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If port provides __weak_alias(), provide an Standard C and POSIX pure
identifier namespace by renaming non standard functions and variables
such that they have a leading underscore.  The library will use those
names internally.  Weak aliases are used to provide the original names
to the API.

This is only the first part of this change.  It is most of the functions
which are implemented in C for all NetBSD ports.  Subsequent changes are
to add the same support to the remaining C files, to assembly files, and
to the automagically generated assembly source used for system calls.
When all of the above is done, ports with weak alias support should add
a definition for __weak_alias to <sys/cdefs.h>.

/*	$NetBSD: radixsort.c,v 1.9 1997/07/21 14:09:00 jtc Exp $	*/

/*-
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Peter McIlroy and by Dan Bernstein at New York University, 
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "from: @(#)radixsort.c	8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: radixsort.c,v 1.9 1997/07/21 14:09:00 jtc Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

/*
 * Radixsort routines.
 * 
 * Program r_sort_a() is unstable but uses O(logN) extra memory for a stack.
 * Use radixsort(a, n, trace, endchar) for this case.
 * 
 * For stable sorting (using N extra pointers) use sradixsort(), which calls
 * r_sort_b().
 * 
 * For a description of this code, see D. McIlroy, P. McIlroy, K. Bostic,
 * "Engineering Radix Sort".
 */

#include "namespace.h"
#include <sys/types.h>
#include <stdlib.h>
#include <errno.h>

#ifdef __weak_alias
__weak_alias(radixsort,_radixsort);
__weak_alias(sradixsort,_sradixsort);
#endif

typedef struct {
	const u_char **sa;
	int sn, si;
} stack;

static __inline void simplesort
	    __P((const u_char **, int, int, const u_char *, u_int));
static void r_sort_a __P((const u_char **, int, int, const u_char *, u_int));
static void r_sort_b __P((const u_char **,
	    const u_char **, int, int, const u_char *, u_int));

#define	THRESHOLD	20		/* Divert to simplesort(). */
#define	SIZE		512		/* Default stack size. */

#define SETUP {								\
	if (tab == NULL) {						\
		tr = tr0;						\
		for (c = 0; c < endch; c++)				\
			tr0[c] = c + 1;					\
		tr0[c] = 0;						\
		for (c++; c < 256; c++)					\
			tr0[c] = c;					\
		endch = 0;						\
	} else {							\
		endch = tab[endch];					\
		tr = tab;						\
		if (endch != 0 && endch != 255) {			\
			errno = EINVAL;					\
			return (-1);					\
		}							\
	}								\
}

int
radixsort(a, n, tab, endch)
	const u_char **a, *tab;
	int n;
	u_int endch;
{
	const u_char *tr;
	int c;
	u_char tr0[256];

	SETUP;
	r_sort_a(a, n, 0, tr, endch);
	return (0);
}

int
sradixsort(a, n, tab, endch)
	const u_char **a, *tab;
	int n;
	u_int endch;
{
	const u_char *tr, **ta;
	int c;
	u_char tr0[256];

	SETUP;
	if (n < THRESHOLD)
		simplesort(a, n, 0, tr, endch);
	else {
		if ((ta = malloc(n * sizeof(a))) == NULL)
			return (-1);
		r_sort_b(a, ta, n, 0, tr, endch);
		free(ta);
	}
	return (0);
}

#define empty(s)	(s >= sp)
#define pop(a, n, i)	a = (--sp)->sa, n = sp->sn, i = sp->si
#define push(a, n, i)	sp->sa = a, sp->sn = n, (sp++)->si = i
#define swap(a, b, t)	t = a, a = b, b = t

/* Unstable, in-place sort. */
void
r_sort_a(a, n, i, tr, endch)
	const u_char **a;
	int n, i;
	const u_char *tr;
	u_int endch;
{
	static int count[256], nc, bmin;
	register int c;
	register const u_char **ak, *r;
	stack s[SIZE], *sp, *sp0, *sp1, temp;
	int *cp, bigc;
	const u_char **an, *t, **aj, **top[256];

	/* Set up stack. */
	sp = s;
	push(a, n, i);
	while (!empty(s)) {
		pop(a, n, i);
		if (n < THRESHOLD) {
			simplesort(a, n, i, tr, endch);
			continue;
		}
		an = a + n;

		/* Make character histogram. */
		if (nc == 0) {
			bmin = 255;	/* First occupied bin, excluding eos. */
			for (ak = a; ak < an;) {
				c = tr[(*ak++)[i]];
				if (++count[c] == 1 && c != endch) {
					if (c < bmin)
						bmin = c;
					nc++;
				}
			}
			if (sp + nc > s + SIZE) {	/* Get more stack. */
				r_sort_a(a, n, i, tr, endch);
				continue;
			}
		}

