git.gag.com Git - debian/openrocket/blob - src/net/sf/openrocket/util/TextUtil.java

   1 package net.sf.openrocket.util;
   2
   3 import java.util.Locale;
   4
   5 public class TextUtil {
   6
   7         /**
   8          * Return a string of the double value with suitable precision.
   9          * The string is the shortest representation of the value including the
  10          * required precision.
  11          *
  12          * TODO: MEDIUM: Extra zeros are added unnecessarily to the end of the string.
  13          *
  14          * @param d             the value to present.
  15          * @return              a representation with suitable precision.
  16          */
  17         public static final String doubleToString(double d) {
  18
  19                 // Check for special cases
  20                 if (MathUtil.equals(d, 0))
  21                         return "0";
  22
  23                 if (Double.isNaN(d))
  24                         return "NaN";
  25
  26                 if (Double.isInfinite(d)) {
  27                         if (d < 0)
  28                                 return "-Inf";
  29                         else
  30                                 return "Inf";
  31                 }
  32
  33
  34                 double abs = Math.abs(d);
  35
  36                 if (abs < 0.001) {
  37                         // Compact exponential notation
  38                         int exp = 0;
  39
  40                         while (abs < 1.0) {
  41                                 abs *= 10;
  42                                 exp++;
  43                         }
  44
  45                         String sign = (d < 0) ? "-" : "";
  46                         return sign + String.format((Locale)null, "%.4fe-%d", abs, exp);
  47                 }
  48                 if (abs < 0.01)
  49                         return String.format((Locale)null, "%.7f", d);
  50                 if (abs < 0.1)
  51                         return String.format((Locale)null, "%.6f", d);
  52                 if (abs < 1)
  53                         return String.format((Locale)null, "%.5f", d);
  54                 if (abs < 10)
  55                         return String.format((Locale)null, "%.4f", d);
  56                 if (abs < 100)
  57                         return String.format((Locale)null, "%.3f", d);
  58                 if (abs < 1000)
  59                         return String.format((Locale)null, "%.2f", d);
  60                 if (abs < 10000)
  61                         return String.format((Locale)null, "%.1f", d);
  62                 if (abs < 100000000.0)
  63                         return String.format((Locale)null, "%.0f", d);
  64
  65                 // Compact exponential notation
  66                 int exp = 0;
  67                 while (abs >= 10.0) {
  68                         abs /= 10;
  69                         exp++;
  70                 }
  71
  72                 String sign = (d < 0) ? "-" : "";
  73                 return sign + String.format((Locale)null, "%.4fe%d", abs, exp);
  74         }
  75
  76 }