BigIntegerIO.cpp

   1 /*
   2 * Big Integer Library
   3 * Filename: BigIntegerIO.h
   4 * Author: Matt McCutchen
   5 * Version: 2004.1205
   6 */
   7
   8 #include "BigIntegerIO.h"
   9
  10 std::ostream& operator<<(std::ostream &os, BigUnsigned x) {
  11         if (x.getLength() == 0)
  12                 os << '0';
  13         else {
  14                 BigUnsigned ten(10);
  15
  16                 /*
  17                 * This buffer is filled with the decimal digits of x.
  18                 * sizeof(BigUnsigned::Blk) * x.getLength() is an upper bound on the
  19                 * number of bytes in x, and a byte takes at most 3 decimal
  20                 * digits, so this is a convenient upper bound.
  21                 */
  22                 char *buf = new char[sizeof(BigUnsigned::Blk) * x.getLength() * 3];
  23                 //std::cout << "bufferlength" << sizeof(BigUnsigned::Blk) * x.getLength() * 3<< std::endl;
  24                 int bufPos = 0; // first unfilled position
  25
  26                 // While x is not zero...
  27                 while (!x.isZero()) {
  28                         //std::cout << "bufPos=" << bufPos << std::endl;
  29                         // Get next digit
  30                         buf[bufPos] = char(int(x % ten) + '0');
  31                         // Remove it from x
  32                         x /= ten;
  33                         // Next buffer slot
  34                         bufPos++;
  35                 }
  36
  37                 // Now print the digits to os.
  38                 while (bufPos > 0) {
  39                         bufPos--;
  40                         os << buf[bufPos];
  41                 }
  42
  43                 // Free the buffer and return the stream (as customary)
  44                 delete buf;
  45                 return os;
  46         }
  47 }
  48
  49 std::ostream& operator<<(std::ostream &os, BigInteger x) {
  50         switch (x.getSign()) {
  51         case BigInteger::positive:
  52                 os << BigUnsigned(x);
  53                 break;
  54         case BigInteger::zero:
  55                 os << '0';
  56                 break;
  57         case BigInteger::negative:
  58                 os << '-' << BigUnsigned(x);
  59                 break;
  60         }
  61         return os;
  62 }