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 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 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 <errno.h> 57 58 #include <errno_private.h> 59 60 typedef struct { 61 const u_char **sa; 62 int sn, si; 63 } stack; 64 65 static inline void simplesort(u_char const **, int, int, u_char const *, u_int); 66 static void r_sort_a(u_char const **, int, int, u_char const *, u_int); 67 static void r_sort_b(u_char const **, u_char const **, int, int, u_char const *, u_int); 68 69 #define THRESHOLD 20 /* Divert to simplesort(). */ 70 #define SIZE 512 /* Default stack size. */ 71 72 #define SETUP { \ 73 if (tab == NULL) { \ 74 tr = tr0; \ 75 for (c = 0; c < endch; c++) \ 76 tr0[c] = c + 1; \ 77 tr0[c] = 0; \ 78 for (c++; c < 256; c++) \ 79 tr0[c] = c; \ 80 endch = 0; \ 81 } else { \ 82 endch = tab[endch]; \ 83 tr = tab; \ 84 if (endch != 0 && endch != 255) { \ 85 /* __set_errno(EINVAL); */ \ 86 return (-1); \ 87 } \ 88 } \ 89 } 90 91 int 92 radixsort(u_char const **a, int n, u_char const *tab, u_int endch) 93 { 94 u_char const *tr; 95 u_int c; 96 u_char tr0[256]; 97 98 SETUP; 99 r_sort_a(a, n, 0, tr, endch); 100 return (0); 101 } 102 103 int 104 sradixsort(u_char const **a, int n, u_char const *tab, u_int endch) 105 { 106 u_char const *tr; 107 u_char const **ta; 108 u_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(u_char const **a, int n, int i, u_char const *tr, u_int endch) 131 { 132 static u_int count[256]; 133 static int nc; 134 static u_int bmin; 135 u_int c; 136 u_char const **ak; 137 u_char const *r; 138 stack s[SIZE]; 139 stack *sp; 140 stack *sp0; 141 stack *sp1; 142 stack temp; 143 u_int *cp; 144 u_int bigc; 145 u_char const **an; 146 u_char const *t; 147 u_char const **aj; 148 u_char const **top[256]; 149 150 /* Set up stack. */ 151 sp = s; 152 push(a, n, i); 153 while (!empty(s)) { 154 pop(a, n, i); 155 if (n < THRESHOLD) { 156 simplesort(a, n, i, tr, endch); 157 continue; 158 } 159 an = a + n; 160 161 /* Make character histogram. */ 162 if (nc == 0) { 163 bmin = 255; /* First occupied bin, excluding eos. */ 164 for (ak = a; ak < an;) { 165 c = tr[(*ak++)[i]]; 166 if (++count[c] == 1 && c != endch) { 167 if (c < bmin) 168 bmin = c; 169 nc++; 170 } 171 } 172 if (sp + nc > s + SIZE) { /* Get more stack. */ 173 r_sort_a(a, n, i, tr, endch); 174 continue; 175 } 176 } 177 178 /* 179 * Set top[]; push incompletely sorted bins onto stack. 180 * top[] = pointers to last out-of-place element in bins. 181 * count[] = counts of elements in bins. 182 * Before permuting: top[c-1] + count[c] = top[c]; 183 * during deal: top[c] counts down to top[c-1]. 184 */ 185 sp0 = sp1 = sp; /* Stack position of biggest bin. */ 186 bigc = 2; /* Size of biggest bin. */ 187 if (endch == 0) /* Special case: set top[eos]. */ 188 top[0] = ak = a + count[0]; 189 else { 190 ak = a; 191 top[255] = an; 192 } 193 for (cp = count + bmin; nc > 0; cp++) { 194 while (*cp == 0) /* Find next non-empty pile. */ 195 cp++; 196 if (*cp > 1) { 197 if (*cp > bigc) { 198 bigc = *cp; 199 sp1 = sp; 200 } 201 push(ak, *cp, i+1); 202 } 203 top[cp-count] = ak += *cp; 204 nc--; 205 } 206 swap(*sp0, *sp1, temp); /* Play it safe -- biggest bin last. */ 207 208 /* 209 * Permute misplacements home. Already home: everything 210 * before aj, and in bin[c], items from top[c] on. 211 * Inner loop: 212 * r = next element to put in place; 213 * ak = top[r[i]] = location to put the next element. 214 * aj = bottom of 1st disordered bin. 215 * Outer loop: 216 * Once the 1st disordered bin is done, ie. aj >= ak, 217 * aj<-aj + count[c] connects the bins in a linked list; 218 * reset count[c]. 219 */ 220 for (aj = a; aj < an; *aj = r, aj += count[c], count[c] = 0) 221 for (r = *aj; aj < (ak = --top[c = tr[r[i]]]);) 222 swap(*ak, r, t); 223 } 224 } 225 226 /* Stable sort, requiring additional memory. */ 227 static 228 void 229 r_sort_b(u_char const **a, u_char const **ta, int n, int i, u_char const *tr, u_int endch) 230 { 231 static int count[256]; 232 static u_int nc; 233 static u_int bmin; 234 u_int c; 235 u_char const **ak, **ai; 236 stack s[512], *sp, *sp0, *sp1, temp; 237 u_char const **top[256]; 238 int *cp; 239 u_int bigc; 240 241 sp = s; 242 push(a, n, i); 243 while (!empty(s)) { 244 pop(a, n, i); 245 if (n < THRESHOLD) { 246 simplesort(a, n, i, tr, endch); 247 continue; 248 } 249 250 if (nc == 0) { 251 bmin = 255; 252 for (ak = a + n; --ak >= a;) { 253 c = tr[(*ak)[i]]; 254 if (++count[c] == 1 && c != endch) { 255 if (c < bmin) 256 bmin = c; 257 nc++; 258 } 259 } 260 if (sp + nc > s + SIZE) { 261 r_sort_b(a, ta, n, i, tr, endch); 262 continue; 263 } 264 } 265 266 sp0 = sp1 = sp; 267 bigc = 2; 268 if (endch == 0) { 269 top[0] = ak = a + count[0]; 270 count[0] = 0; 271 } else { 272 ak = a; 273 top[255] = a + n; 274 count[255] = 0; 275 } 276 for (cp = count + bmin; nc > 0; cp++) { 277 while (*cp == 0) 278 cp++; 279 if ((c = *cp) > 1) { 280 if (c > bigc) { 281 bigc = c; 282 sp1 = sp; 283 } 284 push(ak, c, i+1); 285 } 286 top[cp-count] = ak += c; 287 *cp = 0; /* Reset count[]. */ 288 nc--; 289 } 290 swap(*sp0, *sp1, temp); 291 292 for (ak = ta + n, ai = a+n; ak > ta;) /* Copy to temp. */ 293 *--ak = *--ai; 294 for (ak = ta+n; --ak >= ta;) /* Deal to piles. */ 295 *--top[tr[(*ak)[i]]] = *ak; 296 } 297 } 298 299 static inline 300 void 301 simplesort(u_char const **a, int n, int b, u_char const *tr, u_int endch) /* insertion sort */ 302 { 303 u_char ch; 304 u_char const **ak; 305 u_char const **ai; 306 u_char const *s; 307 u_char const *t; 308 309 for (ak = a+1; --n >= 1; ak++) { 310 for (ai = ak; ai > a; ai--) { 311 for (s = ai[0] + b, t = ai[-1] + b; 312 (ch = tr[*s]) != endch; s++, t++) 313 if (ch != tr[*t]) 314 break; 315 if (ch >= tr[*t]) 316 break; 317 swap(ai[0], ai[-1], s); 318 } 319 } 320 } 321