1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Peter McIlroy and by Dan Bernstein at New York University, 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 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. 23 * 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 34 * SUCH DAMAGE. 35 * 36 * $DragonFly: src/lib/libc/stdlib/radixsort.c,v 1.4 2003/09/06 08:19:16 asmodai Exp $ 37 * 38 * @(#)radixsort.c 8.2 (Berkeley) 4/28/95 39 */ 40 41 /* 42 * Radixsort routines. 43 * 44 * Program r_sort_a() is unstable but uses O(logN) extra memory for a stack. 45 * Use radixsort(a, n, trace, endchar) for this case. 46 * 47 * For stable sorting (using N extra pointers) use sradixsort(), which calls 48 * r_sort_b(). 49 * 50 * For a description of this code, see D. McIlroy, P. McIlroy, K. Bostic, 51 * "Engineering Radix Sort". 52 */ 53 54 #include <sys/types.h> 55 #include <stdlib.h> 56 #include <stddef.h> 57 #include <errno.h> 58 59 typedef struct { 60 const u_char **sa; 61 int sn, si; 62 } stack; 63 64 static inline void simplesort 65 (const u_char **, int, int, const u_char *, u_int); 66 static void r_sort_a (const u_char **, int, int, const u_char *, u_int); 67 static void r_sort_b (const u_char **, 68 const u_char **, int, int, const u_char *, u_int); 69 70 #define THRESHOLD 20 /* Divert to simplesort(). */ 71 #define SIZE 512 /* Default stack size. */ 72 73 #define SETUP { \ 74 if (tab == NULL) { \ 75 tr = tr0; \ 76 for (c = 0; c < endch; c++) \ 77 tr0[c] = c + 1; \ 78 tr0[c] = 0; \ 79 for (c++; c < 256; c++) \ 80 tr0[c] = c; \ 81 endch = 0; \ 82 } else { \ 83 endch = tab[endch]; \ 84 tr = tab; \ 85 if (endch != 0 && endch != 255) { \ 86 errno = EINVAL; \ 87 return (-1); \ 88 } \ 89 } \ 90 } 91 92 int 93 radixsort(a, n, tab, endch) 94 const u_char **a, *tab; 95 int n; 96 u_int endch; 97 { 98 const u_char *tr; 99 int c; 100 u_char tr0[256]; 101 102 SETUP; 103 r_sort_a(a, n, 0, tr, endch); 104 return (0); 105 } 106 107 int 108 sradixsort(a, n, tab, endch) 109 const u_char **a, *tab; 110 int n; 111 u_int endch; 112 { 113 const u_char *tr, **ta; 114 int c; 115 u_char tr0[256]; 116 117 SETUP; 118 if (n < THRESHOLD) 119 simplesort(a, n, 0, tr, endch); 120 else { 121 if ((ta = malloc(n * sizeof(a))) == NULL) 122 return (-1); 123 r_sort_b(a, ta, n, 0, tr, endch); 124 free(ta); 125 } 126 return (0); 127 } 128 129 #define empty(s) (s >= sp) 130 #define pop(a, n, i) a = (--sp)->sa, n = sp->sn, i = sp->si 131 #define push(a, n, i) sp->sa = a, sp->sn = n, (sp++)->si = i 132 #define swap(a, b, t) t = a, a = b, b = t 133 134 /* Unstable, in-place sort. */ 135 static void 136 r_sort_a(a, n, i, tr, endch) 137 const u_char **a; 138 int n, i; 139 const u_char *tr; 140 u_int endch; 141 { 142 static int count[256], nc, bmin; 143 int c; 144 const u_char **ak, *r; 145 stack s[SIZE], *sp, *sp0, *sp1, temp; 146 int *cp, bigc; 147 const u_char **an, *t, **aj, **top[256]; 148 149 /* Set up stack. */ 150 sp = s; 151 push(a, n, i); 152 while (!empty(s)) { 153 pop(a, n, i); 154 if (n < THRESHOLD) { 155 simplesort(a, n, i, tr, endch); 156 continue; 157 } 158 an = a + n; 159 160 /* Make character histogram. */ 161 if (nc == 0) { 162 bmin = 255; /* First occupied bin, excluding eos. */ 163 for (ak = a; ak < an;) { 164 c = tr[(*ak++)[i]]; 165 if (++count[c] == 1 && c != endch) { 166 if (c < bmin) 167 bmin = c; 168 nc++; 169 } 170 } 171 if (sp + nc > s + SIZE) { /* Get more stack. */ 172 r_sort_a(a, n, i, tr, endch); 173 continue; 174 } 175 } 176 177 /* 178 * Set top[]; push incompletely sorted bins onto stack. 