| 1 | /*-
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| 2 | * Copyright (c) 1990, 1993
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| 3 | * The Regents of the University of California. All rights reserved.
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| 4 | *
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| 5 | * This code is derived from software contributed to Berkeley by
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| 6 | * Chris Torek.
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| 7 | *
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| 8 | * Redistribution and use in source and binary forms, with or without
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| 9 | * modification, are permitted provided that the following conditions
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| 10 | * are met:
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| 11 | * 1. Redistributions of source code must retain the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer.
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| 13 | * 2. Redistributions in binary form must reproduce the above copyright
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| 14 | * notice, this list of conditions and the following disclaimer in the
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| 15 | * documentation and/or other materials provided with the distribution.
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| 16 | * 3. All advertising materials mentioning features or use of this software
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| 17 | * must display the following acknowledgement:
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| 18 | * This product includes software developed by the University of
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| 19 | * California, Berkeley and its contributors.
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| 20 | * 4. Neither the name of the University nor the names of its contributors
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| 21 | * may be used to endorse or promote products derived from this software
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| 22 | * without specific prior written permission.
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| 23 | *
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| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 34 | * SUCH DAMAGE.
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| 35 | */
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| 36 |
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| 37 | #if 0
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| 38 | #if defined(LIBC_SCCS) && !defined(lint)
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| 39 | static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93";
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| 40 | #endif /* LIBC_SCCS and not lint */
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| 41 |
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| 42 | #include <sys/cdefs.h>
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| 43 | #include <string.h>
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| 44 | #endif
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| 45 |
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| 46 | /*
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| 47 | * sizeof(word) MUST BE A POWER OF TWO
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| 48 | * SO THAT wmask BELOW IS ALL ONES
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| 49 | */
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| 50 | typedef int word; /* "word" used for optimal copy speed */
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| 51 |
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| 52 | #define wsize sizeof(word)
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| 53 | #define wmask (wsize - 1)
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| 54 |
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| 55 | /* ADR: 1/2004. For gawk, we need memmove(). */
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| 56 | #define MEMMOVE 1
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| 57 |
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| 58 | /*
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| 59 | * Copy a block of memory, handling overlap.
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| 60 | * This is the routine that actually implements
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| 61 | * (the portable versions of) bcopy, memcpy, and memmove.
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| 62 | */
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| 63 | #ifdef MEMCOPY
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| 64 | void *
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| 65 | memcpy(dst0, src0, length)
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| 66 | #else
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| 67 | #ifdef MEMMOVE
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| 68 | void *
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| 69 | memmove(dst0, src0, length)
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| 70 | #else
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| 71 | void
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| 72 | bcopy(src0, dst0, length)
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| 73 | #endif
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| 74 | #endif
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| 75 | void *dst0;
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| 76 | const void *src0;
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| 77 | register size_t length;
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| 78 | {
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| 79 | register char *dst = dst0;
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| 80 | register const char *src = src0;
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| 81 | register size_t t;
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| 82 |
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| 83 | if (length == 0 || dst == src) /* nothing to do */
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| 84 | goto done;
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| 85 |
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| 86 | /*
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| 87 | * Macros: loop-t-times; and loop-t-times, t>0
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| 88 | */
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| 89 | #define TLOOP(s) if (t) TLOOP1(s)
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| 90 | #define TLOOP1(s) do { s; } while (--t)
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| 91 |
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| 92 | if ((unsigned long)dst < (unsigned long)src) {
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| 93 | /*
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| 94 | * Copy forward.
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| 95 | */
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| 96 | t = (int)src; /* only need low bits */
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| 97 | if ((t | (int)dst) & wmask) {
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| 98 | /*
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| 99 | * Try to align operands. This cannot be done
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| 100 | * unless the low bits match.
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| 101 | */
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| 102 | if ((t ^ (int)dst) & wmask || length < wsize)
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| 103 | t = length;
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| 104 | else
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| 105 | t = wsize - (t & wmask);
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| 106 | length -= t;
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| 107 | TLOOP1(*dst++ = *src++);
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| 108 | }
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| 109 | /*
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| 110 | * Copy whole words, then mop up any trailing bytes.
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| 111 | */
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| 112 | t = length / wsize;
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| 113 | TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
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| 114 | t = length & wmask;
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| 115 | TLOOP(*dst++ = *src++);
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| 116 | } else {
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| 117 | /*
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| 118 | * Copy backwards. Otherwise essentially the same.
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| 119 | * Alignment works as before, except that it takes
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| 120 | * (t&wmask) bytes to align, not wsize-(t&wmask).
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| 121 | */
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| 122 | src += length;
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| 123 | dst += length;
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| 124 | t = (int)src;
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| 125 | if ((t | (int)dst) & wmask) {
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| 126 | if ((t ^ (int)dst) & wmask || length <= wsize)
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| 127 | t = length;
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| 128 | else
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| 129 | t &= wmask;
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| 130 | length -= t;
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| 131 | TLOOP1(*--dst = *--src);
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| 132 | }
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| 133 | t = length / wsize;
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| 134 | TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
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| 135 | t = length & wmask;
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| 136 | TLOOP(*--dst = *--src);
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| 137 | }
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| 138 | done:
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| 139 | #if defined(MEMCOPY) || defined(MEMMOVE)
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| 140 | return (dst0);
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| 141 | #else
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| 142 | return;
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| 143 | #endif
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| 144 | }
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| 145 | #undef wsize
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| 146 | #undef wmask
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| 147 | #undef MEMMOVE
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| 148 | #undef TLOOP
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| 149 | #undef TLOOP1
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