101 lines
2.9 KiB
C
101 lines
2.9 KiB
C
/**
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* @file llendianswizzle.h
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* @brief Functions for in-place bit swizzling
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*
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* $LicenseInfo:firstyear=2002&license=viewergpl$
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*
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* Copyright (c) 2002-2009, Linden Research, Inc.
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*
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* Second Life Viewer Source Code
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* The source code in this file ("Source Code") is provided by Linden Lab
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* to you under the terms of the GNU General Public License, version 2.0
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* ("GPL"), unless you have obtained a separate licensing agreement
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* ("Other License"), formally executed by you and Linden Lab. Terms of
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* the GPL can be found in doc/GPL-license.txt in this distribution, or
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* online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
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*
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* There are special exceptions to the terms and conditions of the GPL as
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* it is applied to this Source Code. View the full text of the exception
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* in the file doc/FLOSS-exception.txt in this software distribution, or
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* online at
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* http://secondlifegrid.net/programs/open_source/licensing/flossexception
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*
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* By copying, modifying or distributing this software, you acknowledge
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* that you have read and understood your obligations described above,
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* and agree to abide by those obligations.
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*
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* ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
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* WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
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* COMPLETENESS OR PERFORMANCE.
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* $/LicenseInfo$
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*/
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#ifndef LL_LLENDIANSWIZZLE_H
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#define LL_LLENDIANSWIZZLE_H
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/* This function is intended to be used for in-place swizzling, particularly after fread() of
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binary values from a file. Such as:
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numRead = fread(scale.mV, sizeof(float), 3, fp);
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llendianswizzle(scale.mV, sizeof(float), 3);
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It assumes that the values in the file are LITTLE endian, so it's a no-op on a little endian machine.
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It keys off of typesize to do the correct swizzle, so make sure that typesize is the size of the native type.
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64-bit types are not yet handled.
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*/
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#ifdef LL_LITTLE_ENDIAN
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// little endian is native for most things.
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inline void llendianswizzle(void *,int,int)
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{
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// Nothing to do
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}
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#endif
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#ifdef LL_BIG_ENDIAN
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// big endian requires a bit of work.
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inline void llendianswizzle(void *p,int typesize, int count)
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{
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int i;
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switch(typesize)
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{
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case 2:
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{
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U16 temp;
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for(i=count ;i!=0 ;i--)
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{
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temp = ((U16*)p)[0];
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((U16*)p)[0] = ((temp >> 8) & 0x000000FF) | ((temp << 8) & 0x0000FF00);
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p = (void*)(((U16*)p) + 1);
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}
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}
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break;
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case 4:
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{
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U32 temp;
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for(i=count; i!=0; i--)
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{
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temp = ((U32*)p)[0];
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((U32*)p)[0] =
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((temp >> 24) & 0x000000FF) |
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((temp >> 8) & 0x0000FF00) |
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((temp << 8) & 0x00FF0000) |
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((temp << 24) & 0xFF000000);
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p = (void*)(((U32*)p) + 1);
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}
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}
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break;
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}
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}
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#endif
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// Use this when working with a single integral value you want swizzled
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#define llendianswizzleone(x) llendianswizzle(&(x), sizeof(x), 1)
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#endif // LL_LLENDIANSWIZZLE_H
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