llendianswizzle.h
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- /**
- * @file llendianswizzle.h
- * @brief Functions for in-place bit swizzling
- *
- * $LicenseInfo:firstyear=2002&license=viewergpl$
- *
- * Copyright (c) 2002-2010, Linden Research, Inc.
- *
- * Second Life Viewer Source Code
- * The source code in this file ("Source Code") is provided by Linden Lab
- * to you under the terms of the GNU General Public License, version 2.0
- * ("GPL"), unless you have obtained a separate licensing agreement
- * ("Other License"), formally executed by you and Linden Lab. Terms of
- * the GPL can be found in doc/GPL-license.txt in this distribution, or
- * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
- *
- * There are special exceptions to the terms and conditions of the GPL as
- * it is applied to this Source Code. View the full text of the exception
- * in the file doc/FLOSS-exception.txt in this software distribution, or
- * online at
- * http://secondlifegrid.net/programs/open_source/licensing/flossexception
- *
- * By copying, modifying or distributing this software, you acknowledge
- * that you have read and understood your obligations described above,
- * and agree to abide by those obligations.
- *
- * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
- * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
- * COMPLETENESS OR PERFORMANCE.
- * $/LicenseInfo$
- */
- #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