Commit be6ab549869d5d6e0ab52eac52537963fa6f71c4

Guillem Jover 2011-02-25T18:17:16

Add new mergesort function Taken from FreeBSD.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
diff --git a/Makefile b/Makefile
index 4aa64ef..3c5cdce 100644
--- a/Makefile
+++ b/Makefile
@@ -28,6 +28,7 @@ LIB_SRCS := \
 	flopen.c \
 	getpeereid.c \
 	heapsort.c \
+	merge.c \
 	humanize_number.c \
 	dehumanize_number.c \
 	inet_net_pton.c \
diff --git a/Versions b/Versions
index 7c9437e..cac2efe 100644
--- a/Versions
+++ b/Versions
@@ -68,5 +68,7 @@ LIBBSD_0.2 {
 LIBBSD_0.3 {
     reallocf;
     getpeereid;
+
+    mergesort;
 } LIBBSD_0.2;
 
diff --git a/include/bsd/stdlib.h b/include/bsd/stdlib.h
index 9e1d640..bfe3027 100644
--- a/include/bsd/stdlib.h
+++ b/include/bsd/stdlib.h
@@ -1,7 +1,7 @@
 /*
  * Copyright © 2005 Aurelien Jarno
  * Copyright © 2006 Robert Millan
- * Copyright © 2008, 2009, 2010 Guillem Jover
+ * Copyright © 2008-2011 Guillem Jover
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -52,6 +52,8 @@ const char *getprogname(void);
 void setprogname(const char *);
 
 int heapsort (void *, size_t, size_t, int (*)(const void *, const void *));
+int mergesort(void *base, size_t nmemb, size_t size,
+              int (*cmp)(const void *, const void *));
 
 void *reallocf(void *ptr, size_t size);
 
