Diff: fast_atof.h

Revision:

0:41a49a73580c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/fast_atof.h	Wed Nov 17 20:19:41 2010 +0000
@@ -0,0 +1,138 @@
+// Copyright (C) 2002-2005 Nikolaus Gebhardt
+// This file is part of the "Irrlicht Engine" and the "irrXML" project.
+// For conditions of distribution and use, see copyright notice in irrlicht.h and irrXML.h
+
+#ifndef __FAST_A_TO_F_H_INCLUDED__
+#define __FAST_A_TO_F_H_INCLUDED__
+
+#include <stdlib.h>
+#include <math.h>
+
+namespace irr
+{
+namespace core
+{
+
+const float fast_atof_table[] =	{
+										0.f,
+										0.1f,
+										0.01f,
+										0.001f,
+										0.0001f,
+										0.00001f,
+										0.000001f,
+										0.0000001f,
+										0.00000001f,
+										0.000000001f,
+										0.0000000001f,
+										0.00000000001f,
+										0.000000000001f,
+										0.0000000000001f,
+										0.00000000000001f,
+										0.000000000000001f
+									};
+
+//! Provides a fast function for converting a string into a float,
+//! about 6 times faster than atof in win32.
+// If you find any bugs, please send them to me, niko (at) irrlicht3d.org.
+inline char* fast_atof_move(char* c, float& out)
+{
+	bool inv = false;
+	char *t;
+	float f;
+
+	if (*c=='-')
+	{
+		c++;
+		inv = true;
+	}
+
+	f = (float)strtol(c, &t, 10);
+
+	c = t;
+
+	if (*c == '.')
+	{
+		c++;
+
+		float pl = (float)strtol(c, &t, 10);
+		pl *= fast_atof_table[t-c];
+
+		f += pl;
+
+		c = t;
+
+		if (*c == 'e')
+		{
+			++c;
+			float exp = (float)strtol(c, &t, 10);
+			f *= (float)pow(10.0f, exp);
+			c = t;
+		}
+	}
+
+	if (inv)
+		f *= -1.0f;
+	
+	out = f;
+	return c;
+}
+
+//! Provides a fast function for converting a string into a float,
+//! about 6 times faster than atof in win32.
+// If you find any bugs, please send them to me, niko (at) irrlicht3d.org.
+inline const char* fast_atof_move_const(const char* c, float& out)
+{
+	bool inv = false;
+	char *t;
+	float f;
+
+	if (*c=='-')
+	{
+		c++;
+		inv = true;
+	}
+
+	f = (float)strtol(c, &t, 10);
+
+	c = t;
+
+	if (*c == '.')
+	{
+		c++;
+
+		float pl = (float)strtol(c, &t, 10);
+		pl *= fast_atof_table[t-c];
+
+		f += pl;
+
+		c = t;
+
+		if (*c == 'e') 
+		{ 
+			++c; 
+			f32 exp = (f32)strtol(c, &t, 10); 
+			f *= (f32)powf(10.0f, exp); 
+			c = t; 
+		}
+	}
+
+	if (inv)
+		f *= -1.0f;
+	
+	out = f;
+	return c;
+}
+
+
+inline float fast_atof(const char* c)
+{
+	float ret;
+	fast_atof_move_const(c, ret);
+	return ret;
+}
+
+} // end namespace core
+}// end namespace irr
+
+#endif