socsvn commit: r269341 - soc2014/pedrosouza/lua_loader/head/sys/lua/src

[pedrosouza at FreeBSD.org]

Author: pedrosouza
Date: Tue Jun 10 00:33:31 2014
New Revision: 269341
URL: http://svnweb.FreeBSD.org/socsvn/?view=rev&rev=269341

Log:
  Improve dtostr function

Modified:
  soc2014/pedrosouza/lua_loader/head/sys/lua/src/lstd.c
  soc2014/pedrosouza/lua_loader/head/sys/lua/src/lstd.h

Modified: soc2014/pedrosouza/lua_loader/head/sys/lua/src/lstd.c
==============================================================================
--- soc2014/pedrosouza/lua_loader/head/sys/lua/src/lstd.c	Mon Jun  9 23:11:50 2014	(r269340)
+++ soc2014/pedrosouza/lua_loader/head/sys/lua/src/lstd.c	Tue Jun 10 00:33:31 2014	(r269341)
@@ -170,49 +170,96 @@
 	return ret * exp_m;
 }
 
-char * dtostr(double value, char * buf)
+int dtostr(double v, char * str)
 {
-	int c, i;
+	int exp = 0;
+	int i;
+	long long n;
+	double e = 1;
+	char * ptr;
 	char tmp[20];
-	char *ptr, *bb = buf;
-	long long num = (long long) value;
-	double frac = value - num;
+	char *buf = str;
 
-	tmp[19] = 0;
-	ptr = &tmp[19];
-	while (num > 0)
+	if (v < 0)
 	{
-		c = num % 10;
-		num = num / 10;
-		*(--ptr) = '0' + c;
+		*buf++ = '-';
+		v = -v;
 	}
 
-	if (ptr == &tmp[19])
-		*buf++ = '0';
-	else
+	if (v <= e)
 	{
-		while (*ptr)
+		while (v < e)
 		{
-			*buf++ = *ptr++;
+			--exp;
+			e *= 0.1;
 		}
+	} else
+	{
+		while (v > e)
+		{
+			++exp;
+			e *= 10;
+		}
+		--exp;
+		e /= 10;
 	}
-	if (abs(frac) > 0.0000001)
+	if (exp > 9 || exp < -9)
+	{
+		v /= e;
+	} else
+	{
+		exp = 0;
+	}
+
+	n = (long long)v;
+	v -= n;
+	ptr = &tmp[19];
+	*ptr = 0;
+
+	do 
 	{
-		*buf++ = 0;
-		return bb;
-	} else 
+		i = n % 10;
+		n /= 10;
+		*(--ptr) = i + '0';
+	} while (n > 0);
+
+	while (*ptr != 0) *buf++ = *ptr++;
+	
+	if (v != 0)
 	{
+		ptr = buf;
 		*buf++ = '.';
 
-		for (i = 0; i < 7; ++i)
+		for (i = 0; i < 17; ++i)
+		{
+			v *= 10;
+			n = (long long)v;
+			*buf++ = '0' + n;
+			ptr = n > 0 ? buf : ptr;
+			v -= n;
+		}
+		buf = ptr;
+	}
+
+	if (exp != 0)
+	{
+		*buf++ = 'e';
+		if (exp < 0)
+		{
+			*buf++ = '-';
+			exp = -exp;
+		}
+		ptr = &tmp[19];
+		*ptr = 0;
+		while (exp > 0)
 		{
-			frac *= 10;
-			c = (long long)frac;
-			*buf++ = '0' + c;
-			frac -= c;
+			i = exp % 10;
+			exp /= 10;
+			*(--ptr) = '0' + i;
 		}
-		*buf = 0; 
+		while (*ptr != 0) *buf++ = *ptr++;
 	}
-	return bb;
+	*buf = 0;
+	return buf - str;
 }
 #endif //BOOT_LUA
\ No newline at end of file

Modified: soc2014/pedrosouza/lua_loader/head/sys/lua/src/lstd.h
==============================================================================
--- soc2014/pedrosouza/lua_loader/head/sys/lua/src/lstd.h	Mon Jun  9 23:11:50 2014	(r269340)
+++ soc2014/pedrosouza/lua_loader/head/sys/lua/src/lstd.h	Tue Jun 10 00:33:31 2014	(r269341)
@@ -57,7 +57,7 @@
 
 double strtod(const char *string, char **endPtr);
 
-char * dtostr(double value, char * buf);
+int dtostr(double v, char * str);
 
 #endif
 #endif //LSTD_H