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/**
* @file llendianswizzle.h
* @brief Functions for in-place bit swizzling
*
* $LicenseInfo:firstyear=2002&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2010, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#ifndef LL_LLENDIANSWIZZLE_H
#define LL_LLENDIANSWIZZLE_H
/* This function is intended to be used for in-place swizzling, particularly after fread() of
binary values from a file. Such as:
numRead = fread(scale.mV, sizeof(float), 3, fp);
llendianswizzle(scale.mV, sizeof(float), 3);
It assumes that the values in the file are LITTLE endian, so it's a no-op on a little endian machine.
It keys off of typesize to do the correct swizzle, so make sure that typesize is the size of the native type.
64-bit types are not yet handled.
*/
#ifdef LL_LITTLE_ENDIAN
// little endian is native for most things.
inline void llendianswizzle(void *,int,int)
{
// Nothing to do
}
#endif
#ifdef LL_BIG_ENDIAN
// big endian requires a bit of work.
inline void llendianswizzle(void *p,int typesize, int count)
{
int i;
switch(typesize)
{
case 2:
{
U16 temp;
for(i=count ;i!=0 ;i--)
{
temp = ((U16*)p)[0];
((U16*)p)[0] = ((temp >> 8) & 0x000000FF) | ((temp << 8) & 0x0000FF00);
p = (void*)(((U16*)p) + 1);
}
}
break;
case 4:
{
U32 temp;
for(i=count; i!=0; i--)
{
temp = ((U32*)p)[0];
((U32*)p)[0] =
((temp >> 24) & 0x000000FF) |
((temp >> 8) & 0x0000FF00) |
((temp << 8) & 0x00FF0000) |
((temp << 24) & 0xFF000000);
p = (void*)(((U32*)p) + 1);
}
}
break;
}
}
#endif
// Use this when working with a single integral value you want swizzled
#define llendianswizzleone(x) llendianswizzle(&(x), sizeof(x), 1)
#endif // LL_LLENDIANSWIZZLE_H
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