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GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libc/stdlib/merge.c	Lines:	0	101	0.0 %
Date:	2017-11-07	Branches:	0	132	0.0 %


/*	$OpenBSD: merge.c,v 1.10 2015/06/21 03:20:56 millert Exp $ */
/*-
 * 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.
 * 3. 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.
 */

/*
 * 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 (*)());
static void insertionsort(u_char *, size_t, size_t, int (*)());

#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(void *base, size_t nmemb, size_t size,
    int (*cmp)(const void *, const void *))
{
	int i, 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(u_char *list1, u_char *list2, size_t n, size_t size,
    int (*cmp)(const void *, const void *))
{
	int i, length, size2, sense;
	u_char tmp, *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(u_char *a, size_t n, size_t 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);
		}
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: merge.c,v 1.10 2015/06/21 03:20:56 millert Exp $ */
2			/*-
3			* Copyright (c) 1992, 1993
4			* The Regents of the University of California. All rights reserved.
5			*
6			* This code is derived from software contributed to Berkeley by
7			* Peter McIlroy.
8			*
9			* Redistribution and use in source and binary forms, with or without
10			* modification, are permitted provided that the following conditions
11			* are met:
12			* 1. Redistributions of source code must retain the above copyright
13			* notice, this list of conditions and the following disclaimer.
14			* 2. Redistributions in binary form must reproduce the above copyright
15			* notice, this list of conditions and the following disclaimer in the
16			* documentation and/or other materials provided with the distribution.
17			* 3. Neither the name of the University nor the names of its contributors
18			* may be used to endorse or promote products derived from this software
19			* without specific prior written permission.
20			*
21			* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24			* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31			* SUCH DAMAGE.
32			*/
33
34			/*
35			* Hybrid exponential search/linear search merge sort with hybrid
36			* natural/pairwise first pass. Requires about .3% more comparisons
37			* for random data than LSMS with pairwise first pass alone.
38			* It works for objects as small as two bytes.
39			*/
40
41			#define NATURAL
42			#define THRESHOLD 16 /* Best choice for natural merge cut-off. */
43
44			/* #define NATURAL to get hybrid natural merge.
45			* (The default is pairwise merging.)
46			*/
47
48			#include <sys/types.h>
49
50			#include <errno.h>
51			#include <stdlib.h>
52			#include <string.h>
53
54			static void setup(u_char , u_char , size_t, size_t, int (*)());
55			static void insertionsort(u_char , size_t, size_t, int ()());
56
57			#define ISIZE sizeof(int)
58			#define PSIZE sizeof(u_char *)
59			#define ICOPY_LIST(src, dst, last) \
60			do \
61			(int)dst = (int)src, src += ISIZE, dst += ISIZE; \
62			while(src < last)
63			#define ICOPY_ELT(src, dst, i) \
64			do \
65			(int) dst = (int) src, src += ISIZE, dst += ISIZE; \
66			while (i -= ISIZE)
67
68			#define CCOPY_LIST(src, dst, last) \
69			do \
70			dst++ = src++; \
71			while (src < last)
72			#define CCOPY_ELT(src, dst, i) \
73			do \
74			dst++ = src++; \
75			while (i -= 1)
76
77			/*
78			* Find the next possible pointer head. (Trickery for forcing an array
79			* to do double duty as a linked list when objects do not align with word
80			* boundaries.
81			*/
82			/* Assumption: PSIZE is a power of 2. */
83			#define EVAL(p) (u_char **) \
84			((u_char *)0 + \
85			(((u_char )p + PSIZE - 1 - (u_char ) 0) & ~(PSIZE - 1)))
86
87			/*
88			* Arguments are as for qsort.
