format.java

p2p仿真

/**
 * @(#)Format.java	ver 1.2  6/20/2005
 *
 * Modified by Weishuai Yang ([e-mail]). 
 * 
 * this file is based on the Format.java from Core Java
 */

package gps.util;

/**
 * Formats the number following printf conventions.
 * Modified by Weishuai Yang
 * this file is based on the Format.java from Core Java.
 */
public class Format

{ 
    /** 
     * Formats the number following printf conventions.
     * 
     * Main limitation: Can only handle one format parameter at a time
     * Use multiple Format objects to format more than one number
     * 
     * @param s the format string following printf conventions
     * 
     * The string has a prefix, a format code and a suffix. The prefix and suffix
     * become part of the formatted output. The format code directs the
     * formatting of the (single) parameter to be formatted. The code has the
     * following structure
     * <ul>
     * <li> a % (required)
     * <li> a modifier (optional)
     * <dl>
     * <dt> + <dd> forces display of + for positive numbers
     * <dt> 0 <dd> show leading zeroes
     * <dt> - <dd> align left in the field
     * <dt> space <dd> prepend a space in front of positive numbers
     * <dt> # <dd> use "alternate" format. Add 0 or 0x for octal or hexadecimal numbers. Don't suppress trailing zeroes in general floating point format.
     * </dl>
     * <li> an integer denoting field width (optional)
     * <li> a period followed by an integer denoting precision (optional)
     * <li> a format descriptor (required)
     * <dl>
     * <dt>f <dd> floating point number in fixed format
     * <dt>e, E <dd> floating point number in exponential notation (scientific format). The E format results in an uppercase E for the exponent (1.14130E+003), the e format in a lowercase e.
     * <dt>g, G <dd> floating point number in general format (fixed format for small numbers, exponential format for large numbers). Trailing zeroes are suppressed. The G format results in an uppercase E for the exponent (if any), the g format in a lowercase e.
     * <dt>d, i <dd> integer in decimal
     * <dt>x <dd> integer in hexadecimal
     * <dt>o <dd> integer in octal
     * <dt>s <dd> string
     * <dt>c <dd> character
     * </dl>
     * </ul>
     * @exception IllegalArgumentException if bad format
     */
   public Format(String s)
   {  width = 0;
      precision = -1;
      pre = "";
      post = "";
      leading_zeroes = false;
      show_plus = false;
      alternate = false;
      show_space = false;
      left_align = false;
      fmt = ' '; 
      
      //int state = 0; 
      int length = s.length();
      int parse_state = 0; 
      // 0 = prefix, 1 = flags, 2 = width, 3 = precision,
      // 4 = format, 5 = end
      int i = 0;
      
      while (parse_state == 0)
      {  if (i >= length) parse_state = 5;
         else if (s.charAt(i) == '%')
         {  if (i < length - 1)
            {  if (s.charAt(i + 1) == '%')
               {  pre = pre + '%';
                  i++;
               }
               else
                  parse_state = 1;
            }
            else throw new java.lang.IllegalArgumentException();
         }
         else
            pre = pre + s.charAt(i);
         i++;
      }
      while (parse_state == 1)
      {  if (i >= length) parse_state = 5;
         else if (s.charAt(i) == ' ') show_space = true;
         else if (s.charAt(i) == '-') left_align = true; 
         else if (s.charAt(i) == '+') show_plus = true;
         else if (s.charAt(i) == '0') leading_zeroes = true;
         else if (s.charAt(i) == '#') alternate = true;
         else { parse_state = 2; i--; }
         i++;
      }      
      while (parse_state == 2)
      {  if (i >= length) parse_state = 5;
         else if ('0' <= s.charAt(i) && s.charAt(i) <= '9')
         {  width = width * 10 + s.charAt(i) - '0';
            i++;
         }
         else if (s.charAt(i) == '.')
         {  parse_state = 3;
            precision = 0;
            i++;
         }
         else 
            parse_state = 4;            
      }
      while (parse_state == 3)
      {  if (i >= length) parse_state = 5;
         else if ('0' <= s.charAt(i) && s.charAt(i) <= '9')
         {  precision = precision * 10 + s.charAt(i) - '0';
            i++;
         }
         else 
            parse_state = 4;                  
      }
      if (parse_state == 4) 
      {  if (i >= length) parse_state = 5;
         else fmt = s.charAt(i);
         i++;
      }
      if (i < length)
         post = s.substring(i, length);
   }      