		/*
		 * Set top[]; push incompletely sorted bins onto stack.
		 * top[] = pointers to last out-of-place element in bins.
		 * count[] = counts of elements in bins.
		 * Before permuting: top[c-1] + count[c] = top[c];
		 * during deal: top[c] counts down to top[c-1].
		 */
		sp0 = sp1 = sp;		/* Stack position of biggest bin. */
		bigc = 2;		/* Size of biggest bin. */
		if (endch == 0)		/* Special case: set top[eos]. */
			top[0] = ak = a + count[0];
		else {
			ak = a;
			top[255] = an;
		}
		for (cp = count + bmin; nc > 0; cp++) {
			while (*cp == 0)	/* Find next non-empty pile. */
				cp++;
			if (*cp > 1) {
				if (*cp > bigc) {
					bigc = *cp;
					sp1 = sp;
				}
				push(ak, *cp, i+1);
			}
			top[cp-count] = ak += *cp;
			nc--;
		}
		swap(*sp0, *sp1, temp);	/* Play it safe -- biggest bin last. */

		/*
		 * Permute misplacements home.  Already home: everything
		 * before aj, and in bin[c], items from top[c] on.
		 * Inner loop:
		 *	r = next element to put in place;
		 *	ak = top[r[i]] = location to put the next element.
		 *	aj = bottom of 1st disordered bin.
		 * Outer loop:
		 *	Once the 1st disordered bin is done, ie. aj >= ak,
		 *	aj<-aj + count[c] connects the bins in a linked list;
		 *	reset count[c].
		 */
		for (aj = a; aj < an;  *aj = r, aj += count[c], count[c] = 0)
			for (r = *aj;  aj < (ak = --top[c = tr[r[i]]]);)
				swap(*ak, r, t);
	}
}

/* Stable sort, requiring additional memory. */
void
r_sort_b(a, ta, n, i, tr, endch)
	const u_char **a, **ta;
	int n, i;
	const u_char *tr;
	u_int endch;
{
	static int count[256], nc, bmin;
	register int c;
	register const u_char **ak, **ai;
	stack s[512], *sp, *sp0, *sp1, temp;
	const u_char **top[256];
	int *cp, bigc;

	sp = s;
	push(a, n, i);
	while (!empty(s)) {
		pop(a, n, i);
		if (n < THRESHOLD) {
			simplesort(a, n, i, tr, endch);
			continue;
		}

		if (nc == 0) {
			bmin = 255;
			for (ak = a + n; --ak >= a;) {
				c = tr[(*ak)[i]];
				if (++count[c] == 1 && c != endch) {
					if (c < bmin)
						bmin = c;
					nc++;
				}
			}
			if (sp + nc > s + SIZE) {
				r_sort_b(a, ta, n, i, tr, endch);
				continue;
			}
		}

		sp0 = sp1 = sp;
		bigc = 2;
		if (endch == 0) {
			top[0] = ak = a + count[0];
			count[0] = 0;
		} else {
			ak = a;
			top[255] = a + n;
			count[255] = 0;
		}
		for (cp = count + bmin; nc > 0; cp++) {
			while (*cp == 0)
				cp++;
			if ((c = *cp) > 1) {
				if (c > bigc) {
					bigc = c;
					sp1 = sp;
				}
				push(ak, c, i+1);
			}
			top[cp-count] = ak += c;
			*cp = 0;			/* Reset count[]. */
			nc--;
		}
		swap(*sp0, *sp1, temp);

		for (ak = ta + n, ai = a+n; ak > ta;)	/* Copy to temp. */
			*--ak = *--ai;
		for (ak = ta+n; --ak >= ta;)		/* Deal to piles. */
			*--top[tr[(*ak)[i]]] = *ak;
	}
}
		
static __inline void
simplesort(a, n, b, tr, endch)	/* insertion sort */
	register const u_char **a;
	int n, b;
	register const u_char *tr;
	u_int endch;
{
	register u_char ch;
	const u_char  **ak, **ai, *s, *t;

	for (ak = a+1; --n >= 1; ak++)
		for (ai = ak; ai > a; ai--) {
			for (s = ai[0] + b, t = ai[-1] + b;
			    (ch = tr[*s]) != endch; s++, t++)
				if (ch != tr[*t])
					break;
			if (ch >= tr[*t])
				break;
			swap(ai[0], ai[-1], s);
		}
}