179 * top[] = pointers to last out-of-place element in bins. 180 * count[] = counts of elements in bins. 181 * Before permuting: top[c-1] + count[c] = top[c]; 182 * during deal: top[c] counts down to top[c-1]. 183 */ 184 sp0 = sp1 = sp; /* Stack position of biggest bin. */ 185 bigc = 2; /* Size of biggest bin. */ 186 if (endch == 0) /* Special case: set top[eos]. */ 187 top[0] = ak = a + count[0]; 188 else { 189 ak = a; 190 top[255] = an; 191 } 192 for (cp = count + bmin; nc > 0; cp++) { 193 while (*cp == 0) /* Find next non-empty pile. */ 194 cp++; 195 if (*cp > 1) { 196 if (*cp > bigc) { 197 bigc = *cp; 198 sp1 = sp; 199 } 200 push(ak, *cp, i+1); 201 } 202 top[cp-count] = ak += *cp; 203 nc--; 204 } 205 swap(*sp0, *sp1, temp); /* Play it safe -- biggest bin last. */ 206 207 /* 208 * Permute misplacements home. Already home: everything 209 * before aj, and in bin[c], items from top[c] on. 210 * Inner loop: 211 * r = next element to put in place; 212 * ak = top[r[i]] = location to put the next element. 213 * aj = bottom of 1st disordered bin. 214 * Outer loop: 215 * Once the 1st disordered bin is done, ie. aj >= ak, 216 * aj<-aj + count[c] connects the bins in a linked list; 217 * reset count[c]. 218 */ 219 for (aj = a; aj < an; *aj = r, aj += count[c], count[c] = 0) 220 for (r = *aj; aj < (ak = --top[c = tr[r[i]]]);) 221 swap(*ak, r, t); 222 } 223 } 224 225 /* Stable sort, requiring additional memory. */ 226 static void 227 r_sort_b(a, ta, n, i, tr, endch) 228 const u_char **a, **ta; 229 int n, i; 230 const u_char *tr; 231 u_int endch; 232 { 233 static int count[256], nc, bmin; 234 int c; 235 const u_char **ak, **ai; 236 stack s[512], *sp, *sp0, *sp1, temp; 237 const u_char **top[256]; 238 int *cp, bigc; 239 240 sp = s; 241 push(a, n, i); 242 while (!empty(s)) { 243 pop(a, n, i); 244 if (n < THRESHOLD) { 245 simplesort(a, n, i, tr, endch); 246 continue; 247 } 248 249 if (nc == 0) { 250 bmin = 255; 251 for (ak = a + n; --ak >= a;) { 252 c = tr[(*ak)[i]]; 253 if (++count[c] == 1 && c != endch) { 254 if (c < bmin) 255 bmin = c; 256 nc++; 257 } 258 } 259 if (sp + nc > s + SIZE) { 260 r_sort_b(a, ta, n, i, tr, endch); 261 continue; 262 } 263 } 264 265 sp0 = sp1 = sp; 266 bigc = 2; 267 if (endch == 0) { 268 top[0] = ak = a + count[0]; 269 count[0] = 0; 270 } else { 271 ak = a; 272 top[255] = a + n; 273 count[255] = 0; 274 } 275 for (cp = count + bmin; nc > 0; cp++) { 276 while (*cp == 0) 277 cp++; 278 if ((c = *cp) > 1) { 279 if (c > bigc) { 280 bigc = c; 281 sp1 = sp; 282 } 283 push(ak, c, i+1); 284 } 285 top[cp-count] = ak += c; 286 *cp = 0; /* Reset count[]. */ 287 nc--; 288 } 289 swap(*sp0, *sp1, temp); 290 291 for (ak = ta + n, ai = a+n; ak > ta;) /* Copy to temp. */ 292 *--ak = *--ai; 293 for (ak = ta+n; --ak >= ta;) /* Deal to piles. */ 294 *--top[tr[(*ak)[i]]] = *ak; 295 } 296 } 297 298 static inline void 299 simplesort(a, n, b, tr, endch) /* insertion sort */ 300 const u_char **a; 301 int n, b; 302 const u_char *tr; 303 u_int endch; 304 { 305 u_char ch; 306 const u_char **ak, **ai, *s, *t; 307 308 for (ak = a+1; --n >= 1; ak++) 309 for (ai = ak; ai > a; ai--) { 310 for (s = ai[0] + b, t = ai[-1] + b; 311 (ch = tr[*s]) != endch; s++, t++) 312 if (ch != tr[*t]) 313 break; 314 if (ch >= tr[*t]) 315 break; 316 swap(ai[0], ai[-1], s); 317 } 318 } 319