radixsort.c revision 1.22 1 1.22 christos /* $NetBSD: radixsort.c,v 1.22 2022/03/12 17:31:39 christos Exp $ */
2 1.6 thorpej
3 1.1 cgd /*-
4 1.4 mycroft * Copyright (c) 1990, 1993
5 1.4 mycroft * The Regents of the University of California. All rights reserved.
6 1.4 mycroft *
7 1.4 mycroft * This code is derived from software contributed to Berkeley by
8 1.4 mycroft * Peter McIlroy and by Dan Bernstein at New York University,
9 1.1 cgd *
10 1.1 cgd * Redistribution and use in source and binary forms, with or without
11 1.1 cgd * modification, are permitted provided that the following conditions
12 1.1 cgd * are met:
13 1.1 cgd * 1. Redistributions of source code must retain the above copyright
14 1.1 cgd * notice, this list of conditions and the following disclaimer.
15 1.1 cgd * 2. Redistributions in binary form must reproduce the above copyright
16 1.1 cgd * notice, this list of conditions and the following disclaimer in the
17 1.1 cgd * documentation and/or other materials provided with the distribution.
18 1.15 agc * 3. Neither the name of the University nor the names of its contributors
19 1.1 cgd * may be used to endorse or promote products derived from this software
20 1.1 cgd * without specific prior written permission.
21 1.1 cgd *
22 1.1 cgd * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 1.1 cgd * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 1.1 cgd * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 1.1 cgd * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 1.1 cgd * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 1.1 cgd * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 1.1 cgd * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 1.1 cgd * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 1.1 cgd * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 1.1 cgd * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 1.1 cgd * SUCH DAMAGE.
33 1.1 cgd */
34 1.1 cgd
35 1.8 christos #include <sys/cdefs.h>
36 1.1 cgd #if defined(LIBC_SCCS) && !defined(lint)
37 1.6 thorpej #if 0
38 1.10 perry static char sccsid[] = "@(#)radixsort.c 8.2 (Berkeley) 4/28/95";
39 1.6 thorpej #else
40 1.22 christos __RCSID("$NetBSD: radixsort.c,v 1.22 2022/03/12 17:31:39 christos Exp $");
41 1.6 thorpej #endif
42 1.1 cgd #endif /* LIBC_SCCS and not lint */
43 1.1 cgd
44 1.4 mycroft /*
45 1.4 mycroft * Radixsort routines.
46 1.4 mycroft *
47 1.4 mycroft * Program r_sort_a() is unstable but uses O(logN) extra memory for a stack.
48 1.4 mycroft * Use radixsort(a, n, trace, endchar) for this case.
49 1.4 mycroft *
50 1.4 mycroft * For stable sorting (using N extra pointers) use sradixsort(), which calls
51 1.4 mycroft * r_sort_b().
52 1.4 mycroft *
53 1.4 mycroft * For a description of this code, see D. McIlroy, P. McIlroy, K. Bostic,
54 1.4 mycroft * "Engineering Radix Sort".
55 1.4 mycroft */
56 1.4 mycroft
57 1.9 jtc #include "namespace.h"
58 1.1 cgd #include <sys/types.h>
59 1.12 lukem
60 1.12 lukem #include <assert.h>
61 1.12 lukem #include <errno.h>
62 1.1 cgd #include <stdlib.h>
63 1.9 jtc
64 1.9 jtc #ifdef __weak_alias
65 1.14 mycroft __weak_alias(radixsort,_radixsort)
66 1.14 mycroft __weak_alias(sradixsort,_sradixsort)
67 1.9 jtc #endif
68 1.1 cgd
69 1.4 mycroft typedef struct {
70 1.4 mycroft const u_char **sa;
71 1.4 mycroft int sn, si;
72 1.4 mycroft } stack;
73 1.4 mycroft
74 1.19 dsl static inline void simplesort(const u_char **, int, int, const u_char *, u_int);
75 1.19 dsl static void r_sort_a(const u_char **, int, int, const u_char *, u_int);
76 1.19 dsl static void r_sort_b(const u_char **,
77 1.19 dsl const u_char **, int, int, const u_char *, u_int);
78 1.4 mycroft
