[Dotgnu-pnet-commits] CVS: pnetlib/runtime/System/Private NumberParser.cs,1.9,1.10

[Jonathan Springer <address@hidden>]

Update of /cvsroot/dotgnu-pnet/pnetlib/runtime/System/Private
In directory subversions:/tmp/cvs-serv26040/runtime/System/Private

Modified Files:
        NumberParser.cs 
Log Message:


Refinements/Fixes of FP Formatting/Parsing.


Index: NumberParser.cs
===================================================================
RCS file: /cvsroot/dotgnu-pnet/pnetlib/runtime/System/Private/NumberParser.cs,v
retrieving revision 1.9
retrieving revision 1.10
diff -C2 -r1.9 -r1.10
*** NumberParser.cs     2 Feb 2003 18:26:07 -0000       1.9
--- NumberParser.cs     17 Mar 2003 17:51:38 -0000      1.10
***************
*** 1111,1114 ****
--- 1111,1144 ----
        }
  
+       //  Array of powers of ten -- keeps precision within reason
+       private static double [] powten = {
+               1.0e0, 1.0e1, 1.0e2, 1.0e3, 1.0e4, 1.0e5,
+               1.0e6, 1.0e7, 1.0e8, 1.0e9, 1.0e10,
+               1.0e11, 1.0e12, 1.0e13, 1.0e14, 1.0e15,
+               1.0e16, 1.0e17, 1.0e18, 1.0e19, 1.0e20 };
+ 
+       //  Build a number 10^exponent using the above array.  This
+       //  seems more precise than Math.Pow for two reasons:
+       //  1.  The mantissa is a known constant.
+       //  2.  The exponents are integral.     
+       private static double Pow10(int exponent)
+       {
+               double ret = 1.0d;
+               int exp = exponent;
+       
+               if (exp < 0)
+               {
+                       for (; exp < -20; exp += 20) ret /= powten[20];
+                       ret /= powten[exp*-1];
+               }
+               else
+               {
+                       for (; exp > 20; exp -=20) ret *= powten[20];
+                       ret *= powten[exp];
+               }
+ 
+               return ret;
+       }
+               
        public static double ParseDouble(String s, NumberStyles style,
                                                                     
NumberFormatInfo nfi)
***************
*** 1118,1185 ****
                        throw new FormatException(_("Format_HexNotSupported"));
  
                StringBuilder sb = new StringBuilder(RawString(s, style, nfi));
- 
                bool negative = StripSign(sb, nfi);
  
!               string str = sb.ToString();
!               int stridx = 0;
! 
!               //  Parse up to the decimal
!               double work = 0.0d;
  
!               while (stridx < str.Length 
!                               && str[stridx] >= '0' && str[stridx] <= '9')
                {
!                       work = work * 10.0d + (uint)(str[stridx++] - '0');
                }
  
!               //  Parse after the decimal
!               if (stridx < str.Length && 
!                               
str.Substring(stridx).StartsWith(nfi.NumberDecimalSeparator))
                {
!                       stridx += nfi.NumberDecimalSeparator.Length;
!                       for (double mult = 0.1d;
!                                       stridx < str.Length && 
!                                       str[stridx] >= '0' && str[stridx] <= 
'9';
!                                       mult /= 10.0d)
!                       {
!                               work += (uint)(str[stridx++] - '0') * mult;
!                       }       
                }
  
                //  Parse after the exponent
!               if (stridx < str.Length 
!                               && (str[stridx] == 'e' || str[stridx] == 'E') ) 
                {
!                       uint exponent = 0;
                        bool negExponent = false;
!                       stridx++;
!                       if (str.Substring(stridx).StartsWith(nfi.PositiveSign)) 
                        {
!                               stridx++;
                        } 
!                       else if 
(str.Substring(stridx).StartsWith(nfi.NegativeSign)) 
                        {
                                negExponent = true;
!                               stridx++;
                        } 
-                       /*  --- Removed in response to bug #2222
-                       else 
-                       {
-                               //  Darn it, we're supposed to have a sign.
-                               throw new 
FormatException(_("Format_ExponentRequiresSign"));
-                       }
-                       */
  
!                   while (stridx < str.Length && 
!                                       str[stridx] >= '0' && str[stridx] <= 
'9')
!                       {
!                               exponent = 10 * exponent + (uint)(str[stridx++] 
- '0');
!                       }
  
!                       work *= Math.Pow(10, exponent * (negExponent ? -1 : 1));
                }
  
!               if (stridx < str.Length)
                {
                        //  Oops.  Throw a "junk found" exception.
--- 1148,1218 ----
                        throw new FormatException(_("Format_HexNotSupported"));
  
+               //  Strip out the silliness
                StringBuilder sb = new StringBuilder(RawString(s, style, nfi));
                bool negative = StripSign(sb, nfi);
  
!               //  Figure out what our exponent was, then ditch the decimal 
point
!               int exponent = sb.ToString().IndexOf('.')-1;
  
!               if (exponent == -2)   // Not Found
                {
!                       exponent = Math.Max(sb.ToString().IndexOf('e'), 
!                                                               
sb.ToString().IndexOf('E')) - 1;
!                       if (exponent == -2)   // Not Found
!                               exponent = sb.Length - 1;
                }
+               else sb.Remove(exponent+1,1);
  
!               //  Remove leading zeroes that might gum up the works
!               while (sb.Length > 0 && sb[0] == '0') {
!                       sb.Remove(0,1);
!                       exponent--;
!               }
! 
!               //  Guard case...
!               if (sb.Length == 0) return 0.0;
!               string str = sb.ToString();
! 
!               //  Parse up to the exponent
!               ulong ulwork = 0;
!               int i;
! 
!               //  This loop tops out at 18 -- the most digits in a ulong
!               for (i = 0; 
!                               i < str.Length && i < 18 && str[i] >= '0' && 
str[i] <= '9'; 
!                               i++) 
                {
!                       ulwork = (ulwork * 10) + unchecked((uint)(str[i]-'0'));
                }
+               double work = (double)ulwork * Pow10(exponent - i + 1);
+ 
+               //  Bleed off the over-precise numbers
+               while (i < str.Length && str[i] >= '0' && str[i] <= '9') i++;
  
                //  Parse after the exponent
!               if (i < str.Length && (str[i] == 'e' || str[i] == 'E') ) 
                {
!                       exponent = 0;
                        bool negExponent = false;
!                       i++;
! 
!                       if (str.Substring(i).StartsWith(nfi.PositiveSign)) 
                        {
!                               i++;
                        } 
!                       else if (str.Substring(i).StartsWith(nfi.NegativeSign)) 
                        {
                                negExponent = true;
!                               i++;
                        } 
  
!                   while (i < str.Length && str[i] >= '0' && str[i] <= '9')
!                               exponent = (10*exponent) + (int)(str[i++] - 
'0');
  
!                       if (negExponent) exponent *= -1;
!                       work *= Pow10(exponent);
                }
  
!               if (i < str.Length)
                {
                        //  Oops.  Throw a "junk found" exception.
***************
*** 1191,1195 ****
                return work;
        }
- 
  }; // class NumberParser
  
--- 1224,1227 ----