diff --git a/src/merge.c b/src/merge.c
new file mode 100644
index 0000000..e1078e7
--- /dev/null
+++ b/src/merge.c
@@ -0,0 +1,351 @@
+/*-
+ * Copyright (c) 1992, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Peter McIlroy.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)merge.c	8.2 (Berkeley) 2/14/94";
+#endif /* LIBC_SCCS and not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+/*
+ * Hybrid exponential search/linear search merge sort with hybrid
+ * natural/pairwise first pass.  Requires about .3% more comparisons
+ * for random data than LSMS with pairwise first pass alone.
+ * It works for objects as small as two bytes.
+ */
+
+#define NATURAL
+#define THRESHOLD 16	/* Best choice for natural merge cut-off. */
+
+/* #define NATURAL to get hybrid natural merge.
+ * (The default is pairwise merging.)
+ */
+
+#include <sys/types.h>
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+static void setup(u_char *, u_char *, size_t, size_t,
+    int (*)(const void *, const void *));
+static void insertionsort(u_char *, size_t, size_t,
+    int (*)(const void *, const void *));
+
+#define ISIZE sizeof(int)
+#define PSIZE sizeof(u_char *)
+#define ICOPY_LIST(src, dst, last)				\
+	do							\
+	*(int*)dst = *(int*)src, src += ISIZE, dst += ISIZE;	\
+	while(src < last)
+#define ICOPY_ELT(src, dst, i)					\
+	do							\
+	*(int*) dst = *(int*) src, src += ISIZE, dst += ISIZE;	\
+	while (i -= ISIZE)
+
+#define CCOPY_LIST(src, dst, last)		\
+	do					\
+		*dst++ = *src++;		\
+	while (src < last)
+#define CCOPY_ELT(src, dst, i)			\
+	do					\
+		*dst++ = *src++;		\
+	while (i -= 1)
+
+/*
+ * Find the next possible pointer head.  (Trickery for forcing an array
+ * to do double duty as a linked list when objects do not align with word
+ * boundaries.
+ */
+/* Assumption: PSIZE is a power of 2. */
+#define EVAL(p) (u_char **)						\
+	((u_char *)0 +							\
+	    (((u_char *)p + PSIZE - 1 - (u_char *) 0) & ~(PSIZE - 1)))
+
+/*
+ * Arguments are as for qsort.
+ */
+int
+mergesort(base, nmemb, size, cmp)
+	void *base;
+	size_t nmemb;
+	size_t size;
+	int (*cmp)(const void *, const void *);
+{
+	size_t i;
+	int sense;
+	int big, iflag;
+	u_char *f1, *f2, *t, *b, *tp2, *q, *l1, *l2;
+	u_char *list2, *list1, *p2, *p, *last, **p1;
+
+	if (size < PSIZE / 2) {		/* Pointers must fit into 2 * size. */
+		errno = EINVAL;
+		return (-1);
+	}
+
+	if (nmemb == 0)
+		return (0);
+
+	/*
+	 * XXX
+	 * Stupid subtraction for the Cray.
+	 */
+	iflag = 0;
+	if (!(size % ISIZE) && !(((char *)base - (char *)0) % ISIZE))
+		iflag = 1;
+
+	if ((list2 = malloc(nmemb * size + PSIZE)) == NULL)
+		return (-1);
+
+	list1 = base;
+	setup(list1, list2, nmemb, size, cmp);
+	last = list2 + nmemb * size;
+	i = big = 0;
+	while (*EVAL(list2) != last) {
+	    l2 = list1;
+	    p1 = EVAL(list1);
+	    for (tp2 = p2 = list2; p2 != last; p1 = EVAL(l2)) {
+	    	p2 = *EVAL(p2);
+	    	f1 = l2;
+	    	f2 = l1 = list1 + (p2 - list2);
+	    	if (p2 != last)
+	    		p2 = *EVAL(p2);
+	    	l2 = list1 + (p2 - list2);
+	    	while (f1 < l1 && f2 < l2) {
+	    		if ((*cmp)(f1, f2) <= 0) {
+	    			q = f2;
+	    			b = f1, t = l1;
+	    			sense = -1;
+	    		} else {
+	    			q = f1;
+	    			b = f2, t = l2;
+	    			sense = 0;
+	    		}
+	    		if (!big) {	/* here i = 0 */
+				while ((b += size) < t && cmp(q, b) >sense)
+	    				if (++i == 6) {
+	    					big = 1;
+	    					goto EXPONENTIAL;
+	    				}
+	    		} else {
+EXPONENTIAL:	    		for (i = size; ; i <<= 1)
+	    				if ((p = (b + i)) >= t) {
+	    					if ((p = t - size) > b &&
+						    (*cmp)(q, p) <= sense)
+	    						t = p;
+	    					else
+	    						b = p;
+	    					break;
+	    				} else if ((*cmp)(q, p) <= sense) {
+	    					t = p;
+	    					if (i == size)
+	    						big = 0;
+	    					goto FASTCASE;
+	    				} else
+	    					b = p;
+				while (t > b+size) {
+	    				i = (((t - b) / size) >> 1) * size;
+	    				if ((*cmp)(q, p = b + i) <= sense)
+	    					t = p;
+	    				else
+	    					b = p;
+	    			}
