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 1.5 2005/11/20 12:37:49 swildner 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(const u_char **a, int n, const u_char *tab, u_int endch) 94 { 95 const u_char *tr; 96 int c; 97 u_char tr0[256]; 98 99 SETUP; 100 r_sort_a(a, n, 0, tr, endch); 101 return (0); 102 } 103 104 int 105 sradixsort(const u_char **a, int n, const u_char *tab, u_int endch) 106 { 107 const u_char *tr, **ta; 108 int c; 109 u_char tr0[256]; 110 111 SETUP; 112 if (n < THRESHOLD) 113 simplesort(a, n, 0, tr, endch); 114 else { 115 if ((ta = malloc(n * sizeof(a))) == NULL) 116 return (-1); 117 r_sort_b(a, ta, n, 0, tr, endch); 118 free(ta); 119 } 120 return (0); 121 } 122 123 #define empty(s) (s >= sp) 124 #define pop(a, n, i) a = (--sp)->sa, n = sp->sn, i = sp->si 125 #define push(a, n, i) sp->sa = a, sp->sn = n, (sp++)->si = i 126 #define swap(a, b, t) t = a, a = b, b = t 127 128 /* Unstable, in-place sort. */ 129 static void 130 r_sort_a(const u_char **a, int n, int i, const u_char *tr, u_int endch) 131 { 132 static int count[256], nc, bmin; 133 int c; 134 const u_char **ak, *r; 135 stack s[SIZE], *sp, *sp0, *sp1, temp; 136 int *cp, bigc; 137 const u_char **an, *t, **aj, **top[256]; 138 139 /* Set up stack. */ 140 sp = s; 141 push(a, n, i); 142 while (!empty(s)) { 143 pop(a, n, i); 144 if (n < THRESHOLD) { 145 simplesort(a, n, i, tr, endch); 146 continue; 147 } 148 an = a + n; 149 150 /* Make character histogram. */ 151 if (nc == 0) { 152 bmin = 255; /* First occupied bin, excluding eos. */ 153 for (ak = a; ak < an;) { 154 c = tr[(*ak++)[i]]; 155 if (++count[c] == 1 && c != endch) { 156 if (c < bmin) 157 bmin = c; 158 nc++; 159 } 160 } 161 if (sp + nc > s + SIZE) { /* Get more stack. */ 162 r_sort_a(a, n, i, tr, endch); 163 continue; 164 } 165 } 166 167 /* 168 * Set top[]; push incompletely sorted bins onto stack. 169 * top[] = pointers to last out-of-place element in bins. 170 * count[] = counts of elements in bins. 171 * Before permuting: top[c-1] + count[c] = top[c]; 172 * during deal: top[c] counts down to top[c-1]. 173 */ 174 sp0 = sp1 = sp; /* Stack position of biggest bin. */ 175 bigc = 2; /* Size of biggest bin. */ 176 if (endch == 0) /* Special case: set top[eos]. */ 177 top[0] = ak = a + count[0]; 178 else { 179 ak = a; 180 top[255] = an; 181 } 182 for (cp = count + bmin; nc > 0; cp++) { 183 while (*cp == 0) /* Find next non-empty pile. */ 184 cp++; 185 if (*cp > 1) { 186 if (*cp > bigc) { 187 bigc = *cp; 188 sp1 = sp; 189 } 190 push(ak, *cp, i+1); 191 } 192 top[cp-count] = ak += *cp; 193 nc--; 194 } 195 swap(*sp0, *sp1, temp); /* Play it safe -- biggest bin last. */ 196 197 /* 198 * Permute misplacements home. Already home: everything 199 * before aj, and in bin[c], items from top[c] on. 200 * Inner loop: 201 * r = next element to put in place; 202 * ak = top[r[i]] = location to put the next element. 203 * aj = bottom of 1st disordered bin. 204 * Outer loop: 205 * Once the 1st disordered bin is done, ie. aj >= ak, 206 * aj<-aj + count[c] connects the bins in a linked list; 207 * reset count[c]. 208 */ 209 for (aj = a; aj < an; *aj = r, aj += count[c], count[c] = 0) 210 for (r = *aj; aj < (ak = --top[c = tr[r[i]]]);) 211 swap(*ak, r, t); 212 } 213 } 214 215 /* Stable sort, requiring additional memory. */ 216 static void 217 r_sort_b(const u_char **a, const u_char **ta, int n, int i, const u_char *tr, 218 u_int endch) 219 { 220 static int count[256], nc, bmin; 221 int c; 222 const u_char **ak, **ai; 223 stack s[512], *sp, *sp0, *sp1, temp; 224 const u_char **top[256]; 225 int *cp, bigc; 226 227 sp = s; 228 push(a, n, i); 229 while (!empty(s)) { 230 pop(a, n, i); 231 if (n < THRESHOLD) { 232 simplesort(a, n, i, tr, endch); 233 continue; 234 } 235 236 if (nc == 0) { 237 bmin = 255; 238 for (ak = a + n; --ak >= a;) { 239 c = tr[(*ak)[i]]; 240 if (++count[c] == 1 && c != endch) { 241 if (c < bmin) 242 bmin = c; 243 nc++; 244 } 245 } 246 if (sp + nc > s + SIZE) { 247 r_sort_b(a, ta, n, i, tr, endch); 248 continue; 249 } 250 } 251 252 sp0 = sp1 = sp; 253 bigc = 2; 254 if (endch == 0) { 255 top[0] = ak = a + count[0]; 256 count[0] = 0; 257 } else { 258 ak = a; 259 top[255] = a + n; 260 count[255] = 0; 261 } 262 for (cp = count + bmin; nc > 0; cp++) { 263 while (*cp == 0) 264 cp++; 265 if ((c = *cp) > 1) { 266 if (c > bigc) { 267 bigc = c; 268 sp1 = sp; 269 } 270 push(ak, c, i+1); 271 } 272 top[cp-count] = ak += c; 273 *cp = 0; /* Reset count[]. */ 274 nc--; 275 } 276 swap(*sp0, *sp1, temp); 277 278 for (ak = ta + n, ai = a+n; ak > ta;) /* Copy to temp. */ 279 *--ak = *--ai; 280 for (ak = ta+n; --ak >= ta;) /* Deal to piles. */ 281 *--top[tr[(*ak)[i]]] = *ak; 282 } 283 } 284 285 /* insertion sort */ 286 static inline void 287 simplesort(const u_char **a, int n, int b, const u_char *tr, u_int endch) 288 { 289 u_char ch; 290 const u_char **ak, **ai, *s, *t; 291 292 for (ak = a+1; --n >= 1; ak++) 293 for (ai = ak; ai > a; ai--) { 294 for (s = ai[0] + b, t = ai[-1] + b; 295 (ch = tr[*s]) != endch; s++, t++) 296 if (ch != tr[*t]) 297 break; 298 if (ch >= tr[*t]) 299 break; 300 swap(ai[0], ai[-1], s); 301 } 302 } 303