79 1.4 mycroft #define THRESHOLD 20 /* Divert to simplesort(). */
80 1.4 mycroft #define SIZE 512 /* Default stack size. */
81 1.4 mycroft
82 1.4 mycroft #define SETUP { \
83 1.4 mycroft if (tab == NULL) { \
84 1.4 mycroft tr = tr0; \
85 1.4 mycroft for (c = 0; c < endch; c++) \
86 1.4 mycroft tr0[c] = c + 1; \
87 1.4 mycroft tr0[c] = 0; \
88 1.4 mycroft for (c++; c < 256; c++) \
89 1.4 mycroft tr0[c] = c; \
90 1.4 mycroft endch = 0; \
91 1.4 mycroft } else { \
92 1.4 mycroft endch = tab[endch]; \
93 1.4 mycroft tr = tab; \
94 1.4 mycroft if (endch != 0 && endch != 255) { \
95 1.4 mycroft errno = EINVAL; \
96 1.4 mycroft return (-1); \
97 1.4 mycroft } \
98 1.4 mycroft } \
99 1.4 mycroft }
100 1.1 cgd
101 1.4 mycroft int
102 1.19 dsl radixsort(const u_char **a, int n, const u_char *tab, u_int endch)
103 1.4 mycroft {
104 1.4 mycroft const u_char *tr;
105 1.17 lukem u_int c;
106 1.4 mycroft u_char tr0[256];
107 1.4 mycroft
108 1.12 lukem _DIAGASSERT(a != NULL);
109 1.12 lukem
110 1.4 mycroft SETUP;
111 1.4 mycroft r_sort_a(a, n, 0, tr, endch);
112 1.4 mycroft return (0);
113 1.1 cgd }
114 1.1 cgd
115 1.1 cgd int
116 1.19 dsl sradixsort(const u_char **a, int n, const u_char *tab, u_int endch)
117 1.1 cgd {
118 1.4 mycroft const u_char *tr, **ta;
119 1.17 lukem u_int c;
120 1.4 mycroft u_char tr0[256];
121 1.4 mycroft
122 1.12 lukem _DIAGASSERT(a != NULL);
123 1.18 dsl if (a == NULL) {
124 1.12 lukem errno = EFAULT;
125 1.12 lukem return (-1);
126 1.12 lukem }
127 1.12 lukem
128 1.4 mycroft SETUP;
129 1.4 mycroft if (n < THRESHOLD)
130 1.4 mycroft simplesort(a, n, 0, tr, endch);
131 1.1 cgd else {
132 1.20 nia ta = NULL;
133 1.22 christos errno = reallocarr(&ta, n, sizeof(*ta));
134 1.22 christos if (errno)
135 1.22 christos return -1;
136 1.4 mycroft r_sort_b(a, ta, n, 0, tr, endch);
137 1.4 mycroft free(ta);
138 1.1 cgd }
139 1.4 mycroft return (0);
140 1.4 mycroft }
141 1.1 cgd
142 1.4 mycroft #define empty(s) (s >= sp)
143 1.4 mycroft #define pop(a, n, i) a = (--sp)->sa, n = sp->sn, i = sp->si
144 1.4 mycroft #define push(a, n, i) sp->sa = a, sp->sn = n, (sp++)->si = i
145 1.4 mycroft #define swap(a, b, t) t = a, a = b, b = t
146 1.4 mycroft
147 1.4 mycroft /* Unstable, in-place sort. */
148 1.10 perry static void
149 1.19 dsl r_sort_a(const u_char **a, int n, int i, const u_char *tr, u_int endch)
150 1.4 mycroft {
151 1.17 lukem static u_int count[256], nc, bmin;
152 1.17 lukem u_int c;
153 1.11 perry const u_char **ak, *r;
154 1.4 mycroft stack s[SIZE], *sp, *sp0, *sp1, temp;
155 1.17 lukem u_int *cp, bigc;
156 1.4 mycroft const u_char **an, *t, **aj, **top[256];
157 1.4 mycroft
158 1.12 lukem _DIAGASSERT(a != NULL);
159 1.12 lukem _DIAGASSERT(tr != NULL);
160 1.12 lukem
161 1.4 mycroft /* Set up stack. */
162 1.4 mycroft sp = s;
163 1.4 mycroft push(a, n, i);
164 1.4 mycroft while (!empty(s)) {
165 1.4 mycroft pop(a, n, i);
166 1.4 mycroft if (n < THRESHOLD) {
167 1.4 mycroft simplesort(a, n, i, tr, endch);
168 1.4 mycroft continue;
169 1.4 mycroft }
170 1.4 mycroft an = a + n;
171 1.1 cgd
172 1.4 mycroft /* Make character histogram. */
173 1.4 mycroft if (nc == 0) {
174 1.4 mycroft bmin = 255; /* First occupied bin, excluding eos. */
175 1.4 mycroft for (ak = a; ak < an;) {
176 1.4 mycroft c = tr[(*ak++)[i]];
177 1.4 mycroft if (++count[c] == 1 && c != endch) {
178 1.4 mycroft if (c < bmin)
179 1.4 mycroft bmin = c;
180 1.4 mycroft nc++;
181 1.4 mycroft }
182 1.4 mycroft }
183 1.4 mycroft if (sp + nc > s + SIZE) { /* Get more stack. */
184 1.4 mycroft r_sort_a(a, n, i, tr, endch);
185 1.4 mycroft continue;
186 1.4 mycroft }
187 1.4 mycroft }
188 1.1 cgd
189 1.1 cgd /*
190 1.4 mycroft * Set top[]; push incompletely sorted bins onto stack.
