRONLY);
	if (fd == -1)
		return -1;
	res = ftruncate(fd, length);
	close(fd);
	return res;
}
#endif /* HAVE_TRUNCATE */

#ifdef SOLARIS_2_3
/* 
 * On Solaris 2.3 (SunOS 5.3) systems, gethostbyname() has a bug, it always
 * returns null in h->aliases.  Workaround: use the undocumented
 * _switch_gethostbyname_r(...).
 */
#define HBUFSIZE 4096

struct hostent	*solaris_gethostbyname(const char *name)
{
  static struct hostent hp;
  static char buf[HBUFSIZE];
  
  return _switch_gethostbyname_r(name, &hp, buf, sizeof(buf), &h_errno);
}
#endif /* SOLARIS_2_3 */

#if defined(HAVE_MEMCMP) && defined(MEMCMP_BROKEN)
/*
 * Some OS may have a memcmp that is not 8-bit clean.
 *
 * Copyright (C) 1991, 1993, 1995 Free Software Foundation, Inc.
 * Contributed by Torbjorn Granlund (tege@sics.se).
 *
 * NOTE: The canonical source of this part of the file is maintained with the
 * GNU C Library. Bugs can be reported to bug-glibc@prep.ai.mit.edu.
 */

/* Type to use for aligned memory operations.
   This should normally be the biggest type supported by a single load
   and store.  Must be an unsigned type.  */
#define	op_t	unsigned long int
#define OPSIZ	(sizeof(op_t))

/* Threshold value for when to enter the unrolled loops.  */
#define	OP_T_THRES	16

/* Type to use for unaligned operations.  */
typedef unsigned char byte;

#if !defined(WORDS_BIGENDIAN)
#define MERGE(w0, sh_1, w1, sh_2) (((w0) >> (sh_1)) | ((w1) << (sh_2)))
#else
#define MERGE(w0, sh_1, w1, sh_2) (((w0) << (sh_1)) | ((w1) >> (sh_2)))
#endif

#if defined(WORDS_BIGENDIAN)
#define CMP_LT_OR_GT(a, b) ((a) > (b) ? 1 : -1)
#else
#define CMP_LT_OR_GT(a, b) memcmp_bytes ((a), (b))
#endif

/* BE VERY CAREFUL IF YOU CHANGE THIS CODE!  */

/* The strategy of this memcmp is:

   1. Compare bytes until one of the block pointers is aligned.

   2. Compare using memcmp_common_alignment or
      memcmp_not_common_alignment, regarding the alignment of the other
      block after the initial byte operations.  The maximum number of
      full words (of type op_t) are compared in this way.

   3. Compare the few remaining bytes.  */

#if !defined(WORDS_BIGENDIAN)
/* memcmp_bytes -- Compare A and B bytewise in the byte order of the machine.
   A and B are known to be different.
   This is needed only on little-endian machines.  */
#ifdef  __GNUC__
__inline
#endif
static int	memcmp_bytes(op_t a, op_t b)
{
  long int srcp1 = (long int) &a;
  long int srcp2 = (long int) &b;
  op_t a0, b0;

  do
    {
      a0 = ((byte *) srcp1)[0];
      b0 = ((byte *) srcp2)[0];
      srcp1 += 1;
      srcp2 += 1;
    }
  while (a0 == b0);
  return a0 - b0;
}
#endif

/* memcmp_common_alignment -- Compare blocks at SRCP1 and SRCP2 with LEN `op_t'
   objects (not LEN bytes!).  Both SRCP1 and SRCP2 should be aligned for
   memory operations on `op_t's.  */
#ifdef	__GNUC__
__inline
#endif
static int	memcmp_common_alignment(long int srcp1, long int srcp2,
			size_t len)
{
  op_t a0, a1;
  op_t b0, b1;

  switch (len % 4)
    {
    case 2:
      a0 = ((op_t *) srcp1)[0];
      b0 = ((op_t *) srcp2)[0];
      srcp1 -= 2 * OPSIZ;
      srcp2 -= 2 * OPSIZ;
      len += 2;
      goto do1;
    case 3:
      a1 = ((op_t *) srcp1)[0];
      b1 = ((op_t *) srcp2)[0];
      srcp1 -= OPSIZ;
      srcp2 -= OPSIZ;
      len += 1;
      goto do2;
    case 0:
      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
	return 0;
      a0 = ((op_t *) srcp1)[0];
      b0 = ((op_t *) srcp2)[0];
      goto do3;
    case 1:
      a1 = ((op_t *) srcp1)[0];
      b1 = ((op_t *) srcp2)[0];
      srcp1 += OPSIZ;
      srcp2 += OPSIZ;
      len -= 1;
      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
	goto do0;
      /* Fall through.  */
    }

  do
    {
      a0 = ((op_t *) srcp1)[0];
      b0 = ((op_t *) srcp2)[0];
      if (a1 != b1)
	return CMP_LT_OR_GT (a1, b1);

    do3:
      a1 = ((op_t *) srcp1)[1];
      b1 = ((op_t *) srcp2)[1];
      if (a0 != b0)
	return CMP_LT_OR_GT (a0, b0);

    do2:
      a0 = ((op_t *) srcp1)[2];
      b0 = ((op_t *) srcp2)[2];
      if (a1 != b1)
	return CMP_LT_OR_GT (a1, b1);

    do1:
      a1 = ((op_t *) srcp1)[3];
      b1 = ((op_t *) srcp2)[3];
      if (a0 != b0)
	return CMP_LT_OR_GT (a0, b0);

      srcp1 += 4 * OPSIZ;
      srcp2 += 4 * OPSIZ;
      len -= 4;
    }
  while (len != 0);

