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
57typedef struct {
58 const u_char **sa;
59 int sn, si;
60} stack;
61
62static inline void simplesort
63(const u_char **, int, int, const u_char *, u_int);
64static void r_sort_a(const u_char **, int, int, const u_char *, u_int);
65static 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
90int
91radixsort(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
105int
106sradixsort(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. */
133static void
134r_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. */
235static void
236r_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
307static inline void
308simplesort(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}
| 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
57typedef struct {
58 const u_char **sa;
59 int sn, si;
60} stack;
61
62static inline void simplesort
63(const u_char **, int, int, const u_char *, u_int);
64static void r_sort_a(const u_char **, int, int, const u_char *, u_int);
65static 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
90int
91radixsort(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
105int
106sradixsort(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. */
133static void
134r_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. */
235static void
236r_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
307static inline void
308simplesort(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}
|