89			*/
90			int
91			mergesort(void *base, size_t nmemb, size_t size,
92			int (cmp)(const void , const void *))
93			{
94			int i, sense;
95			int big, iflag;
96			u_char f1, f2, t, b, tp2, q, l1, l2;
97			u_char list2, list1, p2, p, last, *p1;
98
99			if (size < PSIZE / 2) { /* Pointers must fit into 2 * size. */
100			errno = EINVAL;
101			return (-1);
102			}
103
104			if (nmemb == 0)
105			return (0);
106
107			/*
108			* XXX
109			* Stupid subtraction for the Cray.
110			*/
111			iflag = 0;
112			if (!(size % ISIZE) && !(((char )base - (char )0) % ISIZE))
113			iflag = 1;
114
115			if ((list2 = malloc(nmemb * size + PSIZE)) == NULL)
116			return (-1);
117
118			list1 = base;
119			setup(list1, list2, nmemb, size, cmp);
120			last = list2 + nmemb * size;
121			i = big = 0;
122			while (*EVAL(list2) != last) {
123			l2 = list1;
124			p1 = EVAL(list1);
125			for (tp2 = p2 = list2; p2 != last; p1 = EVAL(l2)) {
126			p2 = *EVAL(p2);
127			f1 = l2;
128			f2 = l1 = list1 + (p2 - list2);
129			if (p2 != last)
130			p2 = *EVAL(p2);
131			l2 = list1 + (p2 - list2);
132			while (f1 < l1 && f2 < l2) {
133			if ((*cmp)(f1, f2) <= 0) {
134			q = f2;
135			b = f1, t = l1;
136			sense = -1;
137			} else {
138			q = f1;
139			b = f2, t = l2;
140			sense = 0;
141			}
142			if (!big) { /* here i = 0 */
143			while ((b += size) < t && cmp(q, b) >sense)
144			if (++i == 6) {
145			big = 1;
146			goto EXPONENTIAL;
147			}
148			} else {
149			EXPONENTIAL: for (i = size; ; i <<= 1)
150			if ((p = (b + i)) >= t) {
151			if ((p = t - size) > b &&
152			(*cmp)(q, p) <= sense)
153			t = p;
154			else
155			b = p;
156			break;
157			} else if ((*cmp)(q, p) <= sense) {
158			t = p;
159			if (i == size)
160			big = 0;
161			goto FASTCASE;
162			} else
163			b = p;
164			while (t > b+size) {
165			i = (((t - b) / size) >> 1) * size;
166			if ((*cmp)(q, p = b + i) <= sense)
167			t = p;
168			else
169			b = p;
170			}
171			goto COPY;
172			FASTCASE: while (i > size)
173			if ((*cmp)(q,
174			p = b + (i >>= 1)) <= sense)
175			t = p;
176			else
177			b = p;
178			COPY: b = t;
179			}
180			i = size;
181			if (q == f1) {
182			if (iflag) {
183			ICOPY_LIST(f2, tp2, b);
184			ICOPY_ELT(f1, tp2, i);
185			} else {
186			CCOPY_LIST(f2, tp2, b);
187			CCOPY_ELT(f1, tp2, i);
188			}
189			} else {
190			if (iflag) {
191			ICOPY_LIST(f1, tp2, b);
192			ICOPY_ELT(f2, tp2, i);
193			} else {
194			CCOPY_LIST(f1, tp2, b);
195			CCOPY_ELT(f2, tp2, i);
196			}
197			}
198			}
199			if (f2 < l2) {
200			if (iflag)
201			ICOPY_LIST(f2, tp2, l2);
202			else
203			CCOPY_LIST(f2, tp2, l2);
204			} else if (f1 < l1) {
205			if (iflag)
206			ICOPY_LIST(f1, tp2, l1);
207			else
208			CCOPY_LIST(f1, tp2, l1);
209			}
210			*p1 = l2;
211			}
212			tp2 = list1; /* swap list1, list2 */
213			list1 = list2;
214			list2 = tp2;
215			last = list2 + nmemb*size;
216			}
217			if (base == list2) {
218			memmove(list2, list1, nmemb*size);
219			list2 = list1;
220			}
221			free(list2);
222			return (0);
223			}
224
225			#define swap(a, b) { \
226			s = b; \
227			i = size; \
228			do { \
229			tmp = a; a++ = s; s++ = tmp; \
230			} while (--i); \
231			a -= size; \
232			}
233			#define reverse(bot, top) { \
234			s = top; \
235			do { \
236			i = size; \
237			do { \
238			tmp = bot; bot++ = s; s++ = tmp; \
239			} while (--i); \
240			s -= size2; \
241			} while(bot < s); \
242			}
243
244			/*
245			* Optional hybrid natural/pairwise first pass. Eats up list1 in runs of
246			* increasing order, list2 in a corresponding linked list. Checks for runs
247			* when THRESHOLD/2 pairs compare with same sense. (Only used when NATURAL
248			* is defined. Otherwise simple pairwise merging is used.)
