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/*
* Copyright (c) 2001-2003 The Trustees of Indiana University.
* All rights reserved.
* Copyright (c) 1998-2001 University of Notre Dame.
* All rights reserved.
* Copyright (c) 1994-1998 The Ohio State University.
* All rights reserved.
*
* This file is part of the LAM/MPI software package. For license
* information, see the LICENSE file in the top level directory of the
* LAM/MPI source distribution.
*
* $HEADER$
*
* $Id: rev.c,v 6.5 2003/07/05 21:50:25 jsquyres Exp $
*
* Function: - reverse byte ordering of data types
* - handles 4 and 8-byte types in fast manner
* - handles all other types as byte arrays
*/
#include <portable.h>
#include <t_types.h>
/*
* rev4
*
* Function: - reverse byte ordering of a 4-byte array
* - array is treated as an unsigned 4-byte integer
* Accepts: - ptr source array
* - ptr destination array
*/
void
rev4(void *src, void *dest)
{
uint4 old;
uint4 *d;
old = *((uint4 *) src);
d = (uint4 *) dest;
*d = (old & 0x000000FF) << 16;
*d = (*d | (old & 0x0000FF00)) << 8;
old >>= 8;
*d |= (old & 0x0000FF00);
old >>= 16;
*d |= (old & 0x000000FF);
}
/*
* rev8
*
* Function: - reverse byte ordering of a 8-byte array
* - array is treated as 2 unsigned 4-byte integers
* Accepts: - ptr source array
* - ptr destination array
*/
void
rev8(void *src, void *dest)
{
uint4 old;
char *d;
old = *((uint4 *) src + 1);
d = (char *) dest + 4;
rev4(src, (void *) d);
rev4((void *) &old, dest);
}
/*
* revn
*
* Function: - reverse byte ordering of a multi-byte array
* Accepts: - ptr source array
* - ptr destination array
* - # of bytes
*/
void
revn(void *src, void *dest, int nbytes)
{
char temp;
char *s, *d;
s = (char *) src;
d = (char *) dest + nbytes - 1;
if (src == dest) {
/*
* Same array, swap bytes from both ends.
*/
for (nbytes /= 2; nbytes > 0; --nbytes, ++s, --d) {
temp = *s; *s = *d; *d = temp;
}
}
else {
/*
* Different arrays, just copy the reversed order.
* This assumes the arrays do not overlap.
*/
for ( ; nbytes > 0; --nbytes, ++s, --d) {
*d = *s;
}
}
}
/*
* mrev4
*
* Function: - reverse byte ordering of an array of 4-byte elements
* Accepts: - ptr array
* - # elements in array
*/
void
mrev4(void *array, int num)
{
uint4 old;
uint4 *d;
d = (uint4 *) array;
for ( ; num > 0; --num, ++d) {
old = *d;
*d = (old & 0x000000FF) << 16;
*d = (*d | (old & 0x0000FF00)) << 8;
old >>= 8;
*d |= (old & 0x0000FF00);
old >>= 16;
*d |= (old & 0x000000FF);
}
}
/*
* mrev8
*
* Function: - reverse byte ordering of an array of 8-byte elements
* Accepts: - ptr array
* - # elements in array
*/
void
mrev8(void *array, int num)
{
uint4 old;
uint4 tmp;
uint4 *d;
for (d = (uint4 *) array; num > 0; --num, ++d) {
tmp = *d;
old = *(d+1);
*d = (old & 0x000000FF) << 16;
*d = (*d | (old & 0x0000FF00)) << 8;
old >>= 8;
*d |= (old & 0x0000FF00);
old >>= 16;
*d |= (old & 0x000000FF);
++d;
*d = (tmp & 0x000000FF) << 16;
*d = (*d | (tmp & 0x0000FF00)) << 8;
tmp >>= 8;
*d |= (tmp & 0x0000FF00);
tmp >>= 16;
*d |= (tmp & 0x000000FF);
}
}
/*
* mrevn
*
* Function: - reverse byte ordering of an array of n-byte elements
* Accepts: - ptr array
* - element size
* - # elements in array
*/
void
mrevn(void *array, int size, int num)
{
char *p, *s, *d;
char temp;
int nbytes;
p = (char *) array;
for ( ; num > 0; --num, p += size) {
/*
* Swap bytes from both ends.
*/
s = p;
d = p + size - 1;
for (nbytes = size / 2; nbytes > 0; --nbytes, ++s, --d) {
temp = *s; *s = *d; *d = temp;
}
}
}
/*
* rw
*
* Function: - reverse word byte order (old Trollius call)
* Accepts: - original word
* Returns: - word with reversed byte order
*/
uint4
rw(uint4 oword)
{
uint4 rword;
rword = (oword & 0x000000FF) << 16;
rword = (rword | (oword & 0x0000FF00)) << 8;
oword >>= 8;
rword |= (oword & 0x0000FF00);
oword >>= 16;
rword |= (oword & 0x000000FF);
return(rword);
}
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