   
  /** 
  * Converts a string of digits (decimal, octal or hex) to an integer
  * @param s a string
  * @return the numeric value of the prefix of s representing a base 10 integer
  */
  
   public static int atoi(String s)
   {  return (int)atol(s);
   } 
   
  /** 
  * Converts a string of digits (decimal, octal or hex) to a long integer
  * @param s a string
  * @return the numeric value of the prefix of s representing a base 10 integer
  */
  
   public static long atol(String s)
   {  int i = 0;

      while (i < s.length() && Character.isWhitespace(s.charAt(i))) i++;
      if (i < s.length() && s.charAt(i) == '0')
      {  if (i + 1 < s.length() && (s.charAt(i + 1) == 'x' || s.charAt(i + 1) == 'X'))
            return parseLong(s.substring(i + 2), 16);
         return parseLong(s, 8);
      }
      return parseLong(s, 10);
   }

   private static long parseLong(String s, int base)
   {  int i = 0;
      int sign = 1;
      long r = 0;
      
      while (i < s.length() && Character.isWhitespace(s.charAt(i))) i++;
      if (i < s.length() && s.charAt(i) == '-') { sign = -1; i++; }
      else if (i < s.length() && s.charAt(i) == '+') { i++; }
      while (i < s.length())
      {  char ch = s.charAt(i);
         if ('0' <= ch && ch < '0' + base)
            r = r * base + ch - '0';
         else if ('A' <= ch && ch < 'A' + base - 10)
            r = r * base + ch - 'A' + 10 ;
         else if ('a' <= ch && ch < 'a' + base - 10)
            r = r * base + ch - 'a' + 10 ;
         else 
            return r * sign;
         i++;
      }
      return r * sign;      
   }
      
   /** 
   * Converts a string of digits to an double
   * @param s a string
   */
   
   public static double atof(String s)
   {  int i = 0;
      int sign = 1;
      double r = 0; // integer part
      //double f = 0; // fractional part
      double p = 1; // exponent of fractional part
      int state = 0; // 0 = int part, 1 = frac part
      
      while (i < s.length() && Character.isWhitespace(s.charAt(i))) i++;
      if (i < s.length() && s.charAt(i) == '-') { sign = -1; i++; }
      else if (i < s.length() && s.charAt(i) == '+') { i++; }
      while (i < s.length())
      {  char ch = s.charAt(i);
         if ('0' <= ch && ch <= '9')
         {  if (state == 0)
               r = r * 10 + ch - '0';
            else if (state == 1)
            {  p = p / 10;
               r = r + p * (ch - '0');
            }
         }
         else if (ch == '.') 
         {  if (state == 0) state = 1; 
            else return sign * r;
         }
         else if (ch == 'e' || ch == 'E')
         {  long e = (int)parseLong(s.substring(i + 1), 10);
            return sign * r * Math.pow(10, e);
         }
         else return sign * r;
         i++;
      }
      return sign * r;
   }
            
   /** 
   * Formats a double into a string (like sprintf in C)
   * @param x the number to format
   * @return the formatted string 
   * @exception IllegalArgumentException if bad argument
   */
   
   public String form(double x)
   {  String r;
      if (precision < 0) precision = 6;
      int s = 1;
      if (x < 0) { x = -x; s = -1; }
      if (fmt == 'f')
         r = fixed_format(x);
      else if (fmt == 'e' || fmt == 'E' || fmt == 'g' || fmt == 'G')
         r = exp_format(x);
      else throw new java.lang.IllegalArgumentException();
      
      return pad(sign(s, r));
   }
   
   /** 
   * Formats a long integer into a string (like sprintf in C)
   * @param x the number to format
   * @return the formatted string 
   */
   
   public String form(long x)
   {  String r; 
      int s = 0;
      if (fmt == 'd' || fmt == 'i')
      {  if (x < 0) 
         {  r = ("" + x).substring(1);
            s = -1; 
         }
         else 
         {  r = "" + x; 
            s = 1;
         }
      }
      else if (fmt == 'o')
         r = convert(x, 3, 7, "01234567");
      else if (fmt == 'x')
         r = convert(x, 4, 15, "0123456789abcdef");
      else if (fmt == 'X')
         r = convert(x, 4, 15, "0123456789ABCDEF");
      else throw new java.lang.IllegalArgumentException();
         
      return pad(sign(s, r));
   }
   
   /** 
   * Formats a character into a string (like sprintf in C)
   * @param c the value to format
   * @return the formatted string 
   */
   
   public String form(char c)
   {  if (fmt != 'c')
         throw new java.lang.IllegalArgumentException();