249			*/
250			void
251			setup(u_char list1, u_char list2, size_t n, size_t size,
252			int (cmp)(const void , const void *))
253			{
254			int i, length, size2, sense;
255			u_char tmp, f1, f2, s, l2, last, p2;
256
257			size2 = size*2;
258			if (n <= 5) {
259			insertionsort(list1, n, size, cmp);
260			EVAL(list2) = (u_char) list2 + n*size;
261			return;
262			}
263			/*
264			* Avoid running pointers out of bounds; limit n to evens
265			* for simplicity.
266			*/
267			i = 4 + (n & 1);
268			insertionsort(list1 + (n - i) * size, i, size, cmp);
269			last = list1 + size * (n - i);
270			EVAL(list2 + (last - list1)) = list2 + n size;
271
272			#ifdef NATURAL
273			p2 = list2;
274			f1 = list1;
275			sense = (cmp(f1, f1 + size) > 0);
276			for (; f1 < last; sense = !sense) {
277			length = 2;
278			/* Find pairs with same sense. */
279			for (f2 = f1 + size2; f2 < last; f2 += size2) {
280			if ((cmp(f2, f2+ size) > 0) != sense)
281			break;
282			length += 2;
283			}
284			if (length < THRESHOLD) { /* Pairwise merge */
285			do {
286			p2 = *EVAL(p2) = f1 + size2 - list1 + list2;
287			if (sense > 0)
288			swap (f1, f1 + size);
289			} while ((f1 += size2) < f2);
290			} else { /* Natural merge */
291			l2 = f2;
292			for (f2 = f1 + size2; f2 < l2; f2 += size2) {
293			if ((cmp(f2-size, f2) > 0) != sense) {
294			p2 = *EVAL(p2) = f2 - list1 + list2;
295			if (sense > 0)
296			reverse(f1, f2-size);
297			f1 = f2;
298			}
299			}
300			if (sense > 0)
301			reverse (f1, f2-size);
302			f1 = f2;
303			if (f2 < last \|\| cmp(f2 - size, f2) > 0)
304			p2 = *EVAL(p2) = f2 - list1 + list2;
305			else
306			p2 = EVAL(p2) = list2 + nsize;
307			}
308			}
309			#else /* pairwise merge only. */
310			for (f1 = list1, p2 = list2; f1 < last; f1 += size2) {
311			p2 = *EVAL(p2) = p2 + size2;
312			if (cmp (f1, f1 + size) > 0)
313			swap(f1, f1 + size);
314			}
315			#endif /* NATURAL */
316			}
317
318			/*
319			* This is to avoid out-of-bounds addresses in sorting the
320			* last 4 elements.
321			*/
322			static void
323			insertionsort(u_char *a, size_t n, size_t size,
324			int (cmp)(const void , const void *))
325			{
326			u_char ai, s, t, u, tmp;
327			int i;
328
329			for (ai = a+size; --n >= 1; ai += size)
330			for (t = ai; t > a; t -= size) {
331			u = t - size;
332			if (cmp(u, t) <= 0)
333			break;
334			swap(u, t);
335			}
336			}