2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Peter McIlroy and by Dan Bernstein at New York University,
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)radixsort.c 8.2 (Berkeley) 4/28/95";
39 #endif /* LIBC_SCCS and not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
46 * Program r_sort_a() is unstable but uses O(logN) extra memory for a stack.
47 * Use radixsort(a, n, trace, endchar) for this case.
49 * For stable sorting (using N extra pointers) use sradixsort(), which calls
52 * For a description of this code, see D. McIlroy, P. McIlroy, K. Bostic,
53 * "Engineering Radix Sort".
56 #include <sys/types.h>
66 static inline void simplesort
67 (const u_char **, int, int, const u_char *, u_int);
68 static void r_sort_a(const u_char **, int, int, const u_char *, u_int);
69 static void r_sort_b(const u_char **, const u_char **, int, int,
70 const u_char *, u_int);
72 #define THRESHOLD 20 /* Divert to simplesort(). */
73 #define SIZE 512 /* Default stack size. */
78 for (c = 0; c < endch; c++) \
81 for (c++; c < 256; c++) \
87 if (endch != 0 && endch != 255) { \
95 radixsort(a, n, tab, endch)
96 const u_char **a, *tab;
105 r_sort_a(a, n, 0, tr, endch);
110 sradixsort(a, n, tab, endch)
111 const u_char **a, *tab;
115 const u_char *tr, **ta;
121 simplesort(a, n, 0, tr, endch);
123 if ((ta = malloc(n * sizeof(a))) == NULL)
125 r_sort_b(a, ta, n, 0, tr, endch);
131 #define empty(s) (s >= sp)
132 #define pop(a, n, i) a = (--sp)->sa, n = sp->sn, i = sp->si
133 #define push(a, n, i) sp->sa = a, sp->sn = n, (sp++)->si = i
134 #define swap(a, b, t) t = a, a = b, b = t
136 /* Unstable, in-place sort. */
138 r_sort_a(a, n, i, tr, endch)
144 static int count[256], nc, bmin;
146 const u_char **ak, *r;
147 stack s[SIZE], *sp, *sp0, *sp1, temp;
149 const u_char **an, *t, **aj, **top[256];
157 simplesort(a, n, i, tr, endch);
162 /* Make character histogram. */
164 bmin = 255; /* First occupied bin, excluding eos. */
165 for (ak = a; ak < an;) {
167 if (++count[c] == 1 && c != endch) {
173 if (sp + nc > s + SIZE) { /* Get more stack. */
174 r_sort_a(a, n, i, tr, endch);
180 * Special case: if all strings have the same
181 * character at position i, move on to the next
184 if (nc == 1 && count[bmin] == n) {
186 nc = count[bmin] = 0;
191 * Set top[]; push incompletely sorted bins onto stack.
192 * top[] = pointers to last out-of-place element in bins.
193 * count[] = counts of elements in bins.
194 * Before permuting: top[c-1] + count[c] = top[c];
195 * during deal: top[c] counts down to top[c-1].
197 sp0 = sp1 = sp; /* Stack position of biggest bin. */
198 bigc = 2; /* Size of biggest bin. */
199 if (endch == 0) /* Special case: set top[eos]. */
200 top[0] = ak = a + count[0];
205 for (cp = count + bmin; nc > 0; cp++) {
206 while (*cp == 0) /* Find next non-empty pile. */
215 top[cp-count] = ak += *cp;
218 swap(*sp0, *sp1, temp); /* Play it safe -- biggest bin last. */
221 * Permute misplacements home. Already home: everything
222 * before aj, and in bin[c], items from top[c] on.
224 * r = next element to put in place;
225 * ak = top[r[i]] = location to put the next element.
226 * aj = bottom of 1st disordered bin.
228 * Once the 1st disordered bin is done, ie. aj >= ak,
229 * aj<-aj + count[c] connects the bins in a linked list;
232 for (aj = a; aj < an; *aj = r, aj += count[c], count[c] = 0)
233 for (r = *aj; aj < (ak = --top[c = tr[r[i]]]);)
238 /* Stable sort, requiring additional memory. */
240 r_sort_b(a, ta, n, i, tr, endch)
241 const u_char **a, **ta;
246 static int count[256], nc, bmin;
248 const u_char **ak, **ai;
249 stack s[512], *sp, *sp0, *sp1, temp;
250 const u_char **top[256];
258 simplesort(a, n, i, tr, endch);
264 for (ak = a + n; --ak >= a;) {
266 if (++count[c] == 1 && c != endch) {
272 if (sp + nc > s + SIZE) {
273 r_sort_b(a, ta, n, i, tr, endch);
281 top[0] = ak = a + count[0];
288 for (cp = count + bmin; nc > 0; cp++) {
298 top[cp-count] = ak += c;
299 *cp = 0; /* Reset count[]. */
302 swap(*sp0, *sp1, temp);
304 for (ak = ta + n, ai = a+n; ak > ta;) /* Copy to temp. */
306 for (ak = ta+n; --ak >= ta;) /* Deal to piles. */
307 *--top[tr[(*ak)[i]]] = *ak;
312 simplesort(a, n, b, tr, endch) /* insertion sort */
319 const u_char **ak, **ai, *s, *t;
321 for (ak = a+1; --n >= 1; ak++)
322 for (ai = ak; ai > a; ai--) {
323 for (s = ai[0] + b, t = ai[-1] + b;
324 (ch = tr[*s]) != endch; s++, t++)
329 swap(ai[0], ai[-1], s);