CELT for Windows

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@16414 d0543943-73ff-0310-b7d9-9358b9ac24b2

libs/win32/celt/float_cast.h

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+/*
+** Copyright (C) 2001 Erik de Castro Lopo <erikd AT mega-nerd DOT com>
+**
+** Permission to use, copy, modify, distribute, and sell this file for any 
+** purpose is hereby granted without fee, provided that the above copyright 
+** and this permission notice appear in all copies.  No representations are
+** made about the suitability of this software for any purpose.  It is 
+** provided "as is" without express or implied warranty.
+*/
+
+/* Version 1.1 */
+
+#ifndef FLOAT_CAST_H
+#define FLOAT_CAST_H
+
+/*============================================================================ 
+**	On Intel Pentium processors (especially PIII and probably P4), converting
+**	from float to int is very slow. To meet the C specs, the code produced by 
+**	most C compilers targeting Pentium needs to change the FPU rounding mode 
+**	before the float to int conversion is performed. 
+**
+**	Changing the FPU rounding mode causes the FPU pipeline to be flushed. It 
+**	is this flushing of the pipeline which is so slow.
+**
+**	Fortunately the ISO C99 specifications define the functions lrint, lrintf,
+**	llrint and llrintf which fix this problem as a side effect. 
+**
+**	On Unix-like systems, the configure process should have detected the 
+**	presence of these functions. If they weren't found we have to replace them 
+**	here with a standard C cast.
+*/
+
+/*	
+**	The C99 prototypes for lrint and lrintf are as follows:
+**	
+**		long int lrintf (float x) ;
+**		long int lrint  (double x) ;
+*/
+
+/*	The presence of the required functions are detected during the configure
+**	process and the values HAVE_LRINT and HAVE_LRINTF are set accordingly in
+**	the config.h file.
+*/
+
+#if (HAVE_LRINTF)
+/*#if 0*/
+
+	/*	These defines enable functionality introduced with the 1999 ISO C
+	**	standard. They must be defined before the inclusion of math.h to
+	**	engage them. If optimisation is enabled, these functions will be 
+	**	inlined. With optimisation switched off, you have to link in the
+	**	maths library using -lm.
+	*/
+
+	#define	_ISOC9X_SOURCE	1
+	#define _ISOC99_SOURCE	1
+
+	#define	__USE_ISOC9X	1
+	#define	__USE_ISOC99	1
+
+	#include	<math.h>
+	#define float2int(x) lrintf(x)
+
+#elif (defined(HAVE_LRINT))
+
+#define	_ISOC9X_SOURCE	1
+#define _ISOC99_SOURCE	1
+
+#define	__USE_ISOC9X	1
+#define	__USE_ISOC99	1
+
+#include	<math.h>
+#define float2int(x) lrint(x)
+
+#elif (defined (WIN32) || defined (_WIN32))
+
+	#include	<math.h>
+
+	/*	Win32 doesn't seem to have these functions. 
+	**	Therefore implement inline versions of these functions here.
+	*/
+
+#ifndef _WIN64 
+	__inline long int 
+	float2int (float flt)
+	{	int intgr;
+
+		_asm
+		{	fld flt
+			fistp intgr
+			} ;
+			
+		return intgr ;
+	}
+#else               
+#define float2int   
+#endif            
+  
+
+#else
+
+#ifdef __GNUC__ /* supported by gcc, but not by all other compilers*/
+	#warning "Don't have the functions lrint() and lrintf ()."
+	#warning "Replacing these functions with a standard C cast."
+#endif /* __GNUC__ */
+
+	#include	<math.h>
+
+	#define	float2int(flt)		((int)(floor(.5+flt)))
+
+#endif
+
+
+#endif /* FLOAT_CAST_H */