00001 /*- 00002 * See the file LICENSE for redistribution information. 00003 * 00004 * Copyright (c) 1996, 1997, 1998, 1999 00005 * Sleepycat Software. All rights reserved. 00006 */ 00007 /* 00008 * Copyright (c) 1990, 1993 00009 * The Regents of the University of California. All rights reserved. 00010 * 00011 * Redistribution and use in source and binary forms, with or without 00012 * modification, are permitted provided that the following conditions 00013 * are met: 00014 * 1. Redistributions of source code must retain the above copyright 00015 * notice, this list of conditions and the following disclaimer. 00016 * 2. Redistributions in binary form must reproduce the above copyright 00017 * notice, this list of conditions and the following disclaimer in the 00018 * documentation and/or other materials provided with the distribution. 00019 * 3. Neither the name of the University nor the names of its contributors 00020 * may be used to endorse or promote products derived from this software 00021 * without specific prior written permission. 00022 * 00023 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 00024 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 00025 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 00026 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 00027 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 00028 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 00029 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 00030 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 00031 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 00032 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 00033 * SUCH DAMAGE. 00034 */ 00035 00036 #ifdef HAVE_CONFIG_H 00037 #include "config.h" 00038 #endif /* HAVE_CONFIG_H */ 00039 00040 #ifndef NO_SYSTEM_INCLUDES 00041 #include <sys/types.h> 00042 #endif 00043 00044 #ifndef HAVE_MEMMOVE 00045 /* 00046 * sizeof(word) MUST BE A POWER OF TWO 00047 * SO THAT wmask BELOW IS ALL ONES 00048 */ 00049 typedef int word; /* "word" used for optimal copy speed */ 00050 00051 #undef wsize 00052 #define wsize sizeof(word) 00053 #undef wmask 00054 #define wmask (wsize - 1) 00055 00056 /* 00057 * Copy a block of memory, handling overlap. 00058 * This is the routine that actually implements 00059 * (the portable versions of) bcopy, memcpy, and memmove. 00060 */ 00061 /* 00062 * PUBLIC: #ifndef HAVE_MEMMOVE 00063 * PUBLIC: void *memmove __P((void *, const void *, size_t)); 00064 * PUBLIC: #endif 00065 */ 00066 void * 00067 memmove(dst0, src0, length) 00068 void *dst0; 00069 const void *src0; 00070 register size_t length; 00071 { 00072 register char *dst = dst0; 00073 register const char *src = src0; 00074 register size_t t; 00075 00076 if (length == 0 || dst == src) /* nothing to do */ 00077 goto done; 00078 00079 /* 00080 * Macros: loop-t-times; and loop-t-times, t>0 00081 */ 00082 #undef TLOOP 00083 #define TLOOP(s) if (t) TLOOP1(s) 00084 #undef TLOOP1 00085 #define TLOOP1(s) do { s; } while (--t) 00086 00087 if ((unsigned long)dst < (unsigned long)src) { 00088 /* 00089 * Copy forward. 00090 */ 00091 t = (int)src; /* only need low bits */ 00092 if ((t | (int)dst) & wmask) { 00093 /* 00094 * Try to align operands. This cannot be done 00095 * unless the low bits match. 00096 */ 00097 if ((t ^ (int)dst) & wmask || length < wsize) 00098 t = length; 00099 else 00100 t = wsize - (t & wmask); 00101 length -= t; 00102 TLOOP1(*dst++ = *src++); 00103 } 00104 /* 00105 * Copy whole words, then mop up any trailing bytes. 00106 */ 00107 t = length / wsize; 00108 TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize); 00109 t = length & wmask; 00110 TLOOP(*dst++ = *src++); 00111 } else { 00112 /* 00113 * Copy backwards. Otherwise essentially the same. 00114 * Alignment works as before, except that it takes 00115 * (t&wmask) bytes to align, not wsize-(t&wmask). 00116 */ 00117 src += length; 00118 dst += length; 00119 t = (int)src; 00120 if ((t | (int)dst) & wmask) { 00121 if ((t ^ (int)dst) & wmask || length <= wsize) 00122 t = length; 00123 else 00124 t &= wmask; 00125 length -= t; 00126 TLOOP1(*--dst = *--src); 00127 } 00128 t = length / wsize; 00129 TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src); 00130 t = length & wmask; 00131 TLOOP(*--dst = *--src); 00132 } 00133 done: 00134 return (dst0); 00135 } 00136 #endif /* HAVE_MEMOVE */