191 1.4 mycroft * top[] = pointers to last out-of-place element in bins.
192 1.4 mycroft * count[] = counts of elements in bins.
193 1.4 mycroft * Before permuting: top[c-1] + count[c] = top[c];
194 1.4 mycroft * during deal: top[c] counts down to top[c-1].
195 1.1 cgd */
196 1.4 mycroft sp0 = sp1 = sp; /* Stack position of biggest bin. */
197 1.4 mycroft bigc = 2; /* Size of biggest bin. */
198 1.4 mycroft if (endch == 0) /* Special case: set top[eos]. */
199 1.4 mycroft top[0] = ak = a + count[0];
200 1.4 mycroft else {
201 1.4 mycroft ak = a;
202 1.4 mycroft top[255] = an;
203 1.4 mycroft }
204 1.4 mycroft for (cp = count + bmin; nc > 0; cp++) {
205 1.4 mycroft while (*cp == 0) /* Find next non-empty pile. */
206 1.4 mycroft cp++;
207 1.4 mycroft if (*cp > 1) {
208 1.4 mycroft if (*cp > bigc) {
209 1.4 mycroft bigc = *cp;
210 1.4 mycroft sp1 = sp;
211 1.4 mycroft }
212 1.4 mycroft push(ak, *cp, i+1);
213 1.1 cgd }
214 1.4 mycroft top[cp-count] = ak += *cp;
215 1.4 mycroft nc--;
216 1.1 cgd }
217 1.4 mycroft swap(*sp0, *sp1, temp); /* Play it safe -- biggest bin last. */
218 1.1 cgd
219 1.1 cgd /*
220 1.4 mycroft * Permute misplacements home. Already home: everything
221 1.4 mycroft * before aj, and in bin[c], items from top[c] on.
222 1.4 mycroft * Inner loop:
223 1.4 mycroft * r = next element to put in place;
224 1.4 mycroft * ak = top[r[i]] = location to put the next element.
225 1.4 mycroft * aj = bottom of 1st disordered bin.
226 1.4 mycroft * Outer loop:
227 1.4 mycroft * Once the 1st disordered bin is done, ie. aj >= ak,
228 1.4 mycroft * aj<-aj + count[c] connects the bins in a linked list;
229 1.4 mycroft * reset count[c].
