Imported existing code

indra/llcommon/llendianswizzle.h

@@ -0,0 +1,100 @@
+/** 
+ * @file llendianswizzle.h
+ * @brief Functions for in-place bit swizzling
+ *
+ * $LicenseInfo:firstyear=2002&license=viewergpl$
+ * 
+ * Copyright (c) 2002-2009, 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