+	    			goto COPY;
+FASTCASE:	    		while (i > size)
+	    				if ((*cmp)(q,
+	    					p = b + (i >>= 1)) <= sense)
+	    					t = p;
+	    				else
+	    					b = p;
+COPY:	    			b = t;
+	    		}
+	    		i = size;
+	    		if (q == f1) {
+	    			if (iflag) {
+	    				ICOPY_LIST(f2, tp2, b);
+	    				ICOPY_ELT(f1, tp2, i);
+	    			} else {
+	    				CCOPY_LIST(f2, tp2, b);
+	    				CCOPY_ELT(f1, tp2, i);
+	    			}
+	    		} else {
+	    			if (iflag) {
+	    				ICOPY_LIST(f1, tp2, b);
+	    				ICOPY_ELT(f2, tp2, i);
+	    			} else {
+	    				CCOPY_LIST(f1, tp2, b);
+	    				CCOPY_ELT(f2, tp2, i);
+	    			}
+	    		}
+	    	}
+	    	if (f2 < l2) {
+	    		if (iflag)
+	    			ICOPY_LIST(f2, tp2, l2);
+	    		else
+	    			CCOPY_LIST(f2, tp2, l2);
+	    	} else if (f1 < l1) {
+	    		if (iflag)
+	    			ICOPY_LIST(f1, tp2, l1);
+	    		else
+	    			CCOPY_LIST(f1, tp2, l1);
+	    	}
+	    	*p1 = l2;
+	    }
+	    tp2 = list1;	/* swap list1, list2 */
+	    list1 = list2;
+	    list2 = tp2;
+	    last = list2 + nmemb*size;
+	}
+	if (base == list2) {
+		memmove(list2, list1, nmemb*size);
+		list2 = list1;
+	}
+	free(list2);
+	return (0);
+}
+
+#define	swap(a, b) {					\
+		s = b;					\
+		i = size;				\
+		do {					\
+			tmp = *a; *a++ = *s; *s++ = tmp; \
+		} while (--i);				\
+		a -= size;				\
+	}
+#define reverse(bot, top) {				\
+	s = top;					\
+	do {						\
+		i = size;				\
+		do {					\
+			tmp = *bot; *bot++ = *s; *s++ = tmp; \
+		} while (--i);				\
+		s -= size2;				\
+	} while(bot < s);				\
+}
+
+/*
+ * Optional hybrid natural/pairwise first pass.  Eats up list1 in runs of
+ * increasing order, list2 in a corresponding linked list.  Checks for runs
+ * when THRESHOLD/2 pairs compare with same sense.  (Only used when NATURAL
+ * is defined.  Otherwise simple pairwise merging is used.)
+ */
+void
+setup(list1, list2, n, size, cmp)
+	size_t n, size;
+	int (*cmp)(const void *, const void *);
+	u_char *list1, *list2;
+{
+	int i, length, size2, tmp, sense;
+	u_char *f1, *f2, *s, *l2, *last, *p2;
+
+	size2 = size*2;
+	if (n <= 5) {
+		insertionsort(list1, n, size, cmp);
+		*EVAL(list2) = (u_char*) list2 + n*size;
+		return;
+	}
+	/*
+	 * Avoid running pointers out of bounds; limit n to evens
+	 * for simplicity.
+	 */
+	i = 4 + (n & 1);
+	insertionsort(list1 + (n - i) * size, i, size, cmp);
+	last = list1 + size * (n - i);
+	*EVAL(list2 + (last - list1)) = list2 + n * size;
+
+#ifdef NATURAL
+	p2 = list2;
+	f1 = list1;
+	sense = (cmp(f1, f1 + size) > 0);
+	for (; f1 < last; sense = !sense) {
+		length = 2;
+					/* Find pairs with same sense. */
+		for (f2 = f1 + size2; f2 < last; f2 += size2) {
+			if ((cmp(f2, f2+ size) > 0) != sense)
+				break;
+			length += 2;
+		}
+		if (length < THRESHOLD) {		/* Pairwise merge */
+			do {
+				p2 = *EVAL(p2) = f1 + size2 - list1 + list2;
+				if (sense > 0)
+					swap (f1, f1 + size);
+			} while ((f1 += size2) < f2);
+		} else {				/* Natural merge */
+			l2 = f2;
+			for (f2 = f1 + size2; f2 < l2; f2 += size2) {
+				if ((cmp(f2-size, f2) > 0) != sense) {
+					p2 = *EVAL(p2) = f2 - list1 + list2;
+					if (sense > 0)
+						reverse(f1, f2-size);
+					f1 = f2;
+				}
+			}
+			if (sense > 0)
+				reverse (f1, f2-size);
+			f1 = f2;
+			if (f2 < last || cmp(f2 - size, f2) > 0)
+				p2 = *EVAL(p2) = f2 - list1 + list2;
+			else
+				p2 = *EVAL(p2) = list2 + n*size;
+		}
+	}
+#else		/* pairwise merge only. */
+	for (f1 = list1, p2 = list2; f1 < last; f1 += size2) {
+		p2 = *EVAL(p2) = p2 + size2;
+		if (cmp (f1, f1 + size) > 0)
+			swap(f1, f1 + size);
+	}
+#endif /* NATURAL */
+}
+
+/*
+ * This is to avoid out-of-bounds addresses in sorting the
+ * last 4 elements.
+ */
+static void
+insertionsort(a, n, size, cmp)
+	u_char *a;
+	size_t n, size;
+	int (*cmp)(const void *, const void *);
+{
+	u_char *ai, *s, *t, *u, tmp;
+	int i;
+
+	for (ai = a+size; --n >= 1; ai += size)
+		for (t = ai; t > a; t -= size) {
+			u = t - size;
+			if (cmp(u, t) <= 0)
+				break;
+			swap(u, t);
+		}
+}