      String r = "" + c;
      return pad(r);
   }
   
   /** 
   * Formats a string into a larger string (like sprintf in C)
   * @param s the value to format
   * @return the formatted string 
   */
   
   public String form(String s)
   {  if (fmt != 's')
         throw new java.lang.IllegalArgumentException();
      if (precision >= 0 && precision < s.length()) 
          s = s.substring(0, precision);
      return pad(s);
   }
   
   private static String repeat(char c, int n)
   {  if (n <= 0) return "";
      StringBuffer s = new StringBuffer(n);
      for (int i = 0; i < n; i++) s.append(c);
      return s.toString();
   }

   private static String convert(long x, int n, int m, String d)
   {  if (x == 0) return "0";
      String r = "";
      while (x != 0)
      {  r = d.charAt((int)(x & m)) + r;
         x = x >>> n;
      }
      return r;
   }

   private String pad(String r)
   {  String p = repeat(' ', width - r.length());
      if (left_align) return pre + r + p + post;
      else return pre + p + r + post;
   }
   
   private String sign(int s, String r)
   {  String p = "";
      if (s < 0) p = "-"; 
      else if (s > 0)
      {  if (show_plus) p = "+";
         else if (show_space) p = " ";
      }
      else
      {  if (fmt == 'o' && alternate && r.length() > 0 && r.charAt(0) != '0') p = "0";
         else if (fmt == 'x' && alternate) p = "0x";
         else if (fmt == 'X' && alternate) p = "0X";
      }
      int w = 0;
      if (leading_zeroes) 
         w = width;
      else if ((fmt == 'd' || fmt == 'i' || fmt == 'x' || fmt == 'X' || fmt == 'o') 
         && precision > 0) w = precision;
      
      return p + repeat('0', w - p.length() - r.length()) + r;
   }
   
   private String fixed_format(double d)
   {  boolean removeTrailing
         = (fmt == 'G' || fmt == 'g') && !alternate;
         // remove trailing zeroes and decimal point

      if (d > 0x7FFFFFFFFFFFFFFFL) return exp_format(d);
      if (precision == 0) 
         return (long)(d + 0.5) + (removeTrailing ? "" : ".");

      long whole = (long)d;
      double fr = d - whole; // fractional part
      if (fr >= 1 || fr < 0) return exp_format(d);

      double factor = 1;
      String leading_zeroes = "";
      for (int i = 1; i <= precision && factor <= 0x7FFFFFFFFFFFFFFFL; i++) 
      {  factor *= 10; 
         leading_zeroes = leading_zeroes + "0"; 
      }
      long l = (long) (factor * fr + 0.5);
      if (l >= factor) { l = 0; whole++; } // CSH 10-25-97
      
      String z = leading_zeroes + l;
      z = "." + z.substring(z.length() - precision, z.length());

      if (removeTrailing)
      {  int t = z.length() - 1;
         while (t >= 0 && z.charAt(t) == '0') t--;
         if (t >= 0 && z.charAt(t) == '.') t--;
         z = z.substring(0, t + 1);
      }

      return whole + z;
   }

   private String exp_format(double d)
   {  String f = "";
      int e = 0;
      double dd = d;
      double factor = 1;
      if (d != 0)
      {  while (dd > 10) { e++; factor /= 10; dd = dd / 10; }
         while (dd < 1) { e--; factor *= 10; dd = dd * 10; }
      }
      if ((fmt == 'g' || fmt == 'G') && e >= -4 && e < precision) 
         return fixed_format(d);
      
      d = d * factor;
      f = f + fixed_format(d);
      
      if (fmt == 'e' || fmt == 'g')
         f = f + "e";
      else
         f = f + "E";

      String p = "000";      
      if (e >= 0) 
      {  f = f + "+";
         p = p + e;
      }
      else
      {  f = f + "-";
         p = p + (-e);
      }
         
      return f + p.substring(p.length() - 3, p.length());
   }
   
   private int width;
   private int precision;
   private String pre;
   private String post;
   private boolean leading_zeroes;
   private boolean show_plus;
   private boolean alternate;
   private boolean show_space;
   private boolean left_align;
   private char fmt; // one of cdeEfgGiosxXos
}