230 1.1 cgd */
231 1.4 mycroft for (aj = a; aj < an; *aj = r, aj += count[c], count[c] = 0)
232 1.4 mycroft for (r = *aj; aj < (ak = --top[c = tr[r[i]]]);)
233 1.4 mycroft swap(*ak, r, t);
234 1.4 mycroft }
235 1.4 mycroft }
236 1.4 mycroft
237 1.4 mycroft /* Stable sort, requiring additional memory. */
238 1.10 perry static void
239 1.19 dsl r_sort_b(const u_char **a, const u_char **ta, int n, int i, const u_char *tr,
240 1.19 dsl u_int endch)
241 1.4 mycroft {
242 1.17 lukem static u_int count[256], nc, bmin;
243 1.17 lukem u_int c;
244 1.11 perry const u_char **ak, **ai;
245 1.4 mycroft stack s[512], *sp, *sp0, *sp1, temp;
246 1.4 mycroft const u_char **top[256];
247 1.17 lukem u_int *cp, bigc;
248 1.4 mycroft
249 1.12 lukem _DIAGASSERT(a != NULL);
250 1.12 lukem _DIAGASSERT(ta != NULL);
251 1.12 lukem _DIAGASSERT(tr != NULL);
252 1.12 lukem
253 1.4 mycroft sp = s;
254 1.4 mycroft push(a, n, i);
255 1.4 mycroft while (!empty(s)) {
256 1.4 mycroft pop(a, n, i);
257 1.4 mycroft if (n < THRESHOLD) {
258 1.4 mycroft simplesort(a, n, i, tr, endch);
259 1.4 mycroft continue;
260 1.1 cgd }
261 1.1 cgd
262 1.4 mycroft if (nc == 0) {
263 1.4 mycroft bmin = 255;
264 1.4 mycroft for (ak = a + n; --ak >= a;) {
265 1.4 mycroft c = tr[(*ak)[i]];
266 1.4 mycroft if (++count[c] == 1 && c != endch) {
267 1.4 mycroft if (c < bmin)
268 1.4 mycroft bmin = c;
269 1.4 mycroft nc++;
270 1.4 mycroft }
271 1.4 mycroft }
272 1.4 mycroft if (sp + nc > s + SIZE) {
273 1.4 mycroft r_sort_b(a, ta, n, i, tr, endch);
274 1.4 mycroft continue;
275 1.4 mycroft }
276 1.4 mycroft }
277 1.1 cgd
278 1.4 mycroft sp0 = sp1 = sp;
279 1.4 mycroft bigc = 2;
280 1.4 mycroft if (endch == 0) {
281 1.4 mycroft top[0] = ak = a + count[0];
282 1.4 mycroft count[0] = 0;
283 1.4 mycroft } else {
284 1.4 mycroft ak = a;
285 1.4 mycroft top[255] = a + n;
286 1.4 mycroft count[255] = 0;
287 1.1 cgd }
288 1.4 mycroft for (cp = count + bmin; nc > 0; cp++) {
289 1.4 mycroft while (*cp == 0)
290 1.4 mycroft cp++;
291 1.4 mycroft if ((c = *cp) > 1) {
292 1.4 mycroft if (c > bigc) {
293 1.4 mycroft bigc = c;
294 1.4 mycroft sp1 = sp;
295 1.4 mycroft }
296 1.4 mycroft push(ak, c, i+1);
297 1.4 mycroft }
298 1.4 mycroft top[cp-count] = ak += c;
299 1.4 mycroft *cp = 0; /* Reset count[]. */
300 1.4 mycroft nc--;
301 1.1 cgd }
302 1.4 mycroft swap(*sp0, *sp1, temp);
303 1.4 mycroft
304 1.4 mycroft for (ak = ta + n, ai = a+n; ak > ta;) /* Copy to temp. */
305 1.4 mycroft *--ak = *--ai;
306 1.4 mycroft for (ak = ta+n; --ak >= ta;) /* Deal to piles. */
307 1.4 mycroft *--top[tr[(*ak)[i]]] = *ak;
308 1.1 cgd }
309 1.1 cgd }
310 1.19 dsl
311 1.19 dsl /* insertion sort */
312 1.16 perry static inline void
313 1.19 dsl simplesort(const u_char **a, int n, int b, const u_char *tr, u_int endch)
314 1.1 cgd {
315 1.11 perry u_char ch;
316 1.4 mycroft const u_char **ak, **ai, *s, *t;
317 1.12 lukem
318 1.12 lukem _DIAGASSERT(a != NULL);
319 1.12 lukem _DIAGASSERT(tr != NULL);
320 1.1 cgd
321 1.4 mycroft for (ak = a+1; --n >= 1; ak++)
322 1.4 mycroft for (ai = ak; ai > a; ai--) {
323 1.4 mycroft for (s = ai[0] + b, t = ai[-1] + b;
324 1.4 mycroft (ch = tr[*s]) != endch; s++, t++)
325 1.4 mycroft if (ch != tr[*t])
326 1.1 cgd break;
327 1.4 mycroft if (ch >= tr[*t])
328 1.4 mycroft break;
329 1.4 mycroft swap(ai[0], ai[-1], s);
330 1.4 mycroft }
331 1.1 cgd }
332