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