  /* This is the right position for do0.  Please don't move
     it into the loop.  */
 do0:
  if (a1 != b1)
    return CMP_LT_OR_GT (a1, b1);
  return 0;
}

/* memcmp_not_common_alignment -- Compare blocks at SRCP1 and SRCP2 with LEN
   `op_t' objects (not LEN bytes!).  SRCP2 should be aligned for memory
   operations on `op_t', but SRCP1 *should be unaligned*.  */
#ifdef	__GNUC__
__inline
#endif
static int	memcmp_not_common_alignment(long int srcp1, long int srcp2,
		size_t len)
{
  op_t a0, a1, a2, a3;
  op_t b0, b1, b2, b3;
  op_t x;
  int shl, shr;

  /* Calculate how to shift a word read at the memory operation
     aligned srcp1 to make it aligned for comparison.  */

  shl = 8 * (srcp1 % OPSIZ);
  shr = 8 * OPSIZ - shl;

  /* Make SRCP1 aligned by rounding it down to the beginning of the `op_t'
     it points in the middle of.  */
  srcp1 &= -OPSIZ;

  switch (len % 4)
    {
    case 2:
      a1 = ((op_t *) srcp1)[0];
      a2 = ((op_t *) srcp1)[1];
      b2 = ((op_t *) srcp2)[0];
      srcp1 -= 1 * OPSIZ;
      srcp2 -= 2 * OPSIZ;
      len += 2;
      goto do1;
    case 3:
      a0 = ((op_t *) srcp1)[0];
      a1 = ((op_t *) srcp1)[1];
      b1 = ((op_t *) srcp2)[0];
      srcp2 -= 1 * OPSIZ;
      len += 1;
      goto do2;
    case 0:
      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
	return 0;
      a3 = ((op_t *) srcp1)[0];
      a0 = ((op_t *) srcp1)[1];
      b0 = ((op_t *) srcp2)[0];
      srcp1 += 1 * OPSIZ;
      goto do3;
    case 1:
      a2 = ((op_t *) srcp1)[0];
      a3 = ((op_t *) srcp1)[1];
      b3 = ((op_t *) srcp2)[0];
      srcp1 += 2 * OPSIZ;
      srcp2 += 1 * OPSIZ;
      len -= 1;
      if (OP_T_THRES <= 3 * OPSIZ && len == 0)
	goto do0;
      /* Fall through.  */
    }

  do
    {
      a0 = ((op_t *) srcp1)[0];
      b0 = ((op_t *) srcp2)[0];
      x = MERGE(a2, shl, a3, shr);
      if (x != b3)
	return CMP_LT_OR_GT (x, b3);

    do3:
      a1 = ((op_t *) srcp1)[1];
      b1 = ((op_t *) srcp2)[1];
      x = MERGE(a3, shl, a0, shr);
      if (x != b0)
	return CMP_LT_OR_GT (x, b0);

    do2:
      a2 = ((op_t *) srcp1)[2];
      b2 = ((op_t *) srcp2)[2];
      x = MERGE(a0, shl, a1, shr);
      if (x != b1)
	return CMP_LT_OR_GT (x, b1);

    do1:
      a3 = ((op_t *) srcp1)[3];
      b3 = ((op_t *) srcp2)[3];
      x = MERGE(a1, shl, a2, shr);
      if (x != b2)
	return CMP_LT_OR_GT (x, b2);

      srcp1 += 4 * OPSIZ;
      srcp2 += 4 * OPSIZ;
      len -= 4;
    }
  while (len != 0);

  /* This is the right position for do0.  Please don't move
     it into the loop.  */
 do0:
  x = MERGE(a2, shl, a3, shr);
  if (x != b3)
    return CMP_LT_OR_GT (x, b3);
  return 0;
}

int	irc_memcmp(const __ptr_t s1, const __ptr_t s2, size_t len)
{
  op_t a0;
  op_t b0;
  long int srcp1 = (long int) s1;
  long int srcp2 = (long int) s2;
  op_t res;

  if (len >= OP_T_THRES)
    {
      /* There are at least some bytes to compare.  No need to test
	 for LEN == 0 in this alignment loop.  */
      while (srcp2 % OPSIZ != 0)
	{
	  a0 = ((byte *) srcp1)[0];
	  b0 = ((byte *) srcp2)[0];
	  srcp1 += 1;
	  srcp2 += 1;
	  res = a0 - b0;
	  if (res != 0)
	    return res;
	  len -= 1;
	}

      /* SRCP2 is now aligned for memory operations on `op_t'.
	 SRCP1 alignment determines if we can do a simple,
	 aligned compare or need to shuffle bits.  */

      if (srcp1 % OPSIZ == 0)
	res = memcmp_common_alignment (srcp1, srcp2, len / OPSIZ);
      else
	res = memcmp_not_common_alignment (srcp1, srcp2, len / OPSIZ);
      if (res != 0)
	return res;

      /* Number of bytes remaining in the interval [0..OPSIZ-1].  */
      srcp1 += len & -OPSIZ;
      srcp2 += len & -OPSIZ;
      len %= OPSIZ;
    }

  /* There are just a few bytes to compare.  Use byte memory operations.  */
  while (len != 0)
    {
      a0 = ((byte *) srcp1)[0];
      b0 = ((byte *) srcp2)[0];
      srcp1 += 1;
      srcp2 += 1;
      res = a0 - b0;
      if (res != 0)
	return res;
      len -= 1;
    }

  return 0;
}
#endif /* HAVE_MEMCMP && MEMCMP_BROKEN */