Add nsswitch support.
[dragonfly.git] / lib / libc / string / bcopy.c
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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 * Chris Torek.
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.
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35 *
36 * @(#)bcopy.c 8.1 (Berkeley) 6/4/93
37 * $FreeBSD: src/lib/libc/string/bcopy.c,v 1.1.1.1.14.1 2001/07/09 23:30:03 obrien Exp $
bd4c62e8 38 * $DragonFly: src/lib/libc/string/bcopy.c,v 1.4 2005/09/18 16:32:34 asmodai Exp $
984263bc 39 */
1de703da 40
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41#include <sys/cdefs.h>
42#include <string.h>
43
44/*
45 * sizeof(word) MUST BE A POWER OF TWO
46 * SO THAT wmask BELOW IS ALL ONES
47 */
48typedef int word; /* "word" used for optimal copy speed */
49
50#define wsize sizeof(word)
51#define wmask (wsize - 1)
52
53/*
54 * Copy a block of memory, handling overlap.
55 * This is the routine that actually implements
56 * (the portable versions of) bcopy, memcpy, and memmove.
57 */
58#ifdef MEMCOPY
59void *
bd4c62e8 60memcpy(void *dst0, const void *src0, size_t length)
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61#else
62#ifdef MEMMOVE
63void *
bd4c62e8 64memmove(void *dst0, const void *src0, size_t length)
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65#else
66void
bd4c62e8 67bcopy(const void *src0, void *dst0, size_t length)
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68#endif
69#endif
984263bc 70{
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71 char *dst = dst0;
72 const char *src = src0;
73 size_t t;
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74
75 if (length == 0 || dst == src) /* nothing to do */
76 goto done;
77
78 /*
79 * Macros: loop-t-times; and loop-t-times, t>0
80 */
81#define TLOOP(s) if (t) TLOOP1(s)
82#define TLOOP1(s) do { s; } while (--t)
83
84 if ((unsigned long)dst < (unsigned long)src) {
85 /*
86 * Copy forward.
87 */
88 t = (int)src; /* only need low bits */
89 if ((t | (int)dst) & wmask) {
90 /*
91 * Try to align operands. This cannot be done
92 * unless the low bits match.
93 */
94 if ((t ^ (int)dst) & wmask || length < wsize)
95 t = length;
96 else
97 t = wsize - (t & wmask);
98 length -= t;
99 TLOOP1(*dst++ = *src++);
100 }
101 /*
102 * Copy whole words, then mop up any trailing bytes.
103 */
104 t = length / wsize;
105 TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
106 t = length & wmask;
107 TLOOP(*dst++ = *src++);
108 } else {
109 /*
110 * Copy backwards. Otherwise essentially the same.
111 * Alignment works as before, except that it takes
112 * (t&wmask) bytes to align, not wsize-(t&wmask).
113 */
114 src += length;
115 dst += length;
116 t = (int)src;
117 if ((t | (int)dst) & wmask) {
118 if ((t ^ (int)dst) & wmask || length <= wsize)
119 t = length;
120 else
121 t &= wmask;
122 length -= t;
123 TLOOP1(*--dst = *--src);
124 }
125 t = length / wsize;
126 TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
127 t = length & wmask;
128 TLOOP(*--dst = *--src);
129 }
130done:
131#if defined(MEMCOPY) || defined(MEMMOVE)
132 return (dst0);
133#else
134 